TiO_2负载磷钨杂多酸催化剂催化合成缩醛(酮)

以TiO2负载磷钨杂多酸(H3PW12O40/TiO2)为催化剂,对以乙酰乙酸乙酯、环己酮、丁酮、苯甲醛和正丁醛与二元醇(乙二醇,1,2-丙二醇)为原料合成2-甲基-2-乙氧羰甲基-1,3-二氧环戊烷、2,4-二甲基-2-乙氧羰甲基-1,3-二氧环戊烷、环己酮乙二醇缩酮、环己酮1,2-丙二醇缩酮、丁酮乙二醇缩酮、丁酮1,2-丙二醇缩酮、2-苯基-1,3-二氧环戊烷、4-甲基-2-苯基-1,3-二氧环戊烷、2-丙基-1,3-二氧环戊烷、4-甲基-2-丙基-1,3-二氧环戊烷10个缩醛(酮)的反应条件进行了研究。较系统地研究了醛或酮与二元醇摩尔比、催化剂用量、反应时间诸因素对收率的影响。结果表明,在n(醛或酮)∶n(乙二醇或1,2-丙二醇)=1∶1.5,催化剂的用量占反应物料总质量的1.25%,反应时间为1 h条件下,10种缩醛(酮)的收率为45.2%~92.2%。

Catalytic Synthesis of Acetals and Ketals with H3PW12O40/TiO2

A new environmentally-friendly catalyst H_3PW_(12)O_(40)/TiO_2 was prepared,and was used in the synthesis of a series of acetals and ketals starting from ethyl acetate,cyclohexanone,butanone,benzaldehyde,butyraldehyde,ethylene glycol and 1,2-propanediol.The optimum reaction conditions were found,i.e.,n(aldehyde/ketone)∶n(glycol)=1∶1.5,m(catalyst)∶m(reactants)=(0.0125),and reaction time 1.0 h.The products and yields were 2-methyl-2-ethoxycarbonylmethyl-1,3-dioxolane(76.1%),2,4-dimethyl-2-ethoxycarbonylmethyl-1,3-dioxolane(74.5%),cyclohexanone ethylene glycol ketal(70.3%),cyclohexanone 1,2-propanediol ketal(78.4%),butanone ethylene glycol ketal(45.2%),butanone 1,2-propanediol ketal(63.4%),2-phenyl-1,3-dioxolane(73.2%),4-methyl-2-phenyl-1,3-dioxolane(77.6%),2-propyl-1,3-dioxolane(68.9%),and 4-methyl-2-propyl-1,3-dioxolane(92.2%).