Trinitrotoluene preparation

TNT Production From DNT, Oven Dried NaNO3 and 98% H2SO4

I was using the article Rosco posted earlier, from "The Journal of Industrial and Engineering Chemistry", which had in it the tabulated results of a series of TNT synthesis experiments. I used experiment No. 16 as a rough guide. The article was based on MNT to TNT, but I still used the same mass fractions even though I was going from DNT.

Ammonium nitrate was used to nitrate the toluene to DNT, however, there are a lot of indications that sodium nitrate will not decompose the way ammonium nitrate does at higher temperatures. Ammonium nitrate decomposition products could cause damage to the intermediates or possibly the products of the reaction and will lower the strength of the nitration mixture at the very least. It was decided that sodium nitrate would be used for the last stage of nitration.

From DNT to TNT
Nitration Mixture Composition:
82% Sulfuric Acid
16% Nitric Acid
2% Water

(75% Excess Nitric Acid)

For 1g of DNT:

1g / (182.134g/mol) * 1.75 = 0.00961 moles of HNO3 Specified

HNO3 Production:
mass of NaNO3 needed = 0.00961 * (84.9947g/mol) = 0.8168g
mass of H2SO4 needed = 0.00961 * (98.079g/mol) = 0.9425g
produces 0.00961 moles * (63.01g/mol) = 0.6055g HNO3

Reaction Mixture H2SO4:
mass of H2SO4 needed for nitration mixture= 0.6055g/16 * 82 = 3.103g
mass of H2O specified for nitration mixture = 0.6055g/16 * 2 = 0.07569g

Per 1g of DNT use:
0.6055g HNO3
3.103g + 0.9425g = 4.0455g H2SO4 (anhydrous)
0.07569g H2O

Started off with H2SO4 of >95wt%. From previous experience it was known that 130g of NaHSO4 containing pH down would produce about 25g of SO3 and 1.2g of water by the method used. Since about 260-280g of NaHSO4 was used it was assumed that about 50g of SO3 and 2.4g of water would be produced.

10.67g SO3 to tie up assumed 2.4g water in SO3/Oleum produced
39.33g SO3 left from assumed total of 50g
39.33g SO3 / (80g/mol) * (18g/mol) = 8.85g of H2O it can convert to H2SO4

Assume starting with 95% H2SO4 and are aiming for 99%. There is enough SO3 (39.33g) to convert 8.85g of H2O to anhydrous H2SO4. The next time I would do it right and add enough H2SO4 to get to 98% acid and not add any water after the fact.

99% - 95% = 4% water needs to be removed

H2SO4 needed = 8.85g / 0.04 = 221.23g of 95% H2SO4 (I added 226g by mistake, but the acid still titrated at over 99% after the acid was added to the SO3)

95% H2SO4 added: 221.23g
SO3 plus H2O it binds with from SO3/Oleum produced: 13.07g
SO3 left from assumed 50g total: 39.33g
Total Produced = 273.63g of 99% H2SO4

Can Nitrate: 0.99 * 273.63g / 4.0455g = 67.0g of DNT
NaNO3 needed = 67.0 * (0.8168 g NaNO3/1g DNT) = 54.7g

Note:
Then I did something foolish and added 2.7g of H2O to bring the water concentration in the nitration mixture from about 1% to about 2%. This is not a bad thing in a way, as this amount of water can actually be advantageous for the reaction, but a lot more 98% sulfuric acid could have been produced by adding more 95% H2SO4 instead of water. This would have allowed me to nitrate much more DNT (84.2g instead of only 67.0g).

Procedure:
As stated above the oven dried sodium nitrate was added to the sulfuric acid and then put in the 1L reaction flask. The temperature was brought up to about 80C to start the reaction and then the pre-warmed and molten DNT was pipetted in to the reaction flask about 1mL at a time over the course of 2 hours. During the addition time the temperature was kept between 80 and 90C. After the addition was complete the temperature was slowly raised. By the end of the second hour the temperature was up to 130C and was kept in the 130-135C region for another 2 hours. I think I will use a lower maximum temperature next time (120-125C) since on reviewing the article previously mentioned looks as though this range generally gives the highest yield of the purest product.


