Sciencemadness Discussion Board


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NurdRage - 6-3-2011 at 17:11

OK good you're not pissed then. If you want respect, usually the best way to obtain it is to provide some. I'll forget everything that happened (cause actually, i honestly don't know WHAT happened) and continue on with what we're all really here for: actual chemistry :)

Using azines as synthons for hydrazine reactions sounds like an excellent idea. I'm personally not doing nitrite or azide chemistry, but i might apply it to synthesis of luminol.

I'm still thinking of possible synthetic routes to hydrazine through ketazine. I recall a paper that used air and a copper catalyst to oxidize the imine. It might be worth looking into since it removes the cost of oxidant, although i'm not sure what the exactly catalyst was or if it was easy to make. If its more expensive then obviously we'll need to consider other factors. I'll see what i can find.

NurdRage - 6-3-2011 at 21:47

I hope he was fired... for his own safety.

Consuming toxic stuff from the lab is Olympic level darwin award worthy.

EDIT: Wait... was it intentional? or did he just made a mistake? bronze medal darwin award worthy if that was the case.

[Edited on 7-3-2011 by NurdRage]

Zinc - 8-3-2011 at 11:29

Today I tried to make hydrazine sulfate following Nurdrages ketazine process.

The differences were that I used a little more reagents (300 ml 25% NH3, 484g approx. 4.5% NaClO soln. and 120 ml of MEK) and I used manual stirring (swirling in a flask).

After the ammonia and hypochlorite were cooled to around 0 C, I added the MEK to ammonia and started adding the hypochlorite, but only a little foaming was observed (so I finished adding all of the hypochlorite in a few minutes) and almost no ketazine formed.

To see what would happen if I added more NaClO, I poured 25 ml of the reaction mixture in a 100 ml measurnig cilinder and added around 30 ml of the NaClO soln. It started foaming moderatley and after a few seconds it went out of the cylinder (only a small amount tho). I then added again around 15 ml of hypochlorite solution which again caused foaming but not so strongly.

After trying that I added around 80-100 ml of hypochlorite solution to the main reaxtion mixture (the one in the flask). I started bubbling but not nearly as strong as in the cilynder. After a few seconds the bubbling stopped and would start again for a few seconds (but very weakly) if I swirled the flask.

I have left the flask to stand over night to see if some ketazine forms after all.

Perhaps my hypochlorite soln. was much weaker than I thought, but I doubt that because of the amount of foaming that I observed in the measuring cilynder.

All of the glassware used was washed with 19% HCl, then water and then distilled water to remove any potential metal-ion contamination.

Anyone have any idea what I did wrong?

PS: the smell formed during the reaction is very interesting, like a mix of ammonia, MEK, and something "sweet".

edit: I forgot to write that the NH3 and MEK were reagent grade, and the NaClO soln was bleach.

[Edited on 8-3-2011 by Zinc]

NurdRage - 8-3-2011 at 12:13

Foaming is a BAD sign actually, it means you're decomposing the hydrazine, i think you added too much hypochlorite. There was no need to go over stoichiometric amounts just because it didn't foam. Also, let the MEK react with ammonia longer, sounds to me you added the hypochlorite right after you added the MEK.

[Edited on 8-3-2011 by NurdRage]

Zinc - 8-3-2011 at 15:13

Indeed I added the hypochlorite cca. 1-2 min after the MEK.

I have a question about stirring. Is the highly efficient stirring absolutely required, or is the manual stirring (in my case swirling the RB flask) enough (if i get a little lower yield it is ok as I dont need a lot of hydrazine sulfate?

NurdRage - 8-3-2011 at 15:29

yeah i recommend waiting for at least ten minutes or so after adding the MEK. Most of the time i waited for 30 minutes.

I'm not certain about the stirring, maybe try stirring by hand with a stir rod instead, swirling the flask might not give adequate mixing.

Another concern is the bleach concentration. 4.5% might be too low that the final concentration of ammonia is no longer adequate for the reaction. Especially since it sounded like you added too much bleach, further diluting the reaction.

I'm not too confident about this last idea though since i was able to get it to work well with 6% bleach. I didn't over-dilute though.

Zinc - 10-3-2011 at 03:00

Today I tried the procedure again but with much smaller quantities.

I used 30 ml of 25% NH3, 12 ml MEK and 48 g of 4.5% NaOCl soln.

This time I let the MEK and NH3 react for 15 min, with often vigorous shaking in an erlenmayer flask. When I added the hypochlorite the temp rose (it became warm to touch, but not much, and my hands were cold), and not too much foaming was observed. Again no ketazine formed.

It seems that my hypochlorite is too dilute, or perhaps contains some impurities that hinder the reaction, altogh I doubt that as it looks like pure NaOCl soln. (green with a chlorine smell, on the bottle it says that it contains NaOCl and NaCl) and it is very cheap (around 1.2 dollars per l).
It is also possible that without magnetic stirring the MEK and NH3 should be left to react even longer, as I noticed that when they are mixed the MEK forms a seperate layer wich in time diminishes (by the time I added the NaOCl it was mostly gone, only some drops were visible).

Of course all the glassware was washed with HCl, water and distilled water.

NurdRage - 10-3-2011 at 07:52

When i did my experiments with acetone, it wouldn't phase separate so i extracted with toluene.
Maybe you could try a toluene extraction, then obtain the hydrazine sulfate by reaction with dilute sulfuric acid.

Zinc - 10-3-2011 at 09:12

I did antoher try, this time with 15 ml 25% NH3, 6 ml MEK and 24 ml NaOCl, and let the NH3 and MEK react for around 1.5 h. They were in a measuring cilynder, so that I could observe how much of the MEK mixed with the NH3, after the sitting-time (with frequent shaking) 1-1.5 ml of MEK didn't dissolve. Adding the hypochlorite formed no ketazine.

I belive a good thing to try would be to make my own NaOCl (from p.a. grade NaOH to ensure purity) and try with that, but I don't yet have all the equipment needed to make Cl.

The toluene extraction is a good Idea, I could try that.

NurdRage - 10-3-2011 at 09:33

how long after you added the hypochlorite did you wait?

Ya said some MEK didn't dissolve, was it still undissolved after you added the hypochlorite?

Zinc - 10-3-2011 at 10:40

The last time I waited around 1-1.5 h, the mix was clear, no turbidity like it would be expected from a dispersion. The attempt from yesterday stood over night, with the same result.

When I added the hypochlorite most of the MEK was dissolved. In the last attempt that I did in a measturing cylinder, from 6 ml of the MEK that was added, 1-1.5 ml was not dissolved. Almost all of the MEK dissolved within the first 15-20 min, after that only a very small amount dissolved.

When the hypochlorite was added all of the remaining MEK instantly dissolved in a completely clear solution.

NurdRage - 10-3-2011 at 15:03

i'm outta ideas then. I guess stronger bleach and toluene extraction are the only options left.

I don't know how much it'll help, but have ya tried dissolving some gelatin into the ammonia before adding the rest of the ingredients? it'll precipitate somewhat when things get going but it might help a little.

The only other thing i can think of is to "salt out" the ketazine with sodium hydroxide. This needs to be done outside or in a fumehood as its going to belch out ammonia gas. Not the best option in my opinion since it wastes a tremendous amount of sodium hydroxide. Might as well go with the urea-hypochlorite method.

Ah well, if you do get it to work, or more importantly, if you don't, let us know. :)

Zinc - 11-3-2011 at 03:43

Yesterday I made a batch with 17 ml of NH3, 7 ml of MEK and 26 g of NaOCl soln. and let it stay over night.

Today I added 20 ml of toluene to the mix, swirled it to suspend the toluene, when the toluene separated I again swirled it to suspend it. When it again separated I removed the toluene layer into a flask and added a mix of 5 ml conc. H2SO4 and 7 ml of distilled water (the H2SO4 was added while still hot from the dilution). Upon adding the acid and swirling for a second or two, white powder precipitated (almost all of it in the H2SO4 layer, which was the bottom layer). There was no orange-colouring of the liquids. It seems to have worked :D:D

Now I have all of the remaining attempts (including the large one with excess hypochlorite, some extra water is also in the flask) mixed in a flask. I would be very good if the ketazine is still in that mix, and could be converted to hydrazine sulfate.

NurdRage - 11-3-2011 at 07:35

Ah, so it was just merely a recovery problem due to high dilution, not a reaction problem.

Good thing the toluene can be recycled, it'll take awhile but you can recover a great deal of ketazine with that approach.

Nice work!

If i may ask, have ya tried the urea-hypochlorite process?

Zinc - 11-3-2011 at 07:55

I tested the mixture of batches, and indeed there was ketazine in it. I devided it into three portions, and each was extracted two times with toluene (first time fresh, the second time recycled. I can't remember how much toluene I used, it was all in all 200 or 250 ml. With those larger amounts the orange collor appeared when hydrolising with H2SO4.

The yield of hydrazine sulfate is not good (it is still drying, and I currently don't have access to a precise scale so I can't weigh it but it is around 6-10 g I belive) but that could be because of the long time the ketazine was standing in the solution (with some exess hypochlorite and water), and the flask in which it stood was only covered with a petri dish, so it wasn't airtight (that would only be a reason if the ketazine is air-sensitive). There probably is some still in solution, but I doubt that there is much as there was much less hydrazine sulfate formed from the second extraction than from the first. There is a posibility that my both of extractions partially failed and that there is still much ketazine in solution but I doubt that.

