Sciencemadness Discussion Board

Cheap way of synthesizing TNP? Am I crazy?

joseph6355 - 13-11-2017 at 19:10

First of all. I can be wrong.
I should be wrong, because this is too good to be true.

http://www.powerlabs.org/chemlabs/picric.htm
I was reading about the synthesis of TNP on powerlabs, and I came across the TNP from ASA part.
Yeah, we all know that its possible, but hear me out on this:

------------H2SO4
C9H8O4 -------> C2H4O2 + C7H4O2
(The sulfuric acid breaks down the acetylsalicylic acid to acetic and salicylic acid)

Or if Salicylic acid is used,
C7H4O2 + H2O ---> C6H6O + CO2
(Salicylic acid with heat source converts to carbolic acid (phenol) and carbon dioxide; (in presence of water from 98% H2SO4)

Salicylic acid is cheaper than acetylsalicylic acid, plus, you don't need to recrystallize ASA neither buy Aspirin, which costs more than buying ASA itself.
After the phenol has been obtained and sulfonated to Phenol-4-sulfonic acid, you can use Sodium Nitrate and blah blah blah.

The point is that...
Phenol costs 110-430 USD per kilogram.
68% Nitric Acid costs 40-100 USD per Liter.

Salicylic Acid costs 26 USD per kilogram.
And Sodium Nitrate costs just 9 bucks for a whole 1 kilogram!

The price for the 98% Sulfuric Acid is 38 USD.
(*)

Assuming that we use Phenol and Nitric Acid, we would pay 128 USD for the chemicals and obtain 533 grams of crystallized TNP.
If we use Salicylic Acid and Sodium Nitrate, we would pay only 36,42 USD for the chemicals and obtain 420 grams of recrystallized TNP.
(**)

That is a big difference.
86.71 USD for 1kg of TNP from Salicylic Acid and Sodium Nitrate vs 240 USD of TNP from Phenol and Nitric Acid.

Considering that TNP is about as powerful as TNT and has 20% more sensitivity to shock, we are basically getting a secondary HE for pennies.
Yes, TNP can sublime with time and react with metals to form dangerous salts, but as long as you keep it in a sealed plastic container in a dark place, you are OK. They used to transport TNP in large quantities before all of this overreaction started.
There is no need for a layer of water, it's not going to blow up like a primary explosive, ITS SAFE.
But of course, if you are paranoid you can always go for Ammonium Picrate. You will need a booster charge though.

Is there anything wrong with what I've said? It sound too good to be true.

(*)Prices found on the internet. They can vary from region to region.
(**)Based on the results from this video https://www.youtube.com/watch?v=7es7kMAZyFY

[Edited on 14-11-2017 by joseph6355]

Bert - 14-11-2017 at 12:49

I have never seen an amateur make picric acid starting with phenol. Aspirin usually. You can buy it pure by the pound from veterinary suppliers for cheaper than you estimated. I once used oil of wintergreen (methyl salicylate), I would not do that again.

The price for phenol quoted is probably reagent grade by the litre from a lab supply company? It's not the price you would pay per litre when buying a railroad tank car full of technical grade phenol.

Attachment: methylricinoleate.pdf (42kB)
This file has been downloaded 497 times

Microtek - 15-11-2017 at 03:31

Indeed, phenol is too reactive to be nitrated directly (much like aniline), but I could certainly see salicylic acid working just fine. I don't think there is anything wrong with the proposed process, except perhaps an overestimation of the cost.

GrayGhost- - 15-11-2017 at 15:30

I syntetised long long time ago when benzene was OTC, i used Benzene, nitric acid 65% and mercury nitrate ( catalisator), my improvised reflux condesator was inefficeint then benzene go. Remain in the flask a yellow foam what paint my finger of yellow for two weeks. Never more replicate.




[Edited on 15-11-2017 by GrayGhost-]

[Edited on 15-11-2017 by GrayGhost-]

joseph6355 - 15-11-2017 at 16:34

Interesting.
In my country we can buy phenol very cheap (about $10/lb), and there is no watch list neither a limit of how much you can buy.
Sulfuric acid in the other hand is limited to 2 liters a month. If you want to buy more you need a license, or then you can ask your friend to use his SSN instead of yours. Same thing for nitric acid.

