Sciencemadness Discussion Board

TNT without SO3 or N2O5

Chisholm - 11-4-2017 at 10:10

Every process I've seen for the synthesis of TNT requires fuming sulfuric acid and absolute nitric acid, or else dinitrogen pentoxide in dichloromethane.

My equipment is limited, so I have in the past used phosphorus pentoxide to generate these in situ.

Now, however, I cannot acquire phosphorus pentoxide for the forseeable future.

From what I understand of the mechanism, the difficulty of nitrating dinitrotoluene comes from the two existing nitro groups rendering the aromatic ring highly resistant to electrophilic attack by NO2+.

If I understand correctly, the reason for the additional dehydrating agents (on top of 98% sulfuric acid) is to promote formation of NO2+, as H2NO3+ doesn't participate directly in aromatic nitration.

But are they strictly necessary? Is there a procedure for TNT production via addition of a nitrate salt to a sulfuric acid solution of DNT?

XeonTheMGPony - 11-4-2017 at 10:33

From all my research I never seen the need for any of that, albeit it will improve yields but not essential to making it.


Stirring and heating is more important then any thing.

Fulmen - 11-4-2017 at 13:11

As Xeon points out you can do it with 65% HNO3 and 98% H2SO4, although yields will be lower. A 3 stage process will probably help if you're aiming for quantities.

I have also seen mentioned a process using magnesium nitrate instead of sulfuric acid (for glycerol nitrate IIRC), it might be possible to adapt that to TNT.

NeonPulse - 12-4-2017 at 04:20

https://vimeo.com/182276181 i have done it 3 times now without the supposed requirements being oleum and N2O5 the toluene to DNT was and can be done using nitrate salt and drain cleaner grad sulfuric. there is a huge thread a few pages in detailing TNT preparation using nitrate salts & sulfuric exclusively. it can indeed be done.

Praxichys - 12-4-2017 at 04:57

Why TNT, if not for curiosity?

I think the reason you don't see anyone making it without fuming/anhydrous acids is that it's extremely wasteful. You can get a lot more acid efficiency and explosive performance out of something else.

If you're looking for extreme insensitivity and a little more acid efficiency, try ammonium picrate. It is widely regarded as having slightly higher stability than TNT and has very nearly the same explosive performance. It is made by adding ammonia to picric acid in aqueous suspension.

Drawbacks over TNT include the inability to melt-cast and increased solubility in water.

Chisholm - 12-4-2017 at 07:42

Quote: Originally posted by Praxichys  
Why TNT, if not for curiosity?

I think the reason you don't see anyone making it without fuming/anhydrous acids is that it's extremely wasteful. You can get a lot more acid efficiency and explosive performance out of something else.

If you're looking for extreme insensitivity and a little more acid efficiency, try ammonium picrate. It is widely regarded as having slightly higher stability than TNT and has very nearly the same explosive performance. It is made by adding ammonia to picric acid in aqueous suspension.

Drawbacks over TNT include the inability to melt-cast and increased solubility in water.


I need something melt-castable; I don't have any kind of hydraulic press or machine shop, so melt-casting is the only way I can achieve MTD.

Trinitroazetidine is WAY beyond me, and melt-casting ETN sounds like a great way to kick-start the autocatalytic decomposition process, so it's nitroarenes or nothing.

Praxichys - 12-4-2017 at 08:27

I see your point!

Does it have to be totally solid when cooled? ETN wetted with EGDN, PGDN, or NG forms a paste that will sag to near theoretical density in a few hours. Gently warming this to about 40C (Well below the temp required to melt-cast ETN, about the temp of a hot shower) will make a runny liquid that stiffens up as it cools. You can also phlegmatize these with a few % nitrocellulose to form a nice gel with pretty much the same thermal properties of the above paste. Both of these mixtures are far more brisant than TNT, although at the drawback of increased sensitivity. Nitroesters can be stabilized against decomposition by careful washing with bicarbonate and crystallization in a urea solution.

You might also be able to replace the TNT with ETN, PETN, or RDX with a significant amount of inert binders and still achieve the same performance, assuming that packing a putty can replace melt-casting in your application.

Anyway, if you're set on TNT, I'd recommend doing it in stages. Start with DNT; there are many threads covering this. You can even buy 2,4-dinitrotoluene online without restriction: http://www.firefox-fx.com/ChemD.htm

Once you have that, you can get decent yields by nitrating that with freshly distilled RFNA and drain-cleaner grade H2SO4, with prolonged heating and stirring. The trouble after this is separating the TNT from the DNT. Do you use the sulfite process?

XeonTheMGPony - 12-4-2017 at 10:51

As said above the only way to do it and properly is to do the 3 step process then proper separation via cooling and filtering to get your para and ortho, then continue on.

ETN When don properly is just fine to melt cast, do the proper washings, then recrystallize in methanol with 1% urea by weight of the crude ETN.

Then crash in water bath with an additional 1% urea (Tottal urea 2% by mass of etn crude in 2 steps)

Dry then there ya go, will be white fluffy stabilized ETN.

What is it you're trying to do?

Now days most cold packs are urea, so should be very easy for you to get all you need for a long time that route. Or Diesel exhaust fluid is just purified urea in distilled water, simply evaporate to dryness!

[Edited on 12-4-2017 by XeonTheMGPony]

TNT

Laboratory of Liptakov - 12-4-2017 at 12:35

My opinion is same, what described Praxichys. Is much easily create some from ETN + EGDN + NC, than making TNT and it any ways. Properties is almost same in frame amateur research. Even better....:cool:...LL

Daffodile - 13-4-2017 at 08:57

You guys seem to confuse DNT with TNT a lot of the time (no offense or anything). From my experience it took HPO4 if not oleum to sufficiently dehydrate the acids to make TNT. I was doing it on a 2 gram scale, but the step from DNT to TNT seemed a lot harder than I often see it described here.

Hennig Brand - 17-4-2017 at 00:31

Despite its relatively mediocre power, TNT is usually stated as being the most important military explosive. From what I understand there has been basically no explosion type accidents during industrial manufacture in the last hundred years and the quantity made over that time periood would be mind boggling.

TNT is extremely compatible and makes long term storage stable mixtures with nearly all other military explosives allowing a hugely broad array of compositions with easily controlled and extremely reproducible explosive and physical properties. It can be melted with hot water, a huge advantage!

Its manufacture can be a bit of a challenge in terms of labor involverd for an amateur, but as stated it can be done with relative ease once the process is understood using nitrate salts and concentrated sulfuric acid (check the main TNT thread). DNT can be made extremely easily, and efficiently, with much weaker nitration mixtures.

From what I understand DNT is not easily removed during purification using standard methods (re-crystallization, sulfite sol. soak and rinse, etc). Therefore, it is important to run a strong nitration as much to completion as possible which is easily done with a suitable nitration mixture. The other isomers of TNT can, however, be for the most part easily removed by standard purification methods.

I have had a Mason jar of crystalline TNT sitting on a coffee table for years and my only significant worry would be its toxicity.


[Edited on 17-4-2017 by Hennig Brand]

Microtek - 18-4-2017 at 00:41

In my experience, the last step can be done reasonably efficiently with WFNA and 96% sulfuric acid. I prefer this system to the nitrate salt/sulfuric acid system due to the lower viscosity and (I think) greater solubility of DNT in this system.

IMO, the final recrystallized product should always be tested for melting point, since it is quite difficult to determine how much of the end product is just unchanged DNT.

[Edited on 18-4-2017 by Microtek]

NedsHead - 18-4-2017 at 03:22

Quote: Originally posted by Hennig Brand  
I have had a Mason jar of crystalline TNT sitting on a coffee table for years


Bet it makes for a great conversation piece

Hennig Brand - 23-4-2017 at 04:40

Quote: Originally posted by NedsHead  

Bet it makes for a great conversation piece


It certainly does. It can be difficult to convince some that the explosion dangers are almost nil however.

Microtek, melting points were done, refer to my work in the TNT thread, albeit with relatively crude homemade equipment. The purity of the TNT made was without doubt very high using melting point as an indicator.

Microtek - 25-4-2017 at 23:46

Hennig: I don't doubt that you did, and my comment wasn't directed at you. I just wanted to point out that if one were to run a nitration with dilute acids (or a one-pot process without oleum), the product might look like TNT, but would probably contain quite a bit of DNT/MNT.

Chisholm - 26-4-2017 at 05:49

I have an idea.

Acetone in concentrated sulfuric acid is dehydrated and polymerized into mesitylene (1,3,5-trimethylbenzene). With three activating groups in set positions, mesitylene would nitrate more easily under less rigorous conditions than toluene, and the resulting trinitromesitylene would have only one isomer.

On its own, TNM sucks, but the methyl groups could then be oxidized to carboxylic acid groups with dichromate or permanganate in sulfuric acid, then the product could be decarboxylated via heat to sym-trinitrobenzene, which is superior to sym-TNT in every way, save for TNT's easier synthesis.

Does anyone have any comments on this proposed procedure?

Elemental Phosphorus - 26-4-2017 at 09:01

Permanganate is not used in sulfuric acid, you may get an explosion trying to oxidize that way, as it generates dangerous manganese heptoxide, which can quickly lead to a runaway and explosion. Also, the mesitylene generated by the acetone route will produce other nasty products that may be difficult to separate. Mesitylene could also be generated by the disproportionation of toluene over aluminum trichloride, also producing benzene. If you try dropping a flammable organic solvent into permanganate in sulfuric acid you will see what I mean.

PHILOU Zrealone - 27-4-2017 at 17:09

Quote: Originally posted by Elemental Phosphorus  
Permanganate is not used in sulfuric acid, you may get an explosion trying to oxidize that way, as it generates dangerous manganese heptoxide, which can quickly lead to a runaway and explosion. Also, the mesitylene generated by the acetone route will produce other nasty products that may be difficult to separate. Mesitylene could also be generated by the disproportionation of toluene over aluminum trichloride, also producing benzene. If you try dropping a flammable organic solvent into permanganate in sulfuric acid you will see what I mean.

It will work perfectly if the H2SO4 is dilluted...only concentrate H2SO4 will generate dangerous Mn2O7 (HMnO4 anhydride).

PHILOU Zrealone - 27-4-2017 at 17:17

Quote: Originally posted by Chisholm  
I have an idea.

Acetone in concentrated sulfuric acid is dehydrated and polymerized into mesitylene (1,3,5-trimethylbenzene). With three activating groups in set positions, mesitylene would nitrate more easily under less rigorous conditions than toluene, and the resulting trinitromesitylene would have only one isomer.

On its own, TNM sucks, but the methyl groups could then be oxidized to carboxylic acid groups with dichromate or permanganate in sulfuric acid, then the product could be decarboxylated via heat to sym-trinitrobenzene, which is superior to sym-TNT in every way, save for TNT's easier synthesis.

Does anyone have any comments on this proposed procedure?

The yield of Mesitylene is not that great, also you have to isolate it from phorone, isophorone, mesityle oxyde and other linear polymers or cyclic polymers.

True that the mesytilene is activated...even a little too much so the chance of a runnaway while making TNM is bigger than with TNT...also during the process side chain may oxydise already (probably enhancing the risk of runnaway)...so you would need to use lower concentration of HNO3 maybe even without H2SO4.

TNT --> TNB is economically viable despite the "minor" isomerism trouble

TNM --> TNB will be harly economical because you would need at least 3 times more oxydant and sulfuric acid...

Also the mass yield will be less because TNM has to loose 3 CH3 into fumes vs 1 for TNT to get TNB. So starting from 100 gr TNM will yield less TNB than 100 gr TNT will.

For all those reasons, the process TNM -> TNB will not be advantageous over TNT--> TNB one...but for sure it may be an interesting experiment and a challenge for a hobby chemist.

Feel free to test on little amount of reactants (10 gr) and of course to make a written report with pictures/videos and explanations.

[Edited on 28-4-2017 by PHILOU Zrealone]

Hennig Brand - 28-4-2017 at 00:58

Quote: Originally posted by Microtek  
Hennig: I don't doubt that you did, and my comment wasn't directed at you. I just wanted to point out that if one were to run a nitration with dilute acids (or a one-pot process without oleum), the product might look like TNT, but would probably contain quite a bit of DNT/MNT.


No worries, I wasn't offended at all, I just realized it had been quite a while since I did those experiments and reported here about it. I was just reiterating just in case some other people have memories as bad as mine or didn't even see those earlier posts at all.