Thermodynamics Research Center / ThermoML | Journal of Chemical Thermodynamics

ABSTRACT

Solubility of 2-chlorophenothiazine in nine organic solvents including methanol, ethanol, isopropanol, npropanol, ethyl acetate, acetone, acetonitrile, 1-butanol and 2-butanone was determined experimentally by the isothermal saturation method over a temperature range from T = 283.15 K to T = 318.15 K under 101.1 kPa. Within the studied temperature range, the mole fraction solubility of 2-chlorophenothiazine in these solvents increased with a rise of temperature. Except for the solvent of acetonitrile, they follow the order of 2-butanone greater than (acetone, ethyl acetate) greater than methanol greater than ethanol greater than n-propanol greater than isopropanol greater than 1- butanol. The solubility in ethyl acetate and acetonitrile had the strongest positive dependency on temperature. The determined solubility of 2-chlorophenothiazine in the solvents studied was correlated by using the modified Apelblat equation, Buchowski Ksiazaczak kh equation, Wilson model and NRTL model. The maximum values of root-mean-square deviation (RMSD) and relative average deviation (RAD) were 2.77*10-4 and 0.59%, respectively. In general, the four thermodynamic models were all satisfactory for describing the solubility of 2-chlorophenothiazine, and the Wilson model can correlate the experimental solubility best based on the result of Akaike Information Criterion analysis. Furthermore, the mixing properties including the mixing Gibbs energy, mixing enthalpy, mixing entropy, activity coefficient at infinitesimal concentration (c1 1 ) and reduced excess enthalpy (HE;1 1 ) were computed. The findings will be very useful in optimizing the purification process of 2-chlorophenothiazine.