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froot
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Apologies if this has been discussed, but Mendeleev, in your experience, have you found the optimum amount of water to dump the complete reaction in?
TNP being soluble in H2O, you will obviously lose some yield to solution. I speculate that if you use too little water you'll end up with
sodium/potassium sulfate in your yield if you use the corresponding nitrates, and if you use too much H2O, obviously more of the TNP will dissolve and
escape extraction. There must be an optimum here again and would this be calculated against the amount of H2SO4 used?
I've also found that after filtration I almost freeze the mother liqour and a second batch of crystals form, slightly different in appearence to
the first batch. Would I be correct in assuming the second batch is contaminated with sulfates, DNP and MNP?
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Mendeleev
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I usually use 10 mL cold water and 15g of crushed ice per 1 gram asa nitrated. I am not sure if this is the optimum ratio, but it gives satisfactory
yields.
Trogdor was a man. A dragon man. Or maybe just a dragon. . .
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FloridaAlchemist
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Keep Picric acid wet Dangerous when dry
Picric acid is Dangerous when dry.
Should be stored wet,or under water until needed.
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Mendeleev
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Thanks for your concern Florida Alchemist, but I usually store my picric acid in a cool dry place, and I haven't really had any problems. In
World War I all the artillery shells full of picric acid were stored dry, they didn't have too many problems.
Trogdor was a man. A dragon man. Or maybe just a dragon. . .
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sylla
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I've done TNP resulting in pale yellow crystals.
When I tried to drop TNP into ammonia to make Ammonium Picrate they immediatly turned deep-yellow when the NH3 gaz touched them.
So I've done Ammonium Picrate and kept half of the original amount of TNP to see what happend when I put NH3 on them.
Ammonium Picrate crystals were very deep yellow, TNP through NH3 yellow and original TNP pale yellow.
What is the color of -normal- TNP ? yellow or pale yellow ? What happened exactly with the NH3 gaz ?
Thx for your reply 
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Mendeleev
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As I mentioned I have been storing my picric acid dry up until now, however http://en.wikipedia.org/wiki/Halifax_Explosion . What was Florida Alchemist saying about wet storage?
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Bert
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Every couple of years I hear about some high school's chemistry lab store room blowing up from a jar of picric acid stored dry for too long. Not
sure of the specifics, but I understand it undergoes a change in crystaline form on standing a long time dry. This is NOT a short term storage issue,
but you shouldn't be storing HE anyways.
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Mendeleev
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Does anybody know if one of those paint respirators that one can buy at Lowes or Home Depot (not the dust mask, the actual half-face respirator with
filters) will filter NO2 fumes?
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Haggis
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The one I have, the purple banded P100, will filter nitrogen dioxide. Make sure on the package, it lists acid gas as one of the substances it is able
to filter.
For general nitrations, you shouldn't need a respirator as long as you keep upwind and outside.
Great ideas often receive violent opposition from mediocre minds.
<b> <a href=\"http://pgp.mit.edu:11371/pks/lookup?op=get&search=0xEE41A2B1\">PGP Key</a> </b> 0C0A 7486 B97F
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Darkfire
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Always keep a respirator nearby though, i can think of serveal times i was happy i did, or wishing i had.
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will seek knowledge from those wiser and teach those who wish to learn from me.\" Duane Allman
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thunderfvck
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Okay. I give up.
Sorry to bring up a dead topic but I have a question!
Okay. The chemical equation. I can't find it ANYWHERE, and I need it! I want to work at the mechanism and such but cannot without the equation.
From, phenol, it is no problem. I found it in vogel:
PhOH + H2SO4 ---> o-phenolsulphonic acid & p-phenolsulphonic acid + HNO3 ---> TNP
Quite straight forward!
But with aspirin, hmmm...I just don't know.
Acetic acid would make a nice leaving group from aspirin, especially considering all the acid to protonate the carbonyl orxygen, then water can attack
the carbonyl carbon and acetic acid can leave. Obvious hydrolysis. Then you can have the lone oxygen pick up a proton and there's the hydroxyl.
Is this correct? I'm not so sure considering the solvent is 95% H2SO4, and not water with a catalytic amount of H2SO4.
Then there's that damned actyl group. How the hell is he dealt with?The only way I can think of is just as the former was dealt with. The water
attacks and out comes carbonic acid. But what the hell. This sounds so wrong!
And from there it would be just phenol reacting with the usuals.
But this seems quite wrong. I need assistance!
Another thing, I take it that adding the KNO3/whichever nitrate salt just creates HNO3 in situ?
Thanks guys!
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AngelEyes
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This is what I got from www.powerlabs.org
Aspirin (Acetyl Salicylic Acid) is mixed with Sulphuric Acid.
The sulfuric acid breaks down the acetylsalicylic acid to acetic and salicylic acid.
C9H8O4 -------> C2H4O2 + C7H4O2
Then with gentle heating the Salicylic acid hydrolyses (with the little water in the Sulphuric) to Carbon Dioxide and Phenol.
