超临界CO_2中苯甲酸与乙醇和二甲基亚砜的相互作用

FTIR Study on the Interactions between Benzoic Acid and Ethanol, Benzoic Acid and Dimethyl Sulfoxide in Supercritical CO_2

在35.0℃、12.6MPa条件下，用红外光谱法研究了超临界CO2中苯甲酸与乙醇和二甲基亚砜的相互作用．结果表明，在纯超临界CO2中，苯甲酸以单体和二聚体的形式存在．体系中有乙醇或二甲基亚砜存在时，这些强极性物质与苯甲酸形成氢键缔合体，并且非缔合苯甲酸的浓度随乙醇浓度增加而减小．

Infrared spectra of benzoic acid in CO2-ethanol and CO2-dimethyl sulfoxide(DMSO) mixed supercritical fluids have been determined at 35.0℃ and 12.6MPa. It was observed that benzoic arid exists in both forms of monomer and dimer in pure supercritical CO2. Benzoic acid begin to form hydrogen-bonded complexes with ethanol and DMSO even their concentrations are very low and the concentration of the monomer of benzoic acid decreases with increasing of ethanol concentration, provided that the total concentration of the acid is fixed.