09-15-04 05:11
No 531370
hey guys did a lot of research and checked out the synth's out their on Phenylacetic acid, my question is in regards to mandelic Acid, because i read of rhodium's site this is on prep for PAA... is it suitable to use this if im wanting to pump out "alot" of PAA also it seemed the easyiest to conduct so are their any disadvantages to this?
Also... i have a heap of Methylbenzoate i mean HEAPS that i bought, can it be used for anything productive?
Thanks guys, alan... last thing ive been dieing to know this but whose "SWIM" ??? LOL
(Stranger)
09-15-04 09:50
No 531417
Well for Methylbenzoate pump it into TFSE (The Fuckin Search Engine) if its usefull, youll find out about it.
Second of all SWIM is Someone Who Isnt Me, But if you read the FAQ you would know that.
I suggest you read the FAQ
Your an individual just like everyone else.
09-16-04 02:33
(Rated as: UTFSE!)
(Hive Addict)
09-16-04 03:32
No 531533
(Rated as: good read)
You might try reading some of this post, suggest the whole thread to get the flavor of the post.....java
Post 250348 (ChemicalSolution: "PE-Br --> PAA", Chemistry Discourse)
Post 108296 (dormouse: "phenylacetic acid -Scooby Doo", Novel Discourse)
Post 106952 (Acme: "Re: bezaldehyd --> PAA +++ check this out !! +++", Chemistry Discourse)
Post 98347 (Mo Diddly: "Re: Acetic anhydride from acetic acid and a salt", Chemistry Discourse)
.....also try to use the search function on this board, you'd be suprised how much you can learn
It is better to die on your feet than to live on your knees.......
-Emiliano Zapata-
(Hive Bee)
09-17-04 03:43
No 531707
benzoatefan, I didn't appreciate beeing asked for P2P or PAA (I think it was P2P) about a month ago either.
If I had any, I wouldn't be giving it to my own mother let alone you.
UTFSE.
09-17-04 08:35
(Rated as: Use The Fucking Search Engine; Quit Complaining !!!!)
(Stranger)
09-19-04 12:47
No 532132
Good inquiring question in my opinion! I for one would like to see more posts regarding PAA questions, procedures & practices. I'm so sick of seeing flame happy bee's preying upon posts just to say "Hey Dumbass, Use TFSE!!!" Especially when thier status is rather newbee or stranger themselves.
I do agree TFSE is an invaluable archive but times and practices change along with chem aquisition, etc. TFSE should be the first step before posting but next comes posting questions & insights or even theories/ideas. I believe jumping on a fellow bee for an ocasional dumb question hurts the whole comunity. So he wanted to know what SWIM referred to, who cares, the PAA question could have sparked up a good discusion, posibly answering questions I have of my own.
Props go to JAVA for contributing to the actual question at hand and guiding the post in a positive direction. Thanks for the third reference I havn't researched that one yet. thanks.
Gspot
(Hive Addict)
09-20-04 00:15
No 532216
Sometimes by reading a reaction from different points of view, some insight is gathered , as all was needed for something to be worded in a different way. With that in mind here is another synthesis of PAA which can be read here..........java
http://www.worldwideschool.org/library/b
Note: edited by java, as a bonus many other synthesis are available on this same site, check it out..
It is better to die on your feet than to live on your knees...Emiliano Zapata
(Chief Bee)
09-20-04 02:06
No 532244
(Rated as: good read)
Phenylacetic Acid
Submitted by Roger Adams and A. F. Thal.
Checked by O. Kamm and A. O. Matthews.
