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对苯二甲酸乙二醇酯在间歇缩聚釜中进行缩聚实验,用胺解法测定不同时刻反应物中二甘醇的含量。在前人文献基础上建立了动态非线性的缩聚主反应和生成二甘醇的副反应的动力学数学模型。把Runge-Kutta 法与 Marquardt 法结合起来对该模型进行参数估值和模型识别。在参数估值中由于加强了对阻尼因子λ的调整,有效地防止了目标函数的发散。最后得到的模型与实验点能较好地拟合。该模型中生成二甘醇的反应是总羟端基浓度的0.52级反应,活化能为11.8千卡/克分子,缩聚主反应活化能为16.3千卡/克分子。用所得模型在不同的温度、压力操作条件下进行了模拟,为寻找使产品二甘醇含量较低的操作条件提供了依据。同时提出了缩聚主反应有自稳定特性。
Polyethylene terephthalate was subjected to polycondensation experiments in a batch polycondensation reactor, and the amount of diethylene glycol in the reactants at various times was determined by amineysis. Based on the previous literature, a dynamic nonlinear polycondensation main reaction and a kinetic mathematical model for the side reaction of diethylene glycol were established. The Runge-Kutta method and the Marquardt method are used to evaluate the model and model identification. As the adjustment of the damping factor λ is strengthened in the parameter estimation, the divergence of the objective function is effectively prevented. The final model and experimental points can be better fitted. The reaction for the formation of diethylene glycol in this model is a 0.52 reaction with a total hydroxyl end group concentration of 11.8 kcal / mol and an activation energy of 16.3 kcal / mol. The obtained model was simulated under different operating conditions of temperature and pressure, which provided a basis for searching for the operating conditions of low diglycol product. At the same time, the main reaction of polycondensation has self-stability characteristics.