CARBONYL STRETCHING FREQUENCY-CHARACTERISTICS FOR THE STRONGLY HYDROPHOBIC SOLUTE, N-CYCLOHEXYL-2-PYRROLIDONE IN BINARY AQUEOUS MIXTURES AT 298.15-K - EVIDENCE FOR A 2-DOMAIN MODEL FOR 2-BUTOXYETHANOL WATER MIXTURES

Infrared spectra are reported in the C=O stretching region for N-cyclohexyl-2-pyrrolidone (NCP) in D2O as a function of the mole fraction of added cosolvents. As the solvent composition is changed by adding methanol, ethanol and 2-methylpropan-2-ol, the spectra reveal the presence of two types of hydrogen bonding to the carbonyl group of NCP. When cyanomethane is added, the spectra also show the formation of non-hydrogen-bonded NCP in MeCN-rich mixtures. When 2-butoxyethanol is added to NCP in D2O, the patterns generated by the plots showing the relative amounts of solvates change characteristically in the D2O-rich mixtures consistent with the presence of alcohol-rich and D2O-rich domains.