A method for alkylation of an anhydrosugar compound in which a dialkyl carbonate is reacted with an anhydrosugar compound in the presence of a solid phase basic catalyst. A typical anhydrosugar compound is anhydrosugar alcohol, a dianhydromonoether and mixtures thereof. The reaction step uses zeolyte as the solid phase basic catalyst. The zeolite catalyst is typically a zeolite having ammonium groups. The reaction is carried out at a temperature below 240.degree. C. and the reaction time is 2 hours or less.