Xiaoping Ge

Methanolysis of polycarbonate catalysed by ionic liquid [Bmim][Ac].

The methanolysis of polycarbonate (PC) was studied using ionic liquid [Bmim][Ac] as a catalyst. The effects of temperature, 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: m([Bmim][Ac]):m(PC) = 0.75:1;m(methanol):m(PC) = 0.75:1; a reaction temperature of 90 °C and a total time of 2.5h. 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 167 kJ/mol.

Environmentally benign methanolysis of polycarbonate to recover bisphenol A and dimethyl carbonate in ionic liquids

An environmentally friendly strategy for methanolysis of polycarbonate (PC) to recover bisphenol A (BPA) and dimethyl carbonate (DMC) was developed in which PC could be methanolyzed in an ionic liquid without any acid or base catalyst under moderate conditions. The effects of ionic liquid kinds, temperature, time, and methanol dosage on methanolysis results of PC were examined. It was showed that the methanolysis conversion of PC was almost 100% and the yields of both BPA and DMC were over 95% in presence of ionic liquid 1-n-butyl-3-methylimidazolium chloride ([Bmim][Cl]) and under the conditions of m(PC):m(CH(3)OH):m([Bmim][Cl])=2:3:2, reaction temperature 105 degrees C and time 2.5h. After easily separated from the product, the ionic liquid could be reused 8 times without obvious decrease in the conversion of PC and yields of BPA and DMC.

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.

Mesoporous molecular sieves K2O/Ba(Ca or Mg)-MCM-41 with base sites as heterogeneous catalysts for the production of liquid hydrocarbon fuel from catalytic cracking of rubber seed oil

Mesoporous molecular sieves K2O/Ba(Ca or Mg)-MCM-41, which feature basic sites, were prepared by the coordination effect of ion exchange and impregnation method under hydrothermal conditions, and used as heterogeneous catalysts for the cracking of rubber seed oil (RSO). The structure, base properties and catalytic performance were then studied in detail. The K2O/Ba(Ca or Mg)-MCM-41 exhibited higher catalytic performance than traditional base catalysts such as Na2CO3 and K2CO3. Moreover, the fuels generated from the cracking of RSO have similar chemical compositions to diesel-based fuels and low acid values. The cracking products with low acid values showed good cold flow properties, calorific values and good solubility in diesel oil at low temperature. At the same time, the K2O/Ba(Ca or Mg)-MCM-41 has excellent stability. The catalyst could be recycled and reused with negligible loss in activity over six cycles. The K2O/Ba(Ca or Mg)-MCM-41 is base- and water-tolerant and is an environmentally benign heterogeneous catalyst for the production of liquid hydrocarbon fuels from low quality feed stocks.

Tungsten-based organic mesoporous SBA-15 materials: characterization and catalytic properties in the oxidation of cyclopentene to glutaric acid with H2O2

A series of hybrid heterogeneous catalysts were prepared and their catalytic performance was investigated for the first time in the green oxidation of cyclopentene to glutaric acid (GAC) using 50 wt% H2O2. After tungsten active sites embedded into the mesochannels of SBA-15, partial Si–OH groups from the mesoporous surface are removed by further silylation with diphenyldichlorosilane (DPHS). It can provide a more hydrophobic environment in the mesochannels where the tungsten active sites are immobilized, which in turn generates at least two distinct significant characteristics. First, the aperture entrance size of the catalysts finely modulated by grafting DPHS moieties displays lower tungsten species leaching than those of not possessing organic groups. Moreover, the present catalysis system also provides an unprecedented yield of GAC depending on more hydrophobic nature of the catalysis. In addition, the catalyst W-SBA-15-1.6DPHS was recycled and reused in four successive reaction runs without major loss of reactivity.