Solid–Liquid Phase Equilibrium of 2-Mercapto-1,3,4-thiadiazol in Pure Organic Solvents

Abstract

The solubility of 2-mercapto-1,3,4-thiadiazol (MTD) in 13 pure solvents including methanol, ethanol, n-propanol, i-propanol, n-butanol, i-butanol, s-butanol, n-pentanol, i-pentanol, acetonitrile, ethyl formate, methyl acetate, and ethyl acetate was determined by a static gravimetric method at temperatures ranging from 278.15 to 318.15 K under atmospheric pressure. The results demonstrated that the experimental solubility of MTD increases with the increase of temperature. The mole fraction solubility of MTD in the solvent of methyl acetate was the highest and in acetonitrile was the lowest. The experimental solubility data were correlated with the Yaws model, the modified Apelblat model, the λh model, and the NRTL model. Relative average deviation (RAD) and root mean square deviation (rmsd) were used to evaluate the fitting degree of each model. The fitting results show that the NRTL model fitted the solubility data best among all selected models (with RAD = 0.0008, rmsd = 0.00005).

Measurement and Correlation of the Solubility of 2-Mercapto-1,3,4-thiadiazol in Aqueous Binary Solvent Mixtures

“…The melting point ( T m ) and fusion enthalpy (Δ fus H ) of MTD used in this paper were 416.62 K and 23.49 kJ·mol –1 , respectively. The data were obtained from our previous work …”

“…The solvent selection was based on our previous work on the solubility of MTD in pure solvent. 14 MTD has higher solubility There are strong hydrogen bonds between MTD and water, MTD and acetone, and water and n-propanol. The cosolvency phenomenon plays an important role in controlling the crystallization process.…”

“…7,12,13 At present, only solubility data of MTD in pure solvents can be achieved. 14 There is rare paper on the solubility of MTD in aqueous binary solvents.…”

“…The solubility of a substance in organic solvents is an important property. Solubility data can provide the basic characteristics of the substance dissolution process, which is essential for the selection of solvents in the process of crystallization and purification. − Thermodynamic data also play a role in guiding the organic synthesis process. ,, At present, only solubility data of MTD in pure solvents can be achieved . There is rare paper on the solubility of MTD in aqueous binary solvents.…”

Measurement and Correlation of Solubility of Methyl 1,2,4-Triazole-3-carboxylate in 14 Pure Solvents from 278.15 to 318.15 K

“…The modified Apelblat model is an empirical model to describe the relationship between mole fraction solubility and temperature, − which is shown in eq . where x 1 is the mole fraction solubility, T is the absolute temperature, and A , B , and C are empirical constants.…”