Picric acid synth overdone? Nitration buffs

[mattb]

Forgive me for drawing comparisons with the TNT synthesis(nitration of toluene), but I suspect picric acid synthesis is overdone at least for a pyro's needs. I've heard stories of how much of a bitch the transition from DNT to TNT can be without a hot reaction environment or very concentrated HNO3 and H2SO4. Recall that the methyl group in DNT is a mild electon donating group, yet there are two extra nitro group deactivating the ring. Coming back to picric acid, I wonder why the synths for picric have such concentrated reactants HNO3 and H2SO4. Couldn't one get away with a mild heat source and considerably more dilute reactants like 70% H2SO4 and potassium nitrate because of the hydroxy group in phenol? OH- is a good EDG and stable in resonance. So, did anyone get away with a comparably lower budget synth? Please share your various nitration experiences with different starting materials.

[FUTI]

First post an question!?
hint: you will have problem with NBK.
You obviously have some chemical knowledge or you have researched it elsewhere...if so why in the Gods name you didn't spot that search button that every forum (and so naturally this one too) has.
hint: UTFSE!

When you do so, if NBK doesn't find you before or he isn't hungry today you will notice that most of your questions is asked and answered (at least I see it that way). Question is interesting, and deserve attention at least from production point of view. Let me strike back with another question. If HO- group activates that ring towards nitration, why does ussually we use salicylic acid for synthesis of picric acid? Wouldn't that -COOH block that position for nitration and deactivate the ring?

It is nice to see that students and learners are visiting this forum...but learn more please, we wish you long and prosperous life, to be able to do that you must quickly learn that in explosives chemistry every experiment is your's first one. Picric acid synthesis is a bitch known to bite those who knows little (sometimes even those who knows a lot!).

[Jacks Complete]

in explosives chemistry every experiment is your's first one.And if it is a big beaker full of stuff, it might be your last.

I don't see the harm with a specific and nice question like this FUTI - has it been asked and answered elsewhere?

[mattb]

I assure you picric acid is not priority on my agenda, but its higher than AP and HMTD because these have some downright scary (unstable) looking structures. Can ring strain get any worse? My post didn't come as much as a question, but rather a proposal. Phenol is much more difficult to acquire than aspirin; however, I have seen synths that react acetylsalicy. with H2SO4. H2SO4 is expensive, so why not use HCL. It's same with nitration: HNO3 is used, but it is little more than an expensive way to boost H3O+ conc for nitronium ion formation (NO2+). From what I remember, HCL is more acidic than HSO4-, so adding HCL dropwise to a solution with H2SO4 and (insert metal)N03 seems feasible.

[ultrabuf]

I have read that HCl can be used to get a greater amount of precipitate in the TNP synth, posted on a different forum by Rosco Bodine I believe.

[The_Duke]

If HO- group activates that ring towards nitration, why does ussually we use salicylic acid for synthesis of picric acid? Wouldn't that -COOH block that position for nitration and deactivate the ring?

We use acetylsalicylic acid because it is easily and cheaply available, as opposed to phenol. The HO- radical may activate the ring, but it also makes it more susceptible to oxidation. The -COOH radical is very reactive and does not interfere with nitration much as long as the benzene ring contains a SO2-OH group.

I assure you picric acid is not priority on my agenda, but its higher than AP and HMTD because these have some downright scary (unstable) looking structures. Can ring strain get any worse?

And you can tell that just by looking at the structures, but you are asking a jack-assy question like “can ring strain get any worse”? :rolleyes:

Phenol is much more difficult to acquire than aspirin; however, I have seen synths that react acetylsalicy. with H2SO4. H2SO4 is expensive, so why not use HCL. It's same with nitration: HNO3 is used, but it is little more than an expensive way to boost H3O+ conc for nitronium ion formation (NO2+). From what I remember, HCL is more acidic than HSO4-, so adding HCL dropwise to a solution with H2SO4 and (insert metal)N03 seems feasible.

Because it doesn’t work that way…

Learn more chemistry (or atleast show more of a willingness to learn and not ask stupid newbie questions) and for the love of god use the fuckin’ SEARCH button!!!).

[FUTI]

Duke I'm quite aware of what you are talking. That should be a test question for our newbie to think about and answer. It is obvious that he has learned more then an average kewls that bump here do. It is overconfidence he shows that scared me. I got an impresion that he didn't quite comprehend all that he learned/read.

Jack I agree...I wrote above that this is interesting question...but why did he open a new thread instead of finding some old one is beyond my imagination. I was thinking of going back and quote in this thread particular posts from other threads that could give him an answer for the question he made but since he already has make another "assumption" that I (and it seems Duke too) don't find correct, I give up spoonfeeding - and just strongly advise looong reading on the subject before next post.