Structure-activity relationship for CO2 absorbent

Abstract

In order to show the structure-activity relationship for CO2 absorbent, and identify or screen novel and efficient physical solvents of CO2, the constant-volume method, the Peng-Robinson equation of state, and a molecular simulation were used to investigate the impacts of type of functional groups, carbon chain length and number of functional groups for nine physical solvents. The three methods produced highly consistent results. Comparison of the CO2 solubility in solvents with the same carbon numbers but different functional groups suggested that the ester group could promote CO2 absorption. Investigation of the CO2 solubility in solvents with one ester group but different carbon chain lengths revealed that longer carbon chains could enhance CO2 absorption. Analyses of the CO2 solubility of solvents with one and two ester groups demonstrated that more ester groups could further increase the CO2 absorption. Therefore, the presence and number of ester groups and increased carbon chain length could promote CO2 absorption. It provides direction and method for screening of highly efficient CO2 absorbents and for the design and synthesis of new solvents.