稀土改性复合固体超强酸SO_4^(2-)/TiO_2-MoO_3-La_2O_3催化剂催化合成缩醛(酮)

Synthesis of Acetals and Ketals over Solid Super Acid Catalyst Modified with Rare Earth Element——SO_4^(2-)/TiO_2-MoO_3-La_2O_3

研究了稀土改性复合固体超强酸SO42-/T iO2-M oO3-La2O3催化剂的制备方法,催化剂的适宜制备条件为:n(La3+)∶n(T i4+)=1∶34、M oO3的质量分数25%、硫酸的浸泡浓度0.5mol/L、硫酸浸泡时间24h、焙烧温度450℃、活化时间3h。以SO42-/T iO2-M oO3-La2O3为催化剂,对以乙酰乙酸乙酯、环己酮、丁酮、苯甲醛、正丁醛与二元醇(乙二醇、1,2-丙二醇)为原料合成10种缩醛(酮)的反应条件进行了研究,较系统地研究了醛(酮)与二元醇摩尔比、催化剂用量、反应时间对收率的影响。实验结果表明,在n(醛(酮))∶n(乙二醇(1,2-丙二醇))=1.0∶1.5、催化剂用量占反应物料总质量的0.8%、环己烷为带水剂、反应时间60m in的条件下,10种缩醛(酮)的收率在56.9%~88.2%之间。

Solid super acid catalyst modified with rare earth element SO4^2-/TiO2 -MoO3 -La2O3 was prepared. Optimal preparation conditions were： n （ La^3 ＋ ） ： n （ Ti^4 ＋ ） = 1 ： 34, mass fraction of MoO3 25 % , concentration of impregnating HE SO4 solution 0. 8 mol/L, impregnating time 24 h, calcination temperature 450 ℃ ,and calcination time 3 h. SO4^2-/TiO2 - MoO3 - La2O3 was used as catalyst for synthesis of acetals or ketals, namely 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, and 4 - methyl - 2 - propyl - 1,3 - dioxolane. Effects of n（aldehyde（ketone） ） ： n（glycol）, catalyst mass fraction and reaction time on yield of acetals or ketals were investigated. Under optimal reaction conditions： n （ aldehyde （ketone） ） ： n （ glycol ） 1.0 ： 1.5, mass fraction of catalyst in reactants 0.8 %, reaction time 60 min and cyclohexane as water - stripping agent 8 mL, yields of 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 and 4 - methyl - 2 - propyl - 1,3 - dioxolane were 71.6%, 75.5 %, 82.6%, 82.5 %, 56.9% ,88.2% ,73.3% ,73.6% ,74.1% ,and 72.8% ,respectively.