Aromatic sulfonation 84. Sulfonation of bi- and tri-phenylene

✍ Scribed by Hans Cerfontain; Khosrow Laali; Hans J. A. Lambrechts

• Book ID: 104588449
• Publisher: Elsevier Science
• Year: 2010
• Tongue: English
• Weight: 350 KB
• Volume: 101
• Category: Article
• ISSN: 0165-0513
• DOI: 10.1002/recl.19821010905

✦ Synopsis

Abstract

The mono‐ and di‐sulfonation of biphenylene (1) and triphenylene (2) with SO^3^ in nitromethane as solvent at 0°C has been studied. The monosulfonation of both 1 and 2 leads exclusively to the formation of the 2‐sulfonic acid. In the case of 1, this results from the lower cation localization energy of the 2‐ as compared with the 1‐substitution; with 2, the substitution at the 1‐position is prevented by large steric hindrance. The sulfonation of biphenylene‐2‐sulfonic acid yields 65 % 2,6‐ and 35 % 2,7‐disulfonic acid, while that of triphenylene‐2‐sulfonic acid yields 59% 2,6‐, 1% 2,7‐ and 40% 2,11‐disulfonic acid. For both bi‐ and tri‐phenylene‐2‐sulfonic acid, the reactivity order of the sterically accessible positions in the non‐sulfo‐containing rings is governed by the (electronic) directing effect of the 2‐SO~3~H substituent.