Sciencemadness Discussion Board - Reaction of toluene with acetic acid

Reaction of toluene with acetic acid

Satan - 31-10-2009 at 03:08

When reading old topics in this forum, I found something interesting for amateur chemist like myself. Its reaction of toluene with glacial acetic acid, which produces benzyl alcohol and acetaldehyde at 120 degrees C. Benzyl alcohol synthesis would be nice becouse of its plesant smell, and it also looks easy and not dangerous.

Orginal thread: https://www.sciencemadness.org/whisper/viewthread.php?tid=98...

Is this reaction known by somebody here? Or can somebody check that reference?

UnintentionalChaos - 31-10-2009 at 16:54

Quote: Originally posted by Satan

When reading old topics in this forum, I found something interesting for amateur chemist like myself. Its reaction of toluene with glacial acetic acid, which produces benzyl alcohol and acetaldehyde at 120 degrees C. Benzyl alcohol synthesis would be nice becouse of its plesant smell, and it also looks easy and not dangerous.

Orginal thread: https://www.sciencemadness.org/whisper/viewthread.php?tid=98...

Is this reaction known by somebody here? Or can somebody check that reference?

That appears to be far from a simple reaction. Here is a newer paper on the same conversion.

http://www.springerlink.com/content/m176g45q4uu70758/fulltex...

They use a Pd-Bi catalyst on silica support and run the reaction between 5 and 15atm of of pressure at temperatures of 150-190C

[Edited on 11-1-09 by UnintentionalChaos]

gsd - 1-11-2009 at 04:55

Quote: Originally posted by UnintentionalChaos

Very complex and delicate reaction indeed!
gsd

Attachment: Benzylacetate synthesis.pdf (142kB)
This file has been downloaded 929 times

Satan - 1-11-2009 at 08:17

Maybe I am missing something important, but those reactions that both of you are kindly providing differ from what I am looking for. Reaction that gives benzyl acohol and acetaldehyde is what i am after, not benzyl acetate.

UnintentionalChaos You are saying: "That appears to be far from a simple reaction. Here is a newer paper on the same conversion."

But isnt that different reaction in wich acetic acid is being reduced to acetaldehyde? I would be pleased if somebody proves that I am wrong, even more if somewhere is mechanism of those conversions explained.

entropy51 - 1-11-2009 at 08:25

Quote: Originally posted by Satan

I would be pleased if somebody proves that I am wrong, even more if somewhere is mechanism of those conversions explained.

Perhaps you could track down the reference cited in the image that accompanies the old thread you cited, or even kindly ask if someone here could help you find it. Then perhaps you could try an experiment to prove yourself correct.

Satan - 1-11-2009 at 09:03

I am asking for help becouse I did search for "Gazzetta chimica Italiana" and found many editions, but not form 1931 year. Those books are avaliable at http://www.archive.org but as I said not this one wich contains referenced information, so experiment is probably only way to know for sure.

entropy51 - 1-11-2009 at 10:09

That volume of Gazzetta chimica Italiana is on books.google.com but they aren't allowing full view because it was published post-1923. I think it was from University of California so if there's a member near there they might be able to get it, but it will still be in Italian.

I'm guessing it's a sealed tube reaction at 120 C since toluene refluxes at 110.6 C. There are probably better ways to go from toluene to benzyl alcohol, but none are much fun. Toluene can be oxidized to benzaldehyde then a Cannizaro will give benzyl alcohol.

When all else fails, try the experiment.

[Edited on 1-11-2009 by entropy51]

Nicodem - 1-11-2009 at 11:07

When using a citation like that, which looks like a lot of bullshit ("Toluene shows considerable tendency to react with acetic acid...", yeah right!) you need to be very sceptic about what the author understood of the original source. The reaction in the citation, as is described, obviously has nothing to do with the oxygen oxidation of toluene in acetic acid as described in the paper found by UnintentionalChaos.
If in addition there is no viable mechanism for such a transformation, except maybe a photochemical one, then you need to be doubly sceptical. Even if the reaction is a photochemical Norish variation on a carboxylic acid (never heard about Norish reactions being applicable to COOH groups though), it is certainly not a preparative one, because the acetaldehyde would be much more reactive for further photochemical reactions.

