Xiuyan Song

Hydrolysis of polycarbonate catalyzed by ionic liquid [Bmim][Ac]

Hydrolysis of polycarbonate (PC) was studied using ionic liquid 1-butyl-3-methylimidazolium acetate ([Bmim][Ac]) as a catalyst. The influences of temperature, time, water dosage and [Bmim][Ac] dosage on the hydrolysis reaction were examined. Under the conditions of temperature 140°C, reaction time 3.0 h, m([Bmim][Ac]):m(PC)=1.5:1 and m(H(2)O):m(PC)=0.35:1, the conversion of PC was nearly 100% and the yield of bisphenol A (BPA) was over 96%. The ionic liquid could be reused up to 6 times without apparent decrease in the conversion of PC and yield of BPA. The kinetics of the reaction was also investigated. The results showed that the hydrolysis of PC in [Bmim][Ac] was a first-order kinetic reaction with an activation energy of 228 kJ/mol.

Hydrolysis of polycarbonate using ionic liquid [Bmim][Cl] as solvent and catalyst

The hydrolysis of polycarbonate (PC) was studied using ionic liquid [Bmim][Cl] as solvent and catalyst. The effects of reaction temperature, water dosage and [Bmim][Cl] dosage on reaction results were examined. It was showed that the hydrolysis conversion of PC was almost 100 % and the yield of bisphenol A (BPA) was over 95 % under the reaction conditions of temperature 165 °C, time 3.0 h, m([Bmim][Cl]):m(PC)=1.5:1 and n(H2O):n(PC)=10:1. The ionic liquid could be reused for 8 times without obvious decrease in the conversion of PC and yield of BPA. Therefore, an environmental friendly strategy for chemical recycling of PC was developed.

Highly Active and Recyclable Mesoporous Molecular Sieves CaO(SrO,BaO)/SBA-15 with Base Sites as Heterogeneous Catalysts for Methanolysis of Polycarbonate

Mesoporous molecular sieves CaO(BaO, SrO)/SBA-15, which can produce basic sites, were synthesized by impregnation of a certain amount of CaO(BaO, SrO) on the synthesis of SBA-15 support, and used as heterogeneous catalysts for the methanolysis of polycarbonate (PC). The physicochemical properties, textual structures and catalytic performance were then studied in detail. The results showed that CaO/SBA-15 exhibited better catalytic activity than BaO/SBA-15 and SrO/SBA-15, and its catalytic activity was related to the loading amount of CaO. Moreover, the obtained product from the methanolysis of PC was mainly bisphenol A (BPA) with high purity. The influneces on reaction conditions of PC methanolysis catalyzed by 10%CaO/SBA-15 were also investigated. It was indicated that the PC conversion was nearly 100% and the BPA yield was over 96%. The stability of catalyst showed that 10%CaO/SBA-15 catalysts could be recycled and reused with negligible loss in activity over five cycles. In addition, a possible catalysis mechanism for the methanolysis of PC was proposed.Graphical Abstract

Isobutane/2-butene alkylation catalyzed by Brønsted–Lewis acidic ionic liquids

The alkylation reaction of isobutane with 2-butene to yield C8-alkylates was performed using Bronsted–Lewis acidic ionic liquids (ILs) comprising various metal chlorides (ZnCl2, FeCl2, FeCl3, CuCl2, CuCl, and AlCl3) on the anion. IL 1-(3-sulfonic acid)-propyl-3-methylimidazolium chlorozincinate [HO3S-(CH2)3-mim]Cl-ZnCl2 (x=0.67) exhibited outstanding catalytic performance, which is attributed to the appropriate acidity, the synergistic effect originating from its double acidic sites and the promoting effect of water on the formation and transfer of protons. The Lewis acidic strength of IL played an important role in improving IL catalytic performance. A 100% conversion of 2-butene with 85.8% selectivity for C8-alkylate was obtained under mild reaction conditions. The IL reusability was good because its alkyl sulfonic acid group being tethered covalently, its anion [Zn2Cl5]− inertia to the active hydrogen, and its insolubility in the product. IL [HO3S-(CH2)3-mim]Cl-ZnCl2 had potential applicability in the benzene alkylation reaction with olefins and halohydrocarbons.