ETN synthesis problem

ETN synthesis problem

I would simply buy a destillation setup and work with pure nitric/sulfuric mix, a basic destillation setup simplifies so many things, it's really worth it's money.
If not, you might also mix your nitration acid with some methylene chloride, it should be inert against it, as it's used to seperate HNO3 from water, but I don't know anything about the solubility of ETN in CH2Cl2, so maybe CH2Cl2 dissolves some of the product which has to be removed afterwards.
After my attemps to nitrate nitromethane to tetranitromethane (attack of NO2+ on CH2=NOOH <=> CH3NO2, when the aci form deprotonates, CH2 might have a negative charge) I think NM is also stable against HNO3, my mechanism somehow doesn't work. So it might be used to thin your mixture (ofcourse in absence of an aldehyde or ketone ). But it will increase the explosion hazard. polar stuff like pentane you can forget because they are inmiscible.

[Edited on 13-12-2006 by hinz]

Of course, distilling pure WFNA and using this to nitrate my erythritol and then precipitating with sulphuric acid is the most efficient route to highly nitrated ETN of good stability and in great yeild but at present, in the absence of the glass, the space and the means, the acid/nitrate method cannot be ignored for its simplicity. Crude and tedious albeit, ime sure that if all minor creases can be ironed out, we could have a good honest no-fuss route to ETN.

For now I think I will scrap the idea of trying to water down the nitration as like quicksilver stated, the very fact that my nitration thickens up stiff proves the production of highly nitrated erythritol thats insoluble in my nitration bath! I suppose it depends where my priorities lie... do I want to get the maximum ETN per erythritol or do I want to conserve my somewhat limited quantity of acid and ammonium nitrate. Hell maybe I just want maximum nitric ester per cash spent on reagents!

Fortunately I have nearly a kilo of erythritol so never likely to run out any time soon. I use cheap-ass drain cleaner of 95-97% purity and full of red dyes and shit. Although it severely gunges up my EGDN and lowers yeilds, it doesnt seem to contaminate or get in the way with ETN synths... plus its OTC and after a recent close call with the law, Ime keen to save my hard-won clear 98% reagent grade acid for the experiments that REALLY need it!

This leaves the question of ammonium nitrate. It would appear to be my most difficult to acquire reagent for this synthesis as I have no OTC supply and internet sales of the compound are watched by the government. Ive managed to "find" 7Kg but with so many uses it seems apparent that it would be wise to design a synthesis for ETN that gives the highest yeild of nitric ester per gram of ammonium nitrate used.

So taking my original numbers of 1, 4 and 12 by mass which gives approximately a 50% excess of nitric acid than is need to fully nitrate the erythritol plus a mole of sulphuric acid to mop up every mole of water produced by the esterification... and a little extra to thin the whole deal down a bit. Could I maybe reduce the ammonium nitrate to 3 times the mass of the erythritol and get a good yeild with just a 15% excess of nitric acid or is this going too far?

Maybe I should stick with those original ratios and to thin it all down, just increase the quantity of my cheapest and easiest to acquire reagent, the sulphric acid?

Either way, I have found what appears to be the perfect way to recrystalize raw ETN (with a view to remove lower nitrates, acidity and give larger, easier to handle crystals)

I use generic methylated spirit from the hardware store. Mainly ethanol with methanol, pink dye, bitrex and a small amount of gasoline added. I think the gas is there to prevent it mixing with water and to make it nigh on impossible to distill out the ethanol for consumption. Therefore it isnt taxed and is very cheap to buy.

Basicly all I do is add the dried, raw and neutralised ETN to a small amount of meths in a sealed glass bottle (trial and error needed) and heat to 55C to dissolve (dont let it go over 60C or the ETN will melt or precipitate as a liquid... then its FUCKED!)

When its all in solution and around 55C I take the glass bottle and place in a LARGE jar or hot water at around 57-58C and leave the whole lot to cool very SLOWLY. the ETN precipitates nice and slow into large crystals of much higher bulk density than when in the raw newly nitrated state. And so into the freezer to get the last ETN out of solution and hopefully leaving the more soluble lower nitrates behind dissolved in the meths


[Edited on 15-12-2006 by Deceitful_Frank]

[Edited on 15-12-2006 by Deceitful_Frank]

This is a good topic!

I've been hearing people complain for years about thick nitration mixtures and broken thermometers and so on.

I really don't know what the ultimate answer is. On the one hand if you add an inert solvent you are diluting your acids, which may result in poor nitration, low yield and the need for longer nitration periods. On the other hand concentrated nitric acid may be the answer, but it is not always the best choice in a given nitration such as for erythritol, because of lower yields, problems with oxidation of the erythritol and higher costs for the acid.

Thus far what has worked best for me is to ditch the glass thermometers for a good plastic cooking spoon. They don't break and the plastics I have used have been completly inert to the reaction. In combination with the plastic spoon a much longer nitration period could'nt hurt much in the case of ETN.

Because the ETN nitration using alkali metal nitrates and even AN is very thick like icing, a plastic spatula may prove to get the mixture mixed the best if a mechanical help is not available.

If you are a wealthy fellow, unlike some of us, the answer is obvious. Use a greater acid/nitrate to erythritol ratio, but who among us is a wealthy fellow?

On a similar note: has anyone noticed a difference in final yield when the acid and nitrate is first mixed and then the erythritol is added to it, as opposed to adding the erythritol to the sulfuric acid and then adding the nitrate to that. Upon studying Urbanski a bit I see that order of addition does matter in many cases. Urbanski noted that adding the substance to be nitrated to a mix of acids can result in higher nitration than first sulphonating the material and then adding the nitrating agent to that, (unfortunatly this can also lead to oxidation of the material to be nitrated causing lower yield IMHO). The reason is he explains is that the material being nitrated will have far more contact with the nitration agent in a much higher concentration, as opposed to a more isolated environment were only a small amount of nitratable material is in contact with the nitration agent.

However, first sulphonating the material to be nitrated, for example phenol, in the case of picric acid, has many benifits including easier nitration and less oxidation.

I wonder if there can be a happy balance. I think I might try simply mixing a pre-calculated amount of powdered erythritol with powdered AN and then add the powdered mix directly in portions to the sulfuric acid. Who knows a little tinkering around with ratios and orders of addition may lead us too the highest nitration levels, lowest oxidation of erythritol from the nitric acid and highest yields.

Really? Why do so many get high yields with the commerical Ethanol?
I have distilled my own METHANOL, so I get only around 90%.
Do you really think that's waste now? I have some 50 g ETN to recrystallize, please don't tell me it won't work....

[Edited on 3-4-2010 by maxidastier]

Automotive 'Heet' , (yellow bottle methanol AIRC)MSDS lists content as 99% methanol,.02 xylenes,0-,m-,p- isomers)
Unknown % corrosion inhibitors.Might need add little dist water to incorporate the bicarb.Urea a reasonable stabilizer?If that could be incorporated at some point particularly during a recrystaliztion the urea etc, should be incorporated consistently
thruought?

[Edited on 5-4-2010 by grndpndr]

I'm wondering how many solvable non-ETN material is in the mix.

I prepared some ETN with 20 g Ammonium Nitrate, 25 ml H2SO4 and 5 g of Erythritol.
After four hours of reaction I dumped the thick cream in around 150 ml of ice cold water.
Everything got cloudy, but I realized some stuff at the bottom, that only dissolved after stirring.

After filtrating it and drying a little bit, it was 37g! I thought, uh! This won't be all ETN, with only 5 g of Erythritol used.
Well, the next day I weight it again, more dry now, and it was still 32 g!
So I dumped it again into some cold water and neutralized with baking soda. It needed only some 0,5 gramms of it and it was then neutralized. Lots of ETN was smimming on the top.
I filtrated it and was shocked, that it had lost so much weight. First 32 g, now 20 g.
And I even hadn't recrystallized it.
But I did that an hour later, adding the stuff to some 50 ml of hot Methanol. It was so cloudy that I didn't see, if everything dissolved, but it should be most of it.
Well, after cooling it down in the freezer, filtrating it and drying it, I was REALLY shocked
Guess, what was left of ETN? 4 GRAMMS

I can't believe it yet, and I'm asking you: Was the rest of those 32 g some other stuff or what was my mistake?
Because 4 g ETN from 5 g Erythritol is more than a poor yield.

