纳米介孔Ru-PPh2-SBA-16催化水相中高烯丙醇异构化反应的研究

以2-(二苯基膦)乙基三乙氧基硅烷和正硅酸乙酯为混合硅源, 采用延时共缩聚法经表面活性剂F127自组装合成了二苯基膦(PPh2)修饰的SBA-16纳米介孔分子筛(PPh2-SBA-16), 通过PPh2配体络合Ru(Ⅱ)化合物制备出固载化的Ru(Ⅱ)非均相催化剂(Ru-PPh2-SBA-16), 样品仍然保持了SBA-16的规整孔道结构. 以水相中高烯丙醇异构化反应为探针, 考察了所制备催化剂的催化性能, 发现其对目标产物具有高选择性, 虽然其催化活性略低于对应的均相Ru(Ⅱ)催化剂, 但该催化剂易与产物分离, 且重复使用三次后催化效率基本不变, 活性相与载体结合牢固, 不存在明显的脱落和流失, 因此更适合于工业化应用.

Studies on Isomerization of Homoallylic Alcohol in Water over the Nanostructured Mesoporous Ru-PPh2-SBA-16 Catalyst

Based on the self-assembly of F127, a new SBA-16-like mesoporous silica modified with diphe-nylphosphine group(PPh2-SBA-16) was synthesized by extend co-condensation with tetraethoxysilane(TEOS) and 2-(diphenylphosphino)ethyltriethoxysilane(DPPTS) as the mixed silicon source. The PPh2-SBA-16 was used as a support to immobilize the Ru(Ⅱ) ions through strong coordination between PPh2-group and Ru(Ⅱ), denoted as Ru-PPh2-SBA-16. The characterizations demonstrate that the Ru-PPh2-SBA-16 still remained ordered mesoporous structure. During the isomerization of homoallylic alcohols carried in water as a environmentally friendly medium, the as-prepared Ru-PPh2-SBA-16 catalyst exhibited an excellent selectivity, almost the same as the corresponding homogeneous catalyst RuCl2(PPh3)3]. Although its activity was slightly lower than that of RuCl2(PPh3)3, the Ru-PPh2-SBA-16 could be considered more suitable for industrial application based on the following benefits: (1) The catalyst could be easily separated from the reaction products. (2) The catalyst could be used repetitively at least for 3 times without significant activity decrease. (3) The Ru(Ⅱ) was strongly immobilized on the support which could effectively inhibit the leaching of active sites and protect the environmental pollution from heavy metals.