Vapor-phase alkylation of aroms. over environmentally benign solid catalysts is a valuable alternative to the conventional alkylation carried out traditionally over mineral acids and Friedel-Crafts type catalysts. Two examples for the development of new, simple, non-corrosive and environmentally safe processes of the selective methylation were reported: (1) the selective (80%) formation of 4,4'-dimethylbiphenyl over H-ZSM-5 zeolite, and (2) the prodn. of 3-methylcatechol over g-alumina modified with Mg2+ and Li+. Mechanistic considerations for the alkylation reactions were discussed. [on SciFinder (R)]