硅藻土复合型固体酸的研制及其催化合成异丁酸丁酯

制备了硅藻土复合型固体酸催化剂,采用XRD和TG方法对催化剂进行了表征;并将该催化剂用于异丁酸与正丁醇进行酯化反应合成异丁酸丁酯,考察了催化剂制备条件(焙烧温度和浸渍液硫酸浓度)、催化剂用量、n(正丁醇)∶n(异丁酸)、反应时间、带水剂种类等因素对酯化率的影响。实验结果表明,催化剂的适宜制备条件为:m(SnCl4.5H2O)∶m(硅藻土)=1∶3、硫酸浓度3.0mol/L、焙烧温度550℃、焙烧时间3.5h。该催化剂催化合成异丁酸丁酯的适宜反应条件为:n(正丁醇)∶n(异丁酸)=1.8、催化剂用量为反应物总质量的1.10%、带水剂环己烷用量10mL、反应时间2.5h。在此条件下,酯化率为98.3%。该催化剂使用8次后,酯化率仍可达到92.7%。

Composite Diatomite-Solid Acid Catalyst for Synthesis of Butyl-Isobutyrate

A composite diatomite-solid acid catalyst was prepared and characterized by means of XRD and TG.Butyl-isobutyrate was synthesized through esterification of isobutyric acid with n-butanol over the prepared catalyst.The effects of the catalyst preparation conditions(calcination temperature and sulfuric acid concentration),catalyst dosage,mole ratio of n-butanol to isobutyric acid,reaction time and water entrainer type on the esterification rate were investigated.The results indicated that suitable conditions for the catalyst preparation were:mass ratio of SnCl4·5H2O to diatomite 1∶3,sulfuric acid concentration 3.0 mol/L and calcination at 550 ℃ for 3.5 h.Under the optimized conditions for synthesizing butyl-isobutyrate:mole ratio of n-butanol to isobutyric acid 1.8,mass fraction of the catalyst in all reactants 1.10%,entrainer cyclohexane 10 mL and reaction time 2.5 h,esterification rate could reach 98.3%.After the catalyst was used eight times,esterification rate could still achieve 92.7%.