Alexander Apelblat

Solubility of oxalic, malonic, succinic, adipic, maleic, malic, citric, and tartaric acids in water from 278.15 to 338.15 K

Abstract Solubilities of several dicarboxylic acids (oxalic, malonic, succinic, adipic, and maleic) and hydroxycarboxