Thermodynamics of solubility of the weak water-soluble bioactive compound isatin in various {polyethylene glycol 400 (PEG 400) + water} mixed solvent systems were studied using Van t Hoff and Krug analysis. The solubility of isatin was measured from T = (298.15 to 338.15) K at atmospheric pressure using the shake flask method. Values of the measured solubility were correlated with three semi-empirical models that included an ideal model, the modified Apelblat model and Yalkowsky model. The root mean square deviations were observed to be less than 4.00% by all three semi-empirical models. All three models showed a correlation coefficient of about 0.99. The mole fraction solubility of isatin was found to be highest in pure PEG 400 (9.85 10 2 at T = 298.15 K) and lowest in pure water (5.14 10 5 at T = 298.15 K) over the region studied from T = (298.15 to 338.15) K. The results of thermodynamic parameters (dissolution enthalpy, Gibbs free energy and dissolution entropy) indicated an endothermic, spontaneous and entropy driven dissolution process of isatin in all (PEG 400 + water) mixed solvent systems.
Compounds
#
Formula
Name
1
C8H5NO2
2,3-indolinedione
2
H2O
water
Datasets
The table above is generated from the ThermoML associated json file (link above).
POMD and RXND refer to PureOrMixture and Reaction Datasets. The compound numbers are included in properties, variables, and phases, if specificied;
the numbers refer to the table of compounds on the left.