Isothermal VLE Measurements for Difluoromethane + Dimethyl Ether and an Evaluation of Hydrogen Bonding

Vapor-liquid equilibria (VLE) data for the difluoromethane (R32) + dimethyl ether (RE170) system were measured with the aim of completing our study of hydrogen bonding between hydrofluorocarbons (HFCs) and dimethyl ether. The measurements were taken in an apparatus based on a static analytical method at temperatures ranging between (258.15 and 293.15) K. The R32 + RE170 system shows a slight negative deviation from Raoult's law that is attributed to hydrogen bonding between RE170 and R32. This H bonding was estimated using the homomorphic concept. The physical interaction was represented by the difference between the excess Gibbs energy (gE) of R32 + RE170 and its corresponding homomorphic system, the R32 + propane (R290) system. The VLE data were reduced by means of the Carnahan-Starling-De Santis (CSD) equation of state (EoS) together with the classical mixing rule and then by means of the Redlich-Kwong-Soave (RKS) EoS, with the Huron-Vidal mixing rule, using the NRTL equation for gE at infinite pressure. VLE data for the R32 + RE170 system are not reported elsewhere in the literature.