Thermodynamics Research Center / ThermoML | Journal of Chemical Thermodynamics

ABSTRACT

The solubility of 3-amino-1,2,4-triazole in ten organic solvents including ethanol, isopropanol, n-propanol, methanol, ethyl acetate, acetone, acetonitrile, 1,4-dioxane, N-methyl-2-pyrrolidone and 2-butanone was determined experimentally by the isothermal saturation method over a temperature range from T = 283.15 K to T = 318.15 K under 101.1 kPa. For the studied temperature range, the solubility of 3-amino-1,2,4-triazole in mole fraction in the solvents increased with a rise of temperature. On the whole, they obeyed the following order from high to low in different solvents: N-methyl-2- pyrrolidone greater than methanol greater than ethanol greater than n-propanol greater than (isopropanol, acetone) greater than 1,4-dioxane greater than 2-butanone greater than (ethyl acetate, acetonitrile). The determined solubility results of 3-amino-1,2,4-triazole in the solvents studied were correlated using the modified Apelblat equation, Buchowski Ksiazaczak kh equation, Wilson model and NRTL model. The maximum values of root-mean-square deviation (RMSD) and relative average deviation (RAD) were 9.45 10 4 and 2.16%, respectively. In general, the four thermodynamic models were all acceptable for describing the solubility behaviour of 3-amino-1,2,4-triazole in these solvents. Furthermore, the mixing properties including the mixing Gibbs energy, mixing enthalpy, mixing entropy, activity coefficient at infinitesimal concentration (c1 1 ) and reduced excess enthalpy (HE;1 1 ) were acquired. The solution process of 3-amino-1,2,4-triazole was spontaneous and favourable in the selected solvents. The solubility values obtained and the thermodynamic studies would be very useful for optimizing the purification process of 3-amino-1,2,4-triazole.