FTIR SPECTRAL STUDIES OF THE BINARY SOLUTIONS OF ACETONE WITH XYLENE ISOMERS

FTIR spectra of neat acetone (ACT), xylene isomers (o-xylene (OXY), m-xylene (MXY), and p-xylene (PXY)) and their binary solutions at various ACT molar concentrations are recorded in the range of 4000-400 cm–1. Although neat ACT is a mixture of monomers, dimers, and trimers, the number of dimers is larger than that of monomers/trimers, as suggested by a relatively higher intensity of the dimmer ν(C=O) band with respect to that of the monomers/trimers. The shifts suffered by some of the fundamental absorption bands of xylene isomers/ACT confirm the presence of (ACT)C=O⋯H(OXY/MXY/PXY aromatic C–H or methyl) and (ACT methyl)H⋯π(OXY/MXY/PXY) H-bonds in all the solutions but with different strengths, as suggested by different magnitudes of the vibrational band shifts. The asymmetric and symmetric stretching bands of either C–H or CH3 of OXY/PXY experience unequal force constants in ACTOXY and ACTPXY binary solutions with a 0.2 mole fraction of ACT. The νas(C–H) doublet due to the intramolecular coupling appears only in ACTOXY and ACTPXY binary solutions.