Abstract: The synthesis of methylal from methanol and methanal over different types of molecular sieves was studied. A batch reactor was employed. In a molar ratio of 1∶2 of methanal to methanol and in the presence of 5%(mass fraction) the cata lyst, five sorts of catalysts (HZSM-5, HY, HM, Hβ and γ-Al₂O ₃) were tested at 30 ℃, among them, HZ SM-5 showed the best catalytic activity. HZSM-5 with 38∶1 of Si to Al and 4 of exchange degree was extremely effective for this reaction. The conversion rate of mathanal was 45% and the selectivity of methylal was 99%, both the conversion rate and the selectivity were reproducible after th e catalyst was reused for 20 times.

Key words: organic synthesis, methylal, catalyst, evaluate