A new type of support 'bipyridine containing aromatic polyamide' to CuCl2 for synthesis of dimethyl carbonate (DMC) by oxidative carbonylation of methanol

A new type of heterogeneous catalyst, 'bipyridine containing aromatic polyamide' (poly( N,N'-bisphenylene-2,2'-bipyridine-4,4'-dicarboxylic amide, Bpya)-CuCl(2), for dimethyl carbonate (DMC) synthesis by oxidative carbonylation of methanol in the liquid-phase reaction was investigated. This catalyst showed good performance thigh DMC yield and DMC selectivity), as in the case of poly(vinylpyridine) (PVP)-CuCl(2). Bpya shows higher heat resistance than PVP, and thus Bpya-CuCl(2) is considered to be more stable than PVP-CuCl(2) under the reaction condition. Bpya-CuCl(2) could be easily recycled after filtration, and actually similar activity was found after three repetitions. During the reaction, 20 similar to 30% of total CuCl(2) was eliminated from the immobilized catalyst. Although the elimination of CuCl(2) occurred considerably in the initial step, it became slight during the reaction. The characteristics of corrosion resistance of Bpya-CuCl(2) was studied, and it became obvious that corrosion is closely related to the trend of CuCl(2) elimination. From these results, we proposed two types of reaction mechanism for the reaction system. (C) 2000 Elsevier Science B.V. All rights reserved.