SO3 Production Pictures:




Preparing Reactants: (adding the first bit of NaNO3 to the >99% H2SO4 caused it to fume profusely)




[Edited on 29-11-2014 by Hennig Brand]

Reaction Progression Pictures

[Edited on 28-11-2014 by Hennig Brand]

TNT Synthesis Post Reaction Work-Up

In total there were 2 hours of DNT addition and 4 hours of heating at elevated temperature to complete the reaction. The crude TNT was collected in two batches. The first batch, which is reported to be of much higher purity generally (COPAE, etc) is what floated and settled on the top of the mixed acid. The less pure crude TNT was precipitated from the spend nitration mixture by dilution. Since sodium nitrate was used a lot of sodium (bi)sulfate precipitated as well once the acid cooled. The mixture of crude TNT and sulfate was filtered out and well rinsed with clean water and then put into boiling water whereby the sodium (bi)sulfate dissolved and the crude TNT became molten and pooled on the bottom. The crude TNT was agitated with magnetic stirring for 15-20 minutes while molten to remove water soluble impurities. Some of the first crop of crystals (cake) collected from the surface of the nitration spent acid was recrystallized from methanol, which formed very well defined crystals and brought the melting point up from the low 70C range to around 80C. The last picture shows the very pale yellow, well formed crystals, of purified TNT.


Yield of washed and dried crude TNT was 44.6g from the first crop and 29.0g from the second crop, for a total yield of crude TNT of 73.6g.

Theoretical Yield = 67g / (182.134g/mol) * (227.13g/mol) = 83.55g

%Yield = 73.6g / 83.55g * 100% = 88.1%




Crude product from first crop washed to remove water soluble impurities.




Crude product from spent acid processing.




First Picture: First crop on left & Second crop on right
Second Picture: Sample of first crop recrystallized from methanol with m.p. around 80C.




[Edited on 29-11-2014 by Hennig Brand]

2.0g of TNT Initiated; 7.6mm id Al, 0.25g DDNP & 0.35g of LA (Unreinforced Configuration & ca. 6000psi Loading Pressure)

I initiated 2g of the purified TNT shown in the last picture of the last post. I used DDNP in spite of the fact that the only amount left that I had previously made was sitting on a filter paper on a bureau with dust bunnies in it, etc. It only weighed 0.25g even with all the months of accumulated dust. I decided to use it anyway and mixed it with 0.25g of lead azide and pressed that on top of the TNT. Another 0.10g of lead azide was pressed on top as well for a total of 0.35g of lead azide. A tiny bit of basic lead picrate was also used as a flash igniter. There was a detonation with a fairly large cloud of black smoke, but it wasn't very loud and the damage indicated low order detonation. A dent was made in one side of the witness plate and a nice scab was blown off the back however. It reminded me exactly of how picric acid acts when not overdriven hard enough. I have a bunch of sodium picramate stored, so I may make some DDNP soon and perform a decent test.






The dent and scab on the right, in the witness plate shots, are from this test.




[Edited on 29-11-2014 by Hennig Brand]

Sounds like a decent solution. The TNT did seem like it just needed a little more kick to get it into high gear. Even if it took as much as 0.6 or 0.7g of DDNP and 0.05 or 0.1g of lead azide to initiate TNT, it would still make reasonably sized caps. I did some research early this morning regarding critical diameters of powdered TNT. I re-found a document I had found half a year ago or so; "Critical Parameters For Detonation Propagation And Initiation of Solid Explosives". It is even more useful now, because of all the data in it regarding TNT. Here are a couple useful graphs which should help one design around any critical diameter issues. I have attached the whole document as well. The brief write-up before the second graph said that the researcher used consistent particle size and 1g/cc loading density for all tests for the graph on the right below.




