Measurement and Correlation Studies of Phase Equilibria and Thermophysical Properties of 2,6-Dichlorotoluene

Abstract

The present study summarizes the thermophysical properties and vapor pressure data of 2,6-dichlorotoluene, an important intermediate in the agrochemical industries for the production of herbicides. A Swietoslawski-type ebulliometer was used for generating the vapor pressure data experimentally in the range of 1.2−33.2 kPa. The vapor pressure data generated are correlated with the Antoine equation, and it is observed that the Antoine equation exhibited minimal deviations. The critical properties were also estimated using the group contribution methods, mainly Joback, Constantinou, Gani, and Nannoolal methods. The normal boiling point obtained using the Antoine equation is much closer to the boiling point obtained using the Constantinou and Gani method. Furthermore, the thermophysical properties like density, refractive index, and viscosity were experimentally evaluated at 95.5 kPa for the temperature ranging from 293.15 to 333.15 K. The density of the liquids was estimated using the Joback, Constantinou, Gani, and Nannoolal methods by employing the Rackett equation. It was observed that Joback showed the least relative average deviation of 1.442%. Mansingh viscometer is used to measure the viscosity and used the Vogel− Tamman−Fulcher equation for correlating the data and, on comparison, was found to be in good agreement. Apart from this, group contribution methods Nannoolal, Orrick, and Erbar methods were used to estimate the viscosity, wherein the Orrick and Erbar method showed the least deviation among the two. Other than the thermophysical properties and vapor pressure data for the pure component, i.e., 2,6-dichlorotoluene, vapor liquid equilibrium data for the binary system acetic acid (1) + 2,6-dichlorotoluene ( 2) is generated at three different subatmospheric pressures, 66.7, 60, and 40 kPa. NRTL model was used to fit the experimental data, and it was found that the experimental data are in good correlation with the predicted data. The binary interaction parameters for the NRTL model were reported, and T−x−y diagrams were also plotted, which show the experimental and predicted data. Thermodynamic consistency tests were conducted for the vapor−liquid equilibrium data at three different pressures, and it was observed that all of them have passed.