Preparation of isosorbide by dehydration of sorbitol on hierarchical Beta zeolites under solvent-free conditions

A series of hierarchical Beta zeolites (Q-β) were synthesized using the silanization template method. The characterization results suggested that the pore structure and acidity of the catalysts were influenced by varying the Si/Al molar ratio in the precursor. For the reaction of dehydration of sorbitol to isosorbide, the Q-β-46(8) catalyst exhibited significantly improved catalytic performance with a yield of up to 83 % after 12 h of reaction at moderate temperature (170 °C), higher than any other zeolite catalysts. The catalyst maintained good catalytic performance after five cycles. The unique activity might be attributed to its excellent secondary porosity (77.66 %), higher Brønsted acidic site concentration (63.18 μmol/g) and BAC/LAC ratio (0.172).