Attachment: Critical Parameters For Detonation Propagation And Initiation of Solid Explosives (2).pdf (4.1MB)
This file has been downloaded 1291 times


[Edited on 29-11-2014 by Hennig Brand]

Here is a graph with associated equations for TNT & DNT solubility in methanol. Several of the data point values came from the text "Military Explosives" and a few came from other texts and journal articles. The solubility curves maybe shouldn't be crossing at the bottom, but the graph should be reasonable accurate at any rate. Attached is also a table taken from "Military Explosives", showing the approximate concentrations of impurities before and after purification. It is obvious that crude TNT recrystallization from alcohol, or sulfite washes, are not effective for separating DNTs from 2,4,6 TNT, but they are very effective methods for removing the other isomers of TNT. According to COPAE recrystallization from concentrated sulfuric acid is the most effective method, of the purification methods commonly used at the time, to remove DNT. However, the best solution is to run a good strong nitration and convert as much of the DNT to TNT as possible.





[Edited on 1-12-2014 by Hennig Brand]

A couple updates

I didn't post this earlier because I have already posted so much in this thread in the last while.

A few weeks ago I ran another TNT synthesis. A few points of interest:

1. Maximum nitration temperature of 120-125C was used instead of 130-135C and the results were at least visually superior. Even the TNT which was precipitated from the spent nitration mixture was a nice pale yellow, not orange like the first synthesis where the temperature was taken all the way up to 135C. I suppose there could be other variables involved as well.

2. For production of DNT from toluene, when I stated earlier that the temperature should be gradually raised from 30C to 80-90C during the course of nitration mixture addition, that was an oversimplification. Especially during the first and even second nitro group addition care must be taken to prevent oxidation. Additions must be slow and even and temperature should not be allowed to climb too quickly or nitrogen dioxide will be produced in unacceptable amounts and oxidation will take place.

3. The best way to push the DNT from toluene nitration farther is to add more nitration mixture (increase from 10% excess to 20% excess perhaps). Increasing the final temperature from 80C to 90C did not appear to produce any better results at least when held for 2 hours as I did in both cases.

I got a better yield when producing SO3 the last time and made enough 98% H2SO4, from 95% H2SO4, to nitrate about 110g of DNT. Shown below is 76g of TNT from that batch, recrystallized from methanol, with melting point around 80C. There was much more product, but it was precipitated at a lower temperature, and some by dilution of the methanol with water, and was not in a dense well formed crystal structure as the sample shown was.





[Edited on 14-1-2015 by Hennig Brand]

DNT step Attempt

So finally i got around to my attempt at synthesizing some TNT-well DNT actually, havent done the DNT to TNT nitration yet but that will be done as soon as my sodium sulphite order arrives.
So for this synthesis i used 38.5g ammonium nitrate and some %98 tech grade sulfuric acid 85ml, and 11mls dist water,I also acquired some pure toluene,At least the label says that and its density measurement is pretty spot on a density chart i have, its not "diggers" brand. 25mls of this was used.
I followed the a synthesis that was done by fellow SM user Hennig Brand a few pages back for a guideline, mostly because he had success with the method and got some fine looking end product from it although i did scale it down by half.Also i added the toluene to the mixture not vice versa like HB did. The nitration mixture was made the day before and put in the freezer overnight and warmed to 5c before adding any toluene which was done from a glass syringe in small portions at a time The whole process ran pretty smoothly with the temp rising slightly with each addition and upon finishing it was at around 50C. additions were completed fairly fast in 45mins. 15 mins after the last addition of toluene the heating was then applied very gently with a water bath to 80C where it was held for 1hour 45mins. the mixture was then allowed to cool and the DNT solidified gradually with the waxy oily looking cake fished out crushed a bit and washed several times with cold water. upon drowning the spent nitration mix a bit more DNT was recovered also. these were combined and washed again but molten in hot water and agitated for 10 mins and set to cool with the DNT cake solidified in the vessel. It's still yet to weigh it but the yeild loos good.
The pic of the darker layer im not 100% sure of time in the synthesis but the lighter layered picture was just before i stopped heating it.
The smell of this synthesis was not as bad as i expected either. It kind of took me back to being a kid and being made to get out the tin of nugget and polish up dads army boots.....

