粉煤灰复合型固体酸催化合成马来酸二异辛酯

用质量比为1∶1∶1的ZrOCl2、FeSO4和粉煤灰制备了粉煤灰复合型固体酸催化剂,制备条件为陈化时间12h,浸渍液硫酸的浓度为0.25mol/L,浸渍2h,120℃下干燥24h,600℃下焙烧3h。将该催化剂用于异辛醇与马来酸酐合成马来酸二异辛酯的酯化反应,考察了异辛醇与马来酸酐的摩尔比、催化剂用量、反应时间、带水剂的种类及用量对酯化率的影响。实验结果表明,该催化剂具有较高的活性,在异辛醇与马来酸酐的摩尔比为2.5、催化剂用量为马来酸酐质量的6%、带水剂二甲苯的用量为异辛醇体积的42%、反应时间3.0h的条件下,酯化率达93.2%。所得产物易分离纯化,操作过程简单易行。粉煤灰复合型固体酸催化剂具有成本低、使用寿命长、对环境友好的优点。

Synthesis of Di-2-Ethylhexyl-Maleate with Composite Fly Ash Solid Acid as Catalyst

Di-2-ethylhexyl maleate was prepared from 2-ethylhexanol and maleic anhydride with a new composite solid acid catalyst and xylene as water entrainer. The composite solid acid catalyst was prepared by coprecipitation of ZrOCl2,FeSO4 and fly ash in ammonia. Preparing conditions of the catalyst were: mass ratio of fly ash to FeSO4 and ZrOCl2 1 ∶1 ∶1,ageing time 12 h,concentration of sulfuric acid 0.25 mol/L,impregnation time 2 h,drying at 120 ℃ for 24 h and calcination at 600 ℃ for 3 h. As concerning synthesis of di-2-ethylhexyl maleate,effects of catalyst dosage,mole ratio of 2-ethylhexanol to maleic anhydride,reaction time,and type and dosage of water entrainer on esterification rate were studied. Under the optimal conditions: mole ratio of 2-ethylhexanol to maleic anhydride 2.5,reaction time 3.0 h,xylene as water entrainer 42% of 2-ethylhexanol volume and mass fraction of catalyst in maleic anhydride 6%,esterification rate is 93.2%. Di-2-ehtylhexyl maleate is easily separated from the reaction system and purified. The composite solid acid catalyst takes advantages of low cost,reusability and less pollution to environment.