近临界水中聚醋酸乙烯酯无催化水解动力学

摘要

In order to develop a green technology of polyvinyl acetate(PVAC) hydrolysis,kinetics of non -catalyzed hydrolysis of PVAC in near-critical water was investigated.After examining the repeatability of experiment data,the non-catalyzed hydrolysis kinetics of PVAC in near-critical water was systematically studied at 230-270 ℃.The hydrolysis products were characterized by IR, TG and GPC.The results reveal that non-catalyzed hydrolysis of PVAC in near-critical water is feasible, and is a typical self-catalyzed reaction.Higher temperature accelerates hydrolysis, but speeds up the polymer degradation, too.With a second-order kinetics equation, the activation energy evaluated for PVAC hydrolysis in near-critical water is 51.93 kJ/mol.%为了开发聚醋酸乙烯酯的绿色水解改性工艺,对近临界水中聚醋酸乙烯酯(PVAC)的无催化水解反应动力学进行研究.在实验数据重现性考查基础上,系统地测定聚醋酸乙烯酯在230～270℃反应温度下的水解反应动力学数据,并对其水解产物进行红外色谱(IR),热重分析(TG)以及凝胶色谱(GPC)表征.结果表明,聚醋酸乙烯酯在近临界水中能够进行水解,且该反应为典型的自催化反应,温度的升高可以提高反应速率,但同时也加剧PVAC的降解行为.以二级动力学模型对实验结果进行拟合,得到聚醋酸乙烯酯在近临界水中的水解反应活化能为51.93kJ/mol.