MCM-48分子筛负载硅钨酸催化合成环己酮1,2-丙二醇缩酮

采用浸渍法制备了MCM-48分子筛负载硅钨酸催化剂(H4SiW12O40/MCM-48);采用该催化剂,以环己酮和1,2-丙二醇为原料合成了环己酮1,2-丙二醇缩酮;采用傅里叶变换红外光谱、X射线衍射、核磁共振等方法对试样进行了表征;研究了原料配比、催化剂用量、带水剂环己烷用量、反应时间等因素对合成反应的影响;比较了H4SiW12O40/MCM-48、铌酸、硫酸铁、维生素C催化剂催化该合成反应的活性。表征结果表明,H4SiW12O40在MCM-48分子筛上具有较高的分散度,负载后H4SiW12O40仍保持着Keggin结构。实验结果表明,H4SiW12O40/MCM-48催化剂是合成环己酮1,2-丙二醇缩酮的良好催化剂,在n(环己酮):n(1,2-丙二醇)=1:1.6、催化剂用量为反应物质量的0.6%、带水剂环己烷用量10mL、反应时间45min的优化条件下,环己酮1,2-丙二醇缩酮的收率可达87.2%。

Synthesis of Cyclohexanone 1,2-Propanediol Ketal over H4SiW12O40/MCM-48 Catalyst

A new environment friendly catalyst,H4SiW12 O40/MCM-48,was prepared by impregnation.Cyclohexanone 1,2-propanediol ketal was synthesized from cyclohexanone and 1,2-propanediol in the presence of H4SiW12 O40/MCM-48 as catalyst.The catalyst and product were characterized by means of XRD,FTIR,and 1H NMR.Effects of n(cyclohexanone):n(1,2-propanediol),catalyst dosage,amount of cyclohexane as water entrainer and reaction time on product yield were investigated.Catalytic activities of niobic acid,Fe2(SO4)3·xH2O,vitamin C and H4SiW12O40/MCM-48 as catalysts of the reaction were compared.H4SiW12O40/MCM-48 is most outstanding and the Keggin structure of H4SiW12O40 maintains after its loading on the surface of support.Under optimum conditions:n(cyclohexanone):n(1,2-propanediol)=1:1.6,H4SiW12O40/MCM-48(mass fraction based on total mass of reactants) 0.6%,cyclohexane 10 mL and reaction time 45 min,yield of cyclohexanone 1,2-propanediol ketal was 87.2%.