Solubility and thermodynamic parameters of nicotinic acid in different solvents

Abstract

Nicotinic acid is an important compound needed for the body to keep proper functioning and stay healthy. The determination of solubility parameters in different solvents can be useful for operations such as crystallization or encapsulation of nicotinic acid. In this study, we critically evaluated the solubility of nicotinic acid in nine solvents: water, methanol, ethanol, propanol, propan-2ol, butanol, acetone, ethyl acetone and dimethyl sulfoxide (DMSO). Solubility data are provided as mole fractions of solvent versus temperature. Results showed that DMSO afforded the highest nicotinic acid solubility, greater than the ideal solubility values. Thermodynamic parameters such as the activity coefficient, melting temperature and enthalpy of fusion were determined by differential scanning calorimetry. Non-predictive activity coefficient models were obtained to represent the experimental data through Margules, van Laar, Wilson, NRTL, and UNIQUAC equations. The van Laar, Wilson, and NRTL models showed broadly similar performance. The UNIQUAC model showed an optimum performance for six of the nine solvents.