I am wondering what prevented the ketazine from separating from the solution in the first place, was it the dilution caused by diluted hypochlorite?

Anyway it was interesting to experiment with this, if I attempt this again i should definitley use more concentrated hypochlorite.

No I didin't try the urea-hypochlorite method yet.

NurdRage - 11-3-2011 at 16:11

To be honest i don't really know. The excess hypochlorite might have killed the hydrazine. the dilution might have dissolved the rest.

Maybe you'll need some gelatin dissolved in the ammonia first to reduce the effect of impurities.

At least you got something out of it.

Random - 14-3-2011 at 00:02

After hydrolysis of ketazine with HCl, I would have solution of hydrazine hypochlorite. Could I add some copper, sodium or some other sulfate to precipitate hydrazine?

Zinc - 14-3-2011 at 06:15

Yesterday I weighed the hydrazine sulphate, and there is 18 g, much more than expected :D It seems that my visual determination of quantity is not very good:P

NurdRage - 14-3-2011 at 06:38

@Random Try it and let us know the results, i never tried it myself.

@zinc so what would that be in terms of yield?

Eclectic - 14-3-2011 at 07:21

Has anyone tried this with ice cold NaOH saturated solution and TCCA? Or making a concentrated NaOCl solution thusly?

Zinc - 14-3-2011 at 15:55

Fail, if I calculated it correctly that would be cca. 160% yield (based on NaOCl), impossible.
I am sure that the weight was correct (used a scale of 0.1g resolution). It is possible that the hydrazine sulfate was not completely dry as it was somewhat clumpy but still it couldn't contain that much water (it was dried for around 30-40 h, and the humidity was not too high, also as far as I know hydrazine sulfate is not hygroscopic). Is it possbile that some ammonia was extracted in the toluene (I did notice that the toluene extract smelled somewhat of ammonia, but I didn't think that much of it was in there, should have try to find out how soluble is NH3 in toluene) and formed the sulfate, which due to cooling (I cooled it to around 0 C before filtering it) precipitated along the hydrazine sulfate? Someohw I doubt that as ammonium sulfate is quite soluble in water (around 70g in 100 ml of water at 0 C) but perhaps because of the presence of sulfuric acid and hydrazine sulfate it's solubility was vastly reduced?

NurdRage - 15-3-2011 at 05:46

Your yield sounds low, not too high.

since you combined all reaction mixtures then lets assumed you started with the original 484g of 4.5% hypochlorite. That's 21.78g of equivalent NaOCl, this is around 0.2926 mole, if there is perfect conversion to hydrazine sulfate then we get 38g.

or about 47% yield at 18g.

Since you performed additional reactions the actual yield is probably even lower.

Maybe my math is wrong,

Zinc - 15-3-2011 at 06:23

Actualy I failed in my calculations, I calculated how much pure hydrazine should I get, not how much sulfate and I compared the number for pure hydrazine with the amount of the sulfate I had (quite a stupid mistake indeed, should not do such stuff 1h after midnight).

I used in total 582g of 4.5 % NaOCl, that is 26.19g, or around 0.35 mole, so if the yield was 100% I would get around 45.6g of hydrazine sulfate wich makes my yield around 39 %.

NurdRage - 15-3-2011 at 06:36

thats actually really good considering low concentration bleach was used and a few mistakes were made. Testament to how robust the process is.

What are you going to be using the hydrazine sulfate for?

EDIT: as for the original issue of why it never phase separated, another issue i just remembered is that sometimes MEK has acetone mixed in. Acetone azine is soluble in water. now I know you said your MEK was reagent grade so this is probably nt the issue.

[Edited on 15-3-2011 by NurdRage]

Zinc - 15-3-2011 at 08:05

Quote: Originally posted by NurdRage  
thats actually really good considering low concentration bleach was used and a few mistakes were made. Testament to how robust the process is.

Indeed, and that makes it very suitable for the amateur chemist who doesnt have always access to precise scales, more complicated equipment, very pure reagents, etc.

I used the hydrazine sulfate to make a small amount of NaN3.

Yes the MEK is p.a. grade and contains max. 0.002% acetone.

OneShot - 25-3-2011 at 07:35

nurdrage you have msn? I gotta talk to you thanks

Warnings about anhydrous hydrazine

Formatik - 6-4-2011 at 15:07

The method of initially refluxing hydrazine hydrate with NaOH in as was given in Brauer led to a severe explosion with larger batches (~1kg). Later editions of Georg Brauer's book use less dangerous ammonolysis of hydrazine salts but hazard of this procedure is not mentioned in the later editions.

Hydrazine that's near anhydrous is extremely dangerous to distill (explosion has occurred even in inert atmosphere! But in air it's a deathwish in the making, also results of detonating hydrazine with blasting caps in the ballistic mortar test showed the explosion in an air atmosphere is 11 to 13 times stronger), one would really have to prepare and brace for detonation occuring anytime. Plants which make hydrazine were designed to handle explosion. I've read about several detonations that occurred from distilling anhydrous hydrazine for no apparent reason! Vacuum and inert gas, clean glass equipment, very controlled heating, and small amounts below 100g are a must for starters. Saftey shield and similar protection can not be ignored. Entrainers are used to make detonating hydrazine vapor diluted but this can still get dangerous (entrainers are used in dehydration distillation), blanketing fluids used in distillation have been used for the same purpose.

I've thought about distilling anhydrous hydrazine, because it looked simple but after some research I've just scrapped the idea. More info in:

1) Hydrazine and Its Deriatives by E. Schmidt. 2nd ed. pg.853; pgs. 95-96; pg.99. The whole book basically.
2) Gmelin's Handbuch. 8 Auf. N 314 and Berichte 37, Stollé and Hofmann, [1904] 4524.
3) Explosive Properties of Hydrazine by U.S. Bureau of Mines.
4) Bretherick's Handbook, 6th ed., 4520.

Also hydrazine (and its hydrate) strongest consistent adverse toxic effects are eye (cornea) damage and fatty liver degeneration (E. Schmidt book, pg. 900). Hydrazine is a blood poison since it hemolyzes red blood cells. Carcinogenicity is inconclusive to weak.

Formatik - 12-4-2011 at 10:26

Single inhalation exposure to hydrazine hydrate caused liver effects in a Chinese worker, only a few hours after exposure: Read it and weep.

Magpie - 12-4-2011 at 14:30

Quote: Originally posted by Formatik  
Single inhalation exposure to hydrazine hydrate caused liver effects in a Chinese worker, only a few hours after exposure:

Thank you for this information. Although I don't intend to make anhydrous hydrazine, I probably have been too causal even when making hydrazine sulfate (chlorourea and Hofmann degradation methods). I did attempt to make 25% hydrazine but because of equipment limitations could only make 3%, which worked just as well.

I tend to rely on my nose to warn me when to turn on the hood fan. It seems that in the case of hydrazine, and likely many other compounds, that could lead to serious illness.

Formatik - 12-4-2011 at 18:25

Quote: Originally posted by Magpie  
Thank you for this information. Although I don't intend to make anhydrous hydrazine, I probably have been too causal even when making hydrazine sulfate (chlorourea and Hofmann degradation methods). I did attempt to make 25% hydrazine but because of equipment limitations could only make 3%, which worked just as well.

Well, hydrazine forms an azeotrope with water having 71.5% N2H4 at 120.6 C and 771.8mmHg, so in theory all one would have to do to concentrate it is distill off water. Hydrazine hydrate is much less dangerous to distill. I did this with 35% aq. N2H4 in a copper apparatus cleaned with aqueous thiourea then water, and distilled on a hotplate over 3 hours to get a fuming hydrazine. I'm not sure how strong it is, but it is significantly stronger, because it fumes in outside air (35% N2H4 doesn't fume at all) and when it is dripped onto a small pile of KMnO4, it sizzles and spatters vigorously creating a beige mass and a fireball, and potentially even igniting tissue (35% N2H4 does the same but gives no fireball, or ignition), even though the liquid doesn't ignite by flame (hydrazine and esp. hydrate have high flash points).

I tend to rely on my nose to warn me when to turn on the hood fan. It seems that in the case of hydrazine, and likely many other compounds, that could lead to serious illness.

I do take precautions, and eat healthier than most normal people and take supplements to make up for my exposure. But I still tend to get too comfortable and have to remind myself constantly how toxic the material is.

[Edited on 13-4-2011 by Formatik]

Formatik - 16-4-2011 at 18:46

I just did a rough titration of the fuming stuff with phenol red and it is around 57.4% N2H4 (around 90% N2H5OH).

bdbstone - 23-4-2011 at 20:55

I try to make some Hedrazine sulfate using NurdRage method and it seems I have the same problem as user 'Zinc' before.

Since this is the first time, I was doing this, I divided all the amount by 5times, use 50ml 25% ammonia, 20ml MEK and for bleach there was a label that it contains 43grams in a 1L bottle, I calculated that to be around 4.77% so a 78ml was used. There is also another label on the other side of the bottle: "Ingridients: <5% of bleach substance based on chlor, perfumes". All the chemicals were technical grade, including ammonia so there was no purity written on them.

