Thermophysical properties and isobaric vapor-liquid equilibria for 3,4-difluoronitrobenzene and 2,5-difluoronitrobenzene

Abstract

3,4-Difluoronitrobenzene and 2,5-difluoronitrobenzene are significant fine chemical intermediates, widely applied in the fields of medicine, pesticides, and liquid crystal materials, particularly in pharmaceutical production. The available literature on their thermodynamic properties is scarce. Thermophysical property measurements for pure 3,4-difluoronitrobenzene and 2,5-difluoronitrobenzene liquids were performed in relation to temperature: density (293.15 to 353.15) K, viscosity (293.15 to 353.15) K, saturated vapor pressure (366 to 478) K. Isobaric vapor-liquid equilibria (VLE) data for the 3,4-difluoronitrobenzene and 2,5-difluoronitrobenzene binary system were experimentally determined at 101.2 kPa. The correspondence between density and temperature was successfully modeled utilizing the DIPPR equation. Meanwhile, viscosity data were analyzed using four selected equations, with VFT equation yielding the most precise results. Furthermore, the correlation between saturated vapor pressure and temperature can be precisely established using Antoine and Riedel equations. The binary VLE data were modeled using NRTL and Wilson equations, yielding binary interaction parameters. These parameter-derived predictions closely aligned with experimental findings, revealing the absence of azeotropic behavior in the binary system. The thermophysical properties of these pure components, along with VLE data provided, are significant for the separation process of 3,4-difluoronitrobenzene and 2,5-difluoronitrobenzene.