Solubility measurement and correlation of 2-aminoterephthalic acid in eight alcoholic solvents at different temperatures

Abstract

This research experimentally measured the solubility of 2-aminoterephthalic acid in eight pure alcoholic solvents – methanol, ethanol, 1-propanol, 1-butanol, 2-propanol, 2-butanol, 2-methyl-2-propanol, and 3-methyl-1-butanol – from 303.15 to 338.15 K at normal pressure p = 0.1 MPa by the excess solid method. The measured solubility of 2-aminoterephthalic acid in these pure organic solvents was found to increase with the rise of temperature in the following order: 3-methyl-1-butanol (lowest solubility) < 1-butanol < 2-butanol < 1-propanol < 2-methyl-2-propanol ≈ 2-propanol < ethanol < methanol (highest solubility). The experimental solubility was correlated by the Van’t Hoff equation and the λh (Buchowski) equation. The apparent thermodynamic properties (Δ0Gsol, Δ0Hsol and Δ0Ssol) were calculated by the Van’t Hoff equation, from which it was concluded that the dissolution process is entropy-motivated and endothermal. In addition, the solvent effects on 2-aminoterephthalic acid solubility were studied by the KAT-LSER model, where the results showed that the polarizability accounts for 47.9 ± 4.2 % of the total solvent effect.A volcano-type relation between the dissolution entropy and enthalpy versus the solvent boiling point is reported, showing maximal values of 55.3 J mol−1 K−1 and 29.2 kJ mol−1, respectively, for intermediate molecular interactions of solute and solvent.