Promoted absorption of CO at high temperature by cuprous-based ternary deep eutectic solvents

Achieving efficient dissolution of carbon monoxide (CO) in the solvent is very helpful for the implementation of carbonylation reaction at ambient pressure. However, almost all of common solvents show very low solubilities of CO at high temperature. Herein, a series of cuprous-based ternary deep eutectic solvent (DES) was prepared by mixing imidazolium hydrochloride with CuCl and ZnCl2. The ternary DES [BimH]Cl-CuCl-1.0ZnCl(2) exhibited very large CO absorption capacity (0.075 mol mol(-1), 1 bar) even at a high temperature (353.2 K), which is superior to all of the reported absorbents. Moreover, the ternary DES [BimH]Cl-CuCl-1.0ZnCl(2) could further promote the reactive absorption of CO to conduct the aminocarbonylation reaction effortlessly at ambient pressure, and thus the targeted products benzamides were obtained in 70-97 yields. We believe that this finding opens a new way to design advanced solvents for efficient capture of CO at high temperature.

Automated summary

Copper-based ternary deep eutectic solvents prepared by mixing imidazolium hydrochloride with CuCl and ZnCl2 exhibit high CO absorption capacity at high temperatures, surpassing other absorbents. These solvents can facilitate the reactive absorption of CO, allowing for effortless aminocarbonylation reactions at ambient pressure and yielding benzamides in 70-97% yields. This discovery offers a new approach to designing advanced solvents for efficient CO capture at high temperatures.