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Rosco Bodine
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[*] posted on 17-1-2018 at 13:58


@nitro-genes

Copper picrate has some odd properties and reportedly can decompose in boiling to produce some ammonia and the color of the red orange crystals you show pictured is like ammonium picramate. So there are several possible things going on there. Among the divalent metal salts that could be catalytic in reducing a picrate to picramate iron and copper are both reported. What combinations with ascorbic would work best is unknown, and likewise what proportions and conditions are best is unknown. A set of experiments could be formulated to identify the best process chemistry particulars and optimize the synthesis.

When the synthesis of picramic acid was being first contemplated, ascorbic acid and fructose were both promising reducing agents, also metallic iron and zinc. The observation about Zinin reductions using sulfides requires an alkaline reduction system where the picrate salt is what is being reduced, rather than free picric acid itself being reduced, is a general rule that I think will probably hold true for other reducing agents like ascorbate or fructose or glucose, or the lower oxidation state divalent metal salts as catalysts or reagents.

[Edited on 1/17/2018 by Rosco Bodine]
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[*] posted on 17-1-2018 at 15:10


Where would one start with sub-gramme quantities of an EM ?

I've read about many, yet am scared of the whole idea to be honest, so intend to make a remotely controlled micro-lab to at least try, certainly without having any part of me close enough by to be damaged in case it goes wrong.

A big issue (in my mind at least) is how to dispose of the results of Failed experiments.

As it would be sub-gramme, would simply burning the waste ensure that it was not dangerous ?




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[*] posted on 17-1-2018 at 16:19


@aga, You known once you go to the dark side, there is no turning back eh :D The danger involved when working with EM's depends on the specific EM. When working from pre-existing and thoroughly tested syntheses, relatively insensitive EM's, small quantities and with adequate precautions, the danger involved can be largely limited. Starting with picrates might be an idea, they are relatively benign (most biochemistry labs store it as a dye for tissue staining), easy to make, stable in storage and has an interesting chemistry.

@Rosco, there is a lot going on, pH and temperature probably being crucial factors. I haven't been able to produce the pure picramic again (or maybe it was a dinitro nitrosophenol?)...:( This may be far more difficult than I previously thought, and the reactions and precipitates involved seem really puzzling.

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Rosco Bodine
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[*] posted on 17-1-2018 at 23:01


Quote: Originally posted by nitro-genes  
Ok, so I made the orange-peel-insoluble-in-water-stuff again, trying to determine better the conditions for it's formation.

0.25 grams (~1 mmole) of picric were added to a 25 ml beaker, together with 0.27 grams of copper(II)sulfate pentahydrate (~1 mmole) and heated in 20 ml of distilled water to near boiling, upon which everything dissolved. NaOH solution was added to a pH of 7 to neutralize the picric. Then I weighed out 0.6 grams (~3.2 mmoles) of ascorbic acid and slowly started adding this to the picric/copper sulfate solution. When about 0.27 g was added (1.5 mmoles), a greenish-yellow precipitate started to form abundantly, the pH at this point was about 3-4. This was filtered off and washed thoroughly. The precipitate was resuspended in 10 ml of water and NaOH solution was again added at room temperature (pH of 10-12 or so), upon which it turned to a deep red-orange suspension. Upon acidifying again (this time using dilute HCl, instead of nitric) the bright orange precipitate formed slowly.

So no reduction to picramic, which would have required at least 6 electrons and 3 mmoles of ascorbic (3.5 if you don't count the copper reduction), though IIRC it's also only able to reduce nitro groups under more basic conditions. Curious what this stuff is exactly though. :)

[Edited on 16-1-2018 by nitro-genes]


Try these adjusted proportions for the reduction

Solution A

10 mmole picric acid
5 mmole copper sulfate
10 mmole NaOH

Use sufficient H2O to dissolve at 85C

Solution B

75 mmole NaOH + 63 mmole ascorbic acid

Use sufficient H2O to dissolve at 85C

These proportions should be close to theory

http://www.sciencemadness.org/talk/viewthread.php?tid=433&am...