PS: I'm German, so don't blame me for my English..

[Edited on 11-4-2010 by maxidastier]

[Edited on 11-4-2010 by maxidastier]

[Edited on 11-4-2010 by maxidastier]

Quote: Originally posted by maxidastier

I'm wondering how many solvable non-ETN material is in the mix. I prepared some ETN with 20 g Ammonium Nitrate, 25 ml H2SO4 and 5 g of Erythritol.

You used 20g AN to 25 ml of Sulfuric? This seems to be a lot of AN. When I prepare a nitration bath using a nitrating salt for ETN (It seems to give me excellent yields using this method), I use 55g AN to 100 ml Sulfuric.

I have done dozens of ETN synthesis and this ratio seems to optimize my yields. I actually have a pile of ETN drying right now. I used 200 ml sulfuric to 110g AN. I added 35g Erythritol and have a yield of ~45-50g. Both chemicals used are ACS grade.

Maybe try similar ratios for your nitration bath and see if that makes a difference?

Also what maxidastier said with recrystallization; I had problems with adding too much ketone/alcohol which decreased the yield. Be cautious with adding it, making sure you don't use too much. The stuff you saw that didn't dissolve was probably un-nitrated erythritol or other impurities. Its a good thing to filter those out, another positive result of recrystallization.

Anyway, hope it works out. Good luck!

EDIT: Just so you guys know my ETN is legit



[Edited on 12-4-2010 by rbick]

Well, thankfully I kept that stuff that didn't dissolve in the methanol.
Although I couldn't believe that it would be useful later, it IS now!
It really is ETN, that didn't "want" to dissolve. It is no waste stuff, strange,
but I made some tests with that "stuff" with my hammer an it IS ETN.
I'm wondering how it can be, that it didn't dissolve although I used TOO much of Methanol

Maxidastier: I noticed something interesting today. Your problem motivated me to look back at lab notes and do an experimental ETN synthesis.

Looking back it seemed yields were lower when I kept the nitration at temperatures around 10*C but increased when I let the mix get around 20*C or even a little higher. Today, I made a nitration mixture with 100 ml 98% sulfuric and 60g purified AN. After dissolving all the AN, I put the nitration vessel into an ice bath and let it cool to 10*C.

Before I continue I forgot to mention something I read back on roguesci before it closed down: YOU HAVE TO READ THIS: http://pubs.acs.org/doi/abs/10.1021/ja01681a501

It talks about the dehydration of AN in Sulfuric Acid when it reaches a certain temperature, which means it produces more gas than nitric acid. Read it for details, its interesting.

So anyway; I added the erythritol to my nitration mix slowly over about 10 minutes maintaining 10*C. After adding all of it and letting it sit with occasional stirring for 15 minutes, I noticed the mixture wasn't that thick with ETN crystals. I removed the nitration vessel from the ice bath and let it get up to about 20*C. I then let it sit for an additional 15 minutes with stirring. In the 15 minutes, the mixture became thick with crystals, almost to the point of breaking my glass stirring rod. I filtered it and washed it with bicarb. I didn't recrystallize since I'll be dissolving it in NG and NM for some fun experiments, which I'll post later!

SO in conclusion: Could it be coincidence? Possibly, but try letting the temp get up to 20*C, maybe even a little higher and see what happens if you haven't already. Making ETN usually seems to result in a mild nitration without too much threat of runaway, but be careful anyway. Hope this helps.

[Edited on 14-4-2010 by rbick]

Well jeez I don't know whats going on then ! Since I had to let it warm up to 20*C and waited an additional 15 minutes, the nitration time after all of the erythritol addition was roughly an hour. The yield was pretty good. Haven't measured it yet but its appears to be over 20g from 15g of erythritol.

Read that article I put a link to. If your AN/Sulfuric nitration mix gets above a certain temp during AN addition, very little Nitric Acid is created. That might do it, who knows. Good luck.

oh my god...One hour earlier I prepared a new synthesis and followed your tips with only 20 mins of nitration.
Damn it, why didn't you write that it was one hour, because that's also the way I normally do it...
Well, on that link I can't see an exact temp.
I kept my nitrate salt/ sulfuric mix at very low temp in ice bath, so I think it produced enough nitric acid.

