One-pot acetalizations of cyclohexanone. acetophenone and benzophenone were carried out using methanol over H-montmorillonite clay
(a mesoporous material). silica, alumina, and different zeolites such as HFAU-Y.HBeta, H-ZSM-5, and H-mordenite. In all the cases a single
product-the corresponding dimethylacetal-was obtained in high yields. Hemiacetal formation was not observed with any catalyst. A
comparison of catalytic activity indicated that montmorillonite K-10 is the most active catalyst for the reaction. As evidenced by the reaction
time studies, the catalyst decay is greater over the zeolite catalyst than over the clay.