[Edited on 1/18/2018 by Rosco Bodine]
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[*] posted on 18-1-2018 at 06:08


Why do you assume 6.3 mmoles of ascorbic, instead of half, so 3.15? Sorry if I'm getting this wrong, each mole of ascorbic would be able to donate 2 electrons to form dehydroascorbic right? And if IIRC, reduction of 1 nitro group, 6 electrons would be needed, so 3 moles of ascorbic per mole of picric (unless maybe a pH of >11 (kPa2 of ascorbic) is needed to donate 2 electrons. Another problem that I see is that solution B will have a very high pH, this will precipitate part of the copper as the hydroxide an when reduced by the ascorbic it will result in the insoluble orange-red copper(I) oxide.

[Edited on 18-1-2018 by nitro-genes]
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[*] posted on 18-1-2018 at 10:26


I think you may be seeing one of the hydrogens of ascorbic acid as a reducing hydrogen that is actually another different hydrogen "acidic hydrogen" that is tied up in sodium ascorbate.

The copper oxide was expected to be the insoluble end result byproduct that could be filtered from the hot sodium picramate solution. Likewise is iron oxide and manganese oxide ect for the other metal salts used. For the ascorbate reduction that was from earlier research that has not been reviewed again to confirm but there were some literature references checked. You could be right and it would require experiment to confirm. The slight excess ascorbate was provided for offset to air oxidation loss. Likewise the excess NaOH base was to make certain the reduction reaction system is progressing and increasingly basic.

Reviewed the literature and saw the 3 to 1 ascorbate experiments reported lower yields than expected. A color density development in a dilute sample experiment reaction system should confirm the quantity of ascorbate required, and likewise for reduction using fructose or glucose, because the sodium picramate product is such an intense dye that the reaction system functions as its own color indicating analytical test.

[Edited on 1/18/2018 by Rosco Bodine]
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[*] posted on 18-1-2018 at 11:53


As for even dipping a toe into the 'Dark Side' i'd clearly be on my own, and at risk :

https://www.sltrib.com/news/2018/01/18/utah-man-who-runs-pop...

Hardly seems that the risk will ever be worth the reward.




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[*] posted on 18-1-2018 at 12:39


Quote: Originally posted by aga  
As for even dipping a toe into the 'Dark Side' i'd clearly be on my own, and at risk :

https://www.sltrib.com/news/2018/01/18/utah-man-who-runs-pop...

Hardly seems that the risk will ever be worth the reward.

I thought that possessing explosives and synthesizing them was legal in the US, with an exception of Acetone Peroxide and some other that I don't remember.




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[*] posted on 18-1-2018 at 12:46


What is the best primary? I know, ambiguous question.
I want a low friction sensitivity but it still needs to make DDT reliably when confined and lit with an open flame coming from a fuse, and it also needs to be storable, it can't decompose with time.
SA(DS) was my first choice, but DDNP also drawed my attention.




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[*] posted on 18-1-2018 at 16:17


Quote: Originally posted by joseph6355  
Quote: Originally posted by aga  
As for even dipping a toe into the 'Dark Side' i'd clearly be on my own, and at risk :

https://www.sltrib.com/news/2018/01/18/utah-man-who-runs-pop...

Hardly seems that the risk will ever be worth the reward.

I thought that possessing explosives and synthesizing them was legal in the US, with an exception of Acetone Peroxide and some other that I don't remember.


In USA, under FEDERAL explosives laws, you can make explosives without a license. But you can NOT store them, use them in any commercial activity, move them on public roads, sell them or even give them away.

There is a culture of fireworks enthusiasts who have figured out how to work around the no storage/transport rules. They start with legal OTC ingredients and can make quite large, complex display fireworks shells in a single long work day. Sacks of chemicals, bottles of 2 part curing rubber/epoxy/polyester or whatever, plastic cans or hemispheres, string, paper, tape, hot melt glue. Some of them even look pretty good in the sky.

