DDNP & related compounds: The über thread!

Like the new topic name! Supergeil!

https://www.youtube.com/watch?v=jxVcgDMBU94

Quote: Originally posted by Hennig Brand

Well I have what I hope is iso-picramic acid. It has been drying for the last day or so, so I will include a picture of the dry yield and attempt to make some iso-DDNP using it. Extraction of Paracetamol (acetaminophen) Forty extra strength 500mg Tylenol tablets were put into a Mason jar and an amount of methanol was added which was at least the height of the pills over and above the pills (very scientific measurement ). An oval stir bar was added and the mixture was stirred using magnetic stirring at room temperature until dissolution and erosion caused the pills to break up. The stirring was ceased and the mixture allowed to settle for several hours before pipetting off the clear paracetamol in methanol upper layer. More methanol was added to the pill residue and it was again stirred up and left to settle before removing more solution. This could have been done at least once more, but it wasn't. The combined methanol solution was next heated, below the boil with stirring, until most of the methanol was gone before adding 30-40mL of cold water (the remaining methanol could have easily been evaporated, but the water may have served a function over and above reducing solubility, it may have dissolved some of the trace amounts of water soluble impurities from the pills which made it through the extraction. Dinitration of Acetaminophenol Nitro-Genes posts were used as a general guide. The following numbers were used which were suggested by Rosco: " [A] For each 1 gram of paracetamol to be dinitrated, dissolve in 4 ml H2SO4 [B] For each gram of paracetamol to be dinitrated, use 1.4 gram of NH4NO3 mixed with 1.5 ml H2SO4 Add gradually with stirring B to A maintaining about 5C The quench / dilution mixture should have about 15 grams ice for each gram of paracetamol. It would possibly benefit the nitration mixture to sit for a couple of hours in the ice bath with continued stirring before quenching." I used the following method because I was lazy, busy and very low on ice. 14.4g of paracetamol was started with and 91% sulfuric acid was used throughout. The powdered paracetamol was added to the sulfuric acid in a Mason jar in about six increments with swirling and in between additions the solution was cooled down in the fridge. The ammonium nitrate (fertilizer grade recrystallized from water) was added to sulfuric acid in another Mason jar and left to dissolve over night in the dark at room temperature. The paracetamol in sulfuric acid was kept in the fridge while the nitration mixture was not, though they both probably could have been. A large oval stirrbar was added to the vessel holding the solution of paracetomol in sulfuric acid. When making an addition about 3-5mL of the nitration mixture was added with swirling before placing the mixture back into the fridge to cool. Starting the nitration in the morning I made additions randomly, about once an hour. By early afternoon the additions were complete. It wasn't until the next morning that the nitration mixture was removed from the fridge and quenched with crushed ice and filtered and rinsed with water. De-acetylation to Iso-Picramic Acid About 15mL of 91% sulfuric acid and 15mL of water were mixed and added to the still damp dinitro acetaminophenol in a beaker with stirrbar. The temperature was raised gradually and at about 70C the smell of acetic acid was very noticeable and by 80C the fumes were very strong, almost choking. After about 45 minutes and with the temperature at 100-105C no more smell of acetic acid could be detected. The color change from light to dark occurred mostly in the first 10 minutes or so of heating. About 80mL of water was then added. Filtration was attempted but was then aborted, as a test, but also because not everything was in solution (does it matter?). The amount of acid and water used was likely not ideal. The solution was next allowed to cool and then household ammonia was pipetted in with stirring unit the color change to red became apparent and then a couple drops of 31.45% HCl was added to bring the pH back down slightly (I was going to use sulfuric acid, but the HCl was much closer to me at the time and it was just a couple of drops). The reddish brown iso-picramic acid was easily gravity filtered. The yield is now nearly dry. I will post a picture of the dry yield soon and will attempt diazotisation to iso-DDNP. There were many transfer losses, etc, so the yield may not be great. [Edited on 16-6-2015 by Hennig Brand]

p-DDNP Synthesis

The preliminary dry yield of iso-picramic acid was only about 9.1g, which is very low. There were large transfer losses but nothing to explain such a low yield. Luckily, I didn't throw out the reaction mixture from after the de-acetylation. Upon adding 2-2.5mL of 31.45% HCl a good deal more iso-picramic acid precipitated amounting to an estimated at least two or three more grams (it isn't dry yet). This is one time I should have actually checked the pH. I also noticed that the reddish color of the iso-picramic acid seems to have faded in the last 20 or more hours while drying.

On examining the now only slightly damp recovered iso-picramic acid it is less than first thought (ca. 1-2g). I did hear faint fizzing coming from the solution several different times over the last 24 hours. Since the pH was not adjusted correctly a lot of the iso-picramic acid was left in solution and because the pH was so high a lot of it decomposed (I think). It was obvious that something was wrong yesterday when the volume of iso-picramic acid obtained was so much less than the volume of dinitro acetaminophenol obtained from the nitration.





Diazotization

The method from COPAE was used for the diazotization and went very smoothly. The 9.1g of iso-picramic acid was diazotized. Here are a few pictures of the iso-picramic acid and the produced iso-DDNP.


iso-picramic acid





iso-DDNP

The iso-DDNP was put in the sun just long enough to take a picture.




[Edited on 17-6-2015 by Hennig Brand]

You need to follow nitro-genes on that one, and maybe say the Shepards prayer (Alan Shepard)

http://www.urbandictionary.com/define.php?term=Astronaut%27s...

It was 5ml of a 50/50 by volume mix of H2SO4/H2O per gram of paracetamol that was dinitrated, which nitro-genes used for the deacetylation.

Really after the deacetylation you could probably dilute to a liter volume with distilled H2O and the soluble isopicramic acid sulfate should remain in solution for filtering and it may not even need filtering unless there is undissolved material or is so opaque you cant even see through it to tell if everything is in solution. Likewise using a base to titrate, it would be no issue using a dilute solution. You won't have much loss for any isopicramic acid remaining in solution because it is such low solubility nearly all of it down to a few milligrams will drop out of solution.

[Edited on 6/17/2015 by Rosco Bodine]

Hey, almost a 50% yield isn't bad for a first try. A couple more attempts I might just get it up to 70 or 80% even.
God knows what kind of product I actually have then. A bit of burn & explosive testing will be interesting once it dries.

With all the excess nitrate you probably made the 2,3,5,6,-tetranitro derivative so this could get interesting.

Quote: Originally posted by nitro-genes

Btw, you were right not do the filtration after the deacetylation, like you said, the water acid ratio was too high, causing dissociation of some of the isopicramic sulfate to the free acid. Further depends on the temperature, but adding about an equal volume of dH2O to the 50% H2SO4 after deacetylation is about the maximum that can be added without causing precipiation of the free acid.

Here is the link from when nitro-genes was experimenting with this
http://www.sciencemadness.org/talk/viewthread.php?tid=439&am...

An above 6.5 pH being achieved at any reasonable dilution is unlikely to occur. Maybe it requires a really extreme low pH to keep the isopicramic sulfate associated and soluble . Dilution with dilute acetic acid would be less likely to cause dissociation and even if it did the isopicramic acid would tend to remain in solution up to a point anyway because of the enhanced solubility in acetic acid.

Attached is a data sheet for isopicramic acid but the melting point is incorrect, actual is 170C dec, so I don't know if the other data is good either. The pink pH 4.0 to yellow pH 5.6 color shift range could be a marker for the dissociation of the sulfate. pKa is reported as 5.09

I think the color transition as incorrectly described on this data sheet is actually the reverse of the color shift described by Meldola, with the more alkaline range being pink and the more acid shifting to yellow. So this data sheet certainly has errata. Don't pay 200 bucks for an engineering reference book that has this kind of data error.

The data page (Sabnis) is from Sigma-Aldrich (and CRC) and has an incorrect mp WTF!



[Edited on 6/18/2015 by Rosco Bodine]

The purplisch colour is from the ammonium isopicramate. I know because I tried to recrystallize the ammonium salt to obtain very pure isopicramic once. It forms beautiful purple crystals with a green/gold lustre when dry, I suspect it is a hydrate. Likely, your iso-picramic is brown due to presence of the ammonium salt from over neutralizing, which could also trouble the diazotization. I have been busy and not updated this into the rough synthesis posted earlier, but during neutralization of the isopicramic sulfate it is better to aim for a pH of around 4, like I U2Ud you. I used test strips for that, since I don't have a pH meter.

Here is a daylight picture (as promised earlier) of isopicramic isolated at a pH of 4, it is brick red when wet, drying to an orange brown powder, like the msds above suggests. A very small amount in water makes a purple/pinkish colour indeed, like posted earlier. Strong solutions at high pH are more of a deep/red with violet tint.



Regarding the dissociation of the soluble sulfate, I don't know why it dissociates if this isn't described in earlier articles. I didn't observe it the first time, maybe I missed it because the solution is very dark in colour, or maybe there need to be absolutely no nucleation points for crystallization or depends on impurities, I just don't know other than that there seems indeed a minimal concentration of SA for which the isopicramic stays in solution. There remains a lot to be determined regarding these compounds and I've only attempted the diazotization via the sulfate once, so everything is possible.

[Edited on 18-6-2015 by nitro-genes]

Quote: Originally posted by Hennig Brand

That data sheet doesn't inspire a lot of confidence does it. It is definitely more of a yellow/brown at low pH and then when enough base is added it goes a pink/reddish color.

Quote: Originally posted by nitro-genes

The purplisch colour is from the ammonium isopicramate. I know because I tried to recrystallize the ammonium salt to obtain very pure isopicramic once. It forms beautiful purple crystals with a green/gold lustre when dry, I suspect it is a hydrate. Likely, your iso-picramic is brown due to presence of the ammonium salt from over neutralizing, which could also trouble the diazotization. I have been busy and not updated this into the rough synthesis posted earlier, but during neutralization of the isopicramic sulfate it is better to aim for a pH of around 4, like I U2Ud you. I used test strips for that, since I don't have a pH meter.

When some good solubility data is available for all the materials being manipulated it will be helpful as a starting point, even though there will be variation for the cosolublilty in "system" mixtures where more than just one material is dissolved. Some rough solubility ideas can be gotten at points in these manipulations where losses aren't much a concern for dilutions.

On the inky darkly dyed opaque solutions if a scrap of white teflon sheet like a stirrer paddle is dropped into the beaker or held close to the inside so a thin layer of liquid is observed against the white background in bright light, it can be seen if there are undissolved solids. Likewise if you do a spot test and pipet out about a half ml sample and drop it on a white salad plate so it spreads out in a thin layer it can be a spot test to see if the dark solution has everything in solution, or has solids content. A little rough "chromatography" spot test dilution to inspect any particles may show what is the solid material.

The original solubility data from Dabney I suppose is the starting point for neat solutions of isopicramic acid.

[Edited on 6/18/2015 by Rosco Bodine]

p-DDNP Yield & Deflagration

The yield of p-DDNP from yesterdays diazotization is 9.31g or about a 97% yield. The yield seems dry, though maybe a little too high, so I will check the weight again tomorrow to see if any more moisture is lost.

Attached is a video of about 20mg deflagrating. It is very energetic, but left a lot of residue.






Attachment: p-DDNP Deflagration.avi (6.6MB)
This file has been downloaded 910 times





Here are a couple of interesting snapshots from the video:





[Edited on 19-6-2015 by Hennig Brand]

Yes, although paradoxically, the iso-picramic diazotization at 0 deg C, seems faster than that for o-DDNP under the same conditions. Whereas in my experience, o-DDNP takes agood 5-10 minutes at 0 deg C to diazotize, p-DDNP is much faster. It seems almost instant, which could be the underlying problem, resulting in pDDNP coated isopicramic particles. I even thought about adding a bit of an inert solvent for the pDDNP to overcome this problem, but there are few OTC possibilities. A thing I noticed though, is that the more apparent the pinkish sheen is for the crude p-DDNP, the more impurities are present. The colour of the p-DDNP should be equal to o-DDNP produced by the COPAE method, so a yellow colour with only slight orange/brown shade.That is why the soluble sulfate salt seemed promising for the diazotization, although in this case an orange impurity seems to be formed, maybe due to the excess acid N2 --> OH --> =O or coupling of free isopicramic sulfate with the diazonium salt (just uneducated guesses )

My guess is that the diazotization is also a main culprit for impurities. Notice that even commercial DDNP is brown in colour. Results from the chinese paper or Urbanski (diazotization for o-DDNP at 30 deg C, dripping 5-8% HCl over 2 hours) produces a freeflowing product (as was the aim) but also a very dark brown product (leaving a lot of residues on burning). My guess is that diazotization this way produces a free flowing product only by in situ formation of crystal modifiers by partial oxidation products. IOW: you sacrifice purity for a free flowing product. Stupid suggestion maybe, but maybe free flowing DDNP is not for direct use in detonators, but a better option for transport and subsequent purification. Not sure on this one though, on the other hand, maybe the impurities don't hamper performance too much. I read somewhere though that US mill spec o-DDNP is acetone/ice recrystallized, which also in my hands produces the absolute best grades of both o and p DDNP.

[Edited on 18-6-2015 by nitro-genes]

Acetic acid may help with the solubility issues. The cycling of the materials through manipulations of soluble salts and crystallized are important also as separations and purifications. Since the nitration is uneventful I mentioned tripling the scale, which would provide more of the crude acetylisopicramic acid.

A strategy for economical neutralization of the entire nitration mix could use a baking soda solution very slowly gradually added by drops with stirring due to foaming until a point where the sulfate value is neutralized by sodium to an extent sufficient to have an excess basicity marked by the odor of some evolving ammonia from the decomposition of ammonium bisulfate and any unreacted ammonium nitrate also, using sufficient added water if needed to have everything in solution at the bp. with ammonia in excess evolving. Then into the cold to precipitate the in situ formed ammonium salt of acetylisopicramic acid as the the least soluble constituent, which will tend to be salted out by the sodium sulfate dissolved. If the dilution is not great enough then the hydrated sodium sulfate Glaubers Salt will be a complication because it could likely precipitate too. The mixture might have to be reheated above 32C with stirring and filtered warm above 32C if the Glauber salt becomes a contaminant. Sodium Hydroxide would be superior and produce no foaming if substituted in the same scheme which would go more quickly.

