Sciencemadness Discussion Board

Trinitrotoluene help

NonEthicalPyrotechnics - 1-5-2020 at 08:40

Hi everyone! so I've been having trouble with the third nitration of DNT and I was wondering if oleum could be substituted with something such as phosphorus pentoxide?

[Edited on 1-5-2020 by NonEthicalPyrotechnics]

mackolol - 1-5-2020 at 09:56

If you were to use P2O5, you must have used it together with H2SO4, although I'm not sure if it would work.
If you're not scared, you can prepare oleum by thermal decomposition of persulfate in H2SO4 followed by distillation and then dissolution of resulting SO3 in H2SO4, but that's some nasty shit.

I don't know how were you been doing it, but as I see now TNT can be prepared by mixture of plain concentrated H2SO4 with fuming nitric acid (much simpler to prepare and easier to handle than oleum).

https://www.prepchem.com/synthesis-of-2-4-6-trinitrotoluene/

[Edited on 1-5-2020 by mackolol]

NonEthicalPyrotechnics - 1-5-2020 at 09:59

Would I be able to get oleum just by adding a stronger dehydrating agent to H2SO4?

mackolol - 1-5-2020 at 10:04

Yes, by heating H2SO4 with P2O5, there's even video about it on YT: https://www.youtube.com/watch?v=zLr-PnSQvX0&t=127s

aromaticfanatic - 23-11-2020 at 15:55

The last nitro group is very hard to get on without oleum. Almost every amateur I've known and seen has failed with the exception of one.

dome13 - 23-11-2020 at 16:39

Some times ago I have synthetised TNT, based on this video:
https://www.bitchute.com/video/YkLdtSBKnwd9/

It doesn't needs oleum, and the route is very simple.

aromaticfanatic - 23-11-2020 at 18:04

Quote: Originally posted by dome13  
Some times ago I have synthetised TNT, based on this video:
https://www.bitchute.com/video/YkLdtSBKnwd9/

It doesn't needs oleum, and the route is very simple.


Hey I've seen that video before! I know it doesn't need oleum but from my understanding getting the mixed acids water free enough was a pain. I wasn't kidding when I said most amateurs really struggle with TNT. Even Tom from Ex&F had a lot of issues with it.

Was your ammonium nitrate really dry?

[Edited on 24-11-2020 by aromaticfanatic]

dome13 - 24-11-2020 at 08:36

I used potassium nitrate instead of ammonium nitrate. (I didn't do further drying with the KNO3.) All of my reagent was analytically pure. Starting with 14,4ml toluene, I got 9,93g TNT, wich is correspond to about 32,5% yield.

aromaticfanatic - 24-11-2020 at 16:09

Quote: Originally posted by dome13  
I used potassium nitrate instead of ammonium nitrate. (I didn't do further drying with the KNO3.) All of my reagent was analytically pure. Starting with 14,4ml toluene, I got 9,93g TNT, wich is correspond to about 32,5% yield.


I can't believe it. KNO3 is the worst nitrate salt and you got proper TNT from it? Impressive. What was the melting point range?

[Edited on 25-11-2020 by aromaticfanatic]

B(a)P - 24-11-2020 at 17:23

Quote: Originally posted by aromaticfanatic  


I can't believe it. KNO3 is the worst nitrate salt and you got proper TNT from it? Impressive. What was the melting point range?

[Edited on 25-11-2020 by aromaticfanatic]


Why is KNO3 the worst nitrating salt?
I have not made TNT, but I have always used KNO3 as a nitrating salt. It is very hard to get other nitrates in Australia.

aromaticfanatic - 24-11-2020 at 17:55

Quote: Originally posted by B(a)P  
Quote: Originally posted by aromaticfanatic  


I can't believe it. KNO3 is the worst nitrate salt and you got proper TNT from it? Impressive. What was the melting point range?

[Edited on 25-11-2020 by aromaticfanatic]


Why is KNO3 the worst nitrating salt?
I have not made TNT, but I have always used KNO3 as a nitrating salt. It is very hard to get other nitrates in Australia.


KNO3 typically kicks out the product because the sulfate salt isn't as soluble. With ETN I get dangerous situations where things crystallize and heat up when I get real good yields. Ammonium nitrate was soooo much better and stayed fluid. Yield went way up too.

It does depend on what you are nitrating but KNO3 is considered the worst nitrate salt for nitrations from the common nitrate salts (NaNO3, KNO3, and NH4NO3). Calcium nitrate would be even worse.

