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.