Selectively controlled synthesis of diethyl carbonate and methyl ethyl carbonate via transesterification of dimethyl carbonate over a KATriz/Al2O3 catalyst†

In this work, a series of Al₂O₃-supported KATriz (3-amino-1,2,4-triazole potassium) catalysts were developed and employed for the transesterification of dimethyl carbonate (DMC) with ethanol to synthesize diethyl carbonate (DEC) and methyl ethyl carbonate (EMC). It turned out that the 14 wt% KATriz/Al₂O₃ catalyst displayed high activity and possessed adjustability for selective conversion to DEC or EMC via varying the molar ratio of ethanol to DMC. Under optimized conditions, the selectivity of DEC reached 91% when the ratio of DMC to ethanol was 1 : 10. Meanwhile, the selectivity of EMC reached up to 99% when the ratio was 4 : 1, and the catalyst remained stable after a time on stream of 500 h. The prepared catalysts were characterized by BET, TG, XRD, IR, XPS and TPD to establish the relationship between structure and performance. XPS results indicated a significant interaction between KATriz and Al₂O₃, and TPD results showed that 14 wt% KATriz/Al₂O₃ with more accessible basic sites were beneficial for excellent catalytic performance.