单质碘催化合成缩醛（酮）

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-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40～60 min条件下,10种缩醛(酮)的收率为45.2%～92.2%.

Catalytic Synthesis of Acetals and Ketals with Iodine

Catalytic activities of Iodine in synthesizing 2-methyl-2-ethoxycarbonylmethyl-1,3-dioxolane, 2,4-dimethyl-2-ethoxycarbonylmethyl-1,3-dioxolane, cyclohexanone ethylene ketal, cyclohexanone 1,2-propanediol ketal, butanone 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 40~60 min. 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 80.3%, 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%.