高温聚酯化反应动力学的研究 (Ⅰ)聚酯化反应动力学模型

THE POLYESTERIFICATION KINETICS AT HIGHER TEMPERATURE RANGEⅠ.KINETIC MODEL

通过系统分析和评价前人的研究结果 ,论证了对苯二甲酸 (PTA)与乙二醇的酯化反应符合二级反应的假设 ;通过对该体系中可能存在的各种反应进行分析 ,提出对聚酯化反应动力学的研究需重点研究其中的几个主要反应 ,即 :可逆的酯化反应、酯化缩合反应、缩聚反应和副反应二甘醇的生成。在进行反应体系的物料衡算时 ,考虑到了 PTA与反应液的非均相的影响 。

The process of esterification of terephthalic acid with ethylene glycol was characterized by a mechanism that involves three main equilibrium reactions and a side reaction. i.e. the esterification, potyesterification and polycondensation reactions and the formation of diethylene glycol. The esterification reaction was assumed to belong to the second order reaction. The reactions were concerned between the carboxyl groups and hydroxyl goups. On the basis of the reaction mechanism and material conservation, including the solid liquid equilibrium of the reaction system, a polyesterification kinetic model, which is a group of nonlinear different equations, was derived. The model can be solved numerically and will be employed for the experimental data correlation to obtain the rate constants at higher temperature range in the second part of this paper.