Montmorillonite Clay Catalyzed Tosylation of Alcohols and Selective Monotosylation of Diols with p-Toluenesulfonic Acid: An Enviro-Economic Route

✍ Scribed by Boyapati M. Choudary; Naidu S. Chowdari; Mannepalli L. Kantam

• Book ID: 104202912
• Publisher: Elsevier Science
• Year: 2000
• Tongue: French
• Weight: 169 KB
• Volume: 56
• Category: Article
• ISSN: 0040-4020
• DOI: 10.1016/s0040-4020(00)00626-8

✦ Synopsis

An enviro-economic route for tosylation of alcohols and selective monotosylation of diols in good yield directly using p-toluenesulfonic acid together with metal-exchanged montmorillonite instead of p-toluenesulfonyl chloride or p-toluenesulfonic anhydride is described. The Fe 3ϩ -montmorillonite clay is the most effective catalyst among metal-exchanged montmorillonites for such tosylation reactions. The activity follows the sequence Fe 3ϩ ϾZn 2ϩ ϾCu 2ϩ ϾAl 3ϩ -montmorilloniteϾK10 montmorillonite. Regioselective tosylation of diols to monotosylated derivatives is achieved with high purity. In diols having both primary and secondary hydroxy groups, tosylation occurred only at the primary hydroxy group. The solid catalyst displayed consistent activity for several cycles as exemplified in tosylation of cyclohexanol.