响应面法优化废旧PET一锅法解聚工艺的研究

Optimization on one-pot depolymerization process for waste PET by using response surface methodology

以对苯二甲酸二甲酯(DMT)产率为指标,通过单因素实验和响应面法对一锅法解聚废旧PET工艺进行优化。结果表明,解聚温度、乙二醇(EG)摩尔分数和酯交换时间3个因素对DMT产率的影响显著,最佳解聚工艺条件为:以二水乙酸锌、乙酸钾和十二水磷酸三钠为解聚催化剂,Na OH为酯交换的催化剂,PET解聚温度为230℃,n(EG)∶n(PET)为5.08,解聚时间为4 h,n(甲醇)∶n(PET)为80,酯交换时间为6 h,酯交换温度为75℃,此时,DMT产率为84.39%。在优化条件下再次进行实验,得到DMT产率为83.72%,与模型预测值接近。

Taking the yield of dimethyl terephthalate(DMT)as an indicator,the one-pot method for depolymerizing waste polyethylene terephthalate(PET)is optimized through single factor experiment and response surface methodology.The results show that depolymerization temperature,ethylene glycol(EG)dosage and transesterification time have significant effects on the yield of DMT.The optimum process conditions are obtained as follows:2 H2 O·Zn(OAc)2,KOAc and 12 H2 O·Na3 PO4 are used as catalyst for polymerization,Na OH is used as the catalyst for transesterification,PET depolymerization temperature remains at 230℃,the molar ratio of EG/PET is 5.08,depolymerization performs for 4 h,the molar ratio of methanol/PET is 80,transesterification lasts for 6 h,and transesterification temperature is at 75℃.Under the optimal conditions,the yield of DMT can reach 84.39%.The experiments are performed again under optimized conditions,and the yield of DMT reaches 83.72%,which approaches to the predicted value of the model.