First I mix the ammonia and MEK, for about 1 minute, then let it stand for a while. The two chemicals separated, so I mix with glass rod some more and let it stand. The two chemicals were still separating, no matter how much I mix them, so I continue with another step. I transfered them to another bottle and added slowly bleach to the mix. There was definitelly some bubbles and foam, every time I add bleach. The whole process of adding have go for around 10-20 minutes. I transfered it all to the measuring cylinder and let it stand, however in more than ten hour period there still isn't any sign of separation going on.

I would love to try that with toulouene, but the thing is I don't have any. I am still wondering what was the problem here.

NurdRage - 23-4-2011 at 23:38

in your case and in zinc's case less than 5% hypochlorite concentration was used.

the problem just seems to be one of concentration and dilution.

do you have any other non-polar liquid for which to perform an extraction?

i haven't tried this, so i don't know if it works, but maybe adding more MEK (after adding the hypochlorite) might saturate it enough that a mixture of MEK and Azine separate out.

Exactly how much? i have no idea.

bdbstone - 24-4-2011 at 05:20

I will try that out.

After watching your video again, I have also find out, that you use 30% solution. Since my ammonia solution is 25% percent solution, I should use 60ml instead of 50ml. Maybe that was also the problem..

I will try it again today, with another batch, but I will measure the liquids more carefully.

Thank you.

Random - 26-4-2011 at 10:31

Try using urea instead of ammonia. That could make it less diluted.

plante1999 - 26-4-2011 at 11:33

Anyone tried satured sol. of urea in water + calcium hypochloride in small batch to make hydrazine hydrate?

2CO(NH2)2 + Ca(ClO)2 => 2CaCl2 + 2CO2 + 2N2H4

Edit i have thinked of something that i will test , witch use a catalyst:

First stage:
carbamine peroxide + trimethylamine(catalyst) → urea + water + trimethylamine n-oxide
(NH2)2CO.H2O2 + (CH3)3N →(NH2)2CO + H2O + (CH3)3NO

second stage:
trimethylamine n-oxide + urea → carbon dioxide + hydrazine + trimethylamine
(CH3)3NO + (NH2)2CO → CO2 + N2H4 + (CH3)3N

overal process:
carbamine peroxide + trimethylamine(catalyst) → carbon dioxide + water + hydrazine + trimethylamine
(NH2)2CO.H2O2 + (CH3)3N → CO2 + H2O + N2H4 + (CH3)3N

[Edited on 27-4-2011 by plante1999]

cyanureeves - 28-4-2011 at 06:03

gentlemen i'm trying to make hydrazine sulfate via nurd rage method. i got all the liquids in place but never noticed any strong bubbling when i would add bleach to MEK /ammonia solution.i let the whole thing stand over night as it never seperated into two phases and this morning i got about 50ml of the now orange solution and added bleach and i did see the fizzing. i added more bleach to the rest of the solution and it fizzed and turned white again as i stirred so i think my bleach was weak. my question is if sodium hypochlorite density is 1.11 g/cm3 would this mean that 1ml=1.11 grams? at this point i'm just adding bleach as i see fizzing while i stir but if this does not work then i will get better bleach and proper proportions.i will be using 6% bleach. thank you.

Magpie - 28-4-2011 at 07:48

I found that as my 12% bleach deteriorated to 6% the sp gr stayed the same. I assume that as the NaOCl converts to NaCl there is no effect on density. To get the true strength I titrated with standardized HCl.

cyanureeves - 28-4-2011 at 10:33

magpie i dont understand, in nurd rage's method it calls for 300 grams of 6% sodium hypochlorite and i was thinking if 300ml of 6% bleach was the same as 300 grams in this case. wikipedia states NaCLO density is 1.11g/cm3, is that for 100% solution? but then a 300 gram solution of 6% NaCLO would be like a 55 gal. drum worth. i thought density would tell me how much bleach to use. the mixture smells like a 200 proof bacardi that burns your nose.adding more MEK did cause a two layer separation but i could'nt leave well enough alone and stirred it again.

Magpie - 28-4-2011 at 12:39

Here's a document that will tell you all about aqueous NaOCl, compliments of Rosco Bodine. For questions about NurdRage's procedure it would be best to address them to him as I haven't tried it.

NurdRage - 28-4-2011 at 13:59

Quote: Originally posted by cyanureeves  
magpie i dont understand, in nurd rage's method it calls for 300 grams of 6% sodium hypochlorite and i was thinking if 300ml of 6% bleach was the same as 300 grams in this case. wikipedia states NaCLO density is 1.11g/cm3, is that for 100% solution? but then a 300 gram solution of 6% NaCLO would be like a 55 gal. drum worth. i thought density would tell me how much bleach to use. the mixture smells like a 200 proof bacardi that burns your nose.adding more MEK did cause a two layer separation but i could'nt leave well enough alone and stirred it again.

300g of bleach should be at most 300mL, less if the density is higher.

You might want re-check your calculations or your spreadsheet for an error somewhere. 55 gallons volume for 300g of a substance would seem to indicate the density of a gas rather than a liquid.

i picked 300g of 6% bleach because that gives 18g of "pure" NaClO. i designed the rest of the experiment around that molar amount.

cyanureeves - 28-4-2011 at 14:17

thank you nurd rage. i know bleach from the store is reliable and the MEK is too ,but not so my ammonia solution. your glass with MEK looked alot smaller than mine . i'm using a 600ml kimax glass and 100ml looks like swig,maybe you got huge hands. magpie thank you for the everything you need to know about NaCLO but was afraid to ask document.

Formatik - 3-5-2011 at 16:22

Concerning the set-up I mentioned above: I used all-copper apparatus made from pipes and connections. It was just a simple L-shaped apparatus. The distillation tube was soldered (tin solder, not lead!) to the connecting joint (piece that connects to the vessel). But the joint piece was not soldered to the vessel since I was thinking of doing other things with this. So during the distillation I wrapped Teflon tightly around this area then taped it with a strong tape that can withhold the heat. I filled the vessel with less than half in volume of its capacity with 35% aq. hydrazine solution (about 50mL). Heating this at an angle (with a clamp and stand) over the hotplate was hot enough to distill off water. But it took a long time to begin distilling. It would have been better to have started the hotplate heat on high setting to begin with. Wrapping the vessel in an aluminium foil blanket later helped with the heating process.

But before distillation, it was taking way too long and I got impatient and heated the copper tube with the Bunsen burner (for a few moments), this caused a portion of the whole solution to come over (this wasn't needed at all, I just got impatient). Then after it started distilling, I distilled for around 3 hours just using the hotplate. The outside temperature of the lower portion of the copper vessel was around 154 C. But this temperature was necessary for reasonable distillation. Some hydrazine did come over. The water was collected in a graduated cylinder covered with aluminium foil. After distilling, and when cold the hydrazine left in the copper vessel was then fuming. There is a rough diagram below, except the tube was much longer than what is shown and it was more L-shaped. Copper can likely not be substituted by other metals, maybe except silver, because of ignition point changes. I also washed the entire apparatus with thiourea and then water (prior to distillation). This can most likely be used to make hydrazine hydrate from hydrazine salts and bases, plus enough water. And then a sand bath ought to be better than a hotplate. Hydrazine hydrate can be prepared like this, but near anhydrous hydrazine is too dangerous.

apparatus.png - 1kB

[Edited on 4-5-2011 by Formatik]

cyanureeves - 3-5-2011 at 19:24

o.k. now. i googled hydrazine sulfate and read that it can make one mellow and eat like a pig if eaten and hydrazine can make jet fuel. are these things true? when or how is hydrazine sulfate made flammable? is this set -up the very thing that ties both of my queries?

Formatik - 3-5-2011 at 22:04

This set-up above doesn't address your post above it. Someone asked about how I made concentrated hydrazine hydrate, and this explains it. Yes, strong hydrazine hydrate is used as jet fuel. I wouldn't advise eating hydrazine sulfate.

Jimbo Jones - 27-5-2011 at 09:06

Is it safe to perform Rosco hydrazine sulfate synthesis under kitchen aspirator? Is there any risk of poisoning?

BromicAcid - 27-5-2011 at 15:25

Update / correction!

Back in 2004 (wow, 6 years ago) I attempted to synthesize hydrazine by heating urea with nickel to produce nickel carbonyl / hydrazine. My first experiment used nickel shavings / drillings / pieces all of which were somewhat large and it was done on the small scale in a test tube. My second experiment was done in a RB with nickel powder and urea....

At least that was the intention. Some time ago I was talking to a member of this forum via messenger and they pointed out that heating nickel oxalate does NOT necessarily produce nickel metal but nickel oxide.

Here is just one of many papers attesting to this:

There are methods to produce nickel powder from the oxalate, in one instance the oxalate was dehydrated first with heat and vacuum and then decomposed rapidly at high temp to get nickel metal. But I did not meet this condition and although some nickel may have been formed what I've found is that my 'nickel powder' could have potentially contained little to no elemental nickel. That being the case I would consider the possibility of this reaction once again open for debate.

I apologize for not being more through in my initial research, but hopefully this will allow someone to try this on the right path.

plante1999 - 27-5-2011 at 16:05

Bromic acid , you should try to take nickel piece grind it with a lime , blend the shavings with an electric blander and finish with a ball mill , i only use one time a ball mill for making Fe powder for ferrate and it work after 2-5 week of runing , i made mine from legos....

