High-pressure F-19 NMR measurements of a series of fluorinated benzenes in supercritical carbon dioxide

摘要

The high-pressure and high-resolution NMR cell method has been developed for precise measurements of supercritical carbon dioxide solutions. F-19 NMR chemical shifts of a series of fluorinated benzenes, C6HnFm ( n = 6 - m and m = 1 similar to 6) in CO2 at dilute concentrations dependence of the corrected chemical shift, where the bulk magnetic susceptibility contribution was subtracted, was well represented by a cubic function of CO2 density for any fluorinated benzene. The linear coefficients, arising from pairwise intermolecular interactions, were found to be dependent on the numbers and positions of fluorine atoms in the fluorinated benzenes. The solute - solvent interaction between fluorine and CO2 was discussed.