Modeling and parameters estimation for the solubility calculations of nicotinamide using UNIFAC and COSMO-based models

Abstract

Nicotinamide is an organic acid belonging to the vitamin B3 family. This material holds high nutritional importance especially related to different aspects of health and tissue recovery. The development of alternative strategies for its production depends on studies concerning experiments and modeling. Solubility experiments provide data about the distribution of a target material under solid-liquid equilibrium. This information coupled with mathematical models allows the determination of interaction parameters that can be used both for scientific and industrial improvements. In this work, the solubility of nicotinamide was experimentally studied in binary liquid mixtures formed by methanol + ethanol and methanol + 2-propanol covering the entire molar fraction of the binary liquid solution. The solubility was gravimetrically determined in the temperature range from 293.2 K to 323.2 K. The experimental results were used to perform the parameters optimization for the UNIFAC and UNIFAC-DO models. Furthermore, the COSMO-SAC and COSMO-UNIFAC models (and variants) were used to predict the solid-liquid equilibrium. The model UNIFAC-DO has presented the most reliable results, providing the sum of the absolute errors (SAE) and the sum of the relative errors (SRE) of 0.2448 and 11.4634, respectively, while the original UNIFAC presented 1.5636 and 28.2620, and the COSMO-SAC-based methods presented, as best result, 4.7228 and 75.0050.