Rogeryermaw - 27-5-2011 at 17:47

Quote: Originally posted by plante1999  
i made mine from legos....

i am dying to see a picture of that!!

Hydrazine Sulfate Synthesis

Hennig Brand - 29-5-2011 at 07:12

I made Hydrazine Sulfate again last week and never got around to posting the few pictures I took. I used Rosco's method in general. I find the process to be quite robust as I didn't follow all intructions exactly as outlined in the procedure (because of lack of time and laziness), and still got 81.5g of Hydrazine Sulfate for a half batch. I think my yield has a lot to do with my reagents (probably the hypochlorite), because the first time I made HS I got a very similar yield and I was extremely sloppy. This time I was much more careful (relatively) to temperatures, reactions time and addition rates.

Anyway here are a few pictures. The gross brown color is from the black drain cleaner I used to do the final neutralization and precipitate the HS. The brown color pretty much completely washed away when washing the HS with 70% isopropyl alcohol during filtering/washing.

The first picture was taken sometime during the first 10 minutes, notice with my reagents I have very little foaming. The second picture shows the end of reaction, very pale yellow color. BTW, that is a 5L erlenmeyer, and a 3" stirbar. The third and fourth show the final neutralization with H2SO4. The last shows the damp yield. The dry yield taken a couple of days later was measured as 81.5g.

I should have gotten a picture of the primary neutralization with HCl, it was very neat looking, but I forgot to take a picture. A hotplate-stirrer was used between the first and second pictures, but I forgot to take a picture of that part of the process. The only thing I had on hand to do the acid additions with was a 25mL burette, so I had to top up the burette quite a few times, not ideal.

Initial Reaction.JPG - 231kB Reaction Completion.JPG - 235kB Acid Neutralization.JPG - 264kB Acid Neutralization close-up.JPG - 245kB Damp Yeild.JPG - 229kB

[Edited on 29-5-2011 by Hennig Brand]

Hennig Brand - 29-5-2011 at 07:51

Here is a picture of the stirrer-hotplate with the 5L erlenmeyer sitting on it, you will need to imagine it in action. Also the bottle holding my 81.5 grams of freshly made Hydrazine Sulfate.

Sirrer Hotplate and Big Earl.JPG - 235kBDry Yield.JPG - 232kB


cyanureeves - 15-6-2011 at 13:51

four times i have done hydrazine sulfate sinthesis,twice using roscoe's method and twice nurd rage. roscoe's method produced a salt that does make a mirror when mixed with ammonia and silver nitrate but i think i got alot of sodium chloride contamination because it will burn dry but will leave a black smudge behind. it bubbles over a flame which then burst and release smoke that smell like gunpowder.i cannot get nurd rage's method to separate in two layers and he recommended using toluene as it was successful for him. my question is would a lacquer thinner with petroleum distillate work as toluene?paint thinner has some toluene but also MEK and i already added more MEK to my orange solution. thank you. toluene is getting harder to find. well i googled petroleum distillates and toluene is in the family of petroleum distillates along with napthas,mineral spirits etc...

[Edited on 16-6-2011 by cyanureeves]

cyanureeves - 17-6-2011 at 19:23

well not all petroleum distillates are paint thinner has naptha and it pulled out a red oily liquid after i added the sulfuric acid but it did not salt out. it did however separate easy but i give up on this method of making hydrazine sulfate until i have better reagents. roscoes method on the other had worked pretty well even with recrystalized urea that was dirty. but when i take out the cold bleach/hydroxide solution and add the urea/gel then add the heat when the foaming subsides,it gets super hot quick because of the hydroxide i need to keep adding heat even if it will maintain at about 185 on its own?i didnt get the solution to deep orange but fluorescent green instead, i made a mirror with the salt o.k. but want to know what to do because i will be making more. not that i'm eating hydrazine sulfate all day long but it tastes like the rim on a margarita glass,lime and all.

franklyn - 25-6-2011 at 16:26

Studies on the Raschig's Hydrazine Synthesis

Page 25
It has been shown that on using pure water, pure chemicals, and carefully cleaned
reaction vessels, it is possible to obtain hydrazine yields up to about 46 % of the
hypochlorite in Raschig's hydrazine synthesis, even when no gelatine is added.

Page 32
Fairly good results may also be obtained by addition of carragen. On addition of
a solution of 1 gram of carragen in 100 cc of water to 100 cc of an ordinary
concentration commercial ammonia, followed by an addition of 100 cc of an
approximately 1 molar solution of sodium hypochlorite and by a rapid heating
to boiling etc., hydrazine yields of 48-49% of the hypochlorite could be obtained.


cyanureeves - 2-7-2011 at 17:41

made hydrazine sulfate again today and what a difference 10% bleach makes. the hydroxide/bleach mix turned milky when the urea /gelatin was added just like Hennig Brand's and the precipitate is not salty at all like my other samples. 6% bleach did not give me the froth 10% bleach did. the precipitate dropped as a gel though because i added too much gelatin but it still dries as crystals. the mirror test with ammonia and silver nitrate may not be the best test because sodium hydroxide,ammonia and sugar will also make a mirror with silver nitrate.tommorrow i will burn it after it dries completely

Dr.Bob - 15-7-2011 at 13:18

This discussion reminds me of my youth (a while back now) when I found an ad in Chemical & Engineering News from Olin describing all of the uses of Hydrazine and offering free samples for testing. So I typed (check wikipedia, they can describe what "typed" means) up a nice letter on some letterhead that I created for my "company" and requested a sample. Back then, there was no trivial way to verify if a company was real or not, of course.

Several weeks later a wood crate appeared on the doorstep from Olin, with my 1 quart bottle of hydrazine hydrate in it. I used it to make Luminol as well as a few other experiments from Fieser and Fieser. That used about 10 mls or so, and the rest I eventually donated to the lab I worked in. I have since used quite a bit of hydrazine in chemistry (pyrazoles, hydrazides, etc) so I guess the ad worked. But that was a very different time.

I think I also got chemicals from DuPont, Monsanto, and a few others that way. Don't think it would work so well now.


cyanureeves - 15-7-2011 at 14:19

cool thing Dr.Bob. i dont even know what to do with hydrazine sulfate other than make the mirror thing. i also check these posts to see if anyone has called on me to prove my stuff and i read my own posts and they seem like a diary of a madman to himself.i read up on hydrazine sulfate by that lady who took it for years and swore by it as a remedy for increasing her appetite. it was said to make one calm and hungry and good thing i dont trust my hydrazine sulfate or else i'd be a sluggish big fat pig by now.i got so much salt left over that i'm making a chlorate cell but it is all turning back to green bleach.

franklyn - 15-7-2011 at 16:26

Lower Aliphatic Derivatives of Hydrazine

hydrazodicarbonamide or semicarbazide or hydrazine selectively from chlorourea

Rosco Bodine - 3-8-2011 at 13:34

from page 5 of this thread about the middle of the page

Quote: Originally posted by Rosco Bodine  
The recent discussion about chlorination of NaOH has caused me to remember that this came up once before , and I will have to check my patents , but IIRC there is a more efficient method for use of chlorination in the synthesis of hydrazine and it involves chlorination of a slurry of urea to form chlorourea , which is then
reacted with a base like sodium carbonate
or sodium hydroxide to form hydrazine upon heating and hydrolysis . IIRC , there is no need to even make sodium hypochlorite , if you are going to go the chlorination route , and the yield is better by the chlorourea intermediate . I will see if I can find the patents which reference the method .

GB1063893 Hydrazine or Semicarbazide selectively produced from monochlorourea

Related semicarbazide patents are

[Edited on 4-5-2005 by Rosco Bodine]

This post is also related to the hydrazodicarbonamide thread where if found related discussion.

After six years I am now willing to share the file :D ....hope no one was in a big hurry for it . Anyway the prospect for a more direct method to the hydrazine derivative hydrazodicarbonamide in 70% yield is the matter of most special interest described in US3238226 attached.
If Azide is the intended end product, then attention is called to Example #20 of the patent shows a method for obtaining Semicarbazide as the product in 90% yield. Byproduct hydrazodicarbonamide is separated by filtering and then byproduct hydrazine is separated by acidifying and filtering
from the more soluble Semicarbazide. This should not require isolation, but could be nitrosated to the Carbamyl Azide and then decomposed by heating to leave Ammonium Azide in solution. If it was desired or necessary to isolate and purify the semicarbazide prior to nitrosation then acetone could likely be used to form the semicarbazide addition product for isolation and that could later be converted back to semicarbazide.

The equivalent British patent GB1063893 is also attached.

Also attached are related chlorourea process patents

Also here's a little midi or ringtone music trivia posted some years ago

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Attachment: GB1063893 Semicarbazide from Chlorurea.pdf (643kB)
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Attachment: US5241117 Process for Semicarbazide.pdf (504kB)
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Attachment: GB1153483 Chlorurea Process for Hydrazine.pdf (170kB)
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[Edited on 4-8-2011 by Rosco Bodine]

aaparatuss - 18-10-2011 at 21:04

I am still reading this thread in entirety so i apologize in advance

it seems making HS is quite strait forward with even multiple routes to work with.

I still do wonder if using calcium hydrochlorite is a workable approach

but i wonder much more, if one did need anhydrous hydrazine can it be done from the sulfate ??

