No abstract

The commercial possibilities of crystallization of inorganic salts by means of organic precipitante are being investigated. Since solubility cannot be predicted accurately, experimental data are necessary in order to permit technical and economic consideration of such a process.Solubilities and saturated solution densities are reported at intervals of 5°from 25°to 75°C. for potassium and ammonium nitrates in aqueous isopropanol solutions. Separation into two liquid phases occurs over part of the concentration and temperature range in the case of both systems.

Vapor-liquid equilibrium data at atmospheric pressure for the systems glycerol-water and glycerol-water saturated with sodium chloride were determined in an improved Othmer still. The binary mixtures and salt-saturated solutions were analyzed by refractive index measurements. The equilibrium data for the glycerol-water system were thermodynamically consistent when tested by Herington's method.apor-liquid equilibrium data for the systems glycerolwater and glycerol-water saturated with sodium chloride are of theoretical and industrial importance. Several industrial processes yield glycerol, sodium chloride, and water (4, 12). Adequate knowledge of the vapor-liquid equilibrium data for these systems is useful. Although boiling point-composition data for both systems have been reported (1, 14), it is difficult to predict their vapor-liquid equilibria because of the highly nonideal behavior of the systems, and experimental determinations are necessary. EXPERIMENTAL rated with sodium chloride at 20°C. Salt content was determined by titration against standard silver nitrate ( 14). Refractive indices of the salt-saturated solutions were then determined at 20°C and a calibration curve for the system was

Solubilities and saturated solution densities are reported at intervals of 5°from 25°to 100°C. for sodium sulfate in aqueous ethylene glycol solutions.

Normal trisodium phosphate forms three hydrates-a hemihydrate, a hexahydrate, and an oetahydrate-which can be identified by their optical properties and melting points. All higher hydrates were found to be complex salts.Trisodium phosphate forms hydrated complexes with the sodium salts of monovalent ions. These complexes are of two types. The first is represented by the formula raNasPOi.NaF.-XH20 where = 1 or 2, Y is a monovalent anion, and X = 18 or 19. The best known member of this type is the fluorine complex, 2NaaPC>4.NaF.19H20. The type formula for the second group is ra(Na3P0i.XH20)NaF where = 4 to 7, X = 11 or 12, and F is a monovalent anion. Two complexes are formed by some members of this series, both of which fall within the limits of the type formula. The crystal structure and optical properties of the complexes of the second type are very similar, all of them being trigonal and optically positive, and having similar refractive indexes. Some of the members of this group form an isomorphous series. The best known member of the second type is the hydroxide complex with the formula 5 (NasPOi. 12H20) NaOH, representing the common form of commercial trisodium phosphate. ACKNOWLEDGMENTThe author wishes to thank Howard Adler and W. H. Woodstock for many helpful suggestions, L. P. Audrieth for assistance in preparing the paper for publication, and A. R. Wreath for some of the analyses reported.