Accelerated synthesis of Sn-Beta with high Sn content by tuning crystallization temperature

The crystallization temperature was investigated for the hydrothermal synthesis of Sn-Beta. The crystallization curves of Sn-Beta at different temperature were performed and the crystal growth activation energy was obtained. The synthesized samples, especially the fully crystallized Sn-Beta, were characterized by XRD, SEM, ICP, UV-vis DRS, XPS, FT-IR spectroscopy of framework vibration and pyridine adsorption. The results indicate that the crystallization time shortened from 7 days to 1 day for Sn-Beta with n Si / n Sn of 100 when the crystallization temperature was increased from 140 °C to 180 °C. But no crystal was obtained as the crystallization temperature was higher than 180 °C. The catalytic performance of the fully crystallized Sn-Beta obtained at different crystallization temperature was slightly different in the conversion of ethyl levulinate (EL) to γ-valerolactone (GVL) and the conversion of glucose to methyl lactate due to the slight difference in silanol defects. Sn-Beta with n Si / n Sn of 80 can also be successfully synthesized after crystallization at 160 °C for 3 d, which shows much higher activity and selectivity than Sn-Beta with n Si / n Sn of 100 for the conversion of EL in high concentration (1.6 mol L −1 ) to GVL.