The filtered ammonium acetylisopicramate crystals could be dissolved in boiling water and a 101% neutralization quantity of HCl added gradually to the hot stirred solution which should precipitate the acetylisopicramic acid in pure form as fine crystals. Not knowing the solubility in the cold for the acetylisopicramic acid, this may not be efficient, so there is a "plan B" as follows:

In the alternative it may be possible to simply deacetylate the ammonium acetylisopicramate directly using sufficiently greater amount of H2SO4 to neutralize the ammonia value. When the deacetylation is complete, then dilute and neutralize again using baking soda solution, with everything in solution at bp and marked again by ammonia evolving. Then add to the stirred still hot solution the calculated quantity of HCl just in excess of amount required for neutralization and the free isopicramic acid should precipitate as fine crystals with the supernatant solution going very pale transparent yellowish colored at completion / endpoint.

Rosco breathes on fingernails and buffs them on collar

[Edited on 6/18/2015 by Rosco Bodine]

I was about to say that the soot didn't seem that excessive and that the deflagration seemed very energetic, but after looking at snapshots from the earlier video of unpurified o-DDNP deflagrating there really is no comparison. The o-DDNP burned with a much bigger flash and much less smoke and residue. I remember that the o-DDNP video was taken with less ambient light, so the flash may have looked extra big and bright, but the amount of soot was definitely a lot less regardless.


o-DDNP Deflagrating




[Edited on 19-6-2015 by Hennig Brand]

@ Rosco: I noticed you also attached the relevant passage from the Daphney paper, regarding solubilities of the picramic and isopicramic, in a previous post. Using ethanol or the potassium salt may be interesting a well, though IIRC, they also mention somewhere that the best crystals were obtained from hot water. I'll give it try, I've got more than 100 grams of the isopicramic by now anyway.

[Edited on 18-6-2015 by nitro-genes]

Did the nitration also with 68% HNO3, yield was similar and foaming after adding the ice was still present. A noticeable difference using NA/SA instead of AN/SA though was that the formed DNAc stays completely in solution until it is precipitated by adding the ice, while with AN/SA, the product partially separates at the end of nitration.

What would be your guess of the foaming after nitration, regarding temperatures and reactant quantities? What you mean with reaction mapping and solubility charting? Could you think out loud on this one, would be cool to learn something here.

I've also added 20 ml of 68% nitric acid to 5 grams of DNAc, it's been steering at 0 deg C for 2 hours and RT for 8 hours now and the colour has gone from a distinct orange/yellow, to a sort of sulfur yellow. Faint gas production is evident, sounds like a glass of soda. Could this possibly be the trinitro variant, the colour would sort of match the description from the paper from Klapotke for the Trinitroacetamidophenol they produced.

"N-(4-Hydroxy-3,5,6-trinitrophenyl)acetamide (6): Compound 5
(12 g, 62.1 mmol) was dissolved in nitric acid (100 mL, 65%) at
0 °C. This temperature was kept for 5 h, and then the solution’s
temperature was slowly risen to ambient temperature (6–8 h) and
stirring continued for further 12 h. A yellow precipitate was
formed. The suspension was poured on crushed ice (500 g). After
the ice was molten, the suspension was filtered and washed with
only small amounts of ice-cold water to remove the nitric acid.
Compound 6 was obtained as a bright-shining yellow powder (10 g,
56 %)"

[Edited on 19-6-2015 by nitro-genes]

Nitro-Genes, since you are the only one with reasonably pure p-DDNP I think it would be only right that you should perform a couple of explosive tests. See if you can initiate some picric acid. Either that or you could send me some p-DDNP in the mail.....just kidding.

Don't have any TNP anymore, but I do wonder if acetone/ice water recrystallized o-DDNP might be able to initiate TNP more easily. Analogous to LA, even a few % of inert by products may greatly affect the acceleration of the primary. Just cram in as much DDNP as you can in boiling acetone, decant the solution from ay remaining DDNP and slowly add ce water while stirring, I guarantee you'll see a different product.

Here is a solubility chart for sodium sulfate which is soluble to the extent of 4.7% (anhydrous basis) solution at 0C and any more load in the solution will crystallize out as a decahydrate.

The work up of neutralized solutions should be dilute enough to really not go near that cold saturation maximum loading.

Attachment: Na2SO4 Solubility.pdf (116kB)
This file has been downloaded 549 times

@nitro-genes You say you have probably a hundred grams of the isopicramic acid, so can you do a measured test regarding the stability on incremental dilution of the soluble sulfate of the isopicramic acid? A good ballpark figure there is needed for determining a limit of extent of dilution that can be used for the acetylation mixture particularly so it can be filtered without loss.

The combined solubility of Na2SO4 and NaCl may come into play depending upon the scheme for the manipulations.



Isopicramic Acid: abstracted summary information from Dabney
m. p.170°. Crystallises in bundles of fine brownish-yellow needles,
having a golden lustre when moist, very readily soluble in alcohol.
100 parts water at 22° dissolve 0.082 of acid : at just below the
boiling point 0.812 part of acid. Solutions bluish red.
This crystallises in dark brown plates or needles, melts apparently
with some decomposition at 170°, is sparingly soluble in cold water,
soluble in benzene and naphtha, readily soluble in hot water or in
alcohol; the solutions have a cherry-red colour. It appears to com
bine with acids, dissolving in them to form yellow solutions, but the
compounds so formed could not be isolated. It unites with alkalis,
forming crystalline salts, whose solutions are of a deep bluish-red
colour. The potassium salt crystallises in bluish-black needles, and
is very soluble in water. Both acid and salts explode when heated.

[Edited on 6/19/2015 by Rosco Bodine]

Sure, I'll give it a try, though it may not be as straightforward as purely acid concentration, but also acid:isopicramic ratio and temperature. That would make things a lot more complicated. What would be your suggestion? Maybe I'll start with a 1:1 ratio of 50% v/v H2SO4 solution:picramic acid and RT?

Thought about the neutralization with concentrated ammonia, as was performed the first time I did the nitration, but don't underestimate the exotherm produced, you would either need to go incredibly slow or add fairly quick and chill the solution O/N to precipiate the ammonium salt again, as most will go into solution probably. Using a carbonate will probably produce much less of an exotherm, since a lot of heat will dissipate with the CO2 produced.

Here a picture of 5 grams of DNAc reacting O/N at room temperature in 20 ml 68% nitric acid (left) and 2.5 grams of DNAc reacting with about 5 mole eqv of nitrite in 10% acetic acid O/N. (Right) Its not dry yet.

The product from nitric acid is a sulfur yellow, yield looks not very promising, about 50% estimatefd. I was just curious what would form from DNAc and nitric instead of starting with the diacetylated product. Any guesses what would have formed? I was curious whether p-DDNP might form directly by slow deacetylation and diazotization, but it surely isn't DDNP. Worst case possibility seems that the DNAc is oxidized to picric acid, although the product dissolves in water with a different colour than TNP. I'll try to determine a rough melting point when its dry. Anywhere near 120 should point towards picric, although I don't know melting point of the trinitroacetaminophenol.

The nitrite reaction product on the right has about the same colour as the DNAc started out with. Upon setteling, the solution above the precipitate became a very dark orange. Upon drying it shows some dark red colouration as can be seen in the picture with some difficulty. My guess is that some remaining nitrite produces some NO which oxidized to NO2 with the air, leading to formation of a different product. I did the reaction in a semi closed environment overnight to prevent this.

Quote: Originally posted by nitro-genes

Don't have any TNP anymore, but I do wonder if acetone/ice water recrystallized o-DDNP might be able to initiate TNP more easily. Analogous to LA, even a few % of inert by products may greatly affect the acceleration of the primary. Just cram in as much DDNP as you can in boiling acetone, decant the solution from ay remaining DDNP and slowly add ce water while stirring, I guarantee you'll see a different product.

Yeah your right, was the colour recrystallized this way a sort of bright yellow, orange/brown or dark brown? From acetone icewater, i got bright yellow needles with slight orange sheen, from acettone evaporation more of an orange brown.

Anyway, I determined the melting points of the compounds above. Mind that these are incredible unreliable as they were done on the hotplate. The orange stuff melts at around 170 ish, so similar to isopicramic acid and DNAc, the yellow stuff melts at around 180 ish, with decomposition. When I had them both on the plate at the same time, the yellow stuff melts later than the orange stuff. Hmmm, picric goes out the window I guess. Upon adding 50% SA and heating it smells of AA, (EDIT, actually only a slight smell of AA was noticed that dissapeared very quickly, not like DNAc acetylation at all, the compound does not carry an acetaminogroup anymore, but burns at least as energetic as DNAc or picramic acid, suggesting the nitro groups are still intact, any ideas anyone?)

[Edited on 19-6-2015 by nitro-genes]

Quote: Originally posted by nitro-genes

Sure, I'll give it a try, though it may not be as straightforward as purely acid concentration, but also acid:isopicramic ratio and temperature. That would make things a lot more complicated. What would be your suggestion? Maybe I'll start with a 1:1 ratio of 50% v/v H2SO4 solution:picramic acid and RT? Thought about the neutralization with concentrated ammonia, as was performed the first time I did the nitration, but don't underestimate the exotherm produced, you would either need to go incredibly slow or add fairly quick and chill the solution O/N to precipiate the ammonium salt again, as most will go into solution probably. Using a carbonate will probably produce much less of an exotherm, since a lot of heat will dissipate with the CO2 produced.

Quote: Originally posted by nitro-genes

Yeah your right, was the colour recrystallized this way a sort of bright yellow, orange/brown or dark brown? From acetone icewater, i got bright yellow needles with slight orange sheen, from acettone evaporation more of an orange brown.

Sounds familiar

For the solubilty test in diluted SA, it seemed a good idea to start with very pure isopicramic (I was also just curious whether it would be soluble in warm water as daphney suggested). Strangely, I tried to dissolve 2 grams in 250 ml destilled water at 90 deg C., but almost nothing dissolved, even with long stirring. Could it be that Dapney had a different compound? Other ideas? Maybe this suggests that temperature doesn't matter as much as I thought for the pH dependend solution.

[Edited on 19-6-2015 by nitro-genes]

Quote: Originally posted by nitro-genes

Sounds familiar For the solubilty test in diluted SA, it seemed a good idea to start with very pure isopicramic (I was also just curious whether it would be soluble in warm water as daphney suggested). Strangely, I tried to dissolve 2 grams in 250 ml destilled water at 90 deg C., but almost nothing dissolved, even with long stirring. Could it be that Dapney had a different compound? Other ideas?

It wouldn't be the first time the decimal point is published a place or two off.

This is the reason why the dissociation test for the soluble acid "salt" of isopicramic acid is important needed data. It is a solubility property that can be exploited during purification and separations / isolations / ect. It isn't just idle curisosity but is an important reaction parameter to know.

Dabney reported isopicramic acid being ten times as soluble at the bp as at room temp but the solubility is so low for both conditions that even the order of magnitude difference will not make water a convenient solvent for recrystallization, unless the solubility is enhanced by cycling the pH through the soluble acid salt or by forming a soluble picramate, and titrating to again precipitate the free isopicramic acid.

Isopicramic Acid: abstracted summary information from Dabney
m. p.170°. Crystallises in bundles of fine brownish-yellow needles,
having a golden lustre when moist, very readily soluble in alcohol.
100 parts water at 22° dissolve 0.082 of acid : at just below the
boiling point 0.812 part of acid. Solutions bluish red.
This crystallises in dark brown plates or needles, melts apparently
with some decomposition at 170°, is sparingly soluble in cold water,
soluble in benzene and naphtha, readily soluble in hot water or in
alcohol; the solutions have a cherry-red colour. It appears to com
bine with acids, dissolving in them to form yellow solutions, but the
compounds so formed could not be isolated. It unites with alkalis,
forming crystalline salts, whose solutions are of a deep bluish-red
colour. The potassium salt crystallises in bluish-black needles, and
is very soluble in water. Both acid and salts explode when heated.

[Edited on 6/19/2015 by Rosco Bodine]

Trust but verify on the reported data. It is odd how the ammonium salt for the acetylisopicramic acid is reported a good choice for initial purification and I think unless the quenched nitration mixture using the NH4NO3 + H2SO4 for nitration, is excessively neutralized, it is the ammonium acetylisopicramate salt that will be gotten after that quenched and neutralized nitration mixture is diluted and heated until all is in solution and then cooled.

Meldola and Stephens report that the acetylisopicramic acid is sensitive to and decomposed by excessive base, so it is important to stop the neutralization of the quenched nitration mixture when ammonia evolution is detected. The benzoylisopicramic acid analogue of Dabney is reported as being a strong acid which will decompose carbonates so if the quenched nitration mixture is excessively neutralized by a sodium value, the ammonium salt of the acetylisopicramic which has (probably) formed from the byproduct ammonia will likewise have its ammonia displaced by incoming sodium to form the sodium salt of acetylisopicramic acid, which is more soluble and also vulnerable to decomposition from the stronger base that is sodium compared with the ammonia. (theoretically) I think the quenching and neutralization will proceed by such scheme and if carefully done the ammonium acetylisopicramate will crystallize out pure on the first pass. If not then its recrystallization from boiling water would be trivial.

And I think the ammonium acetylisopicramate salt can then be deacetylated directly as I have described.

I can write the synthesis for this approach when I have the test results on the pH related solubility for the isopicramic acid.




[Edited on 6/20/2015 by Rosco Bodine]

Quote: Originally posted by nitro-genes

Yeah, sorry...you were talking about crystallizing ammonium DNAc directly from the neutralized nitration mix, (compact red crystals)

The neutralization of the quenched nitration mixture from the ammonium nitrate plus sulfuric acid nitration method might possibly not go the way I hope, however I still think it likely will occur as predicted. The proof will be in the pudding. It will depend upon whether or not the ammonium bisulfate (and sodium bisulfate) is a stronger acid than the acetylisopicramic acid, which I am honestly really just guessing is the case. But I think it is a good guess

Edit: See several posts below where a further review of this neutralization shows that using a sodium value alone will not work to free resident ammonia to form the ammonium acetylisopicramate in situ, but a neutralization using an ammonia value will be required, as in the "Plan B" also considered as more certain produce the ammonium acetylisopicramate.

A controlled neutralization of the quenched nitration mixture by gradual addition of a sodium value in solution as hydroxide or carbonate or bicarbonate or sesquicarbonate (whatever is convenient) should result in a sequential neutralization of the acidic components present in the nitration quenched mixture in the following order of neutralization [1] H2SO4 [2] HNO3 [3] HN4HSO4 [4] acetylisopicramic acid [5] any unreacted NH4NO3

The neutralization of [3] to form (either) sodium bisulfate or the normal sodium sulfate will produce byproduct ammonia which should be sequestered by neutralization of [4] forming ammonium acetylisopicramate.

