Acid functionalized MCM-41 as a catalyst for the synthesis of benzal-1,1-diacetate

Solid acid catalysts for the formation of benzal-1,1-diacetate from benzaldehyde and acetic anhydride were prepared. As a catalyst, four various types of MCM-41 were used. The first was MCM-41 without prior rehydration of its surface, then with hydroxylated surface. The others were functionalized by two commercially available silanol agents; 3-mercaptopropyl and 3-cyanopropyl silane and subsequently oxidized to the corresponding acids. The cyano group was oxidized to carboxylic acid and the mercapto group to sulfonic acid. The use of these catalysts has many advantages e.g. these catalysts are environmentally friendly, recyclable, easily separable from the reaction mixture and the reaction is very fast and chemoselective. Using MCM-41 functionalized by carboxyl groups as a catalyst, benzal-1,1-diacetate was obtained in high yield (87 %) and high selectivity (99 %).