Solubility of N-tert-Butylbenzothiazole-2-sulfenamide in Several Pure and Binary Solvents

The solubility of N-tert-butylbenzothiazole-2-sulfenamide (TBBS) in six pure solvents (methanol, ethanol, toluene, 2-propanol, 1-butanol, and tert-butylamine) and three binary solvents (methanol + water, ethanol + water, and tert-butylamine + water) was measured in a temperature range between 273.2 and 313.2 K using a gravimetric determination under a pressure of 0.101 MPa. The initial mole fraction of methanol, ethanol, or tert-butylamine in the binary solvents was in the range of 0.4 to 1.0. The experimental data show that the solubility of TBBS increases as the temperature increases in both the pure and binary solvents. The solubility of TBBS in the six pure solvents has the following sequence: x1, tert-butylamine > x1, toluene > x1, 1-butanol > x1, ethanol > x1, 2-propanol > x1, methanol. The high-temperature solubility of TBBS in tert-butylamine at 318.2–343.2 K under a pressure from 0.156 to 0.213 MPa was also determined using an approach based on turbidity measurement. The experimental solubility data can be correlated by the following four thermodynamic models: the modified Apelblat equation, the λh equation, the CNIBS/R-K model, and the NRTL model. The results showed that the solubility of TBBS fit best with the modified Apelblat equation in both the pure and binary solvents.