Solubility Measurement and Correlation of 2-Amino-5-bromopyrazine in Methanol/Ethanol/Isopropanol/Propylene Glycol Plus Water and 10 Pure Solvents at (278.15–323.15) K

The solubility of 2-amino-5-bromopyrazine in the co-solvent mixtures of methanol, ethanol, isopropanol, and propylene glycol (PG) plus water and 10 monosolvents (methanol, ethanol, isopropanol, N,N-dimethylformamide (DMF), n-propanol, n-butanol, acetone, ethylene glycol (EG), PG, and water) was experimentally measured by the isothermal method at 278.15–323.15 K under 101.2 kPa. The temperature dominated the trend of solubility of 2-amino-5-bromopyrazine in pure and mixed solvents, especially high temperatures had a positive effect on dissolution. For the pure solvent system, the maximum solubility was obtained in DMF. For the mixed systems, isopropanol + water was superior to the other three combinations. The Apelblat model, van’t Hoff model, and NRTL model were used to correlate the solubility of 2-amino-5-bromopyrazine in 10 monosolvents. Furthermore, three thermodynamic co-solvency models including the Jouyban–Acree (JA) model, the Van’t Hoff–Jouyban–Acree (VJA) model, and the modified Apelblat–Jouyban–Acree (AJA) model were used to calculate the solubility data. This study would be helpful to the synthesis and purification processes of the final product.