Measurement and Correlation for the Solubility of Sodium p-Toluenesulfonate, Sodium Sulfite, and Sodium p-Methylphenoxide in Aqueous Sodium Hydroxide Solutions and Sodium Sulfite in Aqueous Ethanol Solutions

Abstract

The solubilities of sodium p-toluenesulfonate (NaPTS), sodium sulfite (Na 2 SO 3 ), and sodium p-methylphenoxide (NaCRS) in aqueous NaOH solutions and Na 2 SO 3 in aqueous ethanol solutions were investigated using a dynamic method over the temperature range from 277 to 341 K at atmospheric pressure. The experimental results showed that the solubilities of NaPTS, Na 2 SO 3 , and NaCRS in aqueous NaOH solutions and Na 2 SO 3 in aqueous ethanol solutions decreased distinctly with the solutefree mass fraction of NaOH (w 4 0 ) and ethanol (w 5 0 ). Further, there were obvious transition points in the solubility−temperature curves of NaPTS and Na 2 SO 3 in aqueous NaOH solutions, and the transition points shifted to lower temperature as w 4 0 rose. The forming of transition point was due to the different equilibrium solid phase, which was revealed by characterization of the equilibrium solid phase. But the transition points in the solubility−temperature curves of Na 2 SO 3 in aqueous ethanol solutions remained constant at different w 5 0 values. As the temperature rose, the solubilities of NaPTS and NaCRS in aqueous NaOH solutions increased, while the solubilities of Na 2 SO 3 increased at first and then decreased after the transition points in both aqueous NaOH and ethanol solutions. The experimental data were correlated with the electrolyte nonrandom two-liquid (E-NRTL) model, and model parameters were determined simultaneously. On the basis of the solubility difference between Na 2 SO 3 and NaCRS, a new process for reusing the NaOH in the alkali fusion reaction residue was proposed theoretically.

Salts and 1‐propanol induced aqueous two‐phase systems: phase separation and application

“…C 2 K 2 O 4, K 3 PO 4 and Na 2 SO 3 also show strong salting‐out effects, albeit not superior to that of K 4 P 2 O 7. However, the solubilities of C 2 K 2 O 4 and Na 2 SO 3 were far less than that of K 3 PO 4 , leading to the poor separation of 1‐propanol from the aqueous solution even under saturation condition, as demonstrated in Fig. .…”

Solubility Measurement, Model Correlation, and Solute–Solvent Interactions of Pidotimod in Nine Pure Solvents and Two Binary Solvents at Temperatures Ranging from 278.15 to 323.15 K

“…The solubility of pidotimod in 11 pure solvents and 2 binary solvent mixtures was measured by a dynamic method − and employing a laser-monitoring observation technique to determine the dissolution data.…”

“…On the basis of the local composition concept, the Wilson equation was first proposed by Wilson in 1964. 16,17,33 According to the traditional solid liquid-phase equilibrium theory, the solubility of a solid solute in a liquid solvent can be described by eq 6.…”

“…x 2 ′, x 3 ′ are the mole fractions of binary solvents in the solution. 16,17,33,34 Moreover, A nonrandom parameter (α 12 ) reflecting the mixing system is introduced to the equation. For the pure solvent system, the equations are as follows.…”

“…Hence, we employed a dynamic equilibrium method to determine the reliable solubility of pidotimod in a variety of pure and binary solvents within the temperature range of 278.15–323.15 K at atmospheric pressure. − Eleven pure solvents, water, methanol, benzyl alcohol, ethanol, acetone, iso -propanol, n -butanol, acetonitrile, N , N -dimethyl formamide (DMF), ethyl acetate, and butyl acetate were selected; the modified Apelblat, Wilson, and NRTL models were applied to correlate the pure solubility data, respectively. Furthermore, the mole fraction solubility of pidotimod in two binary solvents mixtures, methanol + acetone and methanol + butyl acetate was also investigated, the effects of the mass fraction of methanol in binary solvent mixtures (from 0.1 to 0.9) on the equilibrium solubility were studied, ,,− and corresponding binary solubility data were fitted by the Wilson, NRTL, and CNIBS/R–K Models.…”