SiO2负载Ti(SO4)2-Zr(SO4)2复合固体酸催化剂的制备及催化性能

摘要

Silica-supported titanic sulfate and zirconium sulfate solid acid catalyst (Ti(SO4)2Zr(SO4)2/SiO2) was prepared by impregnation method.The supported catalyst was characterized by TG,acidimetric analysis,FT-IR and XRD.The effects of calcination and loading amount on the catalyst activity were investigated.The results indicate that the catalyst prepared has a esterification rate of 95.6％ at the conditions of a catalyst dossage of 20 g for 1 mol of oleic acid,a molar ratio of methanol to oleic acid of 4,a reaction temperature of 85 ℃ and a reaction time of 5 h.It is found after the catalyst was continuously used for 5 times,the esterification rate drops to below 80％ because of coking,proved by infrared analysis of deactivated catalyst,but the activity of the catalyst can successfully recovered after activation by roasting and/or supplementing certain amount of active components needed.%以Ti(SO4)2和Zr(SO4)2为活性组分,以SiO2为载体,通过浸渍法制备复合固体酸催化剂Ti(SO4)2-Zr(SO4)2/SiO2.采用TG、酸量分析、FT-IR、XRD等方法对催化剂进行表征,考察焙烧温度、活性组分负载量对催化剂性能的影响.结果表明,催化剂制备的适宜条件为:焙烧温度300℃、焙烧时间3h、活性组分负载量50％.将制备的催化剂用于油酸甲酯的合成反应,在催化剂用量20 g/mol、醇酸摩尔比4、反应时间5h、反应温度85℃的条件下,酯化率达到95.6％.催化剂的重复使用性能考察结果表明,在不经处理的条件下连续使用5次后,酯化率下降到80％以下.对失活催化剂的红外光谱分析结果表明,积炭是催化剂失活的主要原因,可通过焙烧、补充活性组分恢复其催化性能.