用PET废料制备对苯二甲酸二辛酯新工艺

A NEW PROCESS OF PREPARING PLASTICIZER DOTP FROM WASTE PET

用聚对苯二甲酸乙二醇酯废料 ( PET)和辛醇为原料 ,通过降解酯交换反应制备对苯二甲酸二辛酯。研究了一种用共沸溶剂从反应体系中连续不断排除和分离乙二醇的新工艺 ,有效的提高了酯交换程度和反应速度。同时确定了较佳的催化剂种类为乙酸锌 ,催化剂用量为 2 %～ 5% ,反应物 PET与辛醇适宜配比为 1∶ 2(重量比 ) ,反应温度为 1 90～ 2 30℃ ,反应时间依聚酯废料的比表面积增大而减少 。

In order to accelerate the separation rate of EG from the reaction system containing a large amount of 2ethylhexanol which boiling point is lower than that of EG, one kind of solvent,which can coboil with EG and decrease the boling temperature of EG, is adopted in the new process for preparing plasticizer DOTP from waste PET. As a result of this kind solvent adopted, the reaction rate and conversion ratio from PET to DOTP is increased. The optimum conditions such as catalysts, raw material reactor ratio and are recommand as such follows: The suitable catalyst is Zn(CH 3COO) 2 and its appropriate amount is 2%～5%, The right ratio of PET and 2ethylhexanol is 1∶2(w/w), The better temperature in this reaction system is 190～230 ℃; The reaction time is shorten as the reduction of size of waste PET.