So I am surprised he got such a decent yield and fully nitrated product with KNO3.

[Edited on 25-11-2020 by aromaticfanatic]

dome13 - 25-11-2020 at 15:02

You are right, aromaticfanatic, the KNO3 indeed solidified upon cooling and I got a bit confused. But fortunatelly, the product was on the top, so the separation was easy. I didn't measured the melting point, beacuse I trusted the procedure and everything went well. I still have all of the TNT, and now you made me curious about the melting point. I will do it in a few days and tell you the results.

[Edited on 25-11-2020 by dome13]

aromaticfanatic - 26-11-2020 at 02:20

Quote: Originally posted by dome13  
You are right, aromaticfanatic, the KNO3 indeed solidified upon cooling and I got a bit confused. But fortunatelly, the product was on the top, so the separation was easy. I didn't measured the melting point, beacuse I trusted the procedure and everything went well. I still have all of the TNT, and now you made me curious about the melting point. I will do it in a few days and tell you the results.

[Edited on 25-11-2020 by dome13]


Interesting. Yes please update us as I am really curious! While I have not liked nitrotoluenes too much, if I know I can get TNT even with something like KNO3, I might give it a small scale try in the future!

dome13 - 26-11-2020 at 11:30

So, I measured the melting point. I did it twice and got the same results. It was in range of 60-65°C. It is far from 80°C. Now I am insecure in my things. I am still quite sure, that all step of the synthesis went well. Maybe it started decomposing, because it is nearly 1 year old and a bit discoloured. If there were no covid, maybe I could do an FTIR analysis. But anyway, I recommend you to try the synthesis.

greenlight - 26-11-2020 at 12:39

Hmmmm, I remember when I was a teenager about 16 or 17 I attempted TNT synthesis with azeotropic nitric acid in three consecutive nitrations using increasingly higher temperatures and heating times and fresh acids each time.

I ended up with what looked exactly like TNT but the melting point was similar to what you describe. Getting that last nitro group on there requires a bit of bullying (high temp, oleum, long rxn time).

I think we have got mostly dinitrotoluene as the melting point listed online is about 70°C. Very close to what you have recorded and I had too.
I also detonated some and it explodes but not as high order as it should from memory.

aromaticfanatic - 26-11-2020 at 14:16

Quote: Originally posted by dome13  
So, I measured the melting point. I did it twice and got the same results. It was in range of 60-65°C. It is far from 80°C. Now I am insecure in my things. I am still quite sure, that all step of the synthesis went well. Maybe it started decomposing, because it is nearly 1 year old and a bit discoloured. If there were no covid, maybe I could do an FTIR analysis. But anyway, I recommend you to try the synthesis.


Yikes it sounds like you have the dinitrate more than trinitrate. I had my suspicions that it wouldn't have worked. TNT is quite tricky as I had said.

I suggest a recrystallization and making sure the pH is neutral (I think TNT has a neutral pH). It is very possible that if you didn't recrystallize to remove trapped acids the first time, that the pH will be pretty low and is the cause of discoloration.

Try to cool the solvent as slowly as possible. I find keeping it in a large hot water bath to slowly cool off if ideal. The bigger the crystal, the better the purity.

After you have completed a recrystallization I would suggest testing the melting point again. I assume what you have is not the trinitrate though. It seems that a 20C temperature difference is a bit too much.

You will have some TNT in there but possibly in trace amounts.

aromaticfanatic - 26-11-2020 at 14:19

Quote: Originally posted by greenlight  
Hmmmm, I remember when I was a teenager about 16 or 17 I attempted TNT synthesis with azeotropic nitric acid in three consecutive nitrations using increasingly higher temperatures and heating times and fresh acids each time.

I ended up with what looked exactly like TNT but the melting point was similar to what you describe. Getting that last nitro group on there requires a bit of bullying (high temp, oleum, long rxn time).

I think we have got mostly dinitrotoluene as the melting point listed online is about 70°C. Very close to what you have recorded and I had too.
I also detonated some and it explodes but not as high order as it should from memory.


Yes I agree with you. I am pretty certain he has made the dinitrate. Azeotropic nitric acid will definitely never get you to TNT (sadly). That last nitro group is notoriously hard.

Dinitrotoluene is indeed explosive but less so than TNT. What you describe is indeed very similar to what dome has and since we know for a fact you did not have TNT, I suspect dome has DNT.

What a bummer. I wish TNT were easier to make haha. I prefer plastic explosives but having a small sample of such a classic explosive is pretty awesome.