USE OF MESOPOROUS MCM-41 ALUMINOSILICATES AS CATALYSTS IN THE PREPARATION OF FINE CHEMICALS - A NEW ROUTE FOR THE PREPARATION OF JASMINALDEHYDE WITH HIGH SELECTIVITY

alpha-n-Amylcinnamaldehyde (Jasminaldehyde) has been prepared with hig h selectivity and using low ratios of benzaldehyde/heptanal by means o f mesoporous molecular sieve catalysts and a process which involves th e acetalization of heptanal with methanol, followed, in the same pot, by a slow hydrolysis of dimethylacetal and the aldolic condensation of the two aldehydes as the final step. A large pore zeolite (Beta) as w ell as mesoporous silica-aluminas with regular pore sizes such as MCM- 41 and SAM have been used as catalysts. The results indicate that meso porous silica-aluminas with a very narrow range of pore diameter such as MCM-41 are the most adequate catalysts to produce in one pot the th ree consecutive reactions, avoiding in a very large extent the self-co ndensation of heptanal and undesired consecutive reactions. This new r oute allows us to achieve Jasminaldehyde with high selectivity and wit h a relative high global reaction rates. The influence of the concentr ation of acid sites on MCM-41, reaction temperature, and molar ratio o f the reactants have been also studied. (C) 1998 Academic Press.