Solubilities and vapour pressures of saturated aqueous solutions of sodium tetraborate,sodium carbonate,and magnesium sulfate and freezing-temperature lowerings of sodium tetraborate and sodium carbonate solutions

Solubilities and vapour pressures of water over saturated solutions of sodium tetraborate, sodium carbonate, and magnesium sulfate and freezing-temperature lowerings of sodium tetraborate and sodium carbonate solutions were determined and compared with the literature data. These results permitted the evaluation of osmotic and activity coefficients and molar enthalpies of vaporization.     

Thermogravimetric studies of binary and ternary systems containing salicylic acid,sodium salicylate,sodium carbonate and sodium hydrogen carbonate. Part II

The mechanism of thermal decomposition of binary and ternary systems containing salicylic acid, sodium salicylate and disodium salicylate sesquihydrate, sodium carbonate and sodium hydrogen carbonate were studied by means of thermogravimetric and differential thermal analysis. The possibility was demonstrated of analyzing ternary systems containing three unreactive or three reactive components. The results can be useful for monitoring the course of the commercial-scale manufacture of sodium salicylate and for checking declared compositions of salicylate mixtures.

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Zusammenfassung Ein Mechanismus der thermischen Zersetzung SalicylsÄure, Natriumsalicylat und Dinatriumsalicylat Sesquihydrat, Natriumcarbonat und Natriumhydrocarbonat enthaltender binÄrer und ternÄrer Systeme wurde mittels Thermogravimetrie und Differentialthermoanalyse untersucht. Die Möglichkeit, drei unreaktive oder drei reaktive Komponenten enthaltende ternÄre Systeme zu untersuchen, wurde gezeigt. Die Ergebnisse können dazu eingesetzt werden den Verlauf der Natriumsalicylatfabrikation im Handelsma\stab zu verfolgen und deklarierte Zusammensetzungen von Salicylatmischungen zu überprüfen.

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Résumé On a étudié par thermogravimétrie et par analyse thermique différentielle le mécanisme de la décomposition thermique de systèmes binaires et ternaires contenant de l'acide salicylique, du salicylate monosodique et du salicylate disodique sesquihydraté, du carbonate de sodium et de l'hydrogénocarbonate de sodium. On montre la possibilité d'analyser des systèmes ternaires comprenant trois composants réactifs ou non. Les résultats peuvent Être utilisés pour commander le déroulement de la fabrication du salicylate de sodium à l'échelle commerciale et pour contrÔler les compositions déclarées des mélanges de salicylates.

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Osmotic coefficients of aqueous sodium carbonate solutions at 25°C

Isopiestic vapor pressure measurements are reported for aqueous sodium carbonate solutions at 25°C using sodium chloride as reference electrolyte. Osmotic and activity coefficients are calculated from the concentrations of the solutions in isopiestic equilibrium. The results are used to calculate the trace activity coefficients of carbonate ion in sodium chloride solutions; these should approximate the trace activity coefficient of carbonate ion in seawater. The solubility of sodium carbonate in water at 25°C has been determined.     

The action of carbon dioxide on potassium and sodium carbonate peroxyhydrates

Conclusions The main possibility of how the reaction between sodium and potassium carbonate peroxyhydrates and moist CO₂ proceeds with the formation of the bicarbonate and oxygen evolution was demonstrated.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 7, pp. 1615–1616, July, 1968.     

Thermal analysis of binary and ternary systems of salicylic acid,sodium salicylate and sodium hydrogen carbonate

The thermal decompositions of binary and ternary systems of salicylic acid, monosodium salicylate, disodium salicylate and sodium hydrogen carbonate were studied by thermogravimetry and differential thermal analysis. The possibility was shown of analyzing systems involving components which react with each other upon heat treatment. Use can be made of results of this work to follow the course and extent of the reaction employed in the commercial method of manufacturing sodium salicylate and to check declared compositions of salicylate mixtures.

