单质碘催化合成缩醛(酮)

Catalytic Synthesis of Acetals and Ketals with Iodine

以单质碘为催化剂，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）为原料合成了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2-2-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）=1：1，3，催化剂的用量占反应物料总质量的0.4%，反应时间为40～60min条件下，10种缩醛（酮）的收率为45.2%～92.2%。

Catalytic activities of lodine in synthesizing 2-methyl-2-ethoxycarbonylmethyl-1,3-dioxolane,2,4-dimethyl-2-ethoxy-carbonylmethyl-1,3-dioxolanc,cyclohexanone ethylene ketal,eyclohexanone 1,2-propanedion ketal,butanome ethylene ketal,butanone 1,2-propanediol ketal,2-phenyl-1,3-dioxolane,4-methyl-2-phenyl-1,3-dioxolane,2-propyl-1,3-dioxolane,4-methyl-2-propyl-1,3-dioxolane were reported.It has been demonstrated that Iodine is an excellent catalyst.Various factors concerned in these reactions have been investigated.The optimum conditions have been found,that is,the molar ratio of aldehyde/ketone to glycol is 1/1.3,the mass ratio of the catalyst used to the reactants is 0.4%,and the reaction time is 40～60min.Under these conditions,the yield of 2-methyl-2-ethoxycarbonylmethyl-1,3-dioxolane is 63.8%,and 2,4-dimethyl-2-ethoxycarbonylmethyl-1,3-dioxolane is 70.7%,the yield of cyclohexanone ethylene ketal is 85.9^,and cyclohexanone 1,2-propanediol ketal is 88.8%,the yield of butanone ethylene ketal is 45.2%,and butanone 1,2-propanediol ketal is 86.9%,the yield of 2-phenyl-1,3-dioxolane is 803%,and 4-methyl-2-phenyl-1,3-dioxolane is 86.3%,the yield of 2-propyl-1,3-dioxolane is 83.6%,and 4-methyl-2-propyl-1,3-dioxolane is 91.2%.