C7H4O2 + H2O ---> C6H6O + CO2
You now have Phenol, Sulphuric and you then add your xNO<sub>3</sub> to the mix.
C6H5OH + H2SO4 => (HO.C6H4.SO3H + H2O) + HNO3(aq) => C6H3N3O7
Any good to you?
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Marvin
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This is what happens when people dont use structural formulae for working things out. You end up with a pile of shit that just makes sense in terms
of conservation of atoms.
I'm very glad you got this elsewhere Angel, because it alows me to rant, and thats always fun.
Asprin, C6H4(OOCCH3)(COOH)
Which would be C9H8O4, so thats correct.
Salicylic acid, an OH, and a COOH next to eachother on a benzene ring.
C6H4(OH)(COOH)
Which would be C7H6O3, not C7H4O2
Asprin is an ester, you can see that from the structure and esters need to be hydrolysed to get the alcohol and the acid. So its acid catalysed
hydrolysis to get to salicylic acid.
Phenol, C6H5OH
We only need a decarboxylation to get this from salicylic acid.
These arnt trivial mistakes chemically, esters hydrolyse we all know that, its clueless atom counting. Use structural formulae!
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AngelEyes
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My apologies if that was not as accurate as it should have been - I was a little busy and didn't check it as I should have done. Powerlabs is
usually pretty good...
Aside from the errors in the formulae, though, does it accurately illustrate the reaction process? ie how you get from ASA to TNP?
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thunderfvck
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Well son of a bitch. I thought I looked at that site and found nothing, but evidently it's right there before my face!!
So I had it partly right then, ester hydrolysis to salicylic acid then decarboxylation. Excellent!
But is this a useful way in making phenol? I guess not, as the phenol would now take on an SO3H (o or p) group which would direct the NO2's
(meta!!) from coming in, then the SO3 would leave and the final NO2 would strike.
And of course the concentrated H2SO4 converts the NO3 into NO2 which is easily accepted. But sulphonation can only occur in dilute acid, no? Otherwise
the equilibrium is strongly shifted towards product. But I have no choice here. Unless much of the acid is reacted with by this point.
Yes, this is how the reaction takes place! Much more interesting and rewarding to know it this way!
Thanks for the help!
[Edited on 11-6-2004 by thunderfvck]
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thunderfvck
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Well I tried it twice now.
THe first time I used about 4.5 g of ASA in 40 ml of H2SO4, 9 g of NH4NO3 was added slowly. Nothing special, NO2 vapours, yes, about a 3 g yield of
TNP.
But I did it again tonight, on a larger scale. It was much more exciting. 19 g ASA, 50 ml of H2SO4, 28 g of NH4NO3. MAD NO2 vapours. My god, it was
intense. The bubbling was furious, I'm glad I used my 250 ml RB flask. I got the red goo as madscientist had reported, but I no longer see it
having dumped about 350 ml of water in it. The heat was hard to control. THe higher the temperature, more NO2 vapours, which is what I had been aiming
for the whole time. I equated that with a more thorough reaction though I doubt this is the case. Acetic acid began to boil off at one point and
jesus, did it stink. I'll post my yields tomorrow but I was wondering, maybe the red goo formation is due to using less H2SO4? I had no problems
with it the first time by using a lot more H2SO4. The temperature didn't get out of hand as much either the first time around.
In either case, it was a very fun experiment!!
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thunderfvck
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Alright, well in both cases I let the mix sit in the fridge overnight to fully crystallize out. The first time I got about a 40 something % yield.
Poor! But this time, using less acid, I got a 63% yield! I also expect to get more as I usually obtain a bit more after filtering and letting it sit
for some time. So close to 70%! I think this is very good. However I am very uncertain as to it being entirely TNP, I recall Philou stating that other
products can be formed, all of which are yellow. Well, I'll be recrystallizing tonight and I'll take a melting point to ensure what I got is
the real deal.
BTW, this stuff STAINS REALLY BAD! My god. It looks like I've mutated! My hands are yellow all over!
Oh, and I take it the NO2 vapours are due to the decomposition of HNO3 which evidently takes place at higher temperatures. I wonder if I dissolved all
the NH4NO3 at low temperatures (where I noticed practically no foaming whatsoever), how my yields would look, hmmm....
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thunderfvck
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FINALLY.
I've just spent three hours putting together the mechanism in chemdraw.
<a href="http://lobstertales.tripod.com/lab/TNP/tnpmech1.jpg">Part 1</a>
<a href="http://lobstertales.tripod.com/lab/TNP/tnpmech2.jpg">Part 2</a>
<a href="http://lobstertales.tripod.com/lab/TNP/tnpmech3.jpg">Part 3</a>
<a href="http://lobstertales.tripod.com/lab/TNP/tnpmech4.jpg">Part 4</a>
Good?
What happens to the SO3H cation? I know in dilute acid it reforms H2SO4, will the same apply in concentrated acid? Seeing as how it doesn't have
anywhere else to go...
[Edited on 14-6-2004 by thunderfvck]
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