Edit upon review: What will actually occur here is the ammonia evolved from an ammonium acid sulfate being neutralized by a sodium value will simply attach to any adjacent ammonium acid salt to form the neutral ammonium salt.

System component [4] would tend to be the absorber for any byproduct ammonia up to the point where all the acetylisopicramic acid has been neutralized by forming the ammonium salt. At that point of neutralization no more byproduct ammonia can be absorbed and the free ammonia evolving should be easily detectable by its odor. The detection of ammonia would there mark the completion of neutralization, and when the solution cools the ammonium acetylisopicramate should crystallize out as the only precipitate.

If the neutralization scheme I have contemplated is not correct based upon my guess about the bisulfate, then Plan B would involve a rough just under theoretical neutralization of the estimated free mineral acid values using a sodium value, followed by doing the remainder of the neutralization with an ammonia value like ammonium carbonate, bicarbonate, or hydroxide. From there things should proceed as contemplated otherwise, 100% guaranteed. Plan A will likely work okay and if not, then Plan B for 100% positive certain should work.

Edit: Please note that a further review shows that the "Plan A" first contemplated will not work, but Plan B should work fine.
Both these schemes are the result of effort to achieve economy on use of an ammonia value for the complete neutralization of the quenched nitration mixture. The best that can be done is to use a sodium value for neutralization of the system components where an ammonium salt is not needed or is already present, and reserve the use of more expensive ammonia for the neutralization of the acetylisopicramic acid to faciliate it isolation by crystallization.

I can predict some of what I think should occur according to educated guess and theory. But experimental result is the essential verification. IMO a direct deacetylation of the ammonium acetylisopicramate could work fine and eliminate an intermediate isolation step that may not be needed.

The subsequent dilution of the deacetylation mixture will contain ammonium bisulfate as a spectator ion. The neutralization by a sodium value should follow the neutralization sequence [1] H2SO4 [2] NH4HSO4 [3] isopicramic acid

At the point where the incoming sodium value has neutralized [1], it is expected that likely all of the isopicramic acid will precipitate as the free acid. As incoming sodium value continues and some [2] is neutralized, the byproduct ammonia reacting with trace isopicramic acid in the supernatant liquid should cause a purple marker endpoint showing the appearance of the ammonium isopicramate. Adding back a little acid as H2SO4 or HCl should make the purple color disappear again.

This should mark the endpoint for the neutralization of the deacetylation solution. The precipitated isopicramic acid is filtered out and dried.

P.S. That's some of the reaction map description you were asking me about before.

I need the formation and dilution data for the isopicramic acid sulfate to be able to calculate the dilution volume and acidity that is needed for keeping everything in solution in the diluted deacetylation mixture, which should result in a clean separation and precipitation of the pure isopicramic acid.

At this point it should be noted that I believe it is very likely a technical grade of p-DDNP could be obtained from diazotization of the diluted deacetylation mixture, either prior to any neutralization, or after a partial neutralization that may leave in solution the still soluble isopicramic acid. In a bulk process such as an industrial scale where the p-DDNP may be destined to be used as an explosive fuel component and sensitizer for ammonium nitrate or ammonium perchlorate as examples, perhaps with the p-DDNP dissolved in nitromethane or other solvent, such a technical grade of p-DDNP may be adequate,
and the step of isolation of the isopicramic acid would simply be skipped for the production of technical grade p-DDNP by diazotization of the deacetylation mixture.

If further purification is needed the isopicramic acid can be dissolved in HCl as soluble isopicramic acid hydrochloride and then diluted and neutralized with a sodium value to precipitate again the low solubility free isopicramic acid.

I think that understanding these particulars and applying them as I contemplate is possible, manipulations can be done using fairly heavily loaded solutions comfortably less than saturated, and still get clean separations with minimal transfer losses.

There is an idea I have for a diazotization method that could be interesting. Dabney reports that the potassium salt of isopicramic acid is extremely soluble in water, and possibly the sodium picramate is likewise extremely soluble in water and could work as well. My idea is to mix cold aqueous solutions of sodium or potassium isopicramate with a cold aqueous solution of sodium nitrite, and to the stirred mixture very slowly add an acid such as acetic acid, hydrochloric acid, ect. which may cause the diazotization to proceed very gradually and allow for a crystal growth of the p-DDNP even in a cold reaction system, if there is a reaction between the isopicramate value and the nitrite value that proceeds concurrently as the acid is added, rather than a sequential reactivity. There is a chance this diazotization scheme could work or it may not work. Only an experiment can determine if this idea for the diazotization has validity.

Ha! The "stealth wizard" strikes again!

http://www.sciencemadness.org/talk/viewthread.php?tid=14342&...

Ditto!



I miss the posts of a few old friends who I think would probably have been posting in this thread as in many times past, if they were still among the living in this world. So this thread has been a kind of sad "roll call" for me where many old friends probably gone from this world have not answered.

[Edited on 6/21/2015 by Rosco Bodine]

Quote: Originally posted by Rosco Bodine

There is an idea I have for a diazotization method that could be interesting. Dabney reports that the potassium salt of isopicramic acid is extremely soluble in water, and possibly the sodium picramate is likewise extremely soluble in water and could work as well. My idea is to mix cold aqueous solutions of sodium or potassium isopicramate with a cold aqueous solution of sodium nitrite, and to the stirred mixture very slowly add an acid such as acetic acid, hydrochloric acid, ect. which may cause the diazotization to proceed very gradually and allow for a crystal growth of the p-DDNP even in a cold reaction system, if there is a reaction between the isopicramate value and the nitrite value that proceeds concurrently as the acid is added, rather than a sequential reactivity. There is a chance this diazotization scheme could work or it may not work. Only an experiment can determine if this idea for the diazotization has validity. I miss the posts of a few old friends who I think would probably have been posting in this thread as in many times past, if they were still among the living in this world. So this thread has been a kind of sad "roll call" for me where many old friends probably gone from this world have not answered.

Yes I understand the scheme used and described for variations before, but this is simply an idea that could work which has not been described before to my knowledge. Using the very soluble salts together in a more highly diluted system that would have two soluble reactants very incrementally brought into reaction to form a nearly insoluble product very slowly and gradually could benefit crystal growth in the cold. It just seemed that the incoming acid might have no particular preference for displacement of sodium from one component or the other, and would then result in a smooth diazotization favoring crystal growth. As opposed to a slurry I would think a very dilute reaction system of dissolved precursors would be preferred, where the only thing most likely to be precipitating is the growing crystals of end product uncontaminated by any about as insoluble undiazotized precursor like isopicramic acid. The isopicramic acid has much lower solubility than picramic acid, so i was thinking the modified method might work better, but it is an unknown how it may actually perform.

Yeah its sad all the missing members,
like Axt, and quicksilver, and ordenblitz,
Blaster, Boomer, and Engager and The WiZard is In
All of them missing for awhile and even Len too ....
(also known affectionately) as
I nicked him "Doctor Meteor Shower"
I feel something like the last Mohican.

[Edited on 6/20/2015 by Rosco Bodine]

Thanks for your ideas about performing the reactions. The more I think about it, using AN for the nitration and then adding a strong carbonate solution for precipitating the ammonium salt of DNAc could be a very good idea for retrieving a larger and potentially more pure yield of ammonium DNAc for subsequent deacetylation! NaOH might also work, but since one patent mentioned that the temperature during neutralization should remain below 30 deg C, it will take a long time to make the total addition. A lot of heat will probably dissipate with the CO2 produced, making this the best option IMO. I'm quite sure that A-bisulfate is a much stronger acid than isopicramic, will the carbonate dissplace enough ammonia to provide an olfactory sign for completed neutralization?

With acidicity increasing during diazotization from K-isopicramate and KNO2, the free isopicramic will precipitate from the solution pretty quick when the pH is lowered by adding the acid, so the outcome is more complicated than that. I already tried this synthesis, but than at higher temperatures (30 deg C), according to the chinese article, but this gave a very impure product and dark brown filtrate. Attempting this at 0 deg C would be a better option.

Also tried to determine the concentration of SA that still dissolves all the isopicramic. At 20% SA, almost no dissolution takes place even with supplemetal heating. I used 3 grams of isopicramic, and added 20 ml of a 50/50 v/v 98% SA/dH2O mix. After some heating everything seemed to dissolve, but this also turned out sort of a minimal concentration to keep everything in solution at RT. Upon dilution with distilled water, from there adding 2 ml of water, slight clouding could be seen and, further dilution will pretty much precipitate out most of it. It is VERY difficult to see though, since the solution is VERY dark in colour, so I used a strong light to be able to see something. Maybe, it is best to add no water at all after deacetylation and directly start neutralizing with ammonia right away. I'm very sure I didn't see precipitation to this extend the first time though, since I added an equal volume of water then and upon filtering I didn't see more than maybe 10-50 mg of insolubles.... confusing.

The document Henning posted is also interesting, there they perform the deacetylation of acetaminophen in 1M SA and heat at reflux for 1 hour. The DNAc should deacetylate more easily, so this should work and can be performed in an airtight vessel, perhaps leading to less oxidation (if there is any) during deacetylation. Disadvantage would be that the solution can't be filtered, but would mabe be less of a problem when pure Ammonium DNAc is started out with.

Also performed the diazotization of 2 grams of isopicramic acid in 40 ml 10% acetic acid (stronger would probably be better since solubility of the DDNP will increase, but was not available), and 0.75 grams of NaNO2 at 0 deg C. It is incredibly slow compared to using strong acids, taking a good 30 minutes before the colour shift so yellow/brown became apparent. It is drying right now, but very curious how the p-DDNP will turn out when diazotized this way.

[Edited on 20-6-2015 by nitro-genes]

There is definitely enough ammonia value present for the Neutralization scheme "Plan A" to work if indeed Plan A does work as contemplated. It is the "if" that is the issue there.
As it turns out on further review I discovered I overlooked something simple.

I have been looking at this more and I see a problem there with my first contemplated neutralization scheme "Plan A", because there will be produced a sodium acetylisopicramate
instead of the hoped for ammonium salt, if there is only a sodium value used for the neutralization of the quenched nitration mixture. What would occur is a mixture of neutral ammonium and neutral sodium salts would form preferentially to evolution of ammonia from any decomposition of the ammonium salts. Any ammonia evolved from an ammonium acid salt decomposed by a sodium would simply attach to another ammonium acid salt and form the neutral ammonium salt, and would not evolve to be absorbed by the acetylisopicramic acid. I just didn't see this reaction on first look at the reaction system. I can sure see it now and it is simple so I really should have seen it before. I have other tasks presently as a distraction so please pardon my oversight on this point involving the neutralization of the quenched nitration mixture. Plan B the alternative should work though.

Reviewing what I had described before as Neutralization "Plan B" is positively the more logical approach to the certain formation of the ammonium acetylisopicramate. Doing the initial "undershoot" near neutralization of the theoretical quantity of free mineral acid values in the spent nitration mixture, plus an equivalent sufficient for conversion of just half the acid sulfate salts to neutral salts using a sodium value, (the already resident ammonia will form neutral salts of the remaining half the acid sulfate salts present) and then following that using an ammonium value in excess. That is the 100% sure to work method there. So is also certain to work doing the entire neutralization using ammonia, but more expensive.

I still haven't completed the reaction equations and really Plan B is the more conventional approach there.

I'll look at this again because it isn't yet settled in my own mind.

After reviewing this I have made Edit notes and corrections to my earlier post above while allowed time to edit.
http://www.sciencemadness.org/talk/viewthread.php?tid=439&am...

Review of this neutralization of the quenched nitration mixture shows that a sodium value can be used for only the bulk portion of neutralization, which will need to be completed using an ammonia value to produce the ammonium acetylisopicramate. For the ammonium acetylisopicramate to form in situ from byproduct ammonia from displacement by sodium salts is not likely.

On the other matter regarding the isopicramic acid sulfate, based upon the solubility test done by nitro-genes,
formation of the soluble "acid salt" of isopicramic acid requires an extreme low pH condition for H2SO4 that is more than a 50% strength by weight of H2SO4.

You should believe what your own experiment has shown you and apply that information to calculating what is an ample dilution volume and pH to be provided for the deacetylation step.

You reported figures showing you used 5 ml of 50/50 v / v H2O/H2SO4 per gram of paracetamol then dinitrated and deacetylated, and you may see improvement increasing that to 6 or 7 (or more) that may be fine, based on experiments to follow and determine effect of such adjustments. If the deacetylation is done upon the ammonium acetylisopicramate as I have described should work, an additional equivalent fractional molar amount of H2SO4 will be required to neutralize the ammonia as ammonium sulfate with the remaining usual amount of H2SO4 functioning in the actual deacetylation of the freed acetylisopicramic acid become available from its ammonium salt.

The same pH related solubility scenario with HCl as a comparison would be good to know as well, for the purification step decribed by Dabney using HCl to form the soluble acid hydrochloride salt.

Based upon that information about the H2SO4 soluble acid salt then it would be best to use an ample plenty of 50/50 v/v H2O / H2SO4 for the deacetylation heating to assure that everything dissolves when hot. And for a dilution in advance of neutralization I would recommend then pouring the still hot deacetylation solution in a small stream into a perhaps 6 to 10 times additional volume of stirred and nearly boiling hot water. Upon cooling a lot of free crude isopicramic acid should be precipitated by the dilution alone, and this should be filtered out and set aside as the main harvest and perhaps the complete yield.

Neutralization of the cool diluted deacetylation mixture is likely not going to recover much of anything additional but it could be gradually neutralized as an experiment just to confirm no further quantity of isopicramic acid is being held in solution as acid sulfate.

Dabney reported that the purification of isopicramic acid is best done by dissolving in HCl in which the impurities do not dissolve.

Reasonably, the manipulation thereafter would be filtering the HCl solution from impurities, and recovering the isopicramic acid by dilution and neutralization of the HCl solution to cause precipitation of the low soluble form of free isopicramic acid.

Dabney reported the isopicramic acid is very easily soluble in alcohol. So not only is alcohol a candidate purification recrystallization solvent, it may also be possible to diazotize in alcohol by introducing "nitrous gases" produced from HNO3 plus starch as a gas generator, or in the alternative to diazotize using an organic nitrite added to the cold alcohol solution of isopicramic acid.

