Vapour phase O‐methylation of 2‐naphthol over the solid bases alkali‐loaded silica and Cs‐loaded MCM‐41

Abstract

O‐alkylation of 2‐naphthol has been investigated in the vapour phase over alkali‐loaded fumed silica and Cs‐MCM‐41. Both SiO2 and MCM‐41 had low C‐alkylation activities and no O‐alkylation activity. The introduction of alkali ions considerably increases 2‐naphthol conversion with 2‐methoxynaphthalene being the major product. The activity of the catalysts increases with alkali loading and the basicity of the metal (Cs > K > Na > Li). Very high conversion (∼99%) of 2‐naphthol and selectivity (>95%) for 2‐methoxynaphthalene are obtained over Cs‐loaded fumed silica and MCM‐41. A small amount of 1‐methyl‐2‐hydroxynaphthalene is also formed over the Li‐, Na‐ and K‐loaded silica.