Zn 1,3,5-benzenetricarboxylate as an efficient catalyst for the synthesis of cyclic carbonates from CO.

Development of heterogeneous catalysts for the cycloaddition of CO with epoxides to produce cyclic carbonates is a hot issue in the field of chemical fixation of carbon dioxide. It is fairly promising as production of by-products is quite low. In this study, the [Zn(BTC)]/-BuNBr catalytic system was investigated for the solventless cycloaddition of carbon dioxide with epoxides and had an excellent synergetic effect in promoting the reaction. The reaction parameters were moderate (130 °C and 13 bar CO pressure) and were selected by a study of the catalytic system. Under the optimal reaction conditions, the yield of cyclic carbonate reached 99%. A decrease in the yield of cyclic carbonate was not apparent after [Zn(BTC)] was reused three times, indicating that [Zn(BTC)] was stable. At the same time, the catalytic activity of the catalyst for other epoxides was also verified. The acidic and alkaline nature of the [Zn(BTC)] catalyst did not change obviously after recycling the catalyst three times. In this study it is also verified that the [Zn(BTC)] catalytic cycloaddition reaction was closely related to the Lewis acid/base distribution. In addition, a plausible mechanism for the synergistic effect of the catalyst (Lewis acid and base properties) and the co-catalyst was suggested.