蒸气促进干胶法合成硅胶负载的TS-1纳米晶

采用蒸气促进的干胶法, 在工业硅胶上原位合成出TS-1纳米晶. 先用TS-1合成液浸渍硅胶, 再于130 ℃下和水蒸气作用2 d, 得到硅胶上负载的TS-1纳米晶. 采用XRD, FTIR, UV-Vis和NMR谱以及N2吸附、 ICP、 SEM和TEM等对所得样品进行了表征. 结果表明, 将TS-1纳米晶负载在硅胶上, 其晶粒大小为20 nm左右, Ti进入了分子筛的骨架; 所得的TS-1/silica gel复合材料的比表面积为113.2 m2/g, 平均中孔孔径达到23.7 nm. 将其用于苯的羟基化反应, 以n(C6H6)/n(H2O2)=3进料, 环丁砜为溶剂, 于100 ℃下反应2 h, 苯的转化率达到8.7%, 苯酚的选择性超过99%, 苯的氧化速率(TOF)为11.37, 其催化活性明显高于传统水热合成的TS-1.

Synthesis of TS-1 Nanocrystals on Silica Gel via Steam-assisted Dry Gel Conversion Method

TS-1 nanocrystals were synthesized on silica gel via dry gel conversion method, at first silica gel was impregnated with TS-1 synthesis solution and then followed by steam treatment at 130 ℃ for 2 d. The product was characterized with XRD, FTIR, UV-Vis, NMR, N2 adsorption, ICP, SEM and TEM. The results indicate that TS-1 crystals were grown on silica gel with a size of ca. 20 nm, a BET specific surface area of 113.2 m2/g and a mesopore size of 23.7 nm. The product exhibited a higher catalyst performance than TS-1 powders, which was prepared by conventionally hydrothermal synthesis, for benzene hydroxylation with n(benzene)/n(H2O2)=3 and sulfolane as the solvent at 100 ℃ for 2 h. The benzene conversion and TOF were 8.7% and 11.37, respectively, with more than 99% of phenol selectivity.