Study On Depolymerization Of Polycarbonate And Polyethylene Terephehalate In Ionic Liquild

Different kinds of ionic liquid were synthesized and characterized by FT-IR and NMR. The methanolysis of polycarbonate (PC) was investigated using ionic liquids as catalyst and solvent. The effects of reaction temperature, reaction time, methanol dosage and [Bmim][Ac] dosage on the methanolysis reaction were examined. It was shown that the conversion of PC was nearly 100%, and the yield of bisphenol A (BPA) was over 95% under the following conditions: reaction temperature 90℃, reaction time 2.5 h, n(methanol):n(PC)=6:1 and m([Bmim][Ac]):m(PC)=0.75:1. The structure of obtained product was characterized by FT-IR. The ionic liquid could be reused up to 6 times with no apparent decrease in the conversion of PC and yield of BPA. The kinetics of the reaction was also investigated. The results indicated that the methanolysis of PC in [Bmim][Ac] was a first-order kinetic reaction with an activation energy of 167KJ/mol. The reaction mechanism of PC methanolysis in ionic liquid [Bmim][Ac] was proposed.The hydrolysis of PC was investigated using ionic liquid [Bmim][Ac] as reaction medium and catalyst. The effects of reaction temperature, reaction time, water dosage and [Bmim][Ac] dosage on the hydrolysis reaction were examined. It was shown that the conversion of PC was nearly 100%, and the yield of BPA was over 95% under the following conditions: reaction temperature 140℃, reaction time 3.0 h, m([Bmim][Ac]):m(PC)=1.5:1 and n(water):n(PC)=5:1. The structure of obtained product was characterized by FT-IR. The ionic liquid could be reused up to 6 times with no apparent decrease in the conversion of PC and yield of BPA. The kinetics of the reaction was also investigated. The results indicated that the methanolysis of PC in [Bmim][Ac] was a first-order kinetic reaction with an activation energy of 244KJ/mol. The reaction mechanism of PC hydrolysis in ionic liquid [Bmim][Ac] was proposed.The hydrolysis of poly(ethylene terephthalate) (PET) was investigated using ionic liquid [Bmim][Ac] as reaction medium and catalyst. The effects of [Bmim][Ac] dosage, reaction time, reaction temperature and water dosage on the hydrolysis reaction were examined. It was shown that the conversion of PET was nearly 100%, and the yield of terephthalic acid (TPA) was over 86% under the following conditions: m([Bmim][Ac]):m(PET)=1:1, reaction time 3.0 h, reaction temperature 180℃and n(water):n(PET)=20:1. The structure of obtained product was characterized by FT-IR. The ionic liquid could be reused up to 6 times with no apparent decrease in the conversion of PET and yield of TPA. The reaction mechanism of PET hydrolysis in ionic liquid [Bmim][Ac] was proposed.