Microtek, what did you mean by "phenol is do reactive nitrate directly"?
I was thinking about synthesizing TNP both ways to compare the stability and yield, but I would use the same method as for Salicylic Acid, first sulfonating it to 4-phenolsulfonic acid and then nitrating with sodium nitrate.
I saw a synthesis where TNP was synthesized from phenol and potassium nitrate, so I don't see why it wouldn't work. The source of this synthesis is LambdaSyn.

[Edited on 16-11-2017 by joseph6355]

Bert - 15-11-2017 at 16:55

You might want to go read some of the MASSIVE amount of material on trinitrophenol synthesis already posted here-

There are ways to do what you want with phenol. But the reportedly successful/efficient syntheses are not done quite as you describe.

Start here, then branch out and look at the (many!) similar threads-

Picric acid from Phenol thread, 2015
Quote: Originally posted by Hennig Brand  
Try this it works:

Quote: Originally posted by a_bab  
Try this one. It's a russian method for labs.

94 grams of phenol (1 mole) should be heated at 100 degrees C and add 300 g of H2SO4 monohydrate under agitation. Heat the mix for 1 hour at 100-110 degrees C, then cool it down to 0 degrees C. Under exterior cooling (less than 0 degrees C) and energical agitation, add drop by drop a mix formed of 220 grams (3,5 moles) of HNO3 of 98 % and 220 grams of H2SO4 monohydrate. After all the sulfonitric mix has been added, left the mix at the room temperature overnight and then heat it at max. 45 degrees C, for an hour with agitation. Because the reaction is not finished at 45 degrees, 50 ml from the reaction mass is taken out and heated on a sand bath at 110-125 degrees C. In the heated mass the rest of the mix is added drop by drop under energycal agitation. Afterwards is should kept at 120 degrees and some water should be added until the H2SO4 will be 40 % concentrated (about 700 ml of water). If the reaction was conducted in good conditions a small quantity of NO2 will be released. TNP which will crystalize on cooling and it's not soluble in H2SO4 40 % will be filtered, and washed with cold water. The total amount of TNP obtained it'll be around 210 grams.

Nevermind the mistakes as I translated this on the fly.


This was taken from the first page of the very lengthy thread on picric acid found here:
http://www.sciencemadness.org/talk/viewthread.php?tid=389#pi...

There is a huge amount of information on picric acid in various places on this forum, but you may need to dig a little.

joseph6355 - 15-11-2017 at 17:36

Quote: Originally posted by Bert  
You might want to go read some of the MASSIVE amount of material on trinitrophenol synthesis already posted here-

There are ways to do what you want with phenol. But the reportedly successful/efficient syntheses are not done quite as you describe.

Start here, then branch out and look at the (many!) similar threads-

Picric acid from Phenol thread, 2015


Quote: Originally posted by Hennig Brand  
Try this it works:

Quote: Originally posted by a_bab  
Try this one. It's a russian method for labs.

94 grams of phenol (1 mole) should be heated at 100 degrees C and add 300 g of H2SO4 monohydrate under agitation. Heat the mix for 1 hour at 100-110 degrees C, then cool it down to 0 degrees C. Under exterior cooling (less than 0 degrees C) and energical agitation, add drop by drop a mix formed of 220 grams (3,5 moles) of HNO3 of 98 % and 220 grams of H2SO4 monohydrate. After all the sulfonitric mix has been added, left the mix at the room temperature overnight and then heat it at max. 45 degrees C, for an hour with agitation. Because the reaction is not finished at 45 degrees, 50 ml from the reaction mass is taken out and heated on a sand bath at 110-125 degrees C. In the heated mass the rest of the mix is added drop by drop under energycal agitation. Afterwards is should kept at 120 degrees and some water should be added until the H2SO4 will be 40 % concentrated (about 700 ml of water). If the reaction was conducted in good conditions a small quantity of NO2 will be released. TNP which will crystalize on cooling and it's not soluble in H2SO4 40 % will be filtered, and washed with cold water. The total amount of TNP obtained it'll be around 210 grams.

