Task-specific ionic liquid-grafted mesoporous alumina for chemical fixation of carbon dioxide into cyclic carbonate

Abstract

In this paper, task-specific ionic liquid-grafted mesoporous alumina (MA) was synthesized and applied for CO2 chemical fixation. First, task-specific ionic liquid 1-(2-carboxymethyl)-3-methylimidazolium bromide ([CmMim][Br]) with high thermal stability was successfully prepared. Then [CmMim][Br]-MA material was fabricated via chemical grafting. The crystal structure of the grafted material maintains well compared to the support and its morphology keeps honeycomb with wrinkled surface. The specific surface area of grafted materials varies from 130 to 12 m2/g depending on the grafting degree of [CmMim][Br]. Finally, cycloaddition reaction of CO2 with epichlorohydrin was studied without any solvent and co-catalyst. The yield of 4-(chloromethyl)-1,3-dioxolan-2-one reaches 96.6% with 1.0 wt% [CmMim][Br]-grafted MA-0.2 relative to epichlorohydrin as catalyst at 110 °C, 2 MPa for 6 h . The catalyst can be reused at least 16 cycles with above 90% yield of 4-(chloromethyl)-1,3-dioxolan-2-one and its microstructure keeps well. The mechanism of cycloaddition reaction is also discussed.