Spectroscopic and Thermodynamic Evidence of Dimer and Trimer Hydrogen Bonded Complex Formation Between Chloroform and 2-Butanone. Excess Molar Enthalpy for Chloroform + 2-Butanone Binary System at 303 K

GÓMEZ MARIGLIANO, ANA CLELIA; CAMPOS, VIVIANA; LIS FERNANDEZ DE SOLER; M. LORENA ROLDÁN; SÓLIMO, HORACIO

JOURNAL OF PHYSICAL CHEMISTRY B

AMER CHEMICAL SOC

Año: 2013

1089-5647

FT-Raman and FT-infrared spectra of pure chloroform (A) and 2-butanone (B), as well as of the binary system chloroform + 2-butanone were recorded in order to investigate type and nature of the intermolecular complexes formed when both chemicals are mixed. The optimized structures and vibrational frequencies for 2-butanone, chloroform and their 1:1 and 1:2 complexes were calculated by means of density functional theory (DFT) techniques using the B3LYP functional combined with the 6-31G(d,p) and 6-311++G(d,p) basis set. The recorded FTIR and Raman spectra confirms the existence of these type of hydrogen-bonded complexes, making it possible, furthermore, to calculate the heteroassociation constants. Heat of mixing at 303 K over the whole mole fraction range at atmospheric pressure was also measured. The excess molar enthalpy was fitted to a Redlich?Kister type equation, using least squares in order to obtain its dependence on concentration. The ideal associated solution model was also used in order to calculate these equilibrium constants among the chemical species in solution, which compares well with that calculated with the spectral determinations, and the enthalpy of hydrogen bonds formation. Furthermore, the McGlashan-Rastogi linearization test was also used in order to provides thermodynamic evidence about the stoichiometry of the formed complexes