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Zusammenfassung Die thermische Zersetzung binärer und ternärer Systeme, die Salicylsäure, Mononatriumsalicylat, Dinatriumsalicylat und Natriumhydrocarbonat enthalten, wurde untersucht. Die Möglichkeit der Analyse von Systemen, deren Komponenten bei Hitzebehandlung miteinander reagieren, wurde gezeigt. Die Ergebnisse dieser Arbeit gestatten den Verlauf und das Ausmaß der Reaktionen zu untersuchen, welche bei dem Herstellungsverfahren von handelsüblichen Natriumsalicylat ablaufen und die deklarierte Zusammensetzung von Salicylatmischungen zu prüfen.

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Résumé Etude par thermogravimétrie et analyse thermique différentielle de la décomposition thermique de systèmes binaires et ternaires constitués d' acide salicylique salicylate monosodique, de salicylate disodique et d'hydrogénocarbonate de sodium. On montre la possibilité d'analyser des systèmes dont les composants réagissent entre eux lors du traitement thermique. Les résultats de cette étude permettent de suivre le déroulement et le degré d'avancement de la réaction utilisée dans le procédé commercial de fabrication du salicylate de sodium et de contrôler la composition déclarée des mélanges de salicylates.

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The determination of hydroxide and carbonate in concentrated sodium chloride solutions

A computer method for the determination of carbonate and hydroxide in concentrated (2.89 M) sodium chloride solutions is described. The method is based on multiparametric curve-fitting and can also be applied to salts of dibasic acids with unknown equilibrium constants. The systematic error is not more than 1%. The titration and calculation takes less than 20 min.     

Potentiometric titration of hydroxide,aluminate and carbonate in sodium aluminate solutions

An automated potentiometric titration of hydroxide, aluminate and carbonate in sodium aluminate solutions is described. The addition of barium chloride before titration with hydrochloric acid enables the three components to be determined in one run, involving neutralization of hydroxide, protonation of aluminate and dissolution of barium carbonate. The accuracy and precision of the method are satisfactory for a rapid method used for control of aluminum oxide production.     

Kinetics of the potassium persulfate-initiated inverse emulsion polymerization of sodium acrylate solutions

The kinetics of the K₂S₂O₈-initiated inverse emulsion polymerization of aqueous sodium acrylate solutions in kerosene with Span 80 as the emulsifier has been studied. The conversion-time curves are S-shaped. The following expressions have been obtained for the maximum rate of polymerization and the molecular weight of the polymers under the experimental conditions investigated: R_max ∞ [K₂S₂O₈]^0.78[sodium acrylate]^1.5[Span 80]^0.1, (OVERLINE)M(/OVERLINE)_u ∞ [K₂S₂O₈]^−0.37[sodium acrylate]^2.9[Span 80]^−0.2. The activation energy for the maximum rate of polymerization is 94.8 kJ mol^−1. The results suggest a monomer–droplet–nucleation mechanism for the system studied. © 1996 John Wiley & Sons, Inc.     

Kinetics of sulfuric acid breakdown of beryllium raw material activated by fusion with sodium carbonate

The kinetics of sulfuric acid breakdown of a mixture of beryl and bertrandite–phenakite–fluorite concentrates, activated by fusion with sodium carbonate, was studied. The apparent activation energy of the reaction of the granulated fusion cake with sulfuric acid was determined (E _app = 9.1 kJ mol^–1). This value of E _app is typical of diffusion-controlled processes and suggests that the process is controlled by the rate of diffusion of acid molecules to the reaction surface through the layer of the forming reaction products.     

Foaming and stabilizing activity of binary solutions of sodium carboxylates of different chain length

Influence of short-chain soda soap (sodium pentanoate) on the foaming and stabilizing activity of long-chain sodium carboxylates (laurate, myristate, and palmitate) is studied.     

