NMR Spectroscopic Analyses of o-and m-Xylenesulfonic Acids. Preparation of m-Xylene-5-sulfonic Acid

Abstract

The effects of reaction temperature on the isomer distribution in the monosulfonation of o- and m-xylenes have been studied in 96 % sulfuric acid. m-Xylene-5-sulfonic acid was obtained in a good yield from m-xylene-4- and m-xylene-4-sulfonic acids were prepared by sulfonation of o- and m-xylenes. o-Xylene-3- and m-xylene-2-sulfonic acids were synthesized from the corresponding ami-noxylenes by an adaptation of the method of Moschner11). m-Xylene-5-sulfonic acid was obtained in a considerable yield by heating the 4-sulfonic acid at 200°C with sulfuric acid. The isomeric of the sulfonation products were determined by analyses of their NMR signals of methyl protons. The sulfonic acids were characterized by IR and NMR spectra, and identified by their melting point of sulfonamides and S-benzylthiuronium salts. © 1977, The Society of Synthetic Organic Chemistry, Japan. All rights reserved.