Classes are taught in these techniques at PGI conventions, the Western Winter Blast, etc.

https://www.pgi.org/convention/2018/

https://www.westernpyro.org/events


So if you can make it in a day, or better yet, on site- Yes, you are probably good with BATF. But each state and even county, city or township may have their OWN laws in addition to the Federal laws, and good luck on telling them you're OK with the feds if you piss off the local authorities.

It gets confusing. Beyond the several Federal licenses to import, manufacture, deal in or possess explosives, I have held 3 different state's licenses to USE display fireworks, and every one is a bit different.

-----------
(Edit)

The YouTube guy is damned either way.

If he is a legitimate business using explosives and can beat the state possession felony charge by that finding, then his lack of the Federal license(s) he would have needed as a business using explosives will get him a federal felony charge.

It also sounds lime he admitted keeping that sack of powder around longer than the day he got it, and whoever gave it to him also broke the distributing rules.

The dry ice/soda bottle thing is just plain silly, but they have tried to charge high school kids who did that type of experiment IN SCHOOL, WITH A TEACHER KNOWING it was going to be done with legal charges intended by the legislature for terrorism.

It is all fucked up, but slightly better than some other places.

[Edited on 19-1-2018 by Bert]

[Edited on 19-1-2018 by Bert]




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[*] posted on 19-1-2018 at 05:22


I synthesized a new 90 g batch of picric acid from ASA. I just precipitated it and it dissolved it in boiling water. Now its colling down.
I mentioned earlier that I was looking for small grain-ish crystals. but with high purity and at the same time obtaining a high yield from ASA, so I was thinking about simply crushing it with a ceramic pestle and mortar, but under water, or at least wet with cold water.

I really wanted to use picric acid, but big crystals scare me, specially if I want high density, because I would need to press them. If I cant use picric acid, then ammonium picrate will do. Ammonium picrate is way less sensitive to friction and impact, so I was thinking about throwing small amounts in the blender and leaving it there until it breaks down to smaller grains, almost like a powder.
Is it safe to crush picric acid?

[Edited on 19-1-2018 by joseph6355]




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[*] posted on 23-1-2018 at 01:40


Quote: Originally posted by Bert  
Quote: Originally posted by joseph6355  
Quote: Originally posted by aga  
As for even dipping a toe into the 'Dark Side' i'd clearly be on my own, and at risk :

https://www.sltrib.com/news/2018/01/18/utah-man-who-runs-pop...

Hardly seems that the risk will ever be worth the reward.

I thought that possessing explosives and synthesizing them was legal in the US, with an exception of Acetone Peroxide and some other that I don't remember.


In USA, under FEDERAL explosives laws, you can make explosives without a license. But you can NOT store them, use them in any commercial activity, move them on public roads, sell them or even give them away.

There is a culture of fireworks enthusiasts who have figured out how to work around the no storage/transport rules. They start with legal OTC ingredients and can make quite large, complex display fireworks shells in a single long work day. Sacks of chemicals, bottles of 2 part curing rubber/epoxy/polyester or whatever, plastic cans or hemispheres, string, paper, tape, hot melt glue. Some of them even look pretty good in the sky.

Classes are taught in these techniques at PGI conventions, the Western Winter Blast, etc.

https://www.pgi.org/convention/2018/

https://www.westernpyro.org/events


So if you can make it in a day, or better yet, on site- Yes, you are probably good with BATF. But each state and even county, city or township may have their OWN laws in addition to the Federal laws, and good luck on telling them you're OK with the feds if you piss off the local authorities.

It gets confusing. Beyond the several Federal licenses to import, manufacture, deal in or possess explosives, I have held 3 different state's licenses to USE display fireworks, and every one is a bit different.