But: This synthesis will be waste with only 20 minutes of nitrating

Well, I used different ratios and different nitrates (KNO3 and NH4NO3)
My last synthesis was from http://n3chem.freehostia.com/?p=ETN, but it it was hard work with only the same yields as my other synths. I got 12 g ETN from 7,5g Erythritol. All my synths were like this.

Can one tell me the ratios with KNO3 and NH4NO3?
We need to try out different ways if making ETN, because ETN is a very good, strong HE, close to PETN but way easier (or not ) to make (if you don't get PE)
The best thing about it is that you can melt it easily and dump it into casings, reaching a very high density, resulting in perfect velocity!
I made tests with small amount of ETN in foil and hit it with a hammer. Made nice boom.
But then I made the same with molten ETN. Well, I would be deaf, if I didn't wear ear protection...
Perfect booster, too...

But synthesis and yield, well....

Question..

After the last addition of the Erythritol, instead of letting the mixture sit to nitrate for an hour and stirring every once in a while.. could that nitration time be reduced to say HALF an hour if you stir the mixture continuously by mechanical means?

I was thinking of making a little stand and attaching a hand mixer to it. I'll make one anyway regardless of the answer, just would like to know if I need to turn it off after an hour.. or half an hour.

I actually made such a mixer before, but I took it apart a while back when I decided to quit the hobby. I sold my acids and everything!! Fuck!! People even warned me I would regret it.... I should've listened

Quote: Originally posted by quicksilver

One of the reasons NOT to use recipes is that it doesn't teach chemistry. The convention of using all the same units of measurements (especially weight) is so ingrained that I use it consistently -that one reason NOT to use recipes but do the math and determine if you have it right. 100ml appears correct if the density level is 1.81. But mixing weights and volumes is a poor idea unless it's noted. Recipes are not chemistry. Standard convention aside, I made more than one mistake in notation.

Quote: Originally posted by maxidastier

. I think it doesn't hurt if you use too much of H2SO4 than too little?

Quote: Originally posted by gnitseretni

Is a fast addition time a way to reduce sub-nitrations? I've read posts where folks use long addition times. If after the last addition they let it react for 15 minutes, then the first addition has had a reaction time of one hour and 15 minutes, and the last addition only a mere 15 minutes. Is this large difference in reaction time a cause of sub-nitration?

Made some ETN.





10g Erythritol
50g KNO3
150ml H2SO4

Yeah, I know.. that's a LARGE excess H2SO4
I recrystalized the ETN from acetone/methanol (50/50).
Anyways, I know it's nothing special.. I was just a little bored and felt like sharing

I've used the mixer for a long time, but I only used it with HNO3/H2SO4 mixtures. I just recently started using it with KNO3/H2SO4 mixtures. I used a large excess of H2SO4 in my last synth a few posts up, but the first time I did it I used the right amount of H2SO4 and found that the mixture was too thick... eventually the mixture became so viscous that the container itself began to turn instead of the mixture So if you're gonna use a mixer then either use an excess of H2SO4 or find a way to secure the container to keep it from turning. But best to use it with HNO3/H2SO4 mixtures in my opinion.

I like using the mixer because I have my hands free to do other stuff, like in between additions I can back away to avoid those nasty HNO3 fumes.

Btw, the electric mixer is best used with larger synths. With smaller synths you use smaller containers, obviously, which might create problems. For example, I used a canning jar in my last synth. The mouth of the jar was very narrow and some of the material to be nitrated hit the top of the metal mixer and flew against the walls of the jar, which I had to scrape off from time to time. I didn't have this problem with larger synths, because the mixture completely covered the metal mixer. This problem can be overcome by cutting the four 'blades' on the metal mixer in half.. leave the bottom half of the blades attached to the mixer but remove the top half so there's nothing there that will hit the material to be nitrated against the walls of the container. If I didn't explain that well enough, see picture below.

....if you don't use it immediately or dissolve it in NG or whatever.