Org. Synth. Coll. Vol 1, p. 436 (http://www.orgsyn.org/orgsyn/prep.asp?p
Procedure
In a 5-l. round-bottom flask, fitted with a mechanical stirrer and reflux condenser, are mixed 1150 cc. of water, 840 cc. of commercial sulfuric acid (Note 1) and 700 g. (6 moles) of benzyl cyanide (p. 107). The mixture is heated under a reflux condenser and stirred for three hours (Note 2), cooled slightly, and then poured into 2 l. of cold water. The mixture should be stirred so that a solid cake is not formed; the phenylacetic acid is then filtered off. This crude material is melted under water and washed by decantation several times with hot water. These washings, on cooling, deposit a small amount of phenylacetic acid which is filtered off and added to the main portion of material. The last of the hot water is poured off from the material while it is still molten, and it is then transferred to a 2-l. Claisen distilling flask and distilled under reduced pressure. A small amount of water comes over first and is rejected; about 20 cc., containing an appreciable amount of benzyl cyanide, then distils. This fraction is used in the next run. The distillate boiling at 176–189°C/50 mm. is collected separately and solidifies on standing. It is practically pure phenylacetic acid, m.p. 76–76.5°C, and weighs 630 g. (77.5 per cent of the theoretical amount) (Note 3). As the fraction which is returned to the second run of material contains a considerable portion of phenylacetic acid, the yield actually amounts to at least 80 per cent.
For the preparation of small quantities of phenylacetic acid, it is convenient to use the modified method given in (Note 3).
Notes
1. The standard directions for the preparation of phenylacetic acid specify that the benzyl cyanide is treated with dilute sulfuric acid prepared by adding three volumes of sulfuric acid to two volumes of water. The reaction, however, goes so vigorously that it is always necessary to have a trap for collecting the benzyl cyanide which is blown out of the apparatus. The use of the more dilute acid, as described in the above directions, is more satisfactory.
The odor of phenylacetic acid is disagreeable and persistent.
2. The phenylacetic acid may also be made by boiling under a reflux condenser for eight to fifteen hours, without a stirrer, but this method is not nearly so satisfactory as that described in the procedure.
3. The following modified procedure can be used for the preparation of small quantities of the acid. One hundred grams of benzyl cyanide is added to a mixture containing 100 cc. of water, 100 cc. of concentrated sulfuric acid, and 100 cc. of glacial acetic acid. After this has been heated for forty-five minutes under a reflux condenser, the hydrolysis is practically complete. The reaction mixture is then poured into water, and the phenylacetic acid is isolated in the usual manner.
Discussion
The standard method for the preparation of phenylacetic acid is the hydrolysis of benzyl cyanide with either alkali1 or acid.2 The acid hydrolysis runs by far the more smoothly and so was the only one studied. Phenylacetic acid can also be prepared by the carbonation of benzylmagnesium chloride3 and by the catalytic reduction of mandelic acid.4
References
1. Cannizzaro, Ann. 96, 247 (1855); Mann, Ber. 14, 1465 (1881); Bodroux, Compt. rend. 151, 236 (1910).
2. Staedel, Ber. 19, 1950 (1886).
3. Austin and Johnson, J. Am. Chem. Soc. 54, 655 (1932).
4. Zelinsky, Packendorff, and Leder-Packendorff, Ber. 67, 301 (1934).
The Hive - Clandestine Chemists Without Borders
(Stranger)
09-22-04 10:24
No 532666
thanks Gspot i appreciate that bro :)
guys i was wanting to know becuase i read of of rhodiums site a synth for PAA using Mandelic acid which seems very easy infact the easiest out of the bunch since it only required mandelic acid and red phosphorus and well prob. ether also which is no biggie... so my question was if this procedure clearly seems the easiest, A) is it good to use if ur wanting to pump out large amounts of PAA and B) what disadvantages are their, if people have possibly already proven it to work?
thanks guys :)
(Chief Bee)
09-22-04 18:48
No 532716
is it good to use if ur wanting to pump out large amounts of PAA
It depends on your particular situation, what chemicals you have access to etc. Only you can answer that question.
what disadvantages are their, if people have possibly already proven it to work?
That the Iodine & red Phosphorus used in the reaction are listed precursors in some parts of the world.
The Hive - Clandestine Chemists Without Borders
(Stranger)
09-23-04 02:32
No 532755
the problem has never been having access to the chemicals i have access to all of them mentioned, however the procedure is the problem, but anyway, KI mentioned in the synth.. is that Potassium Iodide ??? and also sodium bisulphite and sodium sulphate are the others that are mentioned right?? i couldnt find any iodine specially.....
thanks..