The need for a deep understanding of CO2 interactions with other molecules is significant given the importance of supercritical CO2 (sc-CO2) as a green solvent, and interest in design of novel materials for CO2 capture and storage. Solubility of fluorinated compounds in sc-CO2 is generally higher than their hydrocarbon analogs and fluorination of hydrocarbon compounds improves “CO2-philicity”. Although dissolution of a compound in sc-CO2 (or any solvent) is a complex process, much can be learned by systematic examination of solute-solvent interactions as a function of solute molecule properties in dimers and other small clusters. In the present study, Fourier-transform microwave spectroscopy and Symmetry Adapted Perturbation Theory (SAPT) calculations have been used to examine intermolecular interactions between CO2 and a series of fluorinated ethylene molecules with varying degree and position of fluorination (1-3 F atoms). While 1-fluoro-, 1,1-difluoro- and 1,1,2-trifluoroethylene…CO2 complexes are planar (with two isomers observed for 1-fluoroethylene), cis-1,2-difluoroethylene…CO2 is nonplanar. Although lowest energy structures predicted by MP2/6-311++G(2d,2p) calculations are not always in agreement with observed configurations, SAPT calculations provide binding energies consistent with the observed structures. We are now extending these studies to trimers containing one fluorinated ethylene with two CO2 “solvent” molecules in order to gain further insight into structural and energetic changes as a solvation shell is formed.

Towards and understanding of CO2 microsolvation: Microwave spectroscopy of CO2 complexes with fluoroethylenes

254th National Meeting (2017)

The official archive and repository for all ACS Meetings & Expositions abstracts and select posters or presentations.