Solubility measurement and modelling of ethyl 5-amino-4-cyano-3-(2-ethoxy-2-oxoethyl)-2-thiophenecarboxylate in four groups mixed solvents

The solubility of ethyl 5-amino-4-cyano-3-(2-ethoxy-2-oxoethyl)-2-thiophenecarboxylate (ACET) in binary (acetone + methanol), (acetone + ethanol), (acetone + 1-butanol) and (acetone + isopropanol) solvent mixtures was investigated by the isothermal dissolution equilibrium method under 101.3 kPa. This study was carried out at different mass fractions of acetone ranging from 0.1 to 0.9 at T = (273.15-318.15) K. For the nine groups with each solvent mixture studied, the solubility of ACET in the mixed solutions increased with increasing temperature and mass fraction acetone. At the same temperature and mass fraction of acetone, the solubility of ACET was greater in (acetone + methanol) than in the other three solvent mixtures. The experimental solubility values were correlated by three co-solvency models (Jouyban-Acree model, van't Hoff-Jouyban-Acree model and Apelblat-Jouyban-Acree model). The relative average deviations (RAD) and the root-mean-square deviations (RMSD) were all less than 1.49 x 10 (2) and 8.99 x 10 (4), respectively. The Apelblat-Jouyban-Acree model provided best representation of the experimental solubility. Furthermore, the standard molar enthalpy of the ACET during the dissolving process (Delta H-sol(o)) was also derived in this work, and the results showed that the dissolution process is endothermic. The experimental solubility and the models used in this work would be helpful in purifying of ACET from its crude mixtures. (C) 2016 Elsevier Ltd.