Kinetics and mechanism of diethyl sulfide oxidation by sodium peroxoborate in aqueous solutions

The kinetics of diethyl sulfide (Et₂S) oxidation by aqueous sodium peroxoborate (Na₂[В₂(О₂)₂(ОН)₄]) solutions in a wide acidity range (from [HClO₄] = 1 mol/L to рН 12) has been studied using a kinetic distribution method. The kinetic data together with the results of ¹¹B NMR spectroscopy demonstrate that the monoperoxoborate B(O₂H) ₃ ^- (OH) and diperoxoborate B(O₂H)₂(OH) ₂ ^- anions are the active species in Et₂S oxidation by sodium peroxoborate at рН 8–12. It is assumed that, at a high acidity of the medium ([HClO₄] = 0.05–1.0 mol/L), peroxoboric acid (ОН)₂ВООН or its protonated form (OH)₂BOOH ₂ ⁺ are direct reactants along with Н₂О₂ and HOOH ₂ ⁺ .     

α-氰基苄基碳负离子钠盐与碳酸二乙酯的单电子转移反应动力学和机理

测定了α-氰基苄基碳负离子钠盐与碳酸二乙酯缩合反应产物的结构及其分布,反应中间体的EPR谱,反应过程中产物和溶剂的CIDNP效应和反应动力学,为这一缩合反应提出了单电子转移-负离子自由基分解-自由基偶合的非链式自由基机理     

Adsorption of sodium dodecyl benzene sulfonate onto carbonate rock: Kinetics,equilibrium and mechanistic study

In this study, kinetics, equilibrium, and mechanisms of SDBS adsorption onto carbonate rock in presence/absence of alkaline/electrolyte, which is not well discussed in the available literature, is analyzed through batch experiments. Analysis of kinetic data showed that adsorption rate of SDBS onto carbonate is controlled by both boundary layer and intraparticle diffusion, also adsorption kinetics meets pseudo second-order model. The coefficient of kinetic model is a linear function of initial and equilibrium concentrations. The adsorption isotherm experiences four distinct regions, with a rising trend in the first regions until reaching to a maximum after which decreases slightly, as the fourth region, due to micellar exclusion. The prevailing mechanisms in other regions were also discussed. Presence of alkaline changes adsorption mechanisms, so that adsorption isotherm matches well with the Langmuir model, while presence of electrolyte does not change the adsorption mechanisms, but it lessens repulsion between surfactant heads which results in a slight reduction in amount of CMC. A new three-parameter equilibrium model is presented which considers all prevailing mechanisms, and matches properly with obtained experimental data, especially the decreasing trend of fourth region which is very difficult to predict along with other regions using a unique isotherm model.     

Kinetics of the radiation chemical reactions of tervalent and quadrivalent actinides and lanthanides in carbonate solutions

The reactions of the ions of tervalent and quadrivalent actinides and lanthanides with hydrated electrons e_aq ^– and CO₃ ^– radicals in concentrated carbonate solutions have been studied by microsecond pulse radiolysis, using spectrophotometric recording of short-lived particles. It is shown that the rate of the reactions of e_aq ^– with carbonato complexes of Ce(IV), Pu(IV), and Np(IV) is controlled by diffusion. The carbonato complex of Eu(III) reacts with e_aq ^–appreciably more slowly. A linear relationship is obtained between the logarithm of the rate constant for the reactions of CO₃ ^– with the carbonato complexes of Am(III), Ce(III), and Pu(III) and the redox potential of the complexes. The rate of the reaction of CO₃ ^– with Np(III) in carbonate solutions is controlled by diffusion.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 1, pp. 28–32, January, 1990.     

Kinetics of solubilization of n-decane and benzene by micellar solutions of sodium dodecyl sulfate

We observed the diminishing of single microscopic oil drops to study the kinetics of solubilization of n-decane and benzene by micellar solutions of sodium dodecyl sulfate (SDS). Each drop is located in a horizontal glass capillary of inner diameter 0.06 cm filled with a thermostated surfactant solution; the small vertical dimension of the cell prevents the appearance of uncontrollable thermal convections. The experiments show that the radius of an n-decane drop decreases linearly with time, whereas for benzene this dependence is nonlinear. To interpret the data, a kinetic model of solubilization is developed. It accounts for the diffusion and capturing of dissolved oil molecules by the surfactant micelles, as well as for the finite rate of oil dissolution at the oil-water interface. By processing the data, we determined the rate constant of solubilization for a given oil and surfactant. It turns out that the elementary act of catching a dissolved oil molecule by a surfactant micelle occurs under a barrier (rather than diffusion) control. The effective rate of solubilization is greater for the oil, which exhibits a higher equilibrium solubility in pure water (benzene), despite the lower value of the solubilization rate constant for this oil.     

