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采用一步法分别制备了单金属介孔催化剂Ti-SBA-15-(36)、Mo-SBA-15-(180/28)和双金属介孔催化剂Mo-Ti-SBA-15-(X)。考察了双金属催化剂Mo-Ti-SBA-15-(X)中Mo含量对催化剂结构和催化性能的影响;分析了催化剂活性差异的原因并探讨了双金属催化剂的协同催化机理。对影响催化环氧化反应的主要因素进行了考察。结果表明:双金属催化剂Mo-Ti-SBA-15-(180/28)在环氧化反应中的催化效果优于单金属催化剂。当反应时间为8 h、反应温度为80℃、催化剂剂量为25 mg、以2.5 mmol环己烯为底物、叔丁基过氧化氢(TBHP)为氧源、1,2-二氯乙烷为溶剂时,Ti-SBA-15-(36)、Mo-SBA-15-(180/28)和Mo-Ti-SBA-15-(180/28)为催化剂对应的环己烯转化率分别为41.07%、46.44%和98.33%,选择性分别为97.56%、93.19%和98.86%。Mo-Ti-SBA-15-(180/28)催化剂经过5次循环利用,环己烯的转化率和选择性均超过95%和97%,说明该催化剂具有很好的可循环利用性。
Single-metal mesoporous catalysts Ti-SBA-15- (36), Mo-SBA-15- (180/28) and bimetallic mesoporous catalysts Mo-Ti-SBA-15- (X) were prepared by one- The effect of Mo content in the bimetallic catalyst Mo-Ti-SBA-15- (X) on the structure and catalytic performance of the catalyst was investigated. The reasons for the difference in the catalyst activity were analyzed and the synergistic catalysis mechanism of the bimetallic catalyst was also discussed. The main factors affecting the catalytic epoxidation were investigated. The results show that the catalytic effect of the bimetallic catalyst Mo-Ti-SBA-15- (180/28) in the epoxidation is better than that of the monometallic catalyst. When the reaction time was 8 h, the reaction temperature was 80 ℃ and the catalyst dosage was 25 mg, 2.5 mmol of cyclohexene as substrate and tert-butyl hydroperoxide (TBHP) as oxygen source, 1,2-dichloroethane As the solvent, the conversion of cyclohexene corresponding to Ti-SBA-15- (36), Mo-SBA-15- (180/28) and Mo-Ti-SBA- 15- (180/28) 41.07%, 46.44% and 98.33%, respectively, with selectivities of 97.56%, 93.19% and 98.86% respectively. After 5 cycles of recycling of Mo-Ti-SBA-15- (180/28) catalyst, the conversion and selectivity of cyclohexene were more than 95% and 97%, indicating that the catalyst has good recyclability.