ABSTRACT
Much attention has been paid to mesoporous materials in recent years (1). But little has been done to investigate them as catalysts, especially as solid base catalysts (2). Since most of organic reactions proceed in liquid phase, mesoporous catalysts are especially preferable in order to reduce inner diffusion resistance. Dimetyl carbonate is an important precursor of polycarbonate resins as well as a useful carbonylation and methylation agent (3,4). Because of the negligible toxicity of DMC, it is promising as a substitute for phosgene, dimethyl sulfate, or methyl iodide as well as a potential petrol octane enhancer. It is known that DMC can be synthesized concomitantly with propylene or ethylene glycol by the following liquid phase ester exchange reaction between propylene or ethylene carbonate
and methanol (5,6), as shown in Scheme 1. For this reaction various base catalyst and group IV homogeneous catalyst are reported to be effective (6, 7). In the present work, KI, K2CO3 and KOH impregnated mesoporous active carbon was studied as solid base catalysts for the synthesis of dimethyl carbonate by transesterification of propylene carbonate with methanol. The effect of preparation method, strength of base site, catalyst content and reaction temperature were examined.
