Reactions of styrene and derivatives with sulfur trioxide; characterization and chemistry of the initial products

✍ Scribed by Ruud M. Schonk; Bert H. Bakker; Hans Cerfontain

• Publisher: Elsevier Science
• Year: 2010
• Tongue: English
• Weight: 553 KB
• Volume: 111
• Category: Article
• ISSN: 0165-0513
• DOI: 10.1002/recl.19921110106

✦ Synopsis

Abstract

The reactions of styrene derivatives 1a‐14a with sulfur trioxide were studied in the temperature range −60 to 25°C using dichloromethane as solvent and 1.5 mol equiv. of dioxane as reactivity moderator. Reaction of styrene (1a) at low temperature yields the carbyl sulfate 1c as the only observable intermediate in the ultimate formation of (E)‐2‐phenylethene‐1‐sulfonic acid (1d). The (phenyl) substituted styrenes 3a‐5a clearly demonstrate the presence of the β‐sultones 3b‐5b as the sole initial products leading to the corresponding carbyl sulfates 3c‐5c. The initially formed β‐sultone b in the reaction of styrene derivatives 3a‐5a, 9a and 10a with 1.0 mol equiv. of SO~3~ disproportionates to yield equal amounts of the corresponding carbyl sulfate and the starting styrene. This is thought to indicate that there is an equilibrium between the β‐sultone and the starting styrene. The group of the 1‐methyl‐substituted styrenes 11a‐13a are an exception to the generally observed eventual conversion of the initial intermediates into the 2‐sulfonic acids d, since they give the corresponding 3‐sulfonic acids f.

Mechanisms for the formation of the various products are proposed.