Nevermind the mistakes as I translated this on the fly.


This was taken from the first page of the very lengthy thread on picric acid found here:
http://www.sciencemadness.org/talk/viewthread.php?tid=389#pi...

There is a huge amount of information on picric acid in various places on this forum, but you may need to dig a little.


Wait, you're telling me that I can't sulfonate Phenol to 4-phenolsulfonic acid?

Rosco Bodine - 16-11-2017 at 18:04

This may be of interest for experimenting with an alternative approach to TNP.

http://www.sciencemadness.org/talk/viewthread.php?tid=4457&a...

more discussion here

http://www.sciencemadness.org/talk/viewthread.php?tid=389&am...

It would seem likely that introducing a mixed strong solution of nitrate and nitrite at the bottom of a stirred reaction flask containing extra H2SO4 sufficient for reaction with the nitrate and nitrite would produce the reactive nitrous gas values in situ, as an alternative to using a separate external nitrous gas generation scheme. The interesting aspect for this reaction system is that it is a relatively mild condition substantially aqueous solution reaction mixture.

joseph6355 - 17-11-2017 at 00:12

Quote: Originally posted by Rosco Bodine  
This may be of interest for experimenting with an alternative approach to TNP.

http://www.sciencemadness.org/talk/viewthread.php?tid=4457&a...

more discussion here

http://www.sciencemadness.org/talk/viewthread.php?tid=389&am...

It would seem likely that introducing a mixed strong solution of nitrate and nitrite at the bottom of a stirred reaction flask containing extra H2SO4 sufficient for reaction with the nitrate and nitrite would produce the reactive nitrous gas values in situ, as an alternative to using a separate external nitrous gas generation scheme. The interesting aspect for this reaction system is that it is a relatively mild condition substantially aqueous solution reaction mixture.

Hi Rosco! :)
Seems very interesting indeed.
It would require a gas sealed apparatus though, wouldn't it? I don't think it's doable, at least with my skills. And I'm also very lazy, I don't feel like setting up all of this glassware together.
I wonder if it would result in a better yield.

Oh, do you think it would be possible to nitrate phenol to TNP by using sodium nitrate instead of nitric acid? I mean, by sulfonating it, we would have 4-phenolsulfonic acid, which is the same precursor to TNP as it would if we were using ASA.
I don't see a reason why it wouldn't work like the other guy said.
In the end, ASA is being reacted with H2SO4 to form salicylic acid and acetic acid, and then the salicylic acid is converted to phenol when heated. CO2 is also formed. Then, phenol sulfonates to the precursor I mentioned and is nitrated with sodium nitrate.

I would like to dissect the theory before I actually try it.
I might not fully understand all the theory, but I like to try at least. :P
The results I get from this experiment will be reported then, and pictures posted.

[Edited on 17-11-2017 by joseph6355]

Rosco Bodine - 17-11-2017 at 02:47

Phenol is not involved in the process reaction sequence as an intermediate. You either aren't reading or aren't understanding the reactions that do occur. Picric acid can be made from phenol but that is not what is occurring when the starting material is ASA or salicylic acid which is then sulfonated followed by nitration of the sulfonate.

It should not require a gas sealed apparatus, but provision for exhausting any unreacted nitrous gas would be needed, due to the fume hazard. Proper venting is a survival conscious plan to follow routinely for young chemists who want to live long enough to become old chemists.

Microtek - 17-11-2017 at 05:44

I just mean that if you try nitrating phenol as you would pentaerythritol, you will get a violent reaction with oxidation of some of the ring carbons, leaving a mess, and poor yields. Therefore you need to deactivate the ring a little first, eg. by sulfonation.

You can read about it in COPAE which can be found here on SM.

[Edited on 17-11-2017 by Microtek]

joseph6355 - 18-11-2017 at 01:22

Quote: Originally posted by Rosco Bodine  
Phenol is not involved in the process reaction sequence as an intermediate. You either aren't reading or aren't understanding the reactions that do occur. Picric acid can be made from phenol but that is not what is occurring when the starting material is ASA or salicylic acid which is then sulfonated followed by nitration of the sulfonate.

