bfesser
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4-hydroxybenzenesulfonic acid
I was reading through the CR Scientific article on the hydrochloric acid-catalyzed hydrolysis of acetylsalicylic acid to salicylic acid, and noticed
their claim that treatment of ASA with 95 % sulfuric acid at 90 °C yields 4-hydroxybenzenesulfonic acid ("phenolsulfonic acid") as the major
constituent.
Has anyone had any experience with this reaction or seen any articles on it? I did a quick lit. search, but was unsuccessful--turning up only
articles on sulfosalicylic acid. My literature searching skills, apparently need improvement. I'll keep searching.
http://www.crscientific.com/article-aspirin.html
[edit]
Sorry, I forgot to post the Merck Index monograph:
| Quote: | Monograph number: 07246
Title: p-Phenolsulfonic Acid
CAS Registry Number: 98-67-9
CAS Name: 4-Hydroxybenzenesulfonic acid
Additional Names: sulfocarbolic acid
Molecular Formula: C6H6O4S
Molecular Weight: 174.17
Percent Composition: C 41.38%, H 3.47%, O 36.74%, S 18.41%
Literature References: Commercially available as a 65% soln. Prepn by hydrolysis of p-chloro- or p-bromobenzenesulfonic acid: Zollinger, Roehling, US
1321271 (1920); by sulfonation of phenol: Davidson, Byrne, GB 820659 (1959 to Hardman & Holden). Prepn of ammonium salt: Oxley et al., J. Chem.
Soc. 1948, 303.
Properties: Deliquescent needles. Miscible with water, alcohol. |
[Edited on 7/28/09 by bfesser]
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Rosco Bodine
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The initial product of the sulfonation in my observation
of the reaction with 95% H2SO4 is not phenolsulfonic acid but is rather salicylsulfonic acid, as the carboxyl group is not immediately split off. If
the salicylsulfonic acid is nitrated, it acquires at least one nitro group concurrent with the loss of the carboxyl, and it may even acquire two nitro
groups before the splitting off of the carboxyl.....I am not positive what is the number
it may even be on the third. I would have to go back and check my own notes observing the nitration, but it is obvious when the carboxyl splits off
because of the attendant foaming from the evolving CO2.
[Edited on 28-7-2009 by Rosco Bodine]
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