A symposium report on the gas-phase methylation of catechol by methanol on g -Al2O3 modified by the basic elements: K, Li, Mg and Ca. Addn. of 7.5 at % Mg to g-Al2O3 was optimal and increased the 3-Me catechol selectivity from 0.26 to 0.65. X-ray diffraction expts. showed the diffusion of Li+ and Mg2+ cations into the g -Al2O3 bulk. This induces a change in the surface species and the surface acid-base properties. Ca2+ and K+ addn. to g-alumina was ineffective due to formation of basic oxide layers on the surface. [on SciFinder (R)]