I have read the literature regarding making the hydrate then distilling under nitrogen of course

It just seems ironic that one would need to make a hydrate to make an anhydrous if you know what a mean:P

any guidance or creativity would be appreciated

aaparatuss - 3-1-2012 at 19:01

pardon the double post

but i did find
evidence that

. 4. The most effective condition for the reaction is a temperature of 60-65○C. maintained for 20-25 min. 5. The reaction takes place equally well in either an open or closed container. 6. When calcium hypochlorite is applied in place of sodium hypochlorite, the yield of hydrazine is increased as much as 17%. 7. The yield of hydrazine is decreased by eliminating the suspension of Ca(OH)2 which results from the use of calcium hypochlorite. 8. When Ca(OH)2 is added to Raschig process, the yield of hydrazine is raised normally. 9. The fact that some metal ions, such as Cu++, inhibit the formation of hydrazine was proved. 10. The suspension of Ca (OH)2 acted as a remarkable adsorbent for Cu++ like gelatin. The suspension of Ca(OH)2 which results from the use of calcium hypochlorite acts as a catalyst, absorbing metal ions, to increase the yield of hydrazine. So I think that calcium hypochlorite is a more efficient oxidant than sodium hypochlorite in hydrazine syntheses” Journal of the Korean Chemical Society Volume 5, Number 1 (1961)

well i hope my modification using 10% ammonia and calciumhypochlorite solid added slowly to avoid dilution issues with weaker ammonia works out thanks

nice thread

roamingnome - 8-1-2012 at 20:35

[img]<a href=" 382%2C836%2C396&source=bookclip"><img src=" 2C382%2C836%2C396&edge=0"/></a>[/img]

for more discourse and details....

[img]<a href=" 91%2C834%2C145&source=bookclip"><img src=" 2C91%2C834%2C145&edge=0"/></a>[/img]

Journal of the American Chemical Society, Volume 33

Adas - 11-1-2012 at 10:13

What about :

CO(NH2)2 + NaOH ----> HCOONa + N2H4

Is you use too much NaOH, only NH3 will be created. In this process, there will also be some ammonia created along with hydrazine, but it may work. What do you think?

ScienceSquirrel - 11-1-2012 at 10:25

Quote: Originally posted by Adas  
What about :

CO(NH2)2 + NaOH ----> HCOONa + N2H4

Is you use too much NaOH, only NH3 will be created. In this process, there will also be some ammonia created along with hydrazine, but it may work. What do you think?

Urea will hydrolyse slowly to ammonia and carbon dioxide. No hydrazine will be formed at all.

Rosco Bodine - 25-2-2012 at 13:13

It has been a dozen pages back in the thread where freebasing schemes were being discussed and I haven't reviewed this entire thread to be certain, but I don't think this more recent possible freebasing scheme has been described here in the dedicated hydrazine thread, so I am importing / pasting from other threads this freebasing hydrazine related information which should have a place here.

Freebasing of anhydrous hydrazine in alcohol could be a possible usefulness for aluminum amalgam in isopropyl alcohol or magnesium in methanol. This could certainly be of usefulness in a sodium azide synthesis or for other syntheses where an anhydrous "tincture of hydrazine" is needed. I have never tried this, so this is offered as a reasonable hypothesis, but now it is definitely on my "to do" list of interesting experiments.

Also there is an anhydrous double salt of calcium sulfate and sodium sulfate which could also be useful in alternative freebasing schemes for hydrazine, using a combination of sodium hydroxide and calcium hydroxide. This could also be useful in schemes for forming hydrazine salts such as the nitrate or perchlorate in aqueous solution by double decomposition schemes.

Hydrazine is stable but it is very chemically reactive. Freebasing dihydrazine sulfate does produce byproduct water but only half as much with respect to the yield of freebased hydrazine as is byproduct water from freebasing hydrazine sulfate. Possibly the extreme solubility of the dhydrazine sufate is such that a lesser total byproduct water would be involved in freebasing even when a hot aqueous concentrated solution of the dihydrazine sulfate might be added dropwise to aluminum isopropoxide for the purpose of preparing an anhydrous tincture of hydrazine in isopropanol, which could be filtered from the byproduct aluminum sulfate. What may be the dangers attendant to such a process I do not know. But it seems like it could be done. I have never seen this described anywhere so it may be novel. This is not a recommended experiment for a beginning or novice chemist....this would be more advanced. Aluminum Isopropoxide video

Hydrazine is stable enough for storing in fuel tanks of spacecraft for months or longer. The descent stage of the Mars lander Phoenix used hydrazine. Evidently there are adequate methods for long term storage.

For purposes of synthesis where hydrazine is a needed intermediate, an alcohol solution of hydrazine would likely be prepared and used in the near term as an intermediate and would not be stored, so stability may not be an issue. And whatever level of hydration is desired could be controlled so this still seems like a valid experiment, but because of the unknowns it definitely is no benign sort of process.

The differing solubilities of Hydrazine Sulfate and Dihydrazine Sulfate may be exploited to advantage in schemes for freebasing hydrazine in order to obtain differing states of hydration for the freebased hydrazine. I am posting this in different threads because it is pertinent in all of them.

I don't have a chart for the solubility curves, so I borrowed this excerpt via printscreen screenshot, you know sort of ripped it ......sharing is caring

Attached and linked also is a recent article of interest
regarding the interaction of free hydrazine and CO2 in aqueous medium. There appears to be a similar case
involving solubility difference for the carbonate, where
the monohydrazine "bi"acid, or acid hydrogen salt is low
solubility compared with the more neutral or normal salt
being highly soluble.

There appears to be a discrepancy in identification of what is the formula and composition of the commercial Hydrazine Carbonate 70% solution as is stated differently by Hummel Croton and VVChem GMBH. I am not sure what to make of this.

Attachment: Hydrazine CO2 adduct.pdf (1.1MB)
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[Edited on 26-2-2012 by Rosco Bodine]

Rosco Bodine - 26-2-2012 at 01:25

This is in reply to the mesage below from page 10 of the thread (link)

Quote: Originally posted by Formatik  
Originally posted by YeOldeImpurities
Compounds of manganese (sulfate, chloride of manganese, permanganates...) in hypochlorite/urea/hydroxide reaction work better than gelatine. They give 5-10% higher yields of hydrazine than mixtures with gelatine. --- this I remember from book "The Chemistry of Hydrazine" by Audrieth and Ogg.
In russian book Греков,Отрошко: "Гидразинометрия" 1981 (Hydrazinometry by Grekov and Otroshko) is a recipe for making hydrazine sulfate with MnSO4.5H2O instead of gelatine (0,3 grams of MnSO4.5H2O to 15 grams of urea, yield 23 grams of hydrazine sulfate).
And also something else for increasing yields- in book Брикун,Козловский,Никит& #1080;на: "Гидразин и гидроксиламин и их применение в аналитической химии" 1967 (Hydrazine and hydroxylamine nad their application in analytical chemistry by Brikun, Kozlovskiy and Nikitina) is this: best compounds for protection of hydrazine/water solutions against oxidizing by air are oxides of calcium, zinc, aluminium and magnesium but the far superior is sulfur in small amounts. btw there is mentioned a method for producing hydrazine by dry destillation of urea/iron powder at 132-150ºC at atmospheric pressure.

What yield is that of the theory? Raschig in German patent #198307 says hypochlorite solution and ammonia with lime can get as much as 80 percent of the theory, and he himself gets 60 to 70 percent in an example.

The yield of 23 grams Hydrazine Sulfate would be 70.7% based upon 15 grams of urea precursor. What the process described by YeOldeImpurities appears to be is a slight variant of the attached file which is originally in Russian and this is the English translation attached. It is especially significant that the increased yield is gotten from a gradual addition scheme for the reaction which allows for a control of the foaming issue. The "dump in a lump" mass reaction has produced the higher yields generally and that could apply here as well for increasing the yields even beyond 70% ....
but this is speculation and unconfirmed. Scale issue also
seems to be eliminated by the Russian reported technique
in a book which appears to be a student textbook guide for a chemistry course where this and other labs would be
experiments actually performed by students taking the course. I can't recall where I came by this book file or I would credit it. Attached excerpt is page 139 from my file for the English translation of the Russian textbook Practical_Inorganic_Chemistry.Vorobyova.O.I_Dunaeva.K.M_Ippolitova.E.A_Tamm.N.S.1987.djvu.rar

An additional item of interest relates to the subsequent post also on page 10 which mentions the Cyanuric Acid salt of Hydrazine mentioned earlier on page 6 of the thread.
Evidently it may be possible on long refluxing of Hydrazine Cyanurate to produce a good yield of Carbohydrazide which is useful as an intermediate in synthesis. This has not been confirmed as a practical method, but seems likely to be possible by comparing the earlier Hydrazine Cyanurate patent GB1073292 with the Carbohydrazide patent US3258485 attached. A variation of the patent process should be possible to make use of Hydrazine Cyanurate
as the precursor since it must be formed in situ as an intermediate in the patent process.

Curiously an identified usefulness for Carbohydrazide nitrate
is as a component of a mixture which may serve as a propellant in ammunition cartridges, operating as a
"liquid gunpowder" substitute for granular gunpowder.
See patent US2970899 attached.

