MCM-48分子筛负载磷钨杂多酸催化合成缩醛(酮)

制备了MCM-48分子筛负载磷钨杂多酸H3PW12O40/MCM-48催化剂,并以乙酰乙酸乙酯、环己酮、丁酮、苯甲醛和正丁醛与二元醇(乙二醇,1,2-丙二醇)等为原料合成了环己酮1,2-丙二醇缩酮等10种缩醛(酮)。采用X射线衍射、傅里叶变换红外光谱、核磁共振等方法对试样进行了表征;研究了酮与醇摩尔比、催化剂用量、环己烷用量、反应时间对环己酮1,2-丙二醇缩酮收率的影响。实验结果表明,H3PW12O40在MCM-48分子筛上具有较高的分散性且催化剂仍能保持较大的介孔孔道,负载后的H3PW12O40仍保持着Keggin基本结构;在n(醛/酮)∶n(乙二醇/1,2-丙二醇)=1∶1.4、催化剂的用量占反应物料总质量的0.4%、反应时间60min条件下,10种缩醛(酮)的收率为80.6%～94.2%。

Synthesis of Acetals and Ketals on H3PW12O40/MCM-48 Catalyst

A novel environmental friendly catalyst,H3PW12O40/MCM-48,was prepared by impregnation.Activities of the catalyst in synthesis of a series of acetals and ketals from acetacetic ester,cyclohexanone,butanone,benzaldehyde,butyraldehyde and diatomic alcohol were investigated.The catalysts were characterized by means of XRD,FTIR and 1H NMR.H3PW12O40/MCM-48 with good mesopores is an excellent catalyst for the above syntheses.The Keggin structure of H3PW12O40 keeps unchanged after being impregnated onto surface of the molecular sieve support and its dipersity on latter is promising.Effects of n(aldehyde(ketone)) ∶n(diatomic alcohol),catalyst dosage and reaction time on yields of the products were studied.Under optimal conditions:mole ratio of aldehyde or ketone to glycol 1 ∶1.4,mass ratio of catalyst used to reactants 0.4% and reaction time 1.0 h,yields of acetals or ketals can reach 80.6%～94.2%.