-----------
(Edit)

The YouTube guy is damned either way.

If he is a legitimate business using explosives and can beat the state possession felony charge by that finding, then his lack of the Federal license(s) he would have needed as a business using explosives will get him a federal felony charge.

It also sounds lime he admitted keeping that sack of powder around longer than the day he got it, and whoever gave it to him also broke the distributing rules.

The dry ice/soda bottle thing is just plain silly, but they have tried to charge high school kids who did that type of experiment IN SCHOOL, WITH A TEACHER KNOWING it was going to be done with legal charges intended by the legislature for terrorism.

It is all fucked up, but slightly better than some other places.

[Edited on 19-1-2018 by Bert]

[Edited on 19-1-2018 by Bert]

I think that, in addition, the ATF has a category of weapons known as "destructive devices" that includes some explosive devices. https://www.law.cornell.edu/uscode/text/26/5845 Destructive devices include :
"(1) any explosive, incendiary, or poison gas (A) bomb, (B) grenade, (C) rocket having a propellent charge of more than four ounces, (D) missile having an explosive or incendiary charge of more than one-quarter ounce, (E) mine, or (F) similar device; (2) any type of weapon by whatever name known which will, or which may be readily converted to, expel a projectile by the action of an explosive or other propellant, the barrel or barrels of which have a bore of more than one-half inch in diameter, except a shotgun or shotgun shell which the Secretary finds is generally recognized as particularly suitable for sporting purposes; and (3) any combination of parts either designed or intended for use in converting any device into a destructive device as defined in subparagraphs (1) and (2) and from which a destructive device may be readily assembled. The term “destructive device” shall not include any device which is neither designed nor redesigned for use as a weapon; any device, although originally designed for use as a weapon, which is redesigned for use as a signaling, pyrotechnic, line throwing, safety, or similar device; surplus ordnance sold, loaned, or given by the Secretary of the Army pursuant to the provisions of section 4684(2), 4685, or 4686 of title 10 of the United States Code; or any other device which the Secretary finds is not likely to be used as a weapon, or is an antique or is a rifle which the owner intends to use solely for sporting purposes."
This seems to apply only to weaponry, but with explosives, "weaponized" might be subjective, and based on intent or the appearance of intent.A bag of sufficiently sensitive and potent explosive could, at least in theory, serve as some kind of weapon by itself. I almost wonder if this specific scenario is a factor in laws against organic peroxide. Of course a bomb, designed to intentionally make shrapnel, with a an attempt to disguise or conceal it, and a trigger mechanism meant to ignite it remotely, would probably be considered a destructive device no matter what. I really don't know whether or not a big homemade firework or an experimental explosive test charge could easily fall into this category, but it might be something to keep in mind.
I'm not a lawyer or an expert in blasting or pyrotechnics by any means, and this law could be a non-issue for things that were not designed as weapons. I thought I'd bring it up here just in case.
Also, your point about state laws is extremely important. Just because something is legal according to federal law does not mean that it will be legal in every state.

[Edited on 23-1-2018 by Vomaturge]
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[*] posted on 23-1-2018 at 09:23


Crystal structure of a copper complex of 2-carboxypentonic acid; A decomposition product of dehydroascorbic acid (Journal of the Chemical Society Dalton Transactions (1987)
DOI10.1039/dt9870002905)

Abstract
In acidic aqueous solution and in the presence of copper(II), ascorbic acid is rapidly oxidized to dehydroascorbic acid, which rearranges to give the branched-chain dicarboxylic acid 2-carboxypentonic acid (1,2,3,4-tetrahydroxybutane-1,1-dicarboxylic acid)(H3cpa). The ion cpa3– is sequestered by copper(II) to produce the insoluble crystalline product [Cu9Cl2(cpa)6(H2O)3]2–·xH2O

This probably explains a lot... :(
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[*] posted on 23-1-2018 at 12:49