Dielectric properties of propylene carbonate and propylene carbonate solutions

Permittivity data at frequencies from 0.9 to 12 GHz for propylene carbonate and for the solutions of NaI, NaClO₄, Bu₄NI, Bu₄NClO₄, ZnBr₂, and Ca(ClO₄)₂ in propylene carbonate at 25°C are reported and discussed. The contaminating influence of water on the dielectric spectra is shown. Measurements were executed by the method of travelling waves with equipment known to produce data of high precision. Evaluation of the data is performed on the basis of models presupposing one or more relaxation regions. The dielectric spectra of all salts with the exception of ZnBr₂ yield relaxation time distributions with a single critical relaxation time or can be analyzed by assuming two critical relaxation times for the solvent. ZnBr₂ solutions show a supplementary relaxation region at low frequencies which is attributed to the solute. The variation of permittivities at zero frequency with the salt concentration is discussed in the framework of kinetic depolarization. Solvation numbers are estimated.     

Studies on recrystallised aluminium mono-hydroxide precipitates. Kinetics of dissolution by sodium hydroxide solutions

Summary Boehmite powders were prepared by controlled hydrolysis of aluminium isopropoxide solution and recrystallisation in hot water; these were cylinders (fibres) of lengths (I ₀) = 0.06 to 0.10m. The dissolution of dilute suspensions of these powders in well-stirred sodium hydroxide solutions was studied at 35 ° to 65 °C. Reaction solid and solution were analysed after different times by chemical and physical methods.Reaction occurred by three-directional dissolution of the cylinders: the reactions of the first (non-aggregated) thirty percent material were four-third order w. r. t. powder weight (and second order w. r. t. powder surface area). The initial rate constantsk _wi (g^– hr^–1) for reactions with sodium hydroxide of unit mean ionic activity at 20 °C varied from 0.012 to 0.040. Rate constants increased linearly with the mean ionic activity of the hydroxide solution and exponentially with reciprocal temperature, five-six times for 15 °C temperature rise. Energies of activation varied from 115–125 kJ mole^–1.

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Zusammenfassung Boehmit-Pulver wurden durch kontrollierte Hydrolyse von Aluminiumisopropoxid-Lösungen hergestellt und in heißem Wasser rekristallisiert. Die Kristalle bildeten Zylinder (Fasern) mit einer Länge von 0,06–0,10m. Die Auflösung dieser Präparate in verdünnten Suspensionen in Natriumhydroxidlösungen wurde bei 35–65 °C untersucht. Festkörper und Lösung wurden nach vorgegebenen Zeiten analysiert.Die Lösung erfolgt in einer 3dimensionalen Reaktion der Zylinder. Die Anfangsgeschwindigkeitskonstanten für Reaktionen mit Natriumhydroxidlösungen bei 20 °C variierte von 0,012 bis 0,040 (g^– h^–1). Die Geschwindigkeitskonstanten steigen linear mit der Ionenaktivität der Hydroxidlösungen und exponentiell mit der reziproken Temperatur. Aktivierungsenergien liegen zwischen 115 und 125 kJ mol^–1.

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With 3 figures and 1 table     

Infrared (attenuated total reflection) study of propylene carbonate solutions containing lithium and sodium perchlorate

Attenuated total reflection infrared spectroscopy was used to examine the concentration dependent solvation of LiClO4 and NaClO4 electrolytes in propylene carbonate (PC). Factor analysis and curve fitting techniques were performed on the measured spectra and the results compared with ab initio computations to provide evidence for ion-solvent solution geometries. Factor analysis of the measured data allowed the identification of the spectrum of ion-associated PC that is uniquely different from the self-associated PC spectrum. The results indicate Li+ and ClO4- ions are contact ion-paired even at relatively low electrolyte concentrations whereas Na+ and ClO4- ions are not, up to approximately 2 mol dm-3.