I was mistaken earlier about the first neutralization scheme
contemplated for the quenched nitration mixture, leading to a desired ammonium salt of isopicramic acid. The neutralization can be done only part way using a sodium value to do the bulk part of the neutralization for economy of reagents, but there is required an ammonia value for neutralizing the acetylisopicramic acid to obtain the ammonium salt.

[Edited on 6/21/2015 by Rosco Bodine]

I was thinking, maybe it doesn't need complete neutralization at all. Maybe adding ice and a very strong solution of sodium sulfate (maximum about 1 mole per mole of sulfuric used can lower the solubility of the DNAc or potential acid soluble compounds, without changing pH leading to an exotherm. Sort of salting out procedure. Can't find a solubility chart for sodium bisulfate, but according to Sigma-Aldrich it is 390g/L at 16 Deg C, meaning it would likely stay in solution.

The attempted 10% acetic acid diazotization produced an amorphous fluffy DDNP with more carbon deposits, no benefit there it seems, maybe stronger AA would be better.

The isopicramic when recrystallized from methylated spirits is really one of the most beautiful compounds I've seen yet. It is almost like pure gold foil. (The imprints are from blotting dry with paper towels). Picture of 3 gram (test run) recrystallized ispicramic attached. The earlier mentioned 12 grams solubility per liter is probably inaccurate, it may be that the insolubles are actually impurities that remain behind and crystallize earlier from solution in the cold. When filtered off and boiled to nearly dryness, this remained, which corrseponds to Dabneys report on the gold lustre. So far it keeps the gold lustre very well, no sign of surface oxidation yet. It is not known what is in the methylated spirits, I just hope that it isn't some compound formed from heating of the solution with isopicramic. Ah well, OTC is gold...



Almost seems like a waste to diazotize

[Edited on 22-6-2015 by nitro-genes]

Thanks, also would be interesting to see what the product will be after diazotization. Hopefully, this will really give an indication how much impurities are formed during diazotization of p-DDNP and nitratio/deacetylation.

The nitration can probably still be optimized, as well as the deacteylation, IIRC GB24409 mentions 90% yields after nitration indeed. It is a lot of hassle to isolate the DNAc as the stable free and drie acid without remaiing SA.Only tried once, by trying to wash with a very dilute ammonia solution in order to estimate yield, and it seemed there is room for improvents. On the other hand, maybe the extended washing took a great deal of product back into solution.

If I do the complete synthesis again, I have some things that I will alter:

1. After nitration, adding crushed ice and after melting add a 30 deg C solution of 40% Na2SO4 to try and salt the remaining DNAc out.
2. For the deacetylation: either 3 days at room temperature in 50 ml 50% SA (v/v), or just performsing the reaction in an airtight container
3. Adding hot water slowly to the deacetylation mix instead of ammonia (would be really cool of that works as good or even better as ammonia)

You mentioned that you were going to try the nitration according to the patent above yourself, any results yet?


[Edited on 22-6-2015 by nitro-genes]

One of the diazotization in alcohol schemes could be needed.
There is a description of various methods found here starting at page 6 of the book. Page 11 and 12 regarding the quinone diazides is most pertinent

https://books.google.com/books?id=XYhY9AUzVD0C&pg=PA4&am...

4-6-dinitro-quinone-2-diazide is synonymous with o-DDNP

2-6-dinitro-quinone-4-diazide is synonymous with p-DDNP

Here is a screen grab excerpt from the book linked above



In a previous post I mentioned the compound [8] of the Klapotke article is an isomer of one of the compounds identified by the Von Herz patent GB207563 for which the potassium salt is reported by Von Herz to have initiating power at least equal to lead azide and detonates in the smallest quantity. I am still looking at this because Von Herz says there are two isomers which are substantially the same in performance. It may be that the compound [8] of the Klapotke article is identical to the patent compound of Von Herz. In either case if it is identical or the isomer, the potassium salt should be extremely useful as reported by Von Herz in GB207563.



We have an easier route to the compound [8] of the Klapotke article and / or the Von Herz patent by use of paracetamol as a starting material first converted to the mononitrate, the 3-nitro derivative, which is separated, and then further nitrated to obtain the 2,3,6 trinitro derivative.

I believe that the 2,3,6 trinitro compound will result if the same nitration is performed as is used to make acetylisopicramic acid, but instead of using paracetamol for the nitration mixture, the 3-nitro derivative of paracetamol is subjected to the same nitration mixture.

In the alternative the same slow nitration method Klapotke applied to compound [5] which is paracetamol acetate may likewise serve to convert 3-nitroparacaetamol to the 2,3,6 trinitro derivative.

A deacetylation procedure was used by Klapotke which was done very slowly at ambient temperature, first dissolving the trinitroparacetamol in sulfuric acid at 0C, and then at ambient temperature stirring in an open flask for 3 days, presumably evaporating the by product acetic acid, and then pouring the mixture onto ice to precipitate the product.

Diazotization was accomplished simply by dissolving the trinitroaminophenol in ordinary concentrated HNO3 and warming to 65 -70 degrees with stirring for 2 hours and pouring the mixture onto ice to precipitate the compound [8]

Attachment: GB207563 Diazodinitroresorcinol.pdf (371kB)
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Attachment: A NEW NITRATION PRODUCT, 3-NITRO-4-ACETAMIDOPHENOL, OBTAINED FROM ACETAMINOPHEN WITH NITROUS ACID.pdf (178kB)
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Attachment: Synthesis & Energetic Properties of 4-Diazo-2,6-dinitrophenol and 6-Diazo-3-hydroxy-2,4-dinitrophenol.pdf (286kB)
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So there you go, if Edmund von Herz knew what he was talking about in May of 1922, and the Japanese pharmacists knew what they were talking about in 1989, then it should be easy enough to make from ordinary paracetamol without much difficulty or expense, a green energetic initiator that is equal in power to lead azide, and that would be
potassium 4-diazo-2-6-dinitro-resorcinol-(1-anhydride)

This is the diazo derivative of styphnamic acid which can be made by a different route

Attachment: from JCS 1881 Styphnamic Acid related pg1133.pdf (303kB)
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This same compound had caught my attention before and was mentioned in an earlier post

http://www.sciencemadness.org/talk/viewthread.php?tid=439&am...

The path to the same compound via styphnamic acid via diazotization analogous to picramic acid is described in US4246052

Attachment: US4246052 SnCl2 reduction of Styphnic Acid and DDNP analogue therefrom.pdf (240kB)
This file has been downloaded 457 times

The same diazodinitroresorcinol can be made more easily and economically from paracetamol

[Edited on 6/26/2015 by Rosco Bodine]

Great finds Rosco! Initiating power equal to lead azide for the potassium salt of DDNR sounds great, looks like it can be recrystallized from water as well. Difficult part will undoublly obtaining the dinitro aminorescorcinol, and SnCl2 to perform the reduction.

The fun with these compounds just doesn't seem to stop. Apart from the fact that paracetamol makes an easy route to isopicramic acid and a word class primary(ies?), the isopicramic acid also seems to crystallize as an almost pure gold compound...and burning it is very funky. Burning one gram reminded me somewhat of mercury(II)thiocyanate, producing these organic looking "branches" of carbon when it is burning. Picture attached, it was even better looking before I tried to move it and part of it fell apart.

Oh, also did an experiment with diazotization in ethanol by the following procedure:

1 gram of recrystallized isopicramic acid was dissolved in 50 ml of ethanol (gentle heat applied to speed things up). This was placed in an ice bath and allowed to cool to about 5 deg C again, after which 1 ml of 98% sulfuric acid was added (no sign of precipitation) and again cooled to 5 deg C. Thereafter, a solution of 0.5 gram sodium nitrite in 4 ml of water was added dropwise while stirring over the course of about 5 minutes. Crystal growth was much better using this method, forming a fine gllistening product over the course of about 10 minutes. It's still drying though.



[Edited on 26-6-2015 by nitro-genes]

Quote: Originally posted by nitro-genes

Great finds Rosco! Initiating power equal to lead azide for the potassium salt of DDNR sounds great, looks like it can be recrystallized from water as well. Difficult part will undoublly obtaining the dinitro aminorescorcinol, and SnCl2 to perform the reduction. The fun with these compounds just doesn't seem to stop. Apart from the fact that paracetamol makes an easy route to isopicramic acid and a word class primary(ies?), the isopicramic acid also seems to crystallize as an almost pure gold compound...and burning it is very funky. Burning one gram reminded me somewhat of mercury(II)thiocyanate, producing these organic looking "branches" of carbon when it is burning. Picture attached, it was even better looking before I tried to move it and part of it fell apart. Oh, also did an experiment with diazotization in ethanol by the following procedure: 1 gram of recrystallized isopicramic acid was dissolved in 50 ml of ethanol (gentle heat applied to speed things up). This was placed in an ice bath and allowed to cool to about 5 deg C again, after which 1 ml of 98% sulfuric acid was added (no sign of precipitation) and again cooled to 5 deg C. Thereafter, a solution of 0.5 gram sodium nitrite in 4 ml of water was added dropwise while stirring over the course of about 5 minutes. Crystal growth was much better using this method, forming a fine gllistening product over the course of about 10 minutes. It's still drying though.

Great news that the alcohol idea is working out. There are several variations using alcohol with or without acetic acid and in different orders of addition for different nitrous precursor reagents to accomplish the diazotization, so I figured one or more of the alcohol processes should work to provide a complete diazotization and decent crystals. Technique is important with difficult solubility of the isopicramic acid being the complication to overcome.

About the DDNR it isn't necessary at all to start from Styphnic Acid and make styphnamic acid by reduction and diazotize that. DDNR is the same material as compound [8] of the Klapotke article and is the same compound as the Von Herz patent and is the same compound as the circa 1881 JCS article, and is the same compound as I am identifying can be made from paracetamol first being made into a 3-nitroparacetamol, and further nitrated to the 2,3,6 trinitroparacetamol, deacetylated, and diazotized by simply heating with azeotropic HNO3 as did Klapotke. What occurs is that one of the 3 nitro groups is hydrolyzed and decomposed to a hydroxyl during the heating with HNO3 which supplies the NO2 that accomplishes the diazotization, and ends with DDNR. DDNR and compound [8] are identical compounds produced by different reaction schemes.

I have identified the scheme for conversion of paracetamol to compound [8] whose potassium salt is identicval with the potassium salt of the Von Herz and later patent also and
identical with the potassium salt in the 1881 JCS article.
They are all 3 or more descriptioins of the same compound,
which can also be made from paracetamol.

There are some later patents which reference the potassium salt of DDNR as having danger during crystallization from synthesis and handling danger and being sensitive, reporting that accidental explosions of the potassium salt have occurred, but no details are given. See patent US6946042 attached column 3 line 5. The patent refers to such compounds as "diazinates" The patents referenced are the German language versions of the same patents attached in the preceding post.

Attachment: US6946042 Pyrotechnic Body.pdf (597kB)
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Thanks to Boffis for the original circa 1881 German language article for which an English language abstract is attached and a screenshot posted above. This Benedikt and Hubl article from 1881 is the original work regarding styphnamic acid and its diazo-oxide or quinone diazide energetic derivative which is analogous to picramic acid and its derivative DDNP, and to the isopicramic acid of Dabney and its derivative iso-DDNP or p-DDNP.

The trivial terms like DDNP for the phenol derivative or DDNR for the resorcinol derivative are somewhat inaccurate abbreviated names for these compounds which actually lose a hydrogen from the 1 position hydroxyl and are anhydrides. This is why the same compounds have a confusing assortment of names that are synonymous because of no single convention for naming, and reverting to the benzene itself and then assigning the 1 position for the Oxygen associated anhydride, the compound is called a benzene diazo-oxide which is probably the most correct, but the trivial name association is lost with what trivial phenol, or resorcinol, or other type phenol is the parent compound most associated with the derivative. So the trivial names like DDNP or DDNR are not exactly correct for the diazo derivatives which are anhydrides, so I assigned a name that seemed most logical to me for the potassium salt which even Von Herz was awkwardly naming different ways.

potassium 4-diazo-2-6-dinitro-resorcinol-(1-anhydride)

The later patents will refer to the DDNR itself as diazine but diazide could be used instead and neither are really correct but are abbreviations on the term quinone diazide which is not entirely descriptive either. And the patents may refer to the salts of DDNR as diazinates which is a nomenclature that makes even less sense to me, because it is not the diazo group which is acidic and forms a salt, but is rather the resorcinol (or other phenolic) hydroxyl. A potassium salt is therefore a diazodinitro-anhydride-resorcinolate which is too much of a mouthful to say and almost as awkward to type or write So the best I can do with naming this compound associated with the recognized trivial name parent compound resorcinol, for the potassium salt is

(3-potassium)-4-diazo-2-6-dinitro-resorcinol-(1-anhydride)

DDNR seems like a winner for the trivial name about as good as DDNP for the monophenol but it should be understood that through the literature there are going to be an assortment of names encountered for the exact same compound DDNR and likewise will be the case for other diazo nitrated polyphenols.

So far as the IUPAC convention for nomenclature well, Klapotke tossed it aside by designating compound [8] which is DDNR
as 6-Diazo-3-hydroxy-2,4-dinitrophenol when it is just about guaranteed the 1 position hydroxyl is only an Oxygen and this is an anhydride similarly as is DDNP. Therefore, more correctly
if a name applies to associate with a conventional name parent phenolic compound I think for most exactness it would be

4-diazo-2-6-dinitro-resorcinol-(1-anhydride)

or maybe that's just me I haven't yet checked the analysis to confirm the math, is it 1 Oxygen and no Hydrogen actually there on that alleged "phenol" ??.....anybody else ????

Don't count your Hydrogens before they are hatched.

See attached

Über Dinitro- und Trinitroresorcin

R. Benedikt, A. Freih v. Hübl

Monatshefte für Chemie und verwandte Teile anderer Wissenschaften

Volume 2, Issue 1 , pp 323-330

Attachment: Di und Trinitroresorcin Montsch f chem 1881 Benedikt & Hubl p323.pdf (164kB)
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With regards to the DDNR and its potassium salt, there is a possibility a double salt with nickel styphnate could form that may have interesting properties. A double salt is reported for ordinary potassium styphnate with nickel styphnate, and it is unknown if likewise a similar double salt may form with the potassium salt of DDNR but this possibility should be tested.