Attachment: Russian Method Hydrazine Sulfate Synthesis.pdf (69kB)
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Attachment: US3258485 Carbohydrazide via Hydrazine Cyanurate.pdf (118kB)
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Attachment: US2970899 Liquid Gunpowder Substitute.pdf (242kB)
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Dealing with hydrazine contamination

dangerous amateur - 29-3-2012 at 05:20

I'd like to know how you guys deal with the toxic residues after working with hydrazine.

How do you decontaminate your equipment?
Can you rely on the fact that it's getting destroyed by aerial oxigen?

Nicodem - 12-5-2012 at 04:03

Quote: Originally posted by Nicodem  
I did a literature search on the topic of the rearrangement of N-haloureas into hydrazines and to my surprise realized that what appeared as a rather obscure reaction is not that obscure after all. In one instance it was even given a name, the Schestakow rearrangement (or Shestakov; after the author of the seminal papers). The reaction was found to proceed in three steps, the same ones I mentioned above, that is N-halogenation/rearrangement/decarboxylation (see J. Am. Chem. Soc., 76, 2572–2574). The N-halogenation reagents most commonly used are NaClO and NaBrO, but other halogenating reagents can be used as well. The rearrangement of N-chlorourea only occurred when heating under highly basic conditions (so I was wrong in saying that the reaction might work without using excess NaOH and alkali carbonates are not necessarily basic enough). Heat is not always used though. The decarboxylation of the so formed N-aminocarbamate salt requires neutralization, so no hydrazine forms until the final addition of the acid. N,N-Disubstituted ureas also undergo the reaction, so the mechanism appears to be that of a Hofmann rearrangement and not Favorsky (though this does not prove or disprove that both mechanisms are operating at the same time where possible, which is however limited only to N-monosubstituted ureas). I could find no examples of rearrangement of N,N’-disubstituted ureas which cannot undergo a Hofmann rearrangement, but could potentially undergo a Favorsky rearrangement. So either nobody bothered trying the reaction on N,N’-disubstituted ureas or the rearrangement cannot proceed through a Favorsky-like mechanism.

In the quoted post I mentioned that I found no examples that would demonstrate the feasibility of an aza-Favorsky mechanistic pathway for the formation of hydrazines from urea. Today I accidentally stumbled upon articles that indisputably prove that such a pathway is possible. In fact, the corresponding aza-Favorsky intermediates, the diaziridinones, can be isolated if an N,N'-dialkylurea with bulky alkyl substituents is used (such as t-butyl; the bulky groups suppress the nucleophilic ring opening reaction). A couple of references:

Organic Syntheses 2009, 86, 315-324. (synthesis of di-t-butyldiaziridinone)
Journal of Organic Chemistry 1969, 34, 2254-2262. (describes the synthesis and chemical properties of diaziridinones, as well as their many ring opening reactions, including the ones giving hydrazines)

Rosco Bodine - 12-5-2012 at 11:03

Interesting. It has always been reasonably suspected by me that a plurality of possible reaction pathways and mechanisms are possible from urea leading to hydrazine, semicarbazide, or related products, and/or simultaneously to various possible byproducts and decomposition products of the reactants, and that dependant upon changes to the reaction conditions a particular pathway may be made favorable for one or another product to predominate. The observed transient and thermally sensitive color transition in the sodium hypochlorite/urea/NaOH/gelatine reaction mixture as a waypoint, appeared to be a probable reaction progress milepost color indicator of sorts, showing a visual clue that a hydrazine intermediate is probably formed. Several years ago I mused about the significance of the color change, observing at one point in the reaction the red orange tea coloration making my reaction flask temporarily appear to be like a red rubber ball .....reminding me of the song by that name from 1966 The Cyrkle - Red Rubber Ball Turn Down Day

Another good one The Three Degrees - When Will I See You Again

<iframe sandbox width="622" height="350" src="" frameborder="0" allowfullscreen></iframe>

Formatik - 3-9-2012 at 11:16

Revisiting my previous attempt of neutralizing hydrazine with bisulfate, this new procedure offered very positive results.


317.51g NaHSO4 (95% pure, assumed to be the monohydrate) was fully dissolved with stirring in 800mL tap water. Temperature was between 20-25 C. Then 99.44g of 35% aq. N2H4 was dumped into the aqueous bisulfate under stirring. The temperature now went from 23 C to 43 C, but the reaction is completely mild and entirely not violent. Then 85.17g of 31% HCl acid was stirred in, where no temperature change was seen. This was let stand until it cooled down to 24.5 C which took about 90 minutes. Then about 425mL of liquid was decanted into a container and let stand for 10 minutes, this was then decanted to a volume of 100mL and this poured back into the original mixture. 20mL of decanted liquid was used to rinse the container and also put back into the original mixture. Now the mixture was filtered. And washed the hydrazine sulfate and the filter with tap water (temp. 24 to 25 C) using the following three portions from first to last: about 45mL, 50mL, 60mL. The filtered solid was then mildly strained (some 100mL liquid removed). And then air dried in a warm area for 3 days. Yield: 130.835g hydrazine sulfate (92.56% theory).

Purity tests.
The chloride content was approximated using 0.250g sulfate in 200mL distilled water, about 25 mL strong aq. AgNO3 and distilled water wash (20mL), the precipitate was not really measurable so that the amount was even likely below 0.005g (scale minimum), and chloride content is maximally around 0.90% NaCl. But it is possible to be even less like 0.5% NaCl or below. The lowest amount of Cl- possible is around 0.08 to 0.1% NaCl. The sodium content was approximated by solvating some part of 11.750g of the hydrazine sulfate in 100.00g distilled water at 24.5 C. The amount that was solvated was about 3.320g. Loss by decantation was very low, maybe 20mg. Solubility of N2H6SO4 in H2O is reported in the lit as 3.302% at 25 C according to Weise (Z. anorg. Ch. 94 [1916] 80,86). Purity is around 99%+. Some more testing would be good to further confirm, but purity is very satisfactory.


If more hydrochloric acid is used this can readily precipitate sodium salts alongside the hydrazine sulfate, the purity of the product shows the addition of hydrochloric acid was ideal. The addition of hydrochloric acid in those amounts bumped the yield up by an estimated 14%. Washing with distilled water instead of tap water should increase purity of the final product more. According to the previous reference p. 79, hydrazine sulfate is insoluble in alcohol so it can be used to dry it quicker. Warm air and temperatures can dry it, but heating hydrazine sulfate with strong heat can cause explosion under the formation of sulfur (Ber. 20, 1633).

The yield seen here was about the same when aqueous hydrazine was neutralized with dilute sulfuric acid. Although the yield can also be increased by the sulfuric acid neutralization by boiling down and crystallizing, and evaporating to dryness, this is more laborious and the small amount not really worth the effort in the small scale.

In the end, sodium bisulfate is much more preferable for neutralizing hydrazine. The reaction of aqueous hydrazine and diluted aqueous sulfuric acid is extremely violent and requires very long slow addition, during which time significant amounts of hydrazine also evaporate and can expose one to the fumes.

Speculating in the preparation of hydrazine like from the Raschig process, etc. one can readily use NaHSO4 to form hydrazine sulfate also, however the sulfate shouldn't be used straight away, the solution should first be neutralized with hydrochloric acid, then the sodium bisulfate added. Though the additional sodium salts could decrease yield somewhat.

Neutralizing aqueous hydrazine is useful for obtaining a much more stable, less reactive, and less toxic material in the form of one of its salts.

[Edited on 3-9-2012 by Formatik]

ANFO_ - 22-10-2012 at 03:04

I'm completely new here, but I've been lurking on this thread for a while now. Hopefully my first post isn't too retarded:)

I'm just wondering: what is the best way to reclaim pure hydrazine hydrate from the Hoffman rearrangement?

The reaction produces sodium carbonate as well as hydrazine, and I want to isolate the hydrazine solution from the carbonate without distilling it.

I was thinking that maybe hydrolysis of the ketazine could work for this, but that might mean putting another unwanted compound in the solution. Or can the hydrazine sulfate be turned back into hydrazine hydrate without producing any soluble salts?

Random - 11-11-2012 at 19:44

Quote: Originally posted by ANFO_  
I'm completely new here, but I've been lurking on this thread for a while now. Hopefully my first post isn't too retarded:)

I'm just wondering: what is the best way to reclaim pure hydrazine hydrate from the Hoffman rearrangement?

The reaction produces sodium carbonate as well as hydrazine, and I want to isolate the hydrazine solution from the carbonate without distilling it.

I was thinking that maybe hydrolysis of the ketazine could work for this, but that might mean putting another unwanted compound in the solution. Or can the hydrazine sulfate be turned back into hydrazine hydrate without producing any soluble salts?

Ketazine with sulfuric acid proved to be the best method as I recall.

Vargouille - 24-11-2012 at 12:48

Has anyone tried the Peroxide Process?

I found a US patent claiming a 86.74% yield with proportions of H2O2:MEK:NH3 of 1:2:3.43, with a "working solution" comprised of three parts acetamide, 1.8 parts ammonium acetate, 0.033 g Na2HPO4, and 1.77 g EDTA, disodium salt (1 part representing 0.35 moles in the example given). It may be significant that the ammonia was gaseous, and H2O2 was 69.27%, although it says that aqueous ammonia and 30% H2O2 are acceptable. Ullmann's says that some sort of catalyst is required, though, or else the reaction will be too slow.

