Solubility Equilibrium of (NaSO₃)₂NH-NaOH-H₂O and (KSO₃)₂NH-KOH-H₂O Systems and Preparation of Sodium and Potassium Imidobissulfates

Abstract

Solubilities of imidobissulfate salts of sodium and potassium in water and their related physical properties were determined, and basic and neutral sodium and potassium imidobissulfates were prepared on the basis of their chemical and physical experimental results. Solubility equilibrium of both ternary (NaS03) 2NH-NaOH-H₂0 and (KSO₃) 2NH-KOH-H₂0 systems were investigated at 30° C, and solubilities of (NaS03) 2NNa-, (NaS03) 2NH, (KS0g) 2NK and (KS03) 2NH in water were determined at 0-70° C. X-ray diffraction data for (NaS0g) 2NNa12 H₂0, (NaS03) 2NNa 20, (NaS03) 2NNa, (NaS03) 2NH.2 H₂0 and (KS03), NK H₂0 powders, pH of aqueous solutions of (NaS03) 2NNa and (KS03) 2NK, and dissociation pressure of (NaS08) iNNa12 H₂0 were also determined.
The basic sodium and potassium imidobissulfates were prepared by evaporating the dilute aqueous solutions in which (NH4S08) 2NH and NaOH or KOH being dissolved in a molar ratio of 1: 3 under a reduced pressure until no NH4+ ions were detected in the solutions. The desired hydrate of basic salt, (NaS03) 2NNa 12 H₂0, (NaS03) 2NNa20 and (KS03) 2NK H₂0, was allowed to crystallize out of the resulting solution by applying solubility data mentioned above as a fundamental of the crystallization. It is considered that this method is the most suitable for the preparation of basic salt.
Neutral salts, (NaS03)2N1-1.2 H₂0 and (KS03) 2NH, were prepared by neutralizing the basic salt solutions with HCl.
The basic salts, especially (NaSO₃) 2NNa, is expected as a new builder for synthetic detergent, reagent for buffer solution, drying agent etc.