Another possibility that seems likely is that DDNR may form basic salts such as a basic lead DDNR salt, and these may form double salts with the normal salt, resulting in a hemi-basic double salt. Also it is a possibility that a basic salt of DDNR such as basic lead DDNR could form a neutral double salt, a bridged double salt could form, for example a picrate if the basic lead DDNR salt was neutralized with picric acid, a neutral lead picrate / lead DDNR double salt may result. The same scheme may follow for other basic DDNR salts which could form neutral double DDNR / picrate salts.

If the basic DDNR salt was treated instead with styphnic acid it is possible a neutral bridged double salt could form from 2 of the basic DDNR salt molecules with styphnic acid, for example a double salt in the case of the lead salt, where 2 basic lead DDNR molecules would be neutralized by 1 styphnic acid to form a complex salt. The same scheme may hold true for other basic salts. For example a nickel complex salt or a strontium complex salt might follow such a scheme where a pair of basic salt DDNR molecules is converted to a neutral complex salt by adding to 1 styphnic acid analogous as adding to 2 picric acids, as the 1:1 scheme first described to form a neutral multiple salt.

Likewise other acidic energetic materials like the tetrazoles may form unique complex salts with basic salts of DDNR.

For any of the schemes described it is also possible the free acid DDNR may likewise react with a basic salt of the other compound such as the basic picrate or basic styphnate, ect. to form a neutral complex salt, with only the order of addition being different.

With regards to the contemplated basic lead salts of DDNR there is also the possibility that such basic salts may form clathrates in like fashion as does basic lead picrate. If this is indeed the case then such clathrates would be expected to have energy greater than the already known clathrates derived from basic lead picrate. It seems possible that basic lead DDNR could serve as a substrate for an assortment of clathrate derivatives that would all in general have greater energy than the analogous picrate based clathrates.

[Edited on 6/27/2015 by Rosco Bodine]

I believe I have just found another structure identification error in the early online preview article by Klapotke which is incorrectly identifying compound [8] as a 6-diazo instead of the 4-diazo ...which could only occur if there was an improbable rearrangement. I am reasonably sure that the compound [8] of the Klapotke article which is being designated as 6-Diazo-3-hydroxy-2,4-dinitrophenol for compound [8] is probably incorrect. Following the same style nomenclature it would correctly be identified as 4-diazo-3-hydroxy-2,6-dinitrophenol (if it actually was a phenol) but is likely a diazo-oxide.

Likewise I believe Von Herz incorrectly identifies the patent compound of GB207563 as being a 6-diazo or a 2-diazo

I was both right and wrong subsequently in my post just above saying compound [8] is identical to the Von Herz patent compound The patent compound of Von Herz is identified by Von Herz the 6-diazo or 2-diazo. They are indeed likely the same compound but are incorrectly identified the same way by both Von Herz and Klapotke!

I know how it sounds that I believe Von Herz AND Klapotke are both incorrect. There it is. I said it anyway.

My personal belief, opinion, and assertion is that ALL of these compounds, the compound of Benedikt and Hubl described in 1881, the compound of Von Herz described in 1922 in GB207563, the compound of Hagel and Redecker in US4246052 from diazotization of styphnamic acid, AND the compound [8] of the Klapotke are all probably identical and are one and the same compound

4-diazo-2,6-dinitroresorcinol-(1-anhydride)

Ha! What are the odds! Anybody want to bet on it ??

I bet the X-ray and NMR people are getting busy about right now! The whole spectrographic analysis routine is going to be needed, infra red analysis included.

It will be interesting to see where this goes from here.

The article by Klapotke which is being referenced is attached in an earlier post

http://www.sciencemadness.org/talk/viewthread.php?tid=439&am...

attached again here
http://www.sciencemadness.org/talk/files.php?pid=409043&...

and the web page for the article preview is here
http://onlinelibrary.wiley.com/doi/10.1002/ejoc.201500465/ab...

To be specific, compound [7] is incorrectly identified in the abstract but correctly identified in the article itself

Also I believe compound [8] is incorrectly identified in both the abstract and the article as the 6-diazo when it should be the 4-diazo

The word description does not reconcile with the diagrams, however the diagrams are showing structure correct for [7] but show a transposing of the anhydride Oxygen and phenol hydroxyl for [8]

The structural diagram in the article is correct for compound [7] however (not correct) for [8]. The diagrams are inverted from what is the usual view. Additionally the anhydride Oxygen and the phenol hydroxyl are transposed on the diagram shown for [8]



[Edited on 6/28/2015 by Rosco Bodine]

Exactly what I was thinking, given the "unfinished business" about structures being left in Reverdin's hands by an aging Meldola a hundred years ago and all the published material about "mobility" of the nitro group, and NOT also mobility of the diazo group, the structural identifications remain perplexing and even an enigma. The older literature is confusing to follow as it would seem there definitely are 2,3,5 and 2,3,6 trinitro compounds and that there would be differing reactivity for them. Changes in nomenclature and synonymous but different names being used including different conventional and different informal common names have added to the confusion.

Reviewing the different methods of synthesis using modern analytical tools as well as the classical chemical analysis such as doing mixed melting points and other mixed sample comparisons will surely remove the uncertainties that are otherwise unanswered questions about the actual identifications of all these compounds which is not presently conclusively known, from what I see.

I have certainly set a needed synthesis and analysis survey task before the chemists who are looking at this.

When looking first at iso-DDNP which we are identifying as p-DDNP, it had been noticed while reviewing the literature that this was leading to many other related interesting energetic compounds that in my opinion are not really settled business in the more than one hundred years since their discovery.

There should be a burning of the midnight oil occurring at a few different laboratories regarding this subject matter.

When I first started looking at this subject matter I had the feeling this was going to be a journey into the tall grass of some detective work

Some of this I have already begun to sort out as really no greater issue than a difference in nomenclature which is a departure from conventional more usually encountered
nomenclature. There are different ways of identifying the exact same compound which are technically correct, depending upon what direction, clockwise (conventional) or counterclockwise (unconventional) is performed the counting of the ring position for substituents and in the case where there are two hydroxyls, which of the hydroxyls is arbitrarily selected as being ring position 1. Generally seen is resorcinol shown as a 1,3-dihydroxybenzene however 1,5-dihydroxybenzene would also apply as would m-dihydroxybenzene be synonymous.
The usual convention for resorcinol and derivatives would be shown as the 1,3-dihydroxy configuration, going clockwise with 1 at 12 o'clock and 3 at 4 o'clock.

PHILOU Zrealone pointed out the differing but synonymous nomenclature

http://www.sciencemadness.org/talk/viewthread.php?tid=22586&...

which illustrates that for example styphnamic acid by conventional nomenclature is 4-amino-2,6-dinitroresorcinol, but in mirror image reverse perspective for the exact same compound could be called 6-amino-2,4-dinitroresorcinol and these are not isomers but are simply different nomenclature being used to describe exactly the same compound.

Given the example by PHILOU Zrealone then the inconsistency about nomenclature could help explain the designation by Klapotke of compound [8] as a 6-diazo-2,4-dinitro gotten from a different nomenclature identified precursor which was called a 4-amino-2,3,6-trinitro. At a reach this is technically correct but it is confusing to change from one nomenclature to another that is a mirror reversal perspective done without any explanation or notation as changing horses in midstream while diagramming a reaction sequence. And the anhydride Oxygen and the phenol hydroxyl are still (I think) transposed, so the nomenclature is an awkward expression.

None of the departures or variations in nomenclature change my opinion that all of the various different descriptions are each in their own special way identifying the same compound.

Anyway, even the IUPAC convention suggests benzene-1,3-diol for resorcinol placing the hydroxyls at the 1,3 position.
And I think the trivial name for compound [8] would be DDNR
analogous to DDNP. I still think the nomenclature I suggested

4-diazo-2,6-dinitroresorcinol-(1-anhydride)

is most exacting, or for the alternative hydroxyl location for the anhydride Oxygen if that proves to be the case

4-diazo-2,6-dinitroresorcinol-(3-anhydride)

Sorting through the many different nomenclature designations for what appears likely the same compound has been confusing for me.


[Edited on 6/29/2015 by Rosco Bodine]

I reply to this here and not in PM because it is of interest for most readers of this tread and of energetic materials...so better keep this public than private , I'm sure Rosco will agree with me on that.

Picramic and isopicramic acid does display amphoteric properties owing to the simultaneous presence of both amino and phenolic groups on the aromatic ring, but acidity of those is increased by the presence of the two nitro groups, of the hydroxy and of the amino groups.
More than certainly there is a zwiterionic effect
NH2-Ar(NO2)2-OH <--> NH3(+)-Ar(NO2)2-O(-)
And this may lead to solubility troubles in neutral media but will ensure good solubility in strong basic or in strong acidic media.

The idea to play with perchloric acid is a very good one!
1°)Because picramic acids are initially not wel oxygen balanced and the introduction of one HClO4 is like having two extra nitro groups into the molecule...
HClO4 --> HCl + 2 O2
2 -NO2 --> N2 + 2 O2
Thus the OB is wel enhanced.
2°)Perchloric acid is very strong acid and thus it will allow formation of a perchlorate even if picramic acid is acidic.
3°)Perchlorate ensure good sensitivity to initiation and crystallinity
4°)Perchlorate ensure good density...it will boost up the density of picramic acid by a few %.

All this will make the resulting picramic perchlorates interesting compounds on their own with regard to brisance and VOD...
HO-C6H2(NO2)2-NH3ClO4

Sadly one can't get reaction with a base from the phenolic part because it will decompose the amine perchlorate ...the base will react with the stronger acid...what is HClO4...
The result will be a mix of picramic acid (or picramate) and metalic perchlorate salt...what will be interesting but much less than the plain picramic perchlorate.

The procedure you propose should work, but MgSO4 is quite soluble...see Epsom salt.

I would go for direct "neutralisation" of 1 equivalent of picramic acid and 1 equivalent of HClO4...then if no precipitation...evaporation in the cold or mild heat and if needed with help of vacuum.
Or alternatively... Picramic sulfate with saturated Ba(ClO4)2 but the resulting solution must be filtered for BaSO4.xH2O and Ba perchlorate is harder to get than plain HClO4...

Corrosivity and hygroscopicity of the compound is not a real concern... because now everybody can work cheap with PE plastic recipient or staws and thermic glue that will be entraped on site into the detonator (I work that way to prevent contact between reactive chemical explosive - personal safety concern due to some bad experiences).

Note that another good idea would be to make the nitroformiate
--> picramic acid trinitromethanate
HO-C6H2(NO2)2-NH3C(NO2)3

If the perchlorate is very good maybe it would be good to invetigate the periodate (owing to the density boost)
--> picramic acid periodate
HO-C6H2(NO2)2-NH3IO4

Since that U2U message was sent I have thought more on that type of metathesis approach to avoid use of HClO4. It may work also to use the soluble isopicramic acid hydrochloride and dissolve into the acidic solution ammonium perchlorate. It may work similarly for the isopicramic acid sulfate. If the perchlorate of isopicramic acid does form a stable salt and shows low solubility it should precipitate without requiring HClO4.

Thanks for the feedback on the perchloric acid idea regarding isopicramic acid. The use of perchloric acid may also be interesting in regards to a possible styphnamic acid perchlorate salt.

A related idea is perchloric acid could react in the synthesis leading to DDNR which is believed to form via a soluble diazonium salt intermediate but the diazonium salt is never isolated and quickly decomposes to form the diazo oxide. Likewise a similar thing may occur during the formation of DDNP or p-DDNP. So an idea I had is that if the intermediate diazonium salt, formed as a perchlorate and precipitated during diazotization, instead of decomposing to the diazo oxide, such a diazomium perchlorate could have interesting explosive properties. But I have found nothing in the literature ever mentioning even any attempt to isolate the theoretical intermediate diazonium salt which is unstable and transitions quickly to the diazo oxide.

I am just about 100% certain that the compound DDNR and/or its potassium salt reported by various methods of synthesis by different researchers beginning with Bemedikt and Hubl circa 1881, Meldola in 1906, Von Herz in 1922, Hagel and Redecker 1981, and Klapotke 2015 are describing exactly the same compound as I gave this name which seemed to fit best.

4-diazo-2,6-dinitroresorcinol-(1-anhydride)

or for the alternative hydroxyl location for the anhydride Oxygen if that proves to be the case

4-diazo-2,6-dinitroresorcinol-(3-anhydride)

The curious thing to me is that there has been no history of citations from the latest article going back to the earliest. None of the 4 reporters of the same compound seem to be aware of the previous original work, which I suppose could happen for an obscure compound. I chuckle at the thought the same compound has now been invented and discovered maybe? 5 times over the course of 134 years maybe just because the compound was never satisfied it had been named correctly

I have in general set forth how I think it is possible to produce DDNR starting from ordinary paracetamol in earlier posts. I have not yet set forth with good clarity the step by step which depends upon sorting out carefully some of the articles by Meldola who worked with the necessary intermediate which is a trinitro derivative of paracetamol that cannot be gotten from direct nitration in one step of paracetamol. Two nitration steps are required starting from paracetamol to avoid need for use of acetic anhydride. I have been carefully rereading the Meldola articles after learning the initial discovery and early work done on the first known trinitroacetylaminophenol had mistakenly identified which isomer was being described in publication. This had been my suspicion and a source of frustration before accessing the later articles that identified and confirmed the errata. So a rereading of the early Meldola articles about the first identified 2,3,5 trinitroacetylaminophenol is required with a mental note being done that it is actually the 2,3,6 isomer which is being described and the chemistry and properties and observations are otherwise valid regarding the subject matter notwithstanding the early work showing a mistaken identification of the isomer.

Here is an example of the sorting out of the information from Meldola, noting that the diazo-oxide later obtained from boiling with sodium acetate the initial diazotization product of 2,3,6-trinitro-4amino-phenol is one and the same compound as compound [8] now described by Klapotke and evidently also 3 times before identified by others probably unaware of the prior art of Benedikt and Hubl since none cite that original work.

The initial diazotization product of 2,3,6,-trinitro-4-aminophenol shows the 3-nitro group remaining intact, and only becomes DDNR via subsequent decomposition of the first obtained 2,3,6-trinitro-4-diazo-phenol-(1-anhydride) which may be even more energetic than DDNR. If the the boiling with initial diazo-oxide having the 3-nitro intact was performed using potassium acetate instead of sodium acetate it is probable the potassium salt of DDNR would be the result, which is likewise the potassium salt of the compound [8] of Klapotke.