Depends on the pH of the reaction system what will occur with regards to copper as well as picrate, and dehydroascorbate. It is known that copper can be reduced all the way to the metal by ascorbate. Metal would be a really insoluble product.
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[*] posted on 23-1-2018 at 13:06


jioseph: Read this chapter on primary explosives, DDNP is extremely friction insensitive compared to most other primaries but it is more static sensitive, SA.DS, TATP, HMTD are in the same ballpark for friction sensitivity, lead azide and pure silver acetylide are about the most friction sensitive of the bunch, mercury fulminate is between SA.DS and DDNP in terms of friction sensitivity

https://www.sciencedirect.com/science/article/pii/S030438941...
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[*] posted on 23-1-2018 at 16:05


Quote: Originally posted by Rosco Bodine  
Depends on the pH of the reaction system what will occur with regards to copper as well as picrate, and dehydroascorbate. It is known that copper can be reduced all the way to the metal by ascorbate. Metal would be a really insoluble product.


Right as always (well usually)...

Did a couple of tests this evening:

1. 0.25 grams of picric were added to 10 ml water and brought to 80 deg C. Then, 0.6 grams of ascorbic acid were added, which produced no obvious colour change. Using NaOH solution, the picric/ascorbic was adjusted to a pH of around 7, which also did not result in any significant change in colour within 5 minutes. A few crystals of copper(II)sulfate (~5 mg) were added, which immediately produced a clear solution changing rapidly in colour, going from yellow, to orange, to dark orange red, finally resulting in a fine orange-red precipitate at the bottom of the beaker (Seemingly too much to be explained by the copper addition alone, though would need to be weighed). Out of curiosity, another 0.6 grams ascorbic acid was added in small increments (everytime adjusting the solution again to pH7. Strangely, after only a few spatules of additional ascorbic, the solution began producing large amounts of some odourless gas, foaming significantly and changing to a very dark red-orange colour, with only a small amount of precipitate, that most likely is copper powder. The dark red-orange solution was acidified using sulfuric acid, resulting in a much lighter orange solution and a precipitate of brownish crystals, that on closer examination proved to be unreacted picric acid.


2. 0.6 grams of ascorbic acid was dissolved in 10 ml water and brought to around 80 deg C.. Then added a few crystals of copper(II) sulfate, there was no colour change. Then adjusted the solution to pH of 7, which produced a slightly opaque solution with slight orange sheen (Probably copper(I) oxide). A spatule of salicylic acid was added, resulting in no colour change. Finally, a spatule of picric was added, immediately going from orange to dark orange-red again.

It seems copper salts are truly hugely affecting the reduction rate at a pH of 7. Very interesting, the question is what formed here, how specific the reduction is and how the conversion efficiency is (if it can truly acts as a catalyst) Probably not since presumably conversion to copper powder is also happening at this pH and temperature, explaining the unreacted picric recovered.

[Edited on 24-1-2018 by nitro-genes]
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[*] posted on 23-1-2018 at 23:26


The copper sulfate / copper hydroxide / copper picrate most probably their "ous" +1 basic salts appears to be functioning as a reduction catalyst, the cupric +2 regenerated to cuprous +1 by the sodium ascorbate. It is the sodium ascorbate solution that should be added gradually.

I'm sticking by what I suggested earlier.

You need to take the acidity of free ascorbic acid out of the reaction mixture by using sodium ascorbate and slight excess base to get the pH distinctly higher maybe 12 doing the entire reduction in an alkaline system. At boiling the end result copper value is likely going to be insoluble copper oxide that can be filtered from a hot supernatant solution of sodium picramate and excess NaOH and sodium dehydroascorbate.

