Epoxidation of Linear Olefins over Stacked TS-1 Zeolite Catalysts

Stacked TS-1 [NSTS-1(MW)] has been prepared by microwave synthesis and applied to the epoxidation of linear olefins with H2O2 under mild conditions, and the epoxidation activities were compared with the non-stacked TS-1 and the conventional TS-1, which were also synthesized by microwave and by typical hydrothermal method, respectively. Stacking of TS-1 crystals was accomplished by using microwave which facilitated the dehydration of hydroxyl groups on the external surface of crystallites through the selective absorption of microwave onto Ti species. The stacked crystallites seemed to allow the running pore structure in the b-axis orientation through the crystallites in the stacked morphology. Besides this unique pore structure, the stacked TS-1 showed peculiar features like higher hydrophobicity and enhanced catalytic property than typical TS-1. Moreover, the NSTS-1(MW) showed the highest activity in the epoxidation of linear olefins among three catalysts, and also coincided with the differences in the adsorption of linear aliphatics due to strong interaction with the straight channel in the stacked morphology, which gave larger Henry's constants, obtained by the tracer chromatographic analysis, as the increase in the carbon chain length.