Dear Satan, Gazzetta chimica Italiana is a fairly common journal in the libraries (at least in Europe). I will check the CA abstract of that paper tomorrow, but I seriously doubt it will be enough interesting for me to waste a couple of hours going to the library and back. But you can obviously visit a library yourself.

JohnWW - 1-11-2009 at 14:59

If you are talking about chemistry in Italy from 1922 until 1943, that would have been during the Fa$cist régime, so watch out for any such propaganda in publications from that period. False material may also have been inserted in Italian scientific publications then, to mislead possible enemies.

S.C. Wack - 1-11-2009 at 18:12

It wouldn't surprise me at all if the Italian reference was something similar to the newer process; like an industrial-type air oxidation of toluene where the alcohol was protected from further oxidation by forming the acetate. And by one author condensing details, and someone else copying, and again, soon we are way off. Because I see this a lot, especially in the type of "reference" material of the OP.

Or maybe not. Just saying, if was was just that simple then it would be in use. And searching for toluene + acetic acid may be more fruitful when searching for benzyl acetate as product, instead of the alcohol.

Nicodem - 2-11-2009 at 00:40

Obviously the unknown author of that unknown book, from which Xxxxx posted the excerpt without even providing the reference, never even bother checking the original paper. The CA abstract mentions no benzyl alchol among the products, it mentions no reaction of acetic acid (it is only used as solvent), and the paper is about the oxidation of toluene with nitrous oxides yielding benzaldehyde and benzoic acid (a nowadays well known reaction anyway).

Quote:

Oxidation of toluene by nitrogen oxides. Giacalone, Antonino. Gazzetta Chimica Italiana (1931), 61, 828-32. CODEN: GCITA9 ISSN: 0016-5603. Journal language unavailable. CAN 26:18211 AN 1932:18211 CAPLUS

Abstract

The expts. show that an AcOH soln. of PhMe, satd. with nitrous vapors and exposed to light or heated in a sealed tube at 120, forms BzH, BzOH and a small proportion of unidentified nitrated products. Anhyd. PhMe in glacial AcOH, satd. with a slow current of dried nitrous vapors (from Cu and HNO3 of d. 1.4) (the soln. turns green, and the treatment is continued several hrs.), exposed in a sealed tube (1/3 full) to light from Feb. 20 to Apr. 20 (Palermo) (on opening considerable colorless gas, chiefly N escapes), water added, the aq. layer removed, yields a PhMe layer which was washed successively with water, concd. NaHSO3 and dil. NaOH. Treatment of the NaHSO3 soln. with Na2CO3 yields BzH, while the yellow NaOH soln. acidified with dil. HCl, yields BzOH. The extd. PhMe liquor and the AcOH liquor leave on evapn. small quantities of yellow substances which could not be identified. The reaction is probably: PhMe + N2O3) BzOH + H2O + N2. For comparison, a similar sealed tube was kept in darkness at the same time. Both BzH and BzOH were formed, but in small yields. Other tubes exposed to light for shorter periods showed the same products in yields which varied directly with the time of exposure. A tube contg. the same mixt. heated for 3 hrs. at 120 in darkness gave the same results. A soln. of anhyd. PhMe (25 g.), glacial AcOH and N2O4 (an excess calcd. from the reaction: 2PhMe + N2O4 2BzH + 2H2O + N2, and prepd. by distg. Pb(NO3)2), exposed to light for several days (protected from moisture) and treated as before, yield BzH, BzOH and a small quantity of unidentified nitrated substances. The reaction is probably that above. No intermediate products could be isolated under any of the conditions.

Satan - 2-11-2009 at 01:09

Thank you Nicodem for clarification, and for pointing lack of reference.
Perheaps this topic should be deleted as it provides nothing of value.