Your brownish crystals you identify as "unreacted picric acid" is likely free picramic acid. Solubility in cold water is extremely low and the microcrystalline material should be as fine as paint or ink pigment, very dull colored like terra cotta or rust not bright canary yellow like picric acid. In basic solution the color should brighten drastically to the blood red dye effect, and bright red color for the sodium picramate salt which is much more soluble and forms coarse reflective crystals. If some of the sodium picramate is dissolved the solution will be intensely red almost black for a concentrated solution that is basic. Neutralized / acidified with acid, the sodium picramate solution will fade as it is titrated to a nearly colorless only very pale yellowish supernatant solution, and the free picramic acid will precipitate as a dull colored extremely fine dust like brown or brown orange precipitate.

I'm betting the reaction is general and will work using copper, or manganese or iron or nickel or cobalt (salts) as the catalyst with sodium ascorbate gradually added to a basic picrate salt solution in a reduction reaction system kept basic. The amphoteric and pH dye indicator property of the picramic acid can be used to track the reaction progress and exploited to isolate the free picramic acid end product.

The picramic acid is analogous to isopicramic acid in its behavior and properties. When a chemically pure picramic and isopicramic acid 50/50 mixture is diazotized according to the special technique for producing higher density crystals of DDNP it is possible a mixed isomer crystal could result having better density than either isomer alone. I think you may have done an experiment with this IIRC, but it was not conclusive what resulted.

[Edited on 1/24/2018 by Rosco Bodine]
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[*] posted on 24-1-2018 at 03:07


Does anyone happen to know if sodium acetate dissolves in acetic acid?



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[*] posted on 24-1-2018 at 03:32


It does not, at least not in very concentrated acetic acid.
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[*] posted on 24-1-2018 at 05:11


@Rosco

Fe(0), Iron(II)sulfate (or the hydroxide formed) can also acts as a reducant, I tried once using 7 moles of ferrous sulfate and ammonia at 80 deg C for half an hour. There is reduction going on, judging by the changes in colour and precipitation of Fe2O3, but it is only very small amounts of picramic acid produced, so hardly selective like using hydrosulfides e.g..The Strange thing is that the copper system does seem to have the potential to be very selective for the reduction of 1 ortho nitro group even in aquaous solution. I've made a spatule of very clean DDNP somehow from a spatule of picric, but can't reproduce it. :mad: If the copper oxide/copper indeed needs to be filtered off, it may be beneficial to do the reduction using ammonia, IIRC, ammonium picramate is much more soluble than sodium picramate. This may also help keep the Cu(I) in solution maybe as the diamine complex? Is copper(I)oxide soluble in ammonia? Ammonium picramate solutions may also be more stable at higher temperatures than the sodium one.

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[*] posted on 24-1-2018 at 11:14


Quote: Originally posted by Σldritch  
It does not, at least not in very concentrated acetic acid.


Good to know. I wonder if it is an effective drying agent for concentrated acetic acid.




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[*] posted on 24-1-2018 at 13:41


@ nitro-genes

It's Deja Vu all over again. Using ammonia as the base sounds good and reportedly works fine.

I am not sure what solubility is best for a glycine complexed transition metal in alkaline pH but that could be a useful strategy for enhancing the solubility of the catalytic reducing metal.

Manganese nitrate would possibly be a good bet for a candidate, but glycine could be helpful with copper or the others.

http://www.sciencemadness.org/talk/viewthread.php?tid=433&am...

http://www.sciencemadness.org/talk/viewthread.php?tid=433&am...

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

https://www.youtube.com/watch?v=u4xp2lgiAjY

From our recently departed friend RIP Don Haarmann AKA

The Wizard is In

a good read about copper mirror electroless deposition

https://groups.google.com/forum/?hl=en#!msg/sci.chem/t65BM8x...

