Disodium Hydrogenphosphate

Abstract

Disodium Hydrogenphosphat e 9 7 COMPONENTS: (1) Sodium dihydrogenphosphate; NaH.PO,; [7558-80-7] 1 4 (2) Sodium perchlorate; NaClO^; [7601-89-0] (3) 2-Propanone (acetone); CoH.0; [67-64-1] J 0 (4) Water; H20; [7732-18-5] ORIGINAL MEASUREMENTS: Ferroni, G.; Galea, J.; Antonetti, G. BudW. Soc. Chim. Tl. 1974, 72, (Pt. 1), 273-81. VARIABLES: Concentration of NaClO. at 25°C. 4 PREPARED BY: J. Eysseltova EXPERIMENTAL VALUES: Composition of the saturated solutions at 25°C. Disodium Hydrogenphosphat e COMPONENTS: (1) Disodium hydrogenphosphate; Na2HP0,; [7558-79-4] (2) Water; H20; [7732-18-5] EVALUATOR: CRITICAL EVALUATION: THE BINARY SYSTEM Solubility data have been reported for the temperature interval 273-373 Κ (1), for the 272-313 Κ interval (2), and at 273, 291 and 298 Κ (3). Wendrow and Kobe (4) report their own extrapolated data as well as data obtained by others (5). Older data (7-13) are cited in the article by D'Ans and Schreiner (6). But these data appear to have a systematic error and were eliminated from consideration during the first graphical examination of the material. On the other hand, some data from studies of multicomponent systems (14-19) were consistent with those reported by others (1-3) and were included in the evaluation procedure.Several hydrates of disodium hydrogenphosphate have been reported. Wendrow and Kobe (4) stated that the transition temperatures of the dodecahydrate to the heptahydrate and of the heptahydrate to the dihydrate were 308.7 and 321.2 K, respectively. A more pre cise determination of these values (6) gives transition temperatures of 308.55 and 321.55 K, respectively. There is also a report of the existence of two forms of the dodeca hydrate with a transition temperature of 302.8 Κ (2), but this has not been confirmed by any other investigators. The transition temperature of the dihydrate to the anhydrous salt was said to be 368.2 Κ (4).All the experimental data that were not eliminated in the first graphical examina tion were evaluated by the method described in chapter 3. The data were fitted to equation [1], The precision of the published data was estimated to be about the same as Disodium Hydrogenphosphat e COMPONENTS: EVALUATOR:(1) Disodium hydrogenphosphate; Na2HP0,; [7558-79-4](2) Water; H20; [7732-18-5]

Solid–Liquid Equilibrium for the Ternary Systems (Na2SO4 + NaH2PO4 + H2O) and (Na2SO4 + NaCl + H2O) at 313.15 K and Atmospheric Pressure

“…Therefore, to optimize the solvent extraction process of sodium dihydrogen phosphate and prepare a high quality of sodium dihydrogen phosphate, the solid–liquid equilibria of the ternary systems (Na 2 SO 4 + NaH 2 PO 4 + H 2 O) and (Na 2 SO 4 + NaCl + H 2 O) are of vital importance in the crystallization process. Although the complete phase equilibrium data for the system (Na 2 SO 4 + Na 2 HPO 4 + H 2 O) at (298.15 and 313.15 K) has been reported in the literature, sodium dihydrogen phosphate (NaH 2 PO 4 , CAS: 7558-79-4) in our study and disodium hydrogen phosphate (Na 2 HPO 4 , CAS: 7558-80-7) in the references are not alike. However, the complete phase equilibrium data for the systems (Na 2 SO 4 + NaH 2 PO 4 + H 2 O) and (Na 2 SO 4 + NaCl + H 2 O) at 313.15 K have not been reported in the literature yet, which is an impediment to the further exploration of the solvent extraction process of sodium dihydrogen phosphate.…”

Parameter Dependence of the Solubility Limit for Disodium Phosphate

“…Among the initially tested parameters, ΔR min = 0.1275 and 0.1338 Å resulted in solubility limits of 0.5 and 0.9 mol/kg, respectively, which were closest to the experimental solubility limit of 0.8 mol/kg. 27 To determine the optimal fit, we performed a linear regression analysis of ΔR min versus the logarithm of the simulated solubility. We found the following relationship between ΔR min and solubility: c solubility = 9.17 × 10 −6 × e 86.28 × ΔRmin .…”

“…As shown in Figure , the solubility of Na 2 HPO 4 was found to be exponentially related to Δ R min , with higher Δ R min resulting in higher solubility. Among the initially tested parameters, Δ R min = 0.1275 and 0.1338 Å resulted in solubility limits of 0.5 and 0.9 mol/kg, respectively, which were closest to the experimental solubility limit of 0.8 mol/kg …”

“…To verify, this value was then simulated for 300 ns, starting from the initial structure as the other simulations, as summarized in Table under the curve-fit parameter . Molality was chosen as the concentration unit as many references reported experimental molal values; these values ranged from 0.77 to 0.86 m . However, one source reported both molality and molarity, and they were the same to the first significant digit, namely, 0.84 m and 0.86 M .…”

“…To verify, this value was then simulated for 300 ns, starting from the initial structure as the other simulations, as summarized in Table 2 under the curve-f it parameter. Molality was chosen as the concentration unit as many references reported experimental molal values; these values ranged from 0.77 to 0.86 m. 27 However, one source reported both molality and molarity, and they were the same to the first significant digit, namely, 0.84 m and 0.86 M. 27 To verify that the molality and molarity are similar in our simulations, molarity was calculated by excluding the volume of the insoluble cluster using the Mol_Volume package. 28 Osmotic Pressure Simulation Setup.…”