AndersHoveland - 4-2-2013 at 22:36

Here is an interesting excerpt taken from D. Todd, in R. Adams, ed., Organic Reactions, Vol. 4, John Wiley & Sons, Inc., New York, 1948, Chapt. 8. "Hydrazine and its Derivitives" :


"A process developed by Produits Chimiques Ugine Kuhlmana (PcUK), and practiced by Atofina (France) and Mitsubish Gas (Japan) involves the oxidation of ammonia by hydogen peroxide in the presence of butanone (MEK) and another component that apparently serves as an oxygen-transfer agent. The reaction is carried out... at at 50degC. The ratio of H2O2/MEK:NH3 used is 1:2:4. Hydrogen peroxide is activated by acetamide and disodium hydrogen phosphate (117). The mechanism of this reaction involves an activation of the ammonia and hydrogen peroxide because these compounds do not themselves react (118-121). It appears that acetamide functions as an oxygen transfer agent, [possibly as the iminoperacetic acid, HOOC(=NH)CH3 ], which then oxidizes the transient Schiff base formed between MEK and ammonia to give give the oxaziridine, with regeneration of acetamide."

(117) U.S. Pat. 3,962,878 (aug. 3, 1976), J.P. Schirmann, J. Combroux, and S. Y. Delavarenne
(118) J.P. Schirmann and S. Y. Delavarenne, Tetrahedtron :ett. 635 (1972)
(119) E. G. E. Hawkins, J. Chem. Soc. C, 2663 (1969)
(120) E. Schmitz, Chem. Ber. 97, 2521 (1964)
(121) Can. Pat. 2,017,458 (Nov. 24, 1990), J.P. Schirmann, J. P. Pleuvry, and P. Tellier (to Atochem)

[Edited on 5-2-2013 by AndersHoveland]

carbohydrazide ( diaminourea )

Rosco Bodine - 21-3-2013 at 21:05

attached is more of interest about carbohydrazide mentioned above in my post 26-02-2012
Carbohydrazide forms metal complexes whose oxy-acid salts are energetic materials

related post in Exotic Primaries - Complex Salts

franklyn mentions that carbohydrazide is also known as diaminourea ( DAU )

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Attachment: Explosives Based on Diaminourea (carbohydrazide).pdf (240kB)
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[Edited on 22-3-2013 by Rosco Bodine]

catalytic use for manganese sulfate

Rosco Bodine - 28-3-2013 at 23:00

Several related threads are involved with these references I am adding lately.

Related thread easier methods for Biurea / Hydrazodicarbonamide

Related thread Azides

US2692281 Biurea from hydrazine sulfate and urea

US3227753 Biurea or Hydrazine from Hypochlorite and Urea

Attachment: US2692281 Hydrazodicarbonamide from Hydrazine sulfate and Urea.pdf (76kB)
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Attachment: US3227753 Biurea (Hydrazodicarbonamide).pdf (254kB)
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[Edited on 29-3-2013 by Rosco Bodine]

plante1999 - 4-4-2013 at 11:42

Does anyone have some hydrazine salt/hydrazine to trade for something here? I simply don't have easy access to NaOH or ammonia, I got one to urea and hypochlorite, and the synth is not fun anyway.

cobalt oxide
sodium cyanide
lead metal
lead acetate
Lead IV oxide
Anhydrous aluminium chloride
Silicon tetrachloride
Anhydrous iron III chloride
nickel metal
silver nitrate

If yes I can be contacted by email at or by U2Us.


Mailinmypocket - 4-4-2013 at 13:20

Quote: Originally posted by plante1999  
Does anyone have some hydrazine salt/hydrazine to trade for something here? I simply don't have easy access to NaOH or ammonia, I got one to urea and hypochlorite, and the synth is not fun anyway.

cobalt oxide
sodium cyanide
lead metal
lead acetate
Lead IV oxide
Anhydrous aluminium chloride
Silicon tetrachloride
Anhydrous iron III chloride
nickel metal
silver nitrate

If yes I can be contacted by email at or by U2Us.


Are you sure you cannot get ammonia or NaOH anywhere? This is very strange given the fact that eBay and other places sell these things so readily... What kind of hardware stores do you have where you live? I'm not sure if hydrazine would be able to be sent through regular mail either ... :S

plante1999 - 4-4-2013 at 13:51

Yes they do ship, but I would need like 5Kg to have a good ratio for the shipping, and my local hardware store don't carry NaOH (they carry CuSO4 tough). I will keep a 500g bottle of it for when I really need it.

Well, I guess it can be neutralised...

Boffis - 22-7-2013 at 15:36

While rummaging through some old Berichte der Deutsch Chem. Gesellschaft on line I came across this interesting little paper. Its in German so I have a done a quick translation of it. It basically concerns the preparation of hydrous hydrazine from hydrazine hydrate using calcium oxide. The paper also has references to a couple of other methods which I'll dig out if anyone is interested though they may already have been posted before.

Attachment: Berichte Stahler hydrazine 1909.rar (923kB)
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Attachment: Action of CaO on Hydrazine Hydrate Ber. D. Chem. A Stahler 1909.docx (17kB)
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I would add a few comments to this translation.
1-I would flush the equipment with an inert gas, in this case natural gas (methane) is probably the most convenient for most people.
2-Run the thermal decomposition under reduced pressure to reduce decomposition. (water pump pressure)
3-The quantity of calcium oxide seems excessive unless the hydrate is fairly dilute. With >85% hydrate 350g of good commercial 95% CaO should be sufficient.

TheChemiKid - 17-11-2013 at 05:20

I have lots of Urea, and not much Ammonia. Do you think it would be easier for me to do the Hoffmann rearrangement instead of Nurdrage's method? PS. I have all of the chemicals and equipment needed for both methods. Also, I will use UC235's method if I go with the Hoffmann rearrangement.

zenosx - 25-12-2013 at 11:19

An initial search of this thread didn't show this site so thought I would throw it in here for Hydrazine

Hydrazine Production -

AJKOER - 19-7-2014 at 09:17

Quote: Originally posted by Vargouille  
Has anyone tried the Peroxide Process?

I found a US patent claiming a 86.74% yield with proportions of H2O2:MEK:NH3 of 1:2:3.43, with a "working solution" comprised of three parts acetamide, 1.8 parts ammonium acetate, 0.033 g Na2HPO4, and 1.77 g EDTA, disodium salt (1 part representing 0.35 moles in the example given). It may be significant that the ammonia was gaseous, and H2O2 was 69.27%, although it says that aqueous ammonia and 30% H2O2 are acceptable. Ullmann's says that some sort of catalyst is required, though, or else the reaction will be too slow.

I recently read a patent (see ) that used singlet oxygen (formed from exposing O2 to an electrically formed corona, and for more details on singlet oxygen, please see my recent thread at ) as a means to process polluting exhaust gases. Apparently, SO2 in water vapor is converted to H2SO4, which is then scrubbed with Ca(OH)2 to CaSO4. HCN is broken down into less toxic gases, H2S and water to H2SO4 as well, but interestingly, no mention of the action of singlet oxygen on ammonia. I suspect, in the presence of excess NH3, a possible reaction product with singlet oxygen to be:

4 NH3 + O2* --?--) 2 N2H4 + 2 H2O

which would not be desirable for an invention that reputedly controls toxic emmissions, but in line with the Peroxide process cited above by Vargouille.

Note, water is to be avoided (so no aqueous ammonia) as it is a quenching agent for singlet oxygen (forming H2O2, and with water vapor, more likely, very concentrated H2O2, paralleling the preparation cited above). Also interestingly, the Peroxide Process mentions the employment of Ammonium acetate, which per my research, is cited as a H+ absorbent allowing the formation of singlet oxygen with non-basic H2O2. As such, when I attempt the above reaction, I will perform a run with ammonium acetate as well.

For those looking to a simple, but still speculative, small scale synthesis of N2H4, here is possibly something of note. First, it is known that the photolysis of solid (cold) ammonia proceeds (see for example a recent article in "THE JOURNAL OF CHEMICAL PHYSICS ", 133,214506(2010), "Photolysis of solid NH3 and NH3–H2O mixtures at 193nm", by M.J.Loeffler and R.A. Baragiol, link: ), with the formation of radical (X) species:

NH3 + uv ----) NH2(X) + H (X)
NH2(X) + NH2(X) ---) N2H4

which is not practical for the most part (frozen NH3). However, one can absorb NH3 on MgCl2 forming MgCl2(NH3)6. Place the latter in a transparent sealed tube, permitting uv treatment, and a little heat to expell the now highly pressurized ammonia while applying uv light. In essence, simulating the action of uv light on condensed ammonia.