[Edited on 1/24/2018 by Rosco Bodine]
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[*] posted on 26-1-2018 at 13:03


I was certain the previous run (using only catalytic amounts of copper(II)) produced mostly unreacted picric, even though I was optimistic when I saw the brown coloured crystals too. 1. The precipitate formed only at a pH of <1. 2. Recrystallized from water and together with a pure picric sample on the hotplate, both melted sharply and simultaneously. 3. A comparative burn test between the two behaved exactly the same. 4. Diazotization did not produce DDNP

Addition of ammonia to a picric/copper(II)sulfate solution to adjust the pH did not seem to help at all, it produced a golden coloured precipitate very insoluble, even at higher temperatures, probably some tetra/diamine cupric/curprous picrate or a basic copper(II) tetramine picrate. Anyway, I was able to produce the pure picramic again, keeping the pH slightly basic as you suggested, I need to get all the detials sorted out yet, but after drying the putative copper picramate (air exposure changed the colour, maybe additional reduction or air oxidation of the copper(I)) and redissolving in boiling 10% HCl, upon cooling and dilution beautiful pom grenade coloured needles separate. The copper/ascorbate system seems to have the potential to produce a very high yield as well. Deja-vu or not, this is a remarkable find! I doubt other catalyzing transition metal salts would be able to perform this well, though additional experiments would need to be done to be sure.

It is also interesting whether the copper may be able to catalyze the reduction, my guess is it failed in the last experiment due to the production of copper powder. Maybe changing the addition order, pH or simply running the reduction at a lower temperature may allow the copper to act truly as a catalyst by preventing reduction all the way to metallic copper, which presumably behaves inert.

The selectivity seems to be most interesting to me, even more than the end product, would be really interesting to look at this further and test copper(II) catalysis in combination with other (more economical/green) reducing agents (which would depend on the requisite for precipitation of the copper picramate formed), and may even be of help in removal of polynitrophenols from contaminated waste water for example.

[Edited on 26-1-2018 by nitro-genes]
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[*] posted on 26-1-2018 at 13:53


Definitely interesting

All of the transition metals should work to some extent but some are likely to work better than others.

If the manganese salt is tried, the presence of ammonium chloride is reported to inhibit precipitation of the soluble manganese, and a similar effect may occur for other metal salts than manganese, allowing for a greater concentration of the reducing agent and making the reduction go faster and cleaner.

There is going to be an optimum concentration and temperature and pH for this reaction to proceed. The reaction mixture will probably self-regulate at saturation over an excess of reactants in stirred suspension. A bit of guesswork and visual information will guide you. About the addition sequence.....

The reaction system concentration and reduction reaction rate should be rate governed and limited by the addition rate of the sodium ascorbate, keeping a "steady state" maintained for the reduction, but not making addition of the ascorbate too fast so as not to excessively reduce the copper +1 value all the way to the metal, or to accumulate excess cuprous hydroxide, with the idea being to continually refresh the available cuprous hydroxide and maintain its concentration, but not overfeed the ascorbate faster than it is utilized.

The copper +1 cuprous hydroxide is being produced and is the likely reducing agent but is low solubility limited which will rate limit the reduction by its limited concentration.

There are two exit paths from the reduction reaction for the copper catalyst, as the spent oxide which won't be recycled by the ascorbate, or as the metal. And another possible exit path for the copper value is to form the copper salt of the picramate, but I was thinking the sodium salt more likely.

If the reaction is "running out of soluble copper" during the reduction because it is being consumed and is only acting as a quasi catalyst or an inefficient regenerable catalyst being partly regenerated and partly consumed as a reagent, converted to insoluble "spent copper" oxide ....deactivated and precipitated, then a concurrent drip of "makeup" copper value may be needed to replenish the available copper as the reduction proceeds. So long as the reduction reaction mixture is alkaline the makeup copper salt solution with convert to the hydroxide and become available immediately as it is added.

All of these picramic acid related posts need to be exported to the picramic from picric thread.


[Edited on 1/27/2018 by Rosco Bodine]
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[*] posted on 27-1-2018 at 15:04


Just a quick question.
Will 2 grams of "X" explosive, with lets assume its VoD is 4000m/s, have the same power or about the same power as 1 gram of "Z" explosive with VoD 8000m/s ?

[Edited on 27-1-2018 by underground]
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