Abstract: Terephthalic acid (TPA) was prepared from the degradation of waste polyethylene terephthalate (PET)with microwave-assisted and alkali catalysis. The Box-Behnken center-united experimental design principles were applied. Dosages of catalyst and alkali, pyrolysis temperature and time were chosen as causal factors on the basic of single-factors experiments. The responsive surface analysis of 4-factors-3-levels was adopted. The quadratic surface model of TAP yield was established. The optimum combination was obtained. The structure and property of TPA were determined. Results indicated that TPA yield and the four factors conform with the quadratic model, the linear and quadratic term of four factors, and the interaction between the dosages of catalyst and alkali have significant effects on the yield of TPA. Modified and verified experiments were completed after considering product performance and actual operation. The optimum parameters were determined, 2.7g TOMAB, 260mL 15%NaOH, 85℃, 2.2 h. Under these conditions, the average value of the actual yield of TPA in three replicated experiments is 97.53%, and it is not significantly different from the value of 98.59% predicted by the model. Results demonstrate that this method is feasible.

Key words: waste PET plastic, preparation, optimization, TPA, responsive surface methodology(RSM)

摘要： 采用微波辅助碱催化降解废聚对苯二甲酸乙二醇酯(PET)塑料制备对苯二甲酸(TPA),运用Box-Behnken中心组合试验设计原理,通过单因素试验筛选催化剂用量、碱液用量、降解温度和时间为主要因素,进行四因素三水平的响应面分析,建立TPA产率的二次响应面模型,确立制备工艺的优化组合条件,并对产品的结构和性能进行测定。结果表明,TPA产率与四因素关系符合二次模型,四因素的一次项和二次项及催化剂用量和碱液用量的交互作用对TPA产率具有显著影响。综合考虑产品性能和实际操作因素,经修正及近似验证后获得最佳制备工艺为:2.7gTOMAB,260mL15%NaOH,降解温度85℃,降解时间2.2h。在该条件下进行3次重复试验,TPA的实际平均产率为97.53%,与预测值98.59%无显著差异,说明该优化方法是可行的。

关键词: 废聚对苯二甲酸乙二醇酯塑料, 降解, 制备, 优化, 对苯二甲酸, 响应面法