A warning note should be made regarding the observation of Meldola that the trinitroacetylaminophenol is truly extremely reactive and unstable and cannot be dried in contact with filter paper even at low heat, because it will deflagrate. It must be dried only in contact with glass or porcelain.

This first image shows the isomer misidentified



Updated data for the convenient deacetylation is also provided later, here. Also we see another description of the second diazo-oxide derivative identified which is one and the same as compound [8] of Klapotke, which is the compound Meldola names dinitrohydroxyquinonediazide.



Note that all of the 2,3,5 trinitro references above and below are incorrect and actually are the 2,3,6 trinitro compound.



This next image shows the later structure correction data for the same compound/(s) above as earlier designated 2,3,5 trinitro was later amended / corrected by the authors to 2,3,6 trinitro



What this data suggests is that it may be possible to produce DDNR from a modified deacetylation procedure applied to the trinitroacetylaminophenol, which upon deacetylation is subject to self-diazotize from decomposition of the position 3-nitro group. Suggested also is the possibility that active diazotization may be possible to be applied directly to the trinitroacetylaminophenol which may be simultaneously deacetylated and diazotized leading to the desired DDNR, by a process which is a shortcut and may be workable to avoid the isolation of the intermediates by separate steps of deacetylation followed by diazotization. It is unknown if such a shortcut is possible or not or what would be the yield. It may work or may not work to attempt such elimination of the isolation of the intermediates, and combine the reactions in a one-pot kind of reaction scheme.

Attachment: article Meldola and Hay JCS Vol95 pg1378.pdf (1MB)
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[Edited on 6/30/2015 by Rosco Bodine]

Beta Isopicramic Acid and Beta p-DDNP

Earlier in the discussion of p-DDNP and its isopicramic acid precursor I made the observation there is yet another para diazo isomer of the commonly known ortho diazo DDNP, so that in fact there exists the Alpha isomer p-DDNP which is gotten from the isopicramic acid of Dabney, but also there is a Beta isomer p-DDNP obtainable from a Beta Isopicramic Acid identified by Meldola. It is expected that stability for the Beta p-DDNP will be the lowest of the 3 isomers of DDNP but to what extent or what bearing this may have on the explosive power and sensitivity is unknown. No literature reference is found regarding the Beta p-DDNP isomer to provide any further information.

Alpha p-DDNP is the 2,6-dinitro-4-diazophenol-(1-anhydride)

Beta p-DDNP is the 2,3-dinitro-4-diazophenol-(1-anhydride)

In earlier mention of this Beta p-DDNP isomer it was not wished to derail the topic while attention was focused upon the Alpha p-DDNP isomer, so further mention of the Beta p-DDNP isomer has been deliberately delayed until now.
It seems the appropriate time to point to this Beta p-DDNP and its associated Beta Isopicramic Acid precursor.

Structurally this is the Beta Isopicramic Acid of Meldola



And below is the Beta p-DDNP from diazotization of the Beta Isopicramic Acid



A screenshot from the Meldola and Hay article attached below the screenshot provides additional information for which a caveat must be applied to any reference to the 2,3,5 identified trinitro compounds which were being misidentified at the time of the article. The information is otherwise valid, that caveat regarding the misidentification of a third nitro group position notwithstanding. The structure error for that aspect has no bearing on the subject matter of the Beta Isopicramic Acid and the Beta p-DDNP product of its diazotization.



The red crystalline product from deacetylation described below is the Beta Isopicramic Acid which is also reportedly unstable, so to optimize the yield of Beta p-DDNP it would probably be best to proceed with diazotization of the sulfuric acid solution diluted to the extent it may withstand dilution, without attempt to isolate the free Beta Isopicramic Acid. There will be expected losses from decomposition during every manipulation of the unstable Beta Isopicramic Acid.



Attachment: Beta Isopicramic Acid and Beta p-DDNP JCS_London Vol 91 Meldola and Hay pg1477 and 1481.pdf (427kB)
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Of course the door is opened to BOTH the Beta Isopicramic Acid and Beta p-DDNP as well as the synthetic route to DDNR by the availability of the 3-nitroacetaminophen reported obtained in 81% yield from a nitrite nitration scheme applied to paracetamol, this being reported by the Japanese pharmaceutical bulletin which I believe is reliable. This avoids having to work with acetic anhydride to first add an O-acetyl to paracetamol to form the diacetylaminophenol and then nitrate and then deacetylate and then nitrate some more, and then deacetylate again, prior to diazotization. It really saves steps in synthesis and simplifies things greatly to have the 3-nitroacetaminophenol easily available in high yield directly from paracetamol. That is the key to simplifying the synthetic routes and processes described in the literature before, including the most recent article of Klapotke.

So this is breakthrough type work we are discussing here.

Attachment: A NEW NITRATION PRODUCT, 3-NITRO-4-ACETAMIDOPHENOL, OBTAINED FROM ACETAMINOPHEN WITH NITROUS ACID.pdf (178kB)
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I apologize for the somewhat rambling style of posting my thoughts concerning these old references which I have been trying to sort out and understand for the past year as my available time has allowed. I think in these last two posts I have completed the analysis of the available references in a way that connects the dots and makes sense.

There likely is a series of actual 2,3,5 trinitro compounds and chemistry that is analogous to the 2,3,6 trinitro compounds, and other related compounds based on phloroglucinol or other polyphenols. I have not looked at those so far and have tried first to sort out the 2,3,6 trinitro series since it appears to be the logical first step, before looking at the likely more difficult variants. It was the common paracetamol being a precursor which made the 2,6 and 2,3,6 series of compounds especially interesting.

[Edited on 6/30/2015 by Rosco Bodine]

Evidence has been found that establishes to a virtual 100% certainty that my earlier suspicions and conclusions are correct that both Von Herz and Klapotke have misidentified the DDNR compound as 6-diazo when it is actually a 4-diazo.

I have referenced the original work of Fitz regarding the dinitroso derivative of resorcinol which is 2,4-dinitroso resorcinol confirmed by later reviewers.

My earlier assertion about the name for the compound has gained support

4-diazo-2,6-dinitroresorcinol-(1-anhydride) * most likely structure IMO

or for the alternative hydroxyl location for the anhydride Oxygen if that proves to be the case

4-diazo-2,6-dinitroresorcinol-(3-anhydride)

See attached articles and this linked article preview

http://pubs.acs.org/doi/abs/10.1021/jo00258a039

which identifies the much different conditions required for producing the 4,6-dinitroresorcinol which is a historically much later method than the methods of Benedikt and Hubl derived from Fitz, and later repeated by Von Herz, most recently by Klapotke using the different approach of working as did Meldola and Reverdin with nitrated paracetamol derivatives.

The mono amido derivative of 2,4-dinitroresorcinol and the mono amido derivative of 2,4,6-trinitroresorcinol (styphnamic acid) both lead to DDNR. 6-amino cannot be present upon the mono amido derivative of 2,4-dinitroresorcinol, which excludes the 6 position for the resulting diazo derivative DDNR, barring any unlikely and improbable diazo rearrangement.

This leaves position 4 as the most likely amino location for both the mono amido derivative of 2,4-dinitroresorcinol and styphnamic acid.

The remaining possibility of a 2 nitro / 2 amino becoming a 2 diazo seems unlikely, but even at that would seem more possible than a 6-diazo which IMO is just plain wrong. I think the possibility of a 2 nitro / 2 amino has already been ruled out in the early literature, but I don't have the citation.

Anyway, I am sticking to my guns that Von Herz GB207563 and Klapotke are both wrong about the 6 diazo structure which is in nearly all probability a 4-diazo on DDNR.

The synthetic approach of Benedikt and Hubl, Von Herz, et al to DDNR appears to be a technically superior method working from resorcinol itself as a starting material, compared with the alternative approach from paracetamol. All things considered, the use of styphnamic acid as the precursor for DDNR would seem the least technically complicated. The styphnic acid precursor could be reduced to styphnamic acid in the same way as is made picramic acid and the diazotization could then be done by the method of Benedikt and Hubl (and Von Herz) or in the alternative by the method of Hagel and Redecker US4246052. I concur with the structural identification of Hagel and Redecker and I disagree with the structural identification of Von Herz and Klapotke.

It is also possible that the 2,4-dinitroresorcinol may be subjected to reduction to 4-amino-2-nitroresorcinol and then diazotized by the method of Benedikt and Hubl to form DDNR.
Patents of interest for 2,4-dinitroresorcinol are US2945890 and US2811565 and US3933926. Further nitration to styphnic acid via a dinitroso intermediate see US2301912.

Both approaches to DDNR are technically feasible but the approach from resorcinol involves fewer and less complicated synthetic steps and less loss from manipulations of unstable intermediates. However the paracetamol route is necessary for the related compound 2,3,6-trinitro-4-diazophenol-(1-anhydride) which is a potentially useful energetic compound, but will likely have inadequate stability to be practical.


Attachment: Fitz Berichte 1875.pdf (317kB)
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Attachment: US2945890 2,4-dinitroresorcinol.pdf (158kB)
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Attachment: US2811565 2,4-dinitroresorcinol.pdf (306kB)
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Attachment: Dinitrosoresorcinol Fitz A_Dictionary_of_Chemistry_pg1750.pdf (289kB)
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Attachment: DinitrosoResorcinol JACS 1923, 45, pg 1536 to 1539.pdf (292kB)
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Attachment: Nitrophenol pages Dictionary_of_Applied_Chemistry Thorpe.pdf (698kB)
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There is more very interesting information relevant to what I will say next about my survey of the literature and its implications for these energetic diazo compounds generally.

A patent of particular interest is US4329503 particularly interesting is example 6. See also the precedent patent US4115652.

Attachment: US4329503 preparation of 2-amino-4-nitrophenol.pdf (720kB)
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Reviewing the circa 1881 work of Benedikt and Hubl which was doubtlessly followed by Von Herz in 1922 without due attribution to the prior art, it is significant that Von Herz reported that the preferred precursor for DDNR is the mononitroaminoresorcinol and not the dinitroaminoresorcinol which would be styphnamic acid, derived from the partial reduction of styphnic acid, which is analogous to picramic acid derived from partial reduction of picric acid.

The interesting aspect about the diazotization method of Benedikt and Hubl is that it is a combined reaction which not only diazotizes the amino mononitro phenol, but simultaneously adds 1 nitro group, resulting in a diazodinitrophenol as the product instead of the expected diazo-mono-nitrophenol. This unexpected result could be general as a reaction, so that it is not necessary to partially reduce a trinitro compound like picric acid or styphnic acid to a dinitro-mono-amino compound and then diazotize.

What is suggested is that ordinary o-DDNP may be possible to make from a mono-nitro-aminophenol derived from a partial reduction of a dinitrophenol by applying the diazotization method of Benedikt and Hubl which could simultaneously diazotize the 2 position amino while adding a second nitro at the 6 position, or the 4 position, depending on the structure of the 2-amino-(4-nitro or 6-nitro)-phenol precursor used. This general reaction may proceed without preference for any particular ring position amino to diazotize or any particular ring position to add a nitro, but will generally do both as a matter of course, simultaneously diazotizing the existing amino and nitrating a vacant or susceptible to nitration ring position in one step. This would be half confirmed if 4-amino-6-nitroresorcinol is subjected to the same diazotization method and the result is DDNR identical as that produced from 4-amino-2-nitroresorcinol.

Since the diazotization method also works with the usual dinitroamino precursor, it may also serve as a diazotization method that is general and applicable to picramic acid or isopicramic acid or styphnamic acid or any of their anaolgues.

The possibility exists also for a 2-diazo position for DDNR, which was the best guess of Von Herz regarding structure.
As I said earlier IMO position 6 for the diazo is excluded, and position 4 seems most likely however a 2-diazo seems also possible. I think a polarized light rotation study could resolve the structural identification for what is technically possible to be a 4-diazo or a 2-diazo, or could be a dextro-levo racemic combined isomer. DDNR may not be one structure or the other, but both isomers cocrystallized.

Difficulties observed for attempts to obtain good clean crystallizations for some of these diazo compounds suggests the possibility that mixed isomers of indefinite proportions could be the explanation.

Here is a screenshot from the Von Herz 1922 patent GB207563.
What is described by Von Herz regarding the potassium salt of DDNR is what I have termed an unequivocal initiating explosive, having an extremely low critical mass for detonation unconfined. Earlier there was experimentation by Hennig Brand showing that mixture of lead azide with DDNP would accellerate the DDNP to detonation, avoiding the usual kindling phase of a deflagration runup to transition to detonation. Likewise a mixture with a different unequivocal initiator like the potassium salt of DDNR should accomplish the same accelleration for DDNP or for p-DDNP with the advantage that the composite would be a green energetic. The strontium salt of DDNR is also reported interesting in later patents. Strontium is bivalent which should make possible formation of a basic strontium DDNR salt or for a coprecipitated mixture of the normal and basic salt of strontium if needed for control of the sensitivity of the mixture.



[Edited on 7/8/2015 by Rosco Bodine]

Something completely different:

Would something along these lines possibly work?

First of all, thanks to Boffis and Philou for the requested hydroxylamine synthesis from nitrite. I must admit that since I was able to aquire some 99% nitromethane, the nitrite/zinc method suddenly seemed like a lot of hassle.

Hydroxylamine synthesis:

105 grams of 96% SA (1 mole) was added to a container with long reflux condensor attached and put on a hotplate with added stirrer bar. While stirring at 250 rpm, 61 grams of nitromethane (1 mole) was added slowly. Then the heat was turned on and the solution kept at 90-95 deg. C for 24 hours, at which point the bubbling of carbon monoxide had largely ceased. The flask was allowed to cool to room temperature, after which 250 ml 96% ethanol was added, instantly precipitating most of the hydroxylamine sulfate as white feathery crystals. After cooling overnight at -20 deg C, total yield was 59 grams of hydroxylamine sulfate, or 72% of theory. there was still some nitromethane in the condensor, and some may have escaped, IMO the most probable cause of the lower yield than reported.

Unfortunately, there seems no condensation between o-DDNP and hydroxylamine. Adding a pH 6 adjusted solution of hydroxylamine sulfate/NaOH to o-DDNP produced pronounced fizzing of the suspension as it was allowed to warm up, presumably nitrogen gas, indicating decomposition of the diazo group. The same happens, though much more slowly at a pH of 3. Maybe the hydroxylamine coupling with the diazo group is a parasitic side reaction that is more dominant, for which the formed product is unstable and decomposes releasing nitrogen gas. Judging by the colour, the end product in both cases seems to be ordinary picramic acid again, although it wasn't diazotized again to confirm.

