磷钨钼杂多酸/MCM-48催化剂合成缩醛(酮)

采用浸渍法制备了负载型H3PW6Mo6O40/MCM-48催化剂。采用X射线衍射、傅里叶变换红外光谱、核磁共振等方法对催化剂及缩醛(酮)进行了表征。表征结果显示,负载后的H3PW6Mo6O40仍保持着Keggin结构。用H3PW6Mo6O40/MCM-48催化剂对以环己酮、丁酮、苯甲醛、丁醛、乙二醇、1,2-丙二醇为原料合成8种缩醛(酮)的反应条件进行了研究。考察了醛(酮)与二元醇摩尔比、催化剂用量、反应时间对8种缩醛(酮)收率的影响。实验结果表明,在n(醛(酮))∶n(乙二醇(1,2-丙二醇))=1∶1.5、催化剂用量占反应物料总质量的0.6%、反应时间0.5h的条件下,8种缩醛(酮)的收率为67.2%~86.2%。

Synthesis of Acetals and Ketals over H3PW6Mo6O40/MCM-48 Catalyst

A new environmental friendly catalyst, H3PW6Mo6O40/MCM-48, was prepared by impregnation and was characterized by means of XRD, FTIR and 1H NMR. The results showed that Keggin structure of H3PW6Mo6O40 in H3PW6Mo6O40/MCM-48 kept unchanged. Catalytic activities of H3PW6Mo6O40/MCM-48 catalyst in syntheses of cyclohexanone ethylene ketal, cyclohexanone 1,2-propanediol ketal, butanone ethylene ketal, butanal-1,2-propanediol ketal, 2-phenyl-1,3-dioxolane, 4-methyl-2-phenyl-1,3-dioxolane, 2-propyl-1,3-dioxolane and 4-methyl-2-propyl-1,3-dioxolane were separately investigated. Under optimal reaction conditions, mole ratio of aldehyde or ketone to dihydroxy alcohol 1 ∶1.5, mass fraction of catalyst in total reactants 0.6% and reaction time 0.5 h, yields of synthesized acetals or ketals can be in the range of 67.2%-86.2%.