It should not require a gas sealed apparatus, but provision for exhausting any unreacted nitrous gas would be needed, due to the fume hazard. Proper venting is a survival conscious plan to follow routinely for young chemists who want to live long enough to become old chemists.

Oh, I thought 4-phenolsulfonic acid could be formed by sulfonating phenol and it could be reacted with a nitrating salt.

joseph6355 - 18-11-2017 at 01:25

Quote: Originally posted by Microtek  
I just mean that if you try nitrating phenol as you would pentaerythritol, you will get a violent reaction with oxidation of some of the ring carbons, leaving a mess, and poor yields. Therefore you need to deactivate the ring a little first, eg. by sulfonation.

You can read about it in COPAE which can be found here on SM.

[Edited on 17-11-2017 by Microtek]

But I would need nitric acid for that, wouldn't I?
I can get my hands on nitric acid, and even fuming nitric acid (99%), but it costs a lot (like 159 USD for a Liter of fuming nitric acid).
The purpose of the thread is to reach an agreement on how to synthesize a secondary HE for cheap. TNP seemed like a good choice.

caterpillar - 18-11-2017 at 05:43

I made TNP starting from phenol. In my youth, it could be obtained in the shop with reagents. Sulfur acid, otherwise, couldn't be obtained there without special permission - one had to go to another shop and buy there concentrated electrolyte (sulfur acid, 94% approximately). 800 gr of phenol was dissolved in 800 gr of sulfur acid and kept for one hour in hot water bath (100 Celius, boiling water). Then this mist was cooled. One kg of kalium nitrate was mixed with 1500- 2000 gr of sulfur acid. After cooling solution of phenol in sulfur acid was added by small portions (during this process temp shouldn't be too hi) to the mixture of kalium nitrate with sulfur acid. Then this mix was left for a night. next day one-hour treatment with the hot water bath. Temp should be slowly increased and one hour at 100 Celsius (boiling water bath). Then pour this mixture into the large volume of cold water, preferably with crushed ice. Then to filter yellow crystals. That's all. (kalium nitrate can be replaced with natrium one, but I couldn't recommend ammonium nitrate- once I tried it and got large volume of NOx during nitration)

caterpillar - 18-11-2017 at 05:44

Sorry, I meant 250 gr of phenol, not 800!!!!

Rosco Bodine - 19-11-2017 at 02:16

Quote: Originally posted by joseph6355  
Quote: Originally posted by Rosco Bodine  
Phenol is not involved in the process reaction sequence as an intermediate. You either aren't reading or aren't understanding the reactions that do occur. Picric acid can be made from phenol but that is not what is occurring when the starting material is ASA or salicylic acid which is then sulfonated followed by nitration of the sulfonate.

It should not require a gas sealed apparatus, but provision for exhausting any unreacted nitrous gas would be needed, due to the fume hazard. Proper venting is a survival conscious plan to follow routinely for young chemists who want to live long enough to become old chemists.

Oh, I thought 4-phenolsulfonic acid could be formed by sulfonating phenol and it could be reacted with a nitrating salt.



You began by advocating for the cost effectiveness of salicylic acid being used as a starting material, but stated incorrectly what occurs by sulfonation, which produces a sulfosalicylic acid not phenolsulfonic acid. Phenol is not an intermediate in the sulfonation
of ASA or salicylic acid, both of which produce the same sulfosalicylic acid.

Then you speak further about how for you phenol is a more convenient and economical starting material. So it is mysterious what you are arguing if ASA or salicylic acid are not relevant to your choice of phenol as a starting material. The reactions and process using phenol as a starting material are well documented.

In either case the sulfonation product is then nitrated, and use of a nitrate salt as one method is an old and well documented process.

Information I was trying to convey is that it has been reported that a milder nitration mixture is possible where a more dilute nitration mixture is reported using "nitrous gases" to accomplish the nitration. That is a reaction condition that may be possible to be achieved more conveniently using a solution of mixed nitrate and nitrite. Such a scheme for nitration should be applicable regardless of the starting material being ASA, salicylic acid, or phenol.

nitro-genes - 19-11-2017 at 13:01

Quote: Originally posted by Bert  
I once used oil of wintergreen (methyl salicylate), I would not do that again.


