新型有机-无机杂化物(TB0.5Zr0.5H0.5PW)催化合成苯甲醛乙二醇缩醛反应

A unique organic-inorganic hybrid(TB0.5Zr0.5H0.5PW)used in the catalytic synthesis of benzaldehyde glycol acetal

摘要:

通过离子交换法制备了系列季铵盐锆盐共掺杂磷钨酸催化剂,利用SEM、FT-IR、XRD、XPS、TGA-DTG以及正丁胺电位法等技术手段对催化剂结构、酸度进行表征,并对其催化缩醛反应性能进行研究。考察了催化剂用量、醇醛摩尔比、带水剂量和反应时间对苯甲醛乙二醇缩醛产率的影响。研究表明,TB_0.5Zr_0.5H_0.5PW(TB为四丁基溴化铵)固体酸催化剂具有优异的催化性能,催化剂强的Bronsted酸性、Bronsted与Lewis酸中心间的协同效应及“假液相”特性是该催化剂具有高活性的原因。以TB_0.5Zr_0.5H_0.5PW为催化剂,经响应面优化所得苯甲醛乙二醇缩醛最佳制备工艺条件为：乙二醇与苯甲醛摩尔比1.5:1,TB_0.5Zr_0.5H_0.5PW用量为苯甲醛质量的1.9%,反应时间3 h,带水剂环己烷量12.6 mL,该条件下苯甲醛乙二醇缩醛产率为94.6%。TB_0.5Zr_0.5H_0.5PW固体酸催化剂在重复使用6次后仍然表现出优异的催化性能,表明该催化剂具有较好的工业应用前景。关键词：磷钨酸；季铵盐；缩醛反应；苯甲醛乙二醇缩醛；催化技术 中图分类号：TQ655 文献标识码： A 文章编号：1003-5214 (2020) 01-0000-00

Abstract:

A series of quaternary ammonium zirconium salt co doped phosphotungstic acid catalysts were prepared by ion exchange method. The structure, stability and acidity of the composite catalysts were characterized by SEM, FT-IR, XRD, XPS, TGA-DTG, and n-butylamine potential method. And its catalytic performance during acetalization of benzaldehyde (BH) and glycol (GL) were assessed. Meanwhile, the effects of catalyst amount, the molar ratio of alcohol to aldehyde, the amount of water carrying agent and the reaction time on the yield of benzaldehyde glycol acetal (BEGA) were examined. The results showed that the TB_0.5Zr_0.5H_0.5PW (TB was tetrabutylammonium bromide) catalyst had excellent catalytic activity. The strong Bronsted acidity, synergistic effect between Bronsted and Lewis acid centers, and "pseudo liquid phase" characteristics were the reasons for the high activity of the catalyst. Using TB_0.5Zr_0.5H_0.5PW as the catalyst, the yield of BEGA can reach 94.6% under the conditions optimized via response surface methodology (RSM) with BH/GL molar ratio of 1.5:1, catalyst amount of 1.9% of BH, reaction time of 3 h, and amount of cyclohexane 12.6 mL. The TB_0.5Zr_0.5H_0.5PW solid acid catalyst still exhibited excellent catalytic performance after 6 further uses, indicating that the catalyst had promising industrial application possibilities.