纳米介孔Ru-PPh_2-SBA-16催化水相中高烯丙醇异构化反应的研究

Studies on Isomerization of Homoallylic Alcohol in Water over the Nanostructured Mesoporous Ru-PPh_2-SBA-16 Catalyst

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.

Based on the serf-assembly of F127, a new SBA-16-1ike mesoporous silica modified with diphenylphosphine 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.