What exactly happened during the nitration, what did the product look like? Apparently, methylsalicylate can be nitrated to the 3,5 dinitro derivative (patent US4439278, example 4) So it seems only the decarboxylation is problematic, curious how the methylgroup interferes with ipso nitration, maybe because CO2 is a better leaving group or oxidation of the methylgroup leads to a runaway?.

How does the replacement of the sulfonic and carboxy group take place anyway? Is it by direct ring substitution mediated by NO2+ or NO2, or via some other intermediate? One of the things that bothers me for the synthesis of TNP by the high temperature nitration of the sulfonated salicylic acid using SA/NaNO3 is the large amount of NO2 produced. Is this a consequence of ispo nitration or just representative of partial product loss by oxidation? If the latter, TNP might be better produced by a low temperature nitration of salicylic acid to 3,5 dinitrosalicylic acid (DDNP thread, page 25), then performing the decarboxylation at higher temperatures last.


The Volatile Chemist - 20-11-2017 at 09:20

Quote: Originally posted by nitro-genes  
Quote: Originally posted by Bert  
I once used oil of wintergreen (methyl salicylate), I would not do that again.


What exactly happened during the nitration, what did the product look like? Apparently, methylsalicylate can be nitrated to the 3,5 dinitro derivative (patent US4439278, example 4) So it seems only the decarboxylation is problematic, curious how the methylgroup interferes with ipso nitration, maybe because CO2 is a better leaving group or oxidation of the methylgroup leads to a runaway?.

How does the replacement of the sulfonic and carboxy group take place anyway? Is it by direct ring substitution mediated by NO2+ or NO2, or via some other intermediate? One of the things that bothers me for the synthesis of TNP by the high temperature nitration of the sulfonated salicylic acid using SA/NaNO3 is the large amount of NO2 produced. Is this a consequence of ispo nitration or just representative of partial product loss by oxidation? If the latter, TNP might be better produced by a low temperature nitration of salicylic acid to 3,5 dinitrosalicylic acid (DDNP thread, page 25), then performing the decarboxylation at higher temperatures last.



I, too, am curious as to what transpired in this particular nitration, definitely got a good laugh at " would not do that again."

joseph6355 - 22-11-2017 at 06:50

Quote: Originally posted by Rosco Bodine  
Quote: Originally posted by joseph6355  
Quote: Originally posted by Rosco Bodine  
Phenol is not involved in the process reaction sequence as an intermediate. You either aren't reading or aren't understanding the reactions that do occur. Picric acid can be made from phenol but that is not what is occurring when the starting material is ASA or salicylic acid which is then sulfonated followed by nitration of the sulfonate.

It should not require a gas sealed apparatus, but provision for exhausting any unreacted nitrous gas would be needed, due to the fume hazard. Proper venting is a survival conscious plan to follow routinely for young chemists who want to live long enough to become old chemists.

Oh, I thought 4-phenolsulfonic acid could be formed by sulfonating phenol and it could be reacted with a nitrating salt.



You began by advocating for the cost effectiveness of salicylic acid being used as a starting material, but stated incorrectly what occurs by sulfonation, which produces a sulfosalicylic acid not phenolsulfonic acid. Phenol is not an intermediate in the sulfonation
of ASA or salicylic acid, both of which produce the same sulfosalicylic acid.

Then you speak further about how for you phenol is a more convenient and economical starting material. So it is mysterious what you are arguing if ASA or salicylic acid are not relevant to your choice of phenol as a starting material. The reactions and process using phenol as a starting material are well documented.

In either case the sulfonation product is then nitrated, and use of a nitrate salt as one method is an old and well documented process.

Information I was trying to convey is that it has been reported that a milder nitration mixture is possible where a more dilute nitration mixture is reported using "nitrous gases" to accomplish the nitration. That is a reaction condition that may be possible to be achieved more conveniently using a solution of mixed nitrate and nitrite. Such a scheme for nitration should be applicable regardless of the starting material being ASA, salicylic acid, or phenol.

That explains a lot.
Thanks.