Use of delaminated zeolites (ITQ-2) and mesoporous molecular sieves in the production of fine chemicals: Preparation of dimethylacetals and tetrahydropyranylation of alcohols and phenols

Article abstract of DOI:10.1006/jcat.2000.2861

The combination of zeolitic acidities, easy reactant accessibility, and fast desorption-diffusion of products are determinant issues for designing successful catalysts for acid-catalyzed reactions in the field of fine chemicals production. Protection of aldehydes by formation of the corresponding dimethyl acetals and of alcohols and phenols by formation of the corresponding tetrahydropyranyl ethers were performed using ITQ-2 zeolite as acid catalyst. Its catalytic activity for these reactions was compared with those obtained with MCM-22, Beta zeolites, and the mesoporous aluminosilicate MCM-41, all with similar Si/Al ratios. When the reactions involved bulky reactants, ITQ-2 showed, in all cases, the highest activity as a consequence of the combination of its delaminated structure and the presence of strong acid sites. The zeolitic nature of the acid sites present in the delaminated ITQ-2 zeolite made the acid sites more stable than those present in the short range amorphous MCM-41 molecular sieve, providing the former catalyst better activity and thermal regenerability. ITQ-2 and MCM-41 are active and selective catalysts for acetalization reactions involving reactants as large as diphenylacetaldehyde and cholesterol.