A Raman spectroscopic study of complex formation between o-cresol and propionitrile

Raman spectroscopy and band fitting techniques have been used to study comp lex formation in binary mixtures of o-cresol and propionitrile in the conce ntration range 0.10 to 0.67 mole fraction of o-cresol. The envelope of the C=N stretching band of propionitrile in the Raman spectrum between 2300 and 2200 cm(-1) was studied. The presence of a pseudo-isosbestic point in the area-normalized spectra indicated that there were only two linearly indepen dent components in the band envelope. For all concentrations, the C=N stret ching band envelope was resolved into three components. These were assigned in turn to the free propionitrile (2246 cm(-1)), a 1:1 o-cresol-propionitr ile complex (2256 cm(-1)), and an overtone or combination mode of propionit rile which does not involve CEN stretching (2265 cm-L). The equilibrium con stant K-C for the formation of the complex was determined at various mole f ractions of o-cresol. The calculated values of K-C exhibited a strong conce ntration dependence. (C) 1998 Elsevier Science B.V. All rights reserved.