Reaction Mechanism and Kinetics of 1,8-Diazabicyclo[5.4.0]undec-7-ene and Carbon Dioxide in Alkanol Solutions

Carbon dioxide-binding organic liquids (CO2BOL) are a new class of solvents with advantageous properties such as high boiling points, low specific heats, high absorption capacities, and easily reversible reactions. In order to implement these solvents in processes, the reaction characteristics must be determined a priori. This work presents an analysis of the rate constants and activation energies of the reaction between carbon dioxide and 1,8-diazabicyclo[5.4.0]undec-7-ene (DBU) in 1-hexanol and 1-propanol. The reactions were found to comply with a termolecular reaction mechanism and exhibited pseudo-first-order behavior in the presence of excess DBU and 1-alkanol. It was concluded that DBU-based CO2BOL are environmentally friendly and easy-to-handle solvents that may provide great flexibility and improvements over conventional carbon dioxide absorption processes.