Ah well... VNS chemistry is still interesting to experiment with, so the hydroxylamine sulfate will be put to good use anyway.

Regarding the synthesis of DDNR:

In a recent experiment I heated 3 grams of isopicramic acid with 20 ml 65% HNO3 to about 50 deg. C. for 4 hours. (At lower temperatures there is no reaction and/or little dissolution of the isopicramic at all.) I was curious whether this way crystalline pDDNP could be formed for people without access to nitrite, but also whether this could be a possible route to DDNR.

The reaction and colour changes are very interesting. After reaching 50 deg C. most of the isopicramic has gone into solution, forming a deep orange-red solution. After prolonged heating, the colour seems to change to more of a deep dark red (1-2h), to a deep brownish red (3h) to an almost transparent light orange-yellow near the end. It is hard to tell, since the soluble isopicramic nitrate is already a very strong orange-red, but the side of the beaker did seem to show some dark red compound, which would concur with the colour of the trinitroaminophenol, or compound 6, from the Klapotke article.

When the reaction mix was allowed to cool down it was poured onto crushed ice, precipitating a bright yellow-orangeish crystalline compound. A small amount was dried at 50 deg C. on the hotplate, it flashes similarly to DDNP. It is drying now, so no yield yet, though it will be very interesting to react the resulting compound with KHCO3 or PbCO3 in either ethanol or water, as described in one of the patents regarding DDNR salts Rosco posted a while back.

In the worst case it may be a diazotizing scheme to pDDNP, allowing good control of crystal formation, and usable for those without nitrite.

Quite possibly the product consists mostly of pDDNP instead of the DDNR, although I wonder why in the Klapotke article 100% HNO3 and Ac2O is used, while they use 65% nitric and heating for the DDNR analogue, any thoughts on this?

I knew about the fuming NA reaction to produce DDNP, tried it once with freshly distilled NA. It is a very vigerous reaction, with lots of NOx produced and low yields (30-40%) since most of the product is oxidized, yielding the HNO2 in situ. Very interesting find that the use of ammonium picramate gives a quantitative yield, quite possibly DDNP is diazotized in high yield when ammonium nitrate is added to the heated HNO3, or a small amount of concentrated ammonia solution. Definitely worth a try, especially when nitrite is unavailable. The finding that even lower concentrations of nitric are able to diazotize with heating is very interesting as well, since the slow and controled oxidation to yield HNO2 may provide much higher yields, and the DDNP is completely solubilized in the spent reaction mixture, allowing good crystallization indeed.

Quote: Originally posted by nitro-genes

Quite possibly the product consists mostly of pDDNP instead of the DDNR, although I wonder why in the Klapotke article 100% HNO3 and Ac2O is used, while they use 65% nitric and heating for the DDNR analogue, any thoughts on this?

Quote:

I knew about the fuming NA reaction to produce DDNP, tried it once with freshly distilled NA. It is a very vigerous reaction, with lots of NOx produced and low yields (30-40%) since most of the product is oxidized, yielding the HNO2 in situ. Very interesting find that the use of ammonium picramate gives a quantitative yield, quite possibly DDNP is diazotized in high yield when ammonium nitrate is added to the heated HNO3, or a small amount of concentrated ammonia solution. Definitely worth a try, especially when nitrite is unavailable. The finding that even lower concentrations of nitric are able to diazotize with heating is very interesting as well, since the slow and controled oxidation to yield HNO2 may provide much higher yields, and the DDNP is completely solubilized in the spent reaction mixture, allowing good crystallization indeed.

Most likely you are right as usual, I was hoping that somehow water content would be a contributing factor. Without extensive knowledge of organic chemistry, its sort of fishing to me...you have no idea what happens underwater, though sometimes you get the thrill of catching a big one.

Regarding the safety of the heated 65% HNO3 and isopicric, perhaps stronger dilutions would also work, increasing safety, perhaps adding an inert solvent, or large amount of ammonium sulfate or phosphate salt. I think the danger is of performing the reaction is something to keep in minder, although using excess of NA containing 35% water may be enough to prevent spontaneous reaction.

Holy shit!!! It may turn out the nitration of isopicramic with 65% nitric acid at elevated temperatures does produce some DDNR! Some of the yellow orange stuff was carefully neutralized with one mole equivalent of sodium bicarbonate with overnight stirring, after which a strong solution of KNO3 was added. Unlike pDDNP, a speck of the resulting dark brown stuff detonates when heated.

Another equally interesting possibility is that a sort of a neutral potassium nitrate/pDDNP double salt has formed. Maybe crystallization from sodium perchlorate solutions would be interesting to test. Alternatively, the strong KNO3 solution may have precipitated the presumably more energetic diazonium nitrate of pDDNP. The latter would be easy to test, since it would dissociate when added to water again.

[Edited on 24-7-2015 by nitro-genes]

Ha! It would be fortuitous if another error has been found in the literature with the ancient reports that the 2,6-dinitro compound the acetylisopicramic acid or the isopicramic acid itself absolutely resists any further nitration to a trinitro derivative. If that is in fact found to not be so then yes indeed either DDNR or an isomer of DDNR may be produced. Such a development could indeed be very interesting.

I have wondered if the third nitro group could be introduced by some method different from the extreme methods which were tried, maybe at some different temperature or reaction time or even by the use of some catalyst that could effect the introduction of the third nitro group. Water content of the nitration mixture may be that "catalyst" which because it seems counter intuitive was a factor that was overlooked by earlier researchers. It is entirely possible that a certain water content in the nitration acid mixture will result in a "more aggressive" nitrating effect than is seen with a lower H2O content nitrating acid mixture. There can also be a catalytic effect for HNO2 acting in concert with HNO3 and some H2O in mixture particularly at elevated temperature, which results in greater nitrating effect. Such factors could be operative here for this reaction scheme. Earlier researchers may have never found the niche condition required for the further nitration to occur and wrongly concluded that it is not possible to further nitrate the 2,6-dinitro-4-aminophenol (isopicramic acid) when in actuality it is possible under different conditions than what they tried which produced negative results.

It seems possible that perhaps the p-DDNP or the diazonium nitrate salt could form first and that could allow for the third nitro group to enter so that what may be occurring is essentially a further in situ nitration of p-DDNP or its soluble diazonium nitrate salt precursor. Possibly this is an exception observed for the synthetic scheme being used which actually isn't a further nitration of isopicramic acid, but a further nitration of the diazonium derivative of isopicramic acid which must form first as an intermediate for the further nitration to occur. If this does occur it may or may not be possible to first isolate p-DDNP and simply dissolve it in HNO3 for further nitration. That approach may work or it may not. If not, then it would point to the soluble diazonium nitrate salt precursor and intermediate to p-DDNP that is being capable of adding the third nitro before that "upgraded" diazonium nitrate salt is decomposed to the associated diazo-oxide on dilution with water.

Really the probable existence of the soluble diazonium nitrate salt as an intermediate for the p-DDNP has not been described in the literature, but I have hypothesized that it does probably exist and may be of interest particularly if an insoluble perchlorate salt could be isolated. The diazonium salt precursor as a soluble transient intermediate has been identified in the literature for similar compounds, as being hydrolytically unstable and the soluble diazonium intermediate decomposes to and precipitates as the diazo-oxide when the highly acidic diazotization reaction mixture is diluted with H2O.

If a third nitro is being introduced during the diazotization of soluble isopicramic acid nitrate in a strong nitric acid solution, then the same effect is being seen as with the method of Benedikt and Hubl where a combined diazotization and nitration addition of one nitro group is occurring simultaneously.

That third nitro after being introduced is unstable and upon decomposing to a hydroxyl would give DDNR or an isomer, which indeed would be consistent with your reported observation.

Reportedly the Magnesium salt of DDNR has good solubility which makes it useful for double decomposition reactions to produce the potassium and strontium and other less soluble salts of DDNR. This may provide an additional physical means of identifying suspected DDNR to maybe do a long stirring with MgO or Mg carbonate or precipitated Mg(OH)2 to see if the very soluble Mg(DDNR)2 forms. To that solution you can add a solution of the desired ion like K, or Sr, or Pb, ect. as one of its soluble salts and the lower soluble corresponding DDNR salt should precipitate.

You very well could have found a niche reaction condition that leads to DDNR from isopicramic acid.

Wow! If this is the case what reactions are occurring .......

this is NOT previously published AND is very interesting

This appears to be novel and is very likely a new discovery.

How about that! Well done!

[Edited on 7/25/2015 by Rosco Bodine]

Well, after is has dried, yield was only 1.2 grams pDDNP/DDNR from 3 grams of isopicramic (made by AN/SA nitration and deacetylation). Furthermore, the product after neutralization and precipitation with KNO3 does not behave as unequivocal as the pure potassium salt of DDNR does. Behavour on heating is different though and detonates even in very small quantities. Could be a mix of pDDNP and/or other products, including DDNR. What colour does the potassium DDNR salt have, according to the article posted above it should be bright yellow? If the product is a mix, the brown colour may be from isopicramate impurities due to parital destruction of the diazo group, since in that case excess base was used for prolonged reaction time.

Maybe after dissolution of the isopicramic acid, the reaction mix is better kept at a lower temperature for some time, to keep oxidation to a minimum. I must say, I doubt if this would be a conveniant route to DDNR, if it formed at all. Under the reaction conditions utilized, a lot of things happen probably.

I'll try the reaction again soon, using different reaction conditions.

[Edited on 25-7-2015 by nitro-genes]

[Edited on 25-7-2015 by nitro-genes]

Should be light yellow for the color for DDNR and for the K salt

There is a different brown color noted after recrystallization which is odd.

Klapotke's crew should be burning the midnight oil about now

If you are going to try variations on the experiment, using sodium nitrite or if available potassium nitrite added to the nitric acid solution of isopicramic acid could accomplish the diazotization at lower temperature and produce a higher yield.
My intuition is that if a third nitro is entering then it is occurring subsequent to the diazotization which is probably favored at lower temperature. So getting the diazotization done at the lower temperature and then warming to a gentler lower temperature for adding the third nitro may result in less oxidation losses if that was the reason for a low yield from the longer heating of the reaction mixture.




Attachment: Benedikt and Hubl JCS 1881 Styphnamic Acid and DDNR related pg1133.pdf (264kB)
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Something I just noticed is that the Klapotke article has published now apparently with the errors that were identified in the preview article not corrected.

In a post I made last month

http://www.sciencemadness.org/talk/viewthread.php?tid=439&am...

and in earlier and subsequent posts there were errors identified which I expected would be in the preview article that would be reviewed and corrected, but those errors remain.

I suppose our friends in Munich are not reading us or aren't paying attention in class.

http://onlinelibrary.wiley.com/doi/10.1002/ejoc.201500465/ab...



[Edited on 7/25/2015 by Rosco Bodine]

Interesting read from "organic chemistry of explosives", it seems diazophenols are presumably formed through a primary arylnitramine from nitration of the corresponding arylamine. Although the reaction is only described for methyl and chloro dinitroaminophenol, would this somehow be possibble for (iso)picramic acid, or does the hydroxy group lead to excessive oxidation and HNO2 formation? Maybe adding urea or even ammonium nitrate? Ideas anyone?



Attachment: organits_chemistry_of_eksplosives__agraval_j._p._hodgson_r._d._-_2007_g._418_s..pdf (4MB)
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[Edit: Didn't see the book in the SMDB library, so I uploaded it here, if is has already been posted, it can be deleted again, or transfered to the library]

[Edited on 27-7-2015 by nitro-genes]

Many diazo compounds are sensitive to decomposition by bases, so it may be better when making the soluble form of suspected DDNR to digest the material with sodium acetate or magnesium acetate instead of using sodium bicarbonate or carbonate since the buffering effect of the acetate will be less likely to cause partial decomposition of the diazo compound which could reduce yield. This problem of hydrolytic sensitivity has been reported for DDNR and use of sodium acetate resolved that issue. I think the DDNR can actually be boiled with sodium acetate without decomposition.

In an earlier post last month a couple of pages back
http://www.sciencemadness.org/talk/viewthread.php?tid=439&am...

Note that the actual 6 position nitro is shown in error as 5 nitro.
The dense, orange, crystalline sodium salt described is the sodium salt of DDNR, with the 3 hydroxyl obtained by the decomposition of a 3 nitro residing on the precursor 4-diazo-2,3,6-trinitrophenol, dense, yellow, micro-crystalline powder.



There is a theory I have about what may be occurring is indeed a combined reaction that involves diazotization and then subsequent nitration occurring at ring position 3 or possibly 5, with the third entering nitro being unstable and susceptible to decomposition to a hydroxyl. If the third nitro is entering at 3 as seems to be likely, then DDNR is the probable result. If the third nitro is entering at 5 then a mirror image isomer of DDNR is perhaps possible, but I believe it likely that the same DDNR results in either case. If you look at resorcinol as the conventional nomenclature from antiquity associating it with phenol having the first hydroxyl at 12 o'clock position 1, the second hydroxyl is position 3, meta orientation. But if you draw this on tracing paper and flip the page over then the reverse perspective shows 1,5 = 1,3 as functionally synonymous expressions.

Here we have with isopicramic acid only 2 possible ring positions which a third entering nitro could occur either 3 or 5, because all other positions are occupied, and that third nitro on decomposition to hydroxyl will result in the same resorcinol meta oriented pair of hydroxyls where 1,3 = 1,5 and vice versa.

In my opinion, DDNR is the probable result or most likely product from a combined nitrosation of isopicramic acid with subsequent nitration which adds a third nitro at 3 which subsequently decomposes to a hydroxyl at 3.

The orienting effect of the diazo at 4 would be ortho-para but the (para) 1 position is already occupied by a hydroxyl so the (ortho) 3 or 5 would be where an entering nitro would occur as promoted by the diazo, aside from the structural necessity that those are the only possible two vacant locations, with both leading ultimately to DDNR.

Evidently the diazo at 4 is more promoting of nitro substitution than is the amino group at 4 before diazotization, and the conjugate linkage subsequently of the diazo at 4 with the hydroxyl at 1 to form the anhydride as a cross-ring linkage may even further promote the entering nitro at 3 or 5 which are essentially synonymous and lead to DDNR after the entering nitro is hydrolyzed to a hydroxyl.

