Molecular dynamics study of 2,2′-difurylmethane with n-propanol and n-butanol binary liquid mixtures

Abstract

Liquid-liquid mixtures are ubiquitous in many natural and industrial processes. Their excess thermodynamic properties are governed by the intermolecular interactions. As such, experimental techniques such as neutron and x-ray diffractions, or computational chemistry methods can be used to probe structure at atomic level. However, they are rather scarce and expensive. Our interest is on the binary liquid mixtures involving 2,2′-difurylmethane (DFM) and n-alcohol, which have been studied experimentally. For all the efforts in understanding these mixtures, there is still a need to probe molecular structure at microscopic level. Therefore, the aim of this dissertation is to gain information on the molecular level structure of DFM and n-propanol or n-butanol binary mixtures using computational chemistry methods. Molecular dynamics simulations have been performed using optimized potentials for liquid simulations all atom (OPLS AA) force field to study the thermodynamic properties and structural aspects of DFM with n-propanol and n-butanol binary mixtures. The results indicate that for both mixtures the computed and experimental thermodynamic properties are in close agreement. The calculated excess molar volumes show negative and positive deviations in lower and higher DFM mole fractions, respectively. DFM and n-propanol excess molar volumes assume the most negative values and tend to positive values at higher DFM mole fractions than DFM and n-butanol mixtures, which is in accord with the experimental trends. Radial distribution function and ab initio calculations indicate the presence of hydrogen bonding between one of the DFM oxygen atoms and acidic hydrogen of n-propanol or n-butanol. For both mixtures, the calculated coordination numbers reveal that there is better mixing in lower DFM mole fractions. However, DFM and n-propanol mixtures show better mixing than DFM and n-butanol. The dihedral angle distributions show evidence of hydrogen bonding as well as the effect of the alkyl chain. n-butanol seems to have an enhanced hydrogen bonding than n-propanol.