The reaction between CO2 and chloroform in anion-functionalized ionic liquids with the formation of trichloroacetates†

Abstract

Here, 1,2,4-triazolide-based ionic liquids (ILs), N-ethyl-N,N-dimethyl-N-(2-methoxyethyl)ammonium 1,2,4-triazolide ([MOEN₂₁₁][Triz]) and tetraethylammonium 1,2,4-triazolide ([N₂₂₂₂][Triz]), are used to capture CO₂. The interaction results suggest that CO₂ reacts with the anion [Triz]⁻ to form carbamate species. Surprisingly, when deuterated chloroform (CDCl₃) or chloroform (CHCl₃) is added into the absorption system at room temperature, it is found that CO₂ can react with not only the [Triz]⁻ anion but also CDCl₃ (or CHCl₃) to form carbamate and trichloroacetate species, respectively. In other words, CO₂ can easily react with cheap CHCl₃ in the presence of [Triz]-based ILs to form valuable chemical trichloroacetate under ambient conditions. Moreover, the formation of trichloroacetate can also be detected in the systems containing imidazolide ([Im]⁻) and pyrazolide ([Pyr]⁻) ILs. The findings of this work may provide another useful route for carbon capture and utilization.