Bisphenol Catalysed Reaction

A method of converting polycarbonate (PC) to bishydroxyethyl ether of bisphenol A (BHE-BPA) was studied, with a view to recycling PC plastic wastes. Treating PC in ethylene glycol with a catalytic amount of sodium hydroxide produced the monohydroxyethyl ether of bisphenol A (MHE-BPA, 42%), BHE-BPA (11%) and BPA (42%). BHE-BPA was produced quantitatively when 1.6 mol. equiv. ethylene carbonate was added to this reaction system. The reaction of BPA with EC produced both BHE-BPA and MHE-BPA, indicating that ethylene carbonate was formed as an intermediate in the base catalysed reaction of PC with ethylene glycol. A large proportion of this ethylene carbonate formed from PC was, however, lost by decarboxylation so additional ethylene carbonate must be provided for the quantitative preparation of BHE-BPA. 12 refs. 

Transition metal-catalysed carbon-heteroatom coupling reactions primarily comprise the carbonylation polycondensation of dibromoarenes with aromatic diamines and bisphenols in the presence of carbon monoxide... 

The prepolymer contains a 1,2 epoxy linkage which is made by a base-catalysed step-growth reaction between a diol, e.g. bisphenol A, and a 1,2 epoxide, e.g. epichlorhydrin. 

Bisphenol-A (BPA) is an important raw material for the synthesis of polycarbonates, epoxy resins and other polymers as well as polymer additives. It is conventionally produced by acid-catalysed condensation of phenol with acetone. Application of various catalysts for the BPA synthesis is discussed with particular attention to the substrates conversion and the reaction selectivity. Recent developments in the BPA production and its applications are presented. Moreover, potential toxicological and endocrine disrupting properties of BPA are considered with the emphasis on human exposure, general toxicology, and biological effects. 

Huang and co-workers [191] investigated the effects of a nonionic surfactant, Triton X-100, on the laccase-catalysed conversion of bisphenol A. It was found that the addition of Triton X-100 into the reaction system increased the conversion of bisphenol A (BPA), especially near the critical micelle concentration of Triton X-100. In addition, it was fonnd that the stability of laccase was greatly improved in the presence of Triton X-100 and the binding of Triton X-100 to the laccase surface also mitigated the inactivation effect cansed by the free radicals and polymerisation products. Under otherwise identical conditions, a lower dosage of laccase was needed for the higher conversion of BPA in the presence of Triton X-100. 

Acrylamide based acrylics are capable of self crosslinking, when subjected to temperatures in excess of ISiy C. Crosslinking is a complex mixture of condensation reactions and side reactions involving the liberation of water, formaldehyde, primary alcohol and ethers. The reaction is catalysed by acids. Bisphenol A epoxy resins are often incorporated into acrylamide acrylic coating formulations to improve performance. This epoxy resin also takes part in the curing reaction. Figure 4-2 lists the major reactions which take place. 

High molar mass epoxy prepolymers containing rabber dispersions based on carboxyl-terminated butadiene-acrylonitrile copolymer were prepared from initially miscible solution of low molar mass epoxy prepolymers, bisphenol A and carboxyl-terminated NBR. During chain extension inside a twin screw extruder due to epoxy-phenoxy and epoxy-carboxy reactions, a phase separation process occurs. Epoxy-phenoxy and epoxy-carboxy reactions were catalysed by triphenylphosphine. The effect of reaction parameters (temperature, catalyst, reactant stoichiometry) on the reactive extrasion process were analysed. The structure of the prepolymers showed low branching reactions (2-5%). Low molar mass prepolymers had a Newtonian rheological behaviour. Cloud-point temperatures of different reactive liquid butadiene aciylonitrile random copolymer/epoxy resin blends were measured for different rubber concentrations. Rubber... 

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