Also, there is another possible path to N2H4 with ammonia in the presence of water vapor that has been fragmented by uv radiation (see, for example, "Ammonia Photolysis and the Greenhouse Effect in the Primordial Atmosphere of the Earth", by W. R. KUHN AND S. K. ATREYA, link: ):

NH3 + OH(X) ---) NH2(X) + H2O
NH2(X) + NH2(X) ---) N2H4

Note, per this article, "Effect of Nonequilibrium Excitation on the Ignition of Combustible Mixtures", by N.A. Popov at Skobel’tsyn Institute of Nuclear Physics, Moscow State University, link: to quote from page 4:

"Indeed, NH2 radicals formed as a result of UV photolysis of ammonia hardly react with O2 and H2 molecules. However, a fairly fast reaction of NH2 with O(3P) atoms may occur, which causes the emergence of additional channels of production of hydrogen radicals H and OH, as well as nitrogen oxides [26],
NH2 + O → NH + OH; NH2 + O → HNO + H;
NH + O2 → NO + OH; NH + O2 → NO2 + H. "

where the author notes on page 2, with respect to the creation of O(3P), to quote:

"The absorption of radiation by oxygen molecules in the Schumann-Runge continuum region is accompanied by O2 dissociation and excited O(1D) atoms production [22],

O2(X3Σ−g) + h ω → O(3P) + O(1D) "

As such, it is probably best to remove all O2 by flooding with NH3.

I do expect some interesting experiments.

[Edited on 20-7-2014 by AJKOER]

Manifest - 7-8-2014 at 14:52

Is it possible to make Sodium/Lead Azide with Hydrazine sulfate? I don't want to work with hydrazine hydrate and would largely prefer to work with the sulfate salt.

Tdep - 29-12-2014 at 18:40

So I have a free-basing question.

I'm trying to make NHN (well the cobalt analogue) so I can't freebase the hydrazine from the sulfate with sodium hydroxide, as despite my best efforts some sodium hydroxide ends up in the solution, dropping Cobalt Hydroxide instead of the wanted CoHN complex.

I've seen vague murmurs of using calcium hydroxide to freebase in the 'Exotic Primaries' thread but how does this work? Calcium sulfate has a lower solubility in both alcohol and water, so how does that precipitation reaction work (assuming it's driven by drop in solubility of the products?)

CaOH + N2H4.SO4 --> N2H4.OH + CaSO4 ??

If not, how do I freebase without precipitating metal hydroxides later on in hydrazine complex salt synths?


Edit: Or does this proceed more as an acid/base reaction, in which case the solubilities don't matter?

[Edited on 30-12-2014 by Tdep]

Kavion123 - 12-1-2015 at 19:19

Hydrazine... Dealt with that when I worked at a generating plant. Smelled awful... Like ammonia.

Hawkguy - 12-1-2015 at 20:17

Quote: Originally posted by Kavion123  
Hydrazine... Dealt with that when I worked at a generating plant. Smelled awful... Like ammonia.

Dude thats not really diddly doodly dandy, the stuff is pretty damn bad. Were you wearing protection?

Kavion123 - 12-1-2015 at 20:34

Quote: Originally posted by Hawkguy  

Dude thats not really diddly doodly dandy, the stuff is pretty damn bad. Were you wearing protection?

Just goggles and gloves. I only worked there for a few months before being hired by Bayer CropScience. I got to inhale a bunch of pesticides, herbicides, and fungicides there!

Hawkguy - 14-5-2015 at 20:56

How can I test for Hydrazine Hydrate in solution, without Silver Nitrate? I just distilled some stuff at just over a hundred degrees and it has a particular smell. Wanna see if its the stuff, because the Hydrazine Sulfate I started with was collected after a messy explosion...

vmelkon - 7-7-2015 at 10:25


Just for your info:

I redid this experiment --- the Nurdrage method : mix 2-butanone and ammonia solution. Then drip NaClO slowly.
The glassware in which I had my NaClO was contaminated by a copper compound.

My yield was 0%.
Definitely, the presents of Cu2+ messes it up.

2 NH2Cl + N2H4 → N2 + 2 NH4Cl
This reaction is particularly catalyzed by copper. A large excess of ammonia and the addition of complexing agents such as ethylenediaminetetra-acetic acid (EDTA) are used as countermeasures.

AWLB - 27-7-2015 at 04:30

Quote: Originally posted by chemoleo  
Yes, and when I added H2SO4, besides all the gases it produced, the smell it produced didnt seem healthy, thats why I kept it under the fume cupboard at all times. the smell was rather asphyxicating that is. Kind of not painful, but pleasant either.
[Edited on 3-12-2003 by chemoleo]

Please tell me if I am mistaken, but I thought reacting NaOCl and NH3 would produce chloramine, a pungent white/greenish gas,( is that the purpose adding of glue/gelatin/EDTA so ammonia re-reacts with chloramines)?. The description appears to describe the properties of this gas or other by-products. What is the best agent to use to increase surface tension(could the reaction be taken out in a sealed container). Is an excess of ammonia is required to produce hydrazine ?

Thank you. :)

[Edited on 27-7-2015 by AWLB]

Magpie - 27-7-2015 at 08:54

I have used the chloramine process and the Hofmann degradation process to produce hydrazine. This is then converted to the hydrazine sulfate (HS) for convenient storage as a crystalline solid.

I prefer the Hofmann degradation process. I provided a procedure for same in the Prepublication section of this forum. The gelatine (or EDTA) is used to complex heavy metals such as Cu++ as they catalyze decomposition of hydrazine.

I just finished making 3 batches of HS. The first two gave 56% yield and the last, 48%. The yield is very sensitive to temperature control thoughout the multi-step procedure.

Len1 (Leonid Lerner) gives a thorough description of the Hofmann degradation process in his book. He claims to get a 62% yield but his batch is about 2X that of mine (38g). Rosco claims about 60% making a large batch, IIRC.

I have a good fume hood so don't get exposed to the hydrazine fumes. Occaisionally I will accidently get a small whiff before turning on the fan. It has an unpleasant, but not strong, amine (rotten fish) smell.

Hope this helps.

[Edited on 27-7-2015 by Magpie]

Oscilllator - 3-8-2015 at 21:07

Quote: Originally posted by AWLB  
What is the best agent to use to increase surface tension(could the reaction be taken out in a sealed container)

If you are talking about increasing the surface tension to reduce the prodigous foaming of the reaction, silicon oil has been suggested in the past as an agent to reduce foaming. I have no idea if that is effective, but in either case you are probably just better off attaching an enormous funnel to the top of your reaction flask to contain the excess foam.
With regards to conducting the reaction in a sealed container, the answer is basically no. The gas produced is nitrogen formed from the decomposition of hydrazine, and would rapidly build up pressure and rupture all but the strongest of vessels.

Magpie - 4-8-2015 at 08:26

Using the Hofmann degradation process at the 36g batch size I have no foaming problem. I use a 1L suction flask and the foam came up to the following marks for the last 3 batches: 900ml, 900ml, and 1000ml. Therefore, the funnel I had in place was not even needed.

I use gelatine, which is easy and cheap to get at the grocery store. I understand that the viscosity it builds helps reduce the amount of foam produced as well as sequestering the heavy metals.

Methyl Isobutyl Ketone

Ketalyzt - 15-8-2015 at 04:46

I've tried making Hydrazine Sulfate using Methyl Isobutyl Ketone with freshly prepared concentrated ammonia solution made with ammonium bicarbonate and gelatin, i either used 6% hypochlorite solution or 6% hydrogen peroxide solution (in different experiements) but i couldn't get a sufficient amount to crystalize.
Does anyone know how i can improve the yield?

I've even tried heating it up to 85C for about an hour refluxing but i still barely get any crystals to come out of the solution even when i put it for hours in the freezer :(

CMOS - 17-8-2015 at 07:28

I tried Hofmann degradation with MEK, but I think I screwed up, I added the MEK too early and left it overnight. It separated, I added H2SO4 to the organic layer and distilled off the MEK azeotrope (it came through at 72-75*C). BUT the aqueous layer got dark red/brown, and the organic layer got that color when I started distilling. Of course no HS precipitated. Now for the most important question- how can I safely neutralize it and dispose it? I think there have been some aldol condensation, and I hope there wasn't any halohydrin produced from the aldol... I was working in fume hood (and I used gas mask when needed)

DFliyerz - 18-8-2015 at 20:58

Can the version with MEK, bleach, and ammonia be done with ammonia that just has surfactants? I've been looking for some without for months, and am just about ready to buy some online, but I wanted to check here first.

Oscilllator - 18-8-2015 at 22:53

Quote: Originally posted by DFliyerz  
Can the version with MEK, bleach, and ammonia be done with ammonia that just has surfactants? I've been looking for some without for months, and am just about ready to buy some online, but I wanted to check here first.

The reaction foams quite a lot even without surfactants. Don't be surprised if you end up with an enormous and unmanageable quantity of foam.

Tdep - 19-8-2015 at 02:26

Quote: Originally posted by Oscilllator  

The reaction foams quite a lot even without surfactants. Don't be surprised if you end up with an enormous and unmanageable quantity of foam.

I once tried to do a hypochlorite/urea run on a 6L scale with household bleach (read- surfacants). Pretty sure a horror movie could be made about the 20L or so of foam that seeked to swallow me whole before I shut it off. Give it a shot, but try to find a method of stirring that will keep the foam down, and not encourage it

CMOS - 30-8-2015 at 05:12

Have anyone tried using acetone to get hydrazine and know what we are aiming to, azine OR hydrazone? I have a recipe in a book where they are using acetone and they say you get hydrazone of acetone, and they are retrieving it as fraction distilling at 93-107 *C. How good would extraction with toluene be? How big should be portions of toluene for a run at about 0.5 mole of reagents? Would 5-6 extractions with 15-20 cm^3 of toluene be enough?

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