Next step will be the TNT nitration step, and i have enough distilled nitric in the high 90%s for this but it is slightly orange and I would like to know if this is ok for a TNT nitration? or does it need to be cleaned first? looking forward to completing this project in the next few weeks since i have been looking at doing this synthesis for quite a while now.NP

Quote: Originally posted by Hennig Brand

Looks good. The one thing I did notice was that you didn't use any excess of nitrate/nitric acid if my calculations are correct. Assuming the AN used was completely dry and 100% pure, which it wouldn't be, the quantities you gave would give 2% excess of nitrate/nitric acid. I think 10 to 20% excess would be better to ensure a more complete reaction. You probably used my quantities, but didn't see where I multiplied by 1.1 to give a 10% excess. Admittedly my post was a little bit hard to follow, and I half intended to go back and make it more streamlined and easy to follow, and post it again, but never got around to it. A little lower yield and more MNT contamination is not a big problem at this stage anyway.

Quote: Originally posted by Hawkguy

It would be useful to have a bit more acid excess. From experience, the best DNT results come from putting MNT isomer(s) contaminated DNT slag through a second nitration to completely synth DNT, and recrystallizing it from Methanol. VERY pure DNT is created. [Edited on 23-3-2015 by Hawkguy]

Quote: Originally posted by Hennig Brand

I don't want to get too far off topic, but I thought I would include the following jpg of a table taken from an old defense document (Powder and Explosives by A. G. Gorst). It provides some minimum mercury fulminate initiator charge weights for cast and pressed TNT and Picric Acid. As you know, granular TNT and picric acid are much easier to initiate than their cast forms. Very commonly, granular or crystalline TNT or picric acid was used as a booster to initiate cast TNT and cast picric acid. BTW, did you check the melting point of your TNT? TNT even when of high purity is relatively insensitive to initiation. TNT does take a bit of time to make, but after doing it a couple of times I find it fairly straightforward and with the right equipment (large flasks, etc) it could be made in large quantities relatively safely. It wouldn't take much longer to make a pound batch than it would to make a 15g batch.

[Edited on 26-3-2015 by Hennig Brand]

Here is another table, taken from the same text, showing limiting charge weights required to initiate TNT, picric acid and tetryl pressed with the same loading pressure in copper blasting cap casings. The difference in limiting primary charge weight, required for initiation, between TNT and picric acid is much smaller than between the two when pressed to practical densities or when cast.




[Edited on 26-3-2015 by Hennig Brand]

Correct disposal of "red water"

TNT? DNT?

I just dug up a two year old batch of TNT/DNT that was made using Jared Ledgers crapbook method.

I have the notes written down and I used 98% sulphuric acid and 70% nitric for all the steps. I have the amounts I used somewhere but I cannot find them at the moment. They were a scale-down from Legard's amounts for the three step nitration in Prep manual of explosives.
For the mononitro step, the nitrating acids were heated to about 43-45 degrees and the toluene added drop-wise from an addition funnel. The mix was then stirred for 20 minutes at about 50 Degrees before separating the layers.

For the second dinitro step fresh acids were heated to 75 Degrees and the MNT dripped in from an addition funnel again. Addition took about 20 minutes. After the addition , the mix was heated to about 85 degrees for 10 minutes and taken off heat with continued stirring and then put in a sep funnel and the top layer stored.

