【摘要】 在温度160～260℃、压力1.4～8.5MPa、反应时间15～60min条件下,研究聚碳酸酯(PC)在超、亚临界乙醇中的解聚反应,着重考察反应温度、反应时间等条件对聚碳酸酯解聚行为的影响。结果表明:随温度的升高、反应时间的延长,解聚率增加;随温度的升高,主产物双酚A(BPA)产率先升高,之后下降;随着反应时间的延长,双酚A产率下降。其中温度对双酚A产率的影响最大。当投料比为8.0,反应温度为220℃,反应时间为15min时,主产物双酚A产率可达到80.4%,此时解聚率为98.8%。根据聚碳酸酯在超亚临界乙醇中解聚产物的分析,并结合聚碳酸酯的链节特点,提出聚碳酸酯的解聚机理。通过实验数据关联,得出解聚反应级数为一级,解聚反应活化能为58.03kJ·mol-1。研究结果为选择解聚介质和工艺参数提供依据。更多还原

【Abstract】 Depolymerization of polycarbonate (PC) in sub-and supercritical ethanol was carried out in a batch reactor at the condition of temperature 160～260℃,pressure 1.4～8.5 MPa,and reaction time 15～60 min,It was found that the yield of bisphenol A (BPA) varies evidently with the reaction temperature. The influence of depolymerization temperature and time on product yield was studied. The depolymerization yield increases with the increase of reaction temperature and time,while the yield of BPA decreases with the increase of reaction time and increases at first with the increase of reaction temperature and then decreases with the further increase of reaction temperature. It was found that 98.9% PC can be depolymerized and the BPA yield can reach 80.4% under the optimal conditions as follows: reaction temperature of 220℃,reaction time of 15 min and ratio of ethanol to PC of 8.0. The result of kinetic analysis shows that the depolymerization reaction is a first order reaction with respect to the polycarbonate concentration. The activation energy of depolymerizing PC in sub-and supercritical ethanol was calculated by the correlation of rate constant and the reaction temperature,and its value obtained is 58.03 kJ·mol-1. The results obtained here may enforce the basic knowledge of selecting depolymerization medium and its corresponding technological parameters.更多还原