Thermodynamics Research Center / ThermoML | Journal of Chemical and Engineering Data

ABSTRACT

The solubility of pharmacologically active poorly water-soluble compound isatin in nine different green solvents [water, ethanol, butanol-2, Transcutol [2-(2-ethoxyethoxy)ethanol], ethylene glycol (EG), ethyl acetate (EA), isopropyl alcohol (IPA), propylene glycol (PG), and polyethylene glycol-400 (PEG-400)] was measured from (298.15 to 338.15) K at atmospheric pressure. The measured solubilities of isatin were correlated with the Apelblat and ideal equations. For the Apelblat equation, the root-mean-square deviations (RMSD) and correlation coefficients (R2) (n = 5) were found to be (0.20 to 1.45) % and 0.9964 to 0.9999, respectively. However, for an ideal equation, the RMSD and R2 (n = 5) were obtained as (0.19 to 3.00) % and 0.9940 to 0.9990, respectively. The mole fraction solubility of isatin was observed highest in Transcutol (5.23*10 1 at 298.15 K) followed by PEG-400 (9.85*10 2 at 298.15 K), EG (7.54*10 3 at 298.15 K), PG (6.73*10 3 at 298.15 K), EA (5.68*10 3 at 298.15 K), butanol-2 (5.16*10 3 at 298.15 K), IPA (4.19*10 3 at 298.15 K), ethanol (4.09*10 3 at 298.15 K), and water (5.14*10 5 at 298.15 K) from (298.15 to 338.15) K. The mass fraction solubility of isatin was also observed highest in Transcutol (1.20 kg*kg 1 at 298.15 K) followed by PEG-400 (4.02*10 2 kg*kg 1 at 298.15 K), EG (1.80*10 2 kg*kg 1 at 298.15 K), PG (1.32*10 2 kg*kg 1 at 298.15 K), ethanol (1.31*10 2 kg*kg 1 at 298.15 K), IPA (1.04*10 2 kg*kg 1 at 298.15 K), butanol-2 (1.03*10 2 kg*kg 1 at 298.15 K), EA (9.54*10 3 kg*kg 1 at 298.15 K), and water (4.20*10 4 at 298.15 K) from (298.15 to 338.15) K. The data of dissolution enthalpy, Gibbs energy, and dissolution entropy indicated endothermic, spontaneous, and entropy-driven dissolution of isatin in most of the green solvents investigated.