Synthesis and properties of symmetric glycerol-derived 1,2,3-triethers and 1,3-diether-2-ketones for CO2 absorption

Abstract

Five compounds bearing glycerol skeletons: 1,3-diethoxypropan-2-one ([E, K, E]), 2,5,9,12-tetraoxatridecan-7-one ([ME, K, ME]), 1,3-bis(2,2,2-trifluoroethoxy)propan-2-one ([F, K, F]), 7-(2-methoxyethoxy)-2,5,9,12-tetraoxatridecane ([ME, ME, ME]) and 2-(2-methoxyethoxy)-1,3-bis(2,2,2-trifluoroethoxy)propane ([F, ME, F]) – were synthesized from epichlorohydrin at molar scales with high regioselectivity. Density and viscosity were measured over a temperature range of 293.15 to 353.15 K. Henry’s constants for CO2 were obtained under moderate pressures (2 to 10 atm) at 303.15, 318.15, 333.15 and 348.15 K. Comparison of CO2 affinity with dimethyl ethers of polyethylene glycol (DMPEG) and ionic liquids (ILs) indicated that [ME, ME, ME] and [F, ME, F] are excellent candidates as novel physical solvents for CO2 capture. DFT calculations were performed to understand the structure–property-performance relationships for the CO2 absorption mechanism. All five compounds were miscible with most common solvents except hexanes and water. In addition to gas absorption applications, these compounds might also find use as general purpose green solvents.