Abstract:
The objective of this extensive research project was to investigate imidazoles as potential solvents for acid gas removal applications. Imidazoles are integral starting materials and neutral analogs for the synthesis and production of imidazolium-based ionic liquids (ILs) and virtually have not been explored as candidates for novel, CO<sub>2</sub> capture media. N-functionalized imidazoles also provide a similar platform as seen in ILs as tunable structures that govern physical and chemical properties leading towards lower volatilities, lower viscosities, higher CO<sub>2 </sub>uptake, etc. Physical properties (including density, viscosity, and gas solubilities) of N-functionalized imidazoles were recorded providing an initial database for comparisons to commercially-available organic solvents and imidazolium-based ILs. These results show that some novel N-functionalized imidazoles contend with common organic solvents for CO<sub>2</sub> separations in terms of dynamic processing properties (i.e. viscosity and CO<sub>2</sub> uptake). Imidazoles and ILs also provide a non-volatile media in which fugitive emissions and evaporative losses during solvent regeneration are reduced significantly. Chemical simulations and calculations via COSMOtherm software were also employed to rapidly predict thermophysical properties of these imidazoles and ILs, providing a means of screening of such novel solvents to be optimized for CO<sub>2</sub> separation processes. In the concluding chapters of this dissertation, continued research with the N-functionalized imidazole platform are noted, including areas of hybrid solvents, multiply-substituted, isomeric compounds, and imidazole-based polymeric media for acid scavenging (CO<sub>2</sub>, SO<sub>2</sub>, etc).
