山梨醇催化脱水制备异山梨醇的反应动力学

以浓硫酸为催化剂,对山梨醇催化脱水制备异山梨醇进行了研究。考察了催化剂用量(m(浓硫酸)∶m(山梨醇))、反应温度、反应压力对山梨醇催化脱水制备异山梨醇反应性能的影响。实验结果表明,较佳的反应条件为:m(浓硫酸)∶m(山梨醇)=1∶100、反应压力3kPa(绝压)、反应温度403K,在此条件下反应90min后,异山梨醇的收率达到80%。提出了山梨醇催化脱水制备异山梨醇的均相动力学模型,根据实验数据拟合得到动力学参数,山梨醇两步脱水反应的活化能分别为47.92,51.00kJ/mol,指数前因子分别为21655.0,3487.9min-1。对均相动力学模型的统计检验结果表明,该模型能很好地描述山梨醇催化脱水制备异山梨醇的反应过程。

Reaction Kinetics of Sorbitol Catalytic Dehydration to Isosorbide

With concentrated sulfuric acid as catalyst,dehydration of sorbitol to isosorbide and its kinetics were studied. Effects of catalyst dosage,reaction temperature and reaction pressure on the dehydration were investigated. Under optimum reaction conditions:m(concentrated sulfuric acid):m(sorbitol) 1:100,3 kPa(absolute pressure),403 K,90 min,yield of isosorbide could reach 80%. A homogeneous reaction kinetics model for sorbitol catalytic dehydration to isosorbide was established. In the two-step reaction for sorbitol dehydration,activation energy and pre-exponential factor for sorbitol to 1,4-sorbitan are 47.92 kJ/mol and 21 655.0 min-1,and those for 1,4-sorbitan to isosorbide are 51.00 kJ/mol and 3 487.9 min-1,respectively. Statistical test showed that the proposed model could well fit the reaction process.