MSU-S mesoporous materials: An efficient catalyst for isomerization of α-pinene

MSU-S(BEA) and MSU-S(Y) mesoporous molecular sieves with different Si/Al ratios were prepared and characterized by XRD, XRF, N2 adsorption, 27Al MAS NMR, NH3-TPD and 2,6-di-tert-butyl-pyridine adsorption. Their catalytic behavior for the liquid phase isomerization of α-pinene has been investigated and compared with conventional zeolites and mesoporous molecular sieves. The activity correlates well with the amount of the accessible acid sites on the catalyst surface. MSU-S(BEA) with Si/Al ratio of 67 has the highest activity in comparison to others. Ninty-seven percent conversion of α-pinene and 91% yield for main products like camphene, limonene, tricylene and terpinolene can be obtained at 70 °C. The catalyst is stable and reusable, and the product yield is only reduced by 10% after four runs, which is probably caused by the slow dealumination in the framework wall during the reaction.