This sequence of reactions would be likely favored by specific pH and temperature and holding times to produce highest yield as is generally true for many reactions. The optimum temperature for the diazotization may be lower, with a specific warmer temperature and holding time that is optimum for the nitration and possibly hydrolysis combined. There could actually be three sequential reactions done as a one pot process. Or breaking the process into stages may work better.

Really I don't mean to harp on this, but I think the case is pretty convincing for the diazo at 4 and the Klapotke article is simply wrong about DDNR being a 6 diazo which would require some radical and unlikely diazo rearrangement. Before this is done with there is going to be IMO a revision of structural identification done by Klapotke same as occurred a hundred years ago for Meldola History is going to repeat itself like deja vu ....all over again

The occurrence of diazotization with nitration also occurring subsequently or possibly at the same time has been reported for reactions involving other subtrates. It seems possible that a nitration catalyst could possibly be useful also for promoting the introduction of an added nitro group, that the presence of certain salts in the nitrating acid could increase the yield.

In the excerpt below it is mentioned that even nitric oxide can in some cases effect diazotization, which led to my suggestion that paraformaldehyde added to the strong acid solution of isopicramic acid nitrate may serve to diazotize, since in strong acid that is the result, but I think the nitric oxide itself then reacts with HNO3 to produce NO2 which likely does the work, similarly as if NaNO2 had been added, which is another option.

References are sparse but according to one I have read Paraformaldehyde with HNO3 reacts differently according to the concentration at 0.5N to 2N there is NO2 produced directly but at higher concentration NO is the result. See attached article.

Attachment: nitric acid plus formaldehyde.pdf (78kB)
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Here is a screen shot page 10, Chemistry of the Diazo Compounds

https://books.google.com/books?id=XYhY9AUzVD0C&pg=PA10&a...



From the reaction of isopicramic acid heated in nitric acid it would appear there are 3 likely possible products all 3 being energetic.

[1] p-DDNP 4-diazo-2,6-dinitrophenol-(1-anhydride)
[2] 4-diazo-2,3,6-trinitrophenol-(1-anhydride) as a probably transient intermediate having an unstable 3 nitro decomposing to a 3 hydroxyl
[3] DDNR 4-diazo-2,6.-dinitroresorcinol-(1-anhydride)

If what is produced is a mixture which defies easy separation it could still be a useful energetic material as a mixture. But it should likely be possible to resolve such a mixture using sodium acetate since there is formed a soluble salt of the DDNR. Boiling with magnesium acetate or magnesium oxide should work as well, perhaps better to form the soluble magnesium salt of DDNR. The other materials, including unreacted isopicramic acid have extremely low solubility in H2O. According to the Hagel and Redecker patent US4246052 the mixture should be kept slightly acid pH 6.5 and not excessively neutralized to basic, to avoid decomposition.

[Edited on 7/28/2015 by Rosco Bodine]

possible catalyst for 3-nitro acetaminophen and DDNR

Quote: Originally posted by PHILOU Zrealone

Quote: Originally posted by solo   Requested by Rosco Bodine Mild, Efficient and Selective Nitration of Anilides, Non-Activated and Moderately Activated Aromatic Compounds with Ammonium Molybdate and Nitric Acid as a New Nitrating Agent Sariah Sana, K. C. Rajanna, Mir Moazzam Ali, P. K. Saiprakash Chemistry Letters Vol. 29 (2000) No. 1 P 48-49 Just to point out that at the end of the document there is a reference nr 12 that is not a reference but a full paragraph of the actual procedure for the nitration at the wrong place. Besides this it is very interesting since I have several kilograms of NH4 molybdate and now I know what to do with it

Seems old Rosco was right as usual regarding the solubility of the isopicramic acid sulfate after deactylation. The deacetylation mix just needs stronger dilution to precipitate all of the dark brown/black impurities. When the deacylation is performed in more strongly diluted sulfuric acid and is allowed to cool down completely before filtereing, all of the isopicramic acid stays in solution and a much purer product is obtained when titrated with a base to obtain the free and insoluble isopicramic acid again. The resulting isopicramic acid is very pure and gives fine glittering needles of p-DDNP when diazotized using hCl and sodium nitrite.

Version 2.0:

Synthesis of 4-amino-2,6-dinitrophenol (iso-picramic acid) from acetaminophen

Notes: Look for the cheapest brand of Tylenol/Paracetamol tablets, containing the highest amount of acetaminophen (usually 500 mg). Weigh 10 tablets or so to determine the percentage of fillers present and compare different brands for the lowest percentage. Additionally, this extraction procedure may not work equally well with every brand of tablets and would depend on the composition of the binders/fillers. If the nitration produces some sticky residues there are likely remaining impurities present from the tablets. Alternatively, pure acetaminophen is also available commercially, which would eliminate the extraction procedure.

Extraction of acetaminophen from Tylenol or Paracetamol tablets

Collect a number of tablets, translating to a combined weight of 25 grams of pure acetaminophen, (so weight of fillers not included) and grind as fine as possible using a coffee grinder. Transfer the powder to a 250 ml beaker and add 100 ml of denatured spirits. Heat the mix under reflux to the boiling point on a hotplate or boiling water bath and let it stir for about 5 minutes with gentle boil to extract the acetaminophen. Let the solution cool to room temperature and filter the solution into a 250-500 ml beaker, which will remove most of the fillers.

Next, put the beaker on a hotplate and put it on the highest temperature setting and let the solution boil while stirring. The ethanol fumes are very flammable and potentially explosive so do this outside! When the solution has evaporated to about half of its original volume, add 50 ml of water while keeping at boil. When nearly all of the ethanol is evaporated (takes about 15 minutes) the acetaminophen will precipitate over the course of 10-15 minutes as a course sand like precipitate. Take the solution from the hotplate and leave it to cool to room temperature. Add another 50 ml of cold water and filter the suspension. Wash 3-4 times with cold water and filter to collect the acetaminophen. The filtrate will have a slight yellow tint and appears milky, this is normal. Let the acetaminophen dry at room temperature for 24 hours, to obtain pure crystalline acetaminophen as a free flowing powder. (21-22 grams)

Nitration to dinitro acetaminophenol

Prepare a large cooling bath containing crushed ice and water, containing at least 500 grams of crushed ice. Put a 100 ml beaker on a scale and poor in 70 grams of 96-98% sulfuric acid. Transfer to the ice bath and let it cool to 0-10 deg. C. Then add 25 grams of dry ammonium nitrate in small portions, keeping the temperature below 20 deg C. Swirl or stir for about 5 minutes to dissolve all the ammonium nitrate and keep on ice.

To a separate 500 ml beaker, add 100 grams of conc. sulfuric acid and also transfer to the ice bath, let it cool to 0 deg. C. Add a stirrer bar and thermometer, and put the ice bath on a stirrer plate, set at 125-250 rpm. Weigh out 20 grams of finely powdered acetaminophen and add small portions at a time to the sulfuric acid, while keeping temperature below 10 deg C. Let it stir for an additional 10 minutes after the last addition until everything has dissolved.

After the acetaminophen/SA solution has reached 5 deg C, slowly start adding the ammonium nitrate/SA solution. It is best to keep the temperature around 5 deg C during the additions. The nitration responds very rapidly upon the additions, about 2-3 ml with each addition is about the maximum that can be added for the first additions, resulting in a jump from 5 to 10 deg C. Above 15 deg C, foaming starts to become evident, probably due to decomposition of the acetaminophen.

Depending on the efficiency of the cooling bath, the total addition will take about 30 minutes. Halfway the nitration, the solution will attain a dark brown colour with each addition, which will fade to a more orange colour again after some time. After the final addition is made, let the solution stir for another hour while keeping on ice. Finally, ad 250 grams of finely crushed ice (preferably directly from the -20) to the nitration mix. Some foaming will occur, let the solution stir for another 20 minutes while in the ice bath until the foam has mostly dissipated. The dinitro acetaminophenol will settle as an yellow-orange precipitate to the bottom of the beaker, it is filtered and washed with ice cold water from the ice bath. Wear gloves while handling it, as it is a very strong dye! Under acidic conditions it gives a bright yellow colour, while at near neutral pH a very strong grapefruit like colour is obtained to a deep red/violet when further basified.

Note: Yield can be increased by neutralizing the filtrate with concentrated ammonia solution and leaving overnight in the fridge, precipitating the residual dinitro acetaminophenol as the matt red coloured ammonium salt.

Deacetylation to isopicramic acid

After filtering and washing, the dinitro acetaminophenol can be directly transferred to a 500 ml beaker. Set stirring to a low setting of about 100 rpm and add 137.5 ml water + 12.5 ml of concentrated sulfuric acid. Heat the suspension to 95 deg C. for about 1 hour under reflux. Monitor the deactylation and use a pipet to flush down remaining dinitro acetaminophenol from the side of the beaker. The yellow-orange suspension will gradually go from orange to a deep dark red over time and the initial suspension will form a solution of the soluble iso-picramic acid sulfate. Take the beaker from the hot plate and allow to cool down to room temperature. Filter out any dark coloured impurites, and transfer the clear filtrate into a 500 ml beaker, and put it on the stirrer again. Set stirring to 500 rpm, and add small portions of household ammonia over the course of 15-30 minutes, until the solution is just slightly acidic at a pH of around 4. The iso-picramic acid will separate as 18-21 grams of a brick red glistening crystalline precipitate that should filter very easily from gravity alone. After drying the product should be an orange-brownish in colour. Over neutralization from adding too much ammonia will give a more brownish colour due to the presence of the purple coloured ammonium isopicramate, which can affect both storage stability and diazotization, thus is best avoided.

Notes:
1. Filtering of the deacetylation mix after cooling down is very important to remove insoluble impurities from remaining tablet-binders or by-products from the nitration itself, otherwise a clean product will not be obtained.
2. The isopicramic acid can be recrystallized from boiling ethanol (solubility about 3 grams per 100 ml) by slow addition of ice cold water and/or boiling down, upon which the isopicramic acid will precipitate as fine plate like crystals having a beautiful golden appearance.
3. Alternatively, the isopicramic acid/ sulfuric acid solution after deacetylation and filtering can be directly used for the diazotization using sodium nitrite at 0 deg C. giving fine orange-brownish needles of p-DDNP.

[Edited on 9-8-2015 by nitro-genes]

Thanks, after having performed the nitration of acetaminophen again to update the synthesis protocol posted above, there are some interesting things I noticed about the nitration and the formed DNAc. It occured strange to me that the DNAc direcly after filtering from the spent nitration mix has a definite orange colour to it. When a small amount of the water diluted nitration mix was allowed to stand at 4 deg C. overnight, the colour had changed to a more golden yellow colour, which corresponds better with the earlier reported "straw yellow" colour of the DNAc from literature.

I always assumed that this may be an effect of crystal shape, since the orange colour is nearly absent when using HNO3 instead of AN. It occured to me that a lack of water and oxidation of some of the acetaminophen may actually produce quite some HNO2 in situ, which could produce N-nitroso DNAc (or another compound?). To test this possibility, a small amount of the straw coloured DNAc was acidified (no colour change), after which NaNO2 solution was added, immediately producing the bright orange colour again. The colour is almost identical to to the presumed 3-nitro(so) acetaminophen described in the Japanese paper. Since the latter is immediately destroyed when attempting deacetylation in hot conc. SA, leading to fizzing of the solution and ultimately only resulting in brown crud. The dinitro N-nitroso DNAc (or other product from HNO2 reaction), is likely the main impurity, that upon deacetylation produces the dark brown impurities. What would be the likely decomposition products of the N-nitroso destruction in SA, presumably, it's decomposition would be similar to other secondary N-nitroso or nitramine compounds? Would a higher water content in the nitration mix possibly lead to less of the N-nitroso product?

Some things I thought of:

1. Caution is advised when handling the synthesized DNAc, since N-nitroso compounds are usually carcinogenic
2. The nitration using AN instead of NA may need even lower temperatures to prevent oxidation, or perhaps adding urea (or performing the nitration with urea nitrate/nitrourea) would help
3. Apparently, upon standing in diluted acid the N-nitroso DNAc decomposes/hydrolyses to produce DNAc again, is this normal behaviour for a N-nitroso? (trying to confirm the N-nitroso is the most likely impurity)
4. Although Meldola has shown that DNAc cannot be nitrated further, it seems strange that DNAc when added to conc. nitric acid/Ac2O doesn't form the secondary N-nitramine, which could rearrange to a 3-nitro derivative. Is the the result of the keto-enol tautomerism of the OH group?
5. Can the N-nitroso DNAc alternatively be oxidized with H2O2?

[Edited on 11-8-2015 by nitro-genes]

Great minds think alike. The possibility of improving the yield by reducing any nitrous acid present in the nitrating acid was exactly what I was thinking about when looking at sulfamic acid as a possible addition of 1-2% to the nitration mixture, and urea was another possibility, and possibly yes H2O2 may even be best of all for a low temperature. It could be an advantage to change the order of addition and add the acetaminophen in H2SO4 to the nitrating mixture. That would be the first thing to try to see if that will provide any improvement. The thing being nitrated can have a reducing effect on the nitric acid and that effect could be greater when the ratio of the HNO3 is low, as it would be when the HNO3 is being added gradually to a mass of the material to be nitrated, as opposed to the reverse order of addition where the HNO3 would be in excess. It can in some cases change entirely what is the result of the reaction simply to change the order of addition. Avoiding intense sunlight is a good idea too because there can be photosensitivity for such mixtures as is true for HNO3.

With regards to the higher water content actually being of benefit in a nitration mixture by opposing the formation of nitrosylsulfuric acid, yes it is possible to occur that way. Some trinitrations can occur in systems that are 90% H2O but it requires near boiling temperatures and not too easily decomposed materials being nitrated. However it is unknown if the nitration mixture would withstand dilution to 30% H2O where the NO2 nullifying effect of sulfamic acid may be observed, and what would be the effect on temperature requirement for a warmer range or holding time is also unknown and the changes could be counterproductive.
Generally higher H2SO4 content and lower H2O content allow for a lower temperature for nitration and DNAc may not withstand a higher temperature nitration, so it could just end up being a tradeoff what is the optimum nitration mixture and temperature and holding times. Nitration schemes are nuanced by the composition and time and temperature that makes some interesting process algebra to find what is optimum.

[Edited on 8/11/2015 by Rosco Bodine]