Measurement and Correlation of Solubilities of 3-Methyl-2-Nitrobenzoic Acid, 3-Methyl-4-Nitrobenzoic Acid, and 5-Methyl-2-Nitrobenzoic Acid in n-Butanol Isomer Solvents

Abstract

In this study, the solid–liquid equilibrium (SLE) data of 3-methyl-2-nitrobenzoic acid (3-M-2-NBA), 3-methyl-4-nitrobenzoic acid (3-M-4-NBA), and 5-methyl-2-nitrobenzoic acid (5-M-2-NBA) in n-butanol, iso-butanol, tert-butanol, and sec-butanol were determined using the method of dynamic laser at atmospheric pressure. The experimental SLE data indicate that within the temperature range studied (290.15–348.95 K), the solubilities of 3-M-2-NBA, 3-M-4-NBA, and 5-M-2-NBA in the above four solvents are proportional to the temperature. The molar fraction of solubility of the same solute in different solvents from low to high is as follows: iso-butanol < n-butanol< sec-butanol < tert-butanol. The molar fraction of solubility of the three solutes in the same solvent from low to high is as follows: 3-M-4-NBA < 3-M-2-NBA<5-M-2-NBA. The experimental data were correlated using the Apelblat model, λh model, and NRTL activity coefficient model, and the calculated solubilities agree satisfactorily with the measured results. The best model for every system was selected using the result of Akaike information criterion analysis.