Solubility determination and thermodynamic model of 6-hydroxy-3,4-dihydro-2(1H)-quinolone in ten pure solvents and four binary solvents at 278.15 to 323.15 K

6-hydroxy-3,4-dihydro-2(1H)-quinolone is an important chemical intermediate, which has important application value in the fields of medicinal chemistry and material chemistry. In this paper, the static counterpoise method integrated with HPLC was used to detected the solubility of sample in 10 pure solvents (1-Butanol, methanol, ethanol, isopropanol, tetrahydrofuran, 1-Propanol, methyl acetate, ethyl acetate, acetonitrile and isobutanol) and four binary solvents (ethanol + ethyl acetate, ethanol + acetoni trile, methanol + acetonitrile, and methanol + ethyl acetate). The results reveals that the sample has higher solubility in methanol and ethanol in pure solvents. In binary solvents, the solubility has a maximum value at x(A) = 0.7. At the same temperature, the binary system can improve the solubility of sample more than pure solvents. At 278.15-323.15 K, themole fraction solubility ranges of the 6-hydroxy-3,4-dihydro-2(1H)-quinolone respectively are 0.0018-0.0062 (1-Butanol), 0.0022-0.0084 (methanol), 0.0021-0.0076 (ethanol), 0.0019-0.0072 (isopropanol), 0.0025-0.0065 (tetrahydrofuran), 0.0017-0.0064 (1-Propanol), 0.0016-0.0039 (methyl acetate), 0.0007-0.0013 (ethyl acetate), 0.0003-0.0012 (acetonitrile), 0.0011-0.0049 (isobutanol), 0.0010-0.0090 (ethanol + ethyl acetate), 0.0006-0.0095 (ethanol + acetonitrile), 0.0007-0.0092 (methanol + acetonitrile), 0.0009-0.0102 (methanol + ethyl acetate). The five models, such as the SUN model, h model, CNIBS/R-K model, Jouyban-Acree model and modified Apelblat model, were used to fit the experimental data. The CNIBS/R-K model and modified Apelblat model fit the data better in miscible and single solution respectively. In addition, the KAT-LSER model was used to study the relationship between solute-solvent interaction and sample solubility. (C) 2021 Elsevier Ltd.

Automated summary

This paper investigates the solubility of 6-hydroxy-3,4-dihydro-2(1H)-quinolone in different solvents using the static counterpoise method integrated with HPLC. It is found that the sample has higher solubility in methanol and ethanol among the pure solvents. In binary solvents, the solubility reaches its maximum value at x(A) = 0.7. Different models are used to fit the experimental data, and the CNIBS/R-K model and modified Apelblat model show better fitting results in miscible and single solution, respectively. Additionally, the KAT-LSER model is used to study the relationship between solute-solvent interaction and sample solubility.