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The solubilities of sodium 1- and 2-naphthalenesulfonate (1- and 2-SNS) in aqueous sodium hydroxide solutions were measured over the temperature range from 276 to 337 K at atmospheric pressure by a dynamic method. The experimental results showed that the solubilities of 1- and 2-SNS both increased with temperature and decreased with concentrations of aqueous sodium hydroxide solutions. The experimental data were correlated with the new electrolyte nonrandom two-liquid (E-NRTL) model. The calculated results showed good agreement with the experimental data. A new strategy, based on the solubility difference between 1- and 2-SNS in aqueous sodium hydroxide solutions, was carried out in laboratory scale. This new strategy, in which the current process of blowing naphthalene was replaced by removing the byproduct according to the solubility difference, overcame the drawbacks of blowing naphthalene and made a good separation effect. The best separation effect was attained when the concentration of aqueous sodium hydroxide solution was 0.07 and the operating temperature was 298.15 K. The purities of obtained 1- and 2-SNS were 0.8369 and 0.9854 in this operating condition, respectively. The new strategy has potential in industrial application for optimizing the production of 2-naphthol. [ABSTRACT FROM AUTHOR]

Toseparate a salt mixture (mainly consisting of Na2CO3and Na2SO4) which is formedfrom the 4,4′-diaminostilbene-2,2′-disulfonic acid wastewatertreatment, the solubility data of Na2CO3andNaHCO3in Na2SO4–water solventmixtures were measured using a dynamic method over the 275–335K temperature range. The solute-free mass fraction of Na2SO4in the solvent mixtures extended from 0 to 0.25. Thesolubility of Na2CO3and NaHCO3inNa2SO4–water solvent mixtures decreasedwith addition of Na2SO4. With rising temperature,the solubility of NaHCO3increased while the solubilityof Na2CO3increased at first and then decreasedafter transition points. The experimental data were correlated withthe electrolyte nonrandom two-liquid model. The root-mean-square deviationsof solubility temperature varied from 0.35 to 1.50 K. Based on thesolubility data of this work, a new strategy for separating the Na2CO3and Na2SO4mixture wasproposed theoretically. [ABSTRACT FROM AUTHOR]