For the final trinitro step, the fresh nitrating mix was heated to about 90-92 Degrees and the temperature maintained while the DNT was added. Addition took about 20 minutes from what i remember. The DNT had to be warmed and melted back down as most of it had crystallized between steps. After this, the mix was kept at 90 Degrees for 5 minutes and then brought up to 112 Degrees for a further 5 minutes before cooling for 5 minutes and crashing into ice-water.

The final product has been bicarb washed and water washed under hot 80 Degrees water about 10 times before being bagged and stored.

Finally, the question, without the fuming sulfuric acid (oleum) do you think I would have got any TNT product at all or could it all be DNT? Is it possible to obtain trinitrotoluene without it?
I will do a melt test tomorrow and see what temperature the product melts at which should give me a fair idea.


[Edited on 30-10-2015 by greenlight]

Thanks NP, i will do a melt test anyway to get an idea of the dinitrotoluene content.
After the addition of the DNT, Ledgards total heating time is 15 minutes in his book
Looks like i will have to melt it and use a fresh nitration mix with longer time and higher heat to get the third nitro group on. Not a fan of this method as it uses a lot of sulphuric acid.

[Edited on 1-11-2015 by greenlight]

Quote: Originally posted by NeonPulse

Someone has already taken the time to copy the whole TNT synthesis by mega on the first page of this thread about three posts down so there is no need to visit the link.

Instead of SO3 whatever other route, I added 30ml m-phosphoric acid to my acid mix and DNT. Results look pretty good, except the fumes were worse than normal.

[Edited on 14-3-2016 by Daffodile]



[Edited on 14-3-2016 by Daffodile]

[Edited on 14-3-2016 by Daffodile]

Quote: Originally posted by Daffodile

Hmm I tried compressing some in foil, and heating lightly. It would just deflagrate, and not detonate at all.

Just this weekend I decided to revisit making TNT and the results were much more satisfying than my first attempt. Once again I used a synthesis devised by Hennig brand a few pages back where ammonium nitrate is the nitric source along with good old drain cleaner of around 93% if my density measurement was correct. However this time I allowed for 20% excess unlike my 1 st attempt. I made up the nitrating mixture and let it sit in the freezer for an hour while I attended something else. This time I was much better equiped for the task since last time I just used a beaker with hand stirring.
The nitration mixture was charged into a 1l RBF with two necks, and a large oval stir bar dropped in, a thermometer adapter in one mouth and a pressure equalising addition funnel to the other and turned the tap to slowly drip 50g toluene into the reaction mixture at a rate of a drop a second slowing occasionally to let the temp not rise too fast and go above 55 yet. For the last 10 mls I just let it rise and 10 mins after the last drop the funnel was switched for a condenser to reflux. Heating was started cautiously and slowly to get up to 80c where it was held for 3 hours with a brief period where it crept up to 90 without me realising. This was soon fixed though. I let the vessel cool a bit and transferred the RBF contents into a 500 ml beaker to cool completely and solidify.
A funny thing happened though, the DNT did not solidify and had me worried that I had somehow effed it up even after an hour n the fridge so I decided to use a syringe to syphon the layer into water and this is where it decided it set solid slowly like the hot ice effect. Scooped this out and quenched the acid into water precipitating a little more DNTthis was placed with the cake into about 600 ml distilled water and heated to melt it while strong magnetic stirring was applied to wash it. The DNT cake was allowed to set cool and fished our out of the beaker, rinsed off and dried for weighing. It weighed 75.1 g and was crystalline with small needles and had very little MNT smell to it. The first batch I made smelt quite a bit like MNT and this one does not at all. There was pretty much no smell during nitration either except when I switched to the condenser so it was well contained in the chosen reactor. I will be completing the final nitration in the next week or so and am actually considering making oleum with some phosphorus pentoxide that I have around, that is if I find the time to otherwise it's just going to be a standard nitration mix of concentrated mixed acids.
T