MOR/SBA-15复合分子筛的合成、表征及其催化性能评价

Synthesis, Characterization and Catalytic Performance of MOR/SBA-15 Composite Zeolite

采用MOR纳米晶和正硅酸四乙酯为硅源,P123三嵌段共聚物为模板剂水热合成MOR/SBA-15复合分子筛催化剂。采用XRD、SEM、TEM和EDX等手段对催化剂进行了表征,在固定床反应器中评价二甲醚制乙醇催化性能。结果表明,通过控制合适的MOR纳米晶种及MOR纳米晶种在SBA-15水热合成体系中的添加量,可以成功地将MOR纳米晶作为SBA-15的结构单元嫁接到SBA-15的介孔骨架中,水热合成的MOR/SBA-15复合分子筛催化剂同时具有MOR和SBA-15的XRD特征衍射峰,相比于SBA-15,其比表面积和总孔体积由756 m2·g^(-1),1.07 cm3·g^(-1)降低至628 m2·g^(-1),0.85 cm3·g^(-1),平均孔径由8.1 nm提高到9.3nm,Cu修饰的MOR/SBA-15复合分子筛催化剂同时具有Cu MOR羰基化和Cu SBA-15加氢的双功能催化性能,其催化剂评价结果显示二甲醚转化率为43.6%左右,乙醇选择性为95.3%,Cu MOR/SBA-15复合分子筛催化剂实现了二甲醚到乙醇的一步转化。

The hydrothermal synthesis of MOR/SBA-15 composite zeolite has been achieved by employing MOR nanocrystalline and tetraethyl orthosilicate（TEOS） as silica source, and triblock copolymer P123 as hard template. The catalyst was characterized through an integrated method including XRD, SEM, TEM and EDX, and the corresponding catalytic performance was evaluated in the conversion of diethyl ether（DME） to ethanol in a fixed-bed reactor. The results show that MOR nanocrystalline, a building unit for SBA-15, can be successfully grafted in the mesopore framework of SBA-15 by controlling the addition of MOR nanocrystalline. The obtained composite zeolite possesses both the characteristic diffraction peaks of MOR and SBA-15. The specific surface area and total pore volume, compared with SBA-15, decrease from 756 m2·g^（-1）, 1.07 m3·g^（-1） to 628 m2·g^（-1）, 0.85 m3·g^（-1）, respectively. And the pore diameter in average raises from 8.1 to 9.3 nm. An extra Cu modification of the composite zeolite allows a bifunctional catalytic performance of carbonylation with Cu MOR and hydrogenation with Cu SBA-15. The catalyst evaluation tests show that the conversion of DME is 43.6% and the selectivity to ethanol is 95.3%, indicating a one-step transformation from DME to ethanol over Cu MOR/SBA-15 composite zeolite.