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以Al2(SO_4)_3为固体酸催化剂,考察其在乙醇/甲苯体系中催化纤维素生成乙酰丙酸乙酯的工艺,探讨了共溶剂甲苯的体积分数、反应温度、催化剂用量以及反应时间对乙酰丙酸乙酯产率的影响,同时考察了该催化剂对不同碳水化合物的催化作用及其重复利用性.结果表明:在甲苯体积分数为10%,反应温度为180℃,催化剂用量为0.8 g,反应时间为3 h时,纤维素醇解转化为乙酰丙酸乙酯的摩尔产率高达51.6%;果糖、葡萄糖、蔗糖和菊糖转化生成乙酰丙酸乙酯的摩尔产率分别为54.3l%、47.3%、51.4%和49.6%,Al2(SO_4)_3对碳水化合物醇解生成乙酰丙酸乙酯具有良好的普遍适用性.该催化剂经回收重复使用5次后依然具有良好的催化活性.
Al2 (SO_4) _3 was used as solid acid catalyst to investigate the technology of catalyzing cellulose to form ethyl levulinate in ethanol / toluene system. The effects of co-solvent toluene volume fraction, reaction temperature, catalyst dosage and reaction time on the conversion of acetyl Ethyl propionate.The catalytic activity and reusability of the catalyst on different carbohydrates were also investigated.The results showed that when the volume fraction of toluene was 10%, the reaction temperature was 180 ℃, the amount of catalyst was 0.8 g, The molar yield of alcoholysis to ethyl levulinate was up to 51.6% when the reaction time was 3 h. The molar yield of fructose, glucose, sucrose and inulin conversion to ethyl levulinate was 54.31% , 47.3%, 51.4% and 49.6%, respectively. Al2 (SO4) _3 has good general applicability to the alcoholysis of carbohydrates to form ethyl levulinate, and the catalyst still has good catalytic activity after being recycled for 5 times.