SO_4^(2-)/SnO_2/SBA-15固体酸催化剂的制备及其在环酮缩合反应中的应用

Preparation and Application of SO_4^(2-)/SnO_2/SBA-15 Solid Acid Catalyst for Acetalization of Cyclic Ketones

采用等体积浸渍法制备了不同负载量的固体酸催化剂SO42-/SnO2/SBA-15,利用X射线粉末衍射、N2吸附-脱附和透射电镜等手段对样品进行了表征,并考察了催化剂对4-叔丁基环己酮与乙二醇缩合反应的催化性能.结果表明,SO42-/SnO2催化剂负载于SBA-15后其催化性能明显改善.研究了SO42-/20%SnO2/SBA-15催化剂上部分酮类化合物与乙二醇及1,2-丙二醇的缩合反应,并考察了反应时间和催化剂用量等因素对反应性能的影响.在适宜的温和条件下,一些环酮类底物如环己酮、4-甲基环己酮和4-叔丁基环己酮等均可反应得到相应的缩醛化产物,且催化剂至少可循环使用4次.

SO42-/SnO2/SBA-15 catalyst samples with different amounts of SnO2 were prepared by a wetness impregnation method and characterized by X-ray diffraction,N2 adsorption-desorption,and transmission electron microscopy.Their catalytic performance for the acetalization of 4-tert-butylcyclohexanone with glycol was investigated.The results showed that SBA-15 supported SO42-/SnO2 improved the catalytic activity markedly,which was caused by the increasing surface area of the sulfated tin oxide.The catalytic performance of SO42-/20%SnO2/SBA-15 for acetalization of several cyclic ketones with diols was also explored.Under the optimum conditions,a series of cyclic ketones such as cyclohexanone,4-methylcyclohexanone,and 4-tert-butylcyclohexanone were well transformed into the corresponding products.The catalyst can be reused for several times without any significant loss in catalytic activity.