低温陈化法制备SO_4~(2-)/ZrO_2-Al_2O_3固体超强酸催化合成氯乙酸异辛酯

采用ZrOCl2.8H2O和Al(NO3)3.9H2O共沉淀法制备固体超强酸SO42-/ZrO2-Al2O3催化剂。固体超强酸SO24-/ZrO2-Al2O3制备条件为nZr∶nAl=3∶1,-15℃陈化24 h,120℃干燥12 h,浸渍液硫酸浓度为0.5 mol/L,浸渍4 h,120℃干燥1 h,650℃焙烧4 h。将此固体超强酸酯用于氯乙酸和异辛醇合成氯乙酸异辛酯的酯化反应,考察了异辛醇和氯乙酸的摩尔比、催化剂用量、反应时间、带水剂环己烷的用量对酯化反应的影响。结果表明,醇酸比为1.1∶1,催化剂用量为所用氯乙酸质量的1.7%,环己烷为异辛醇体积的46%,反应时间1.5 h条件下酯化率达94.3%。

Catalytic synthesis of isooctyl chloroacetate with SO_4~(2-)/ZrO_2-Al_2O_3 solid superacid prepared by ageing at low temperature

SO2-4/ZrO2-Al2O3 Solid superacid catalyst was prepared by coprecipitation in ammonia with ZrOCl2·8H2O and Al(NO3)3·9H2O.Preparing conditions of the catalyst were molar ratio of ZrOCl2·8H2O and Al(NO3)3·9H2O 3 ∶1,-15 ℃ ageing time 24 h,drying at 120 ℃ for 12 h,concentration of sulfuric acid 0.5 mol/L,impregnation time 4 h,drying at 120 ℃ for 1 h,calcination at 650 ℃ for 4 h.As concerning synthesis of 2-ethylhexyl chloroacetate,effects of catalyst dosage,molar ratio of 2-ethylhexanol to chloroacetic acid,reaction time,dosage of water entrainer on esterification rate were studied.Under the optimal conditions of mole ratio of 2-ethylhexanol to chloroacetic acid 1.1 ∶1,cyclohexane of 46% 2-ethylhexanol volume as water entrainer and mass of catalyst for 1.7% of chloroacetic acid,esterification rate is 94.3% at reaction time 1.5 h.