An Extremely Active Solid Acid Catalyst, Nafion Resin/Silica Composite, for the Friedel−Crafts Benzylation of Benzene and p-Xylene with Benzyl Alcohol

Abstract

Nafion resin, a recently developed Nafion resin/silica composite, and triflic acid are very effective catalysts for the Friedel−Crafts benzylation of benzene (at 80 °C) and p-xylene (at 100 °C) with p-methylbenzyl alcohol under ambient pressure. The composite is nearly 2 orders of magnitude more active than plain Nafion resin beads and even more active than the strong triflic acid based on the same amount of acid groups in the catalysts. The commercial Amberlyst-15 resin catalyst and p-toluenesulfonic acid (p-TSA) are inactive catalysts. Flowing nitrogen through the reactor to carry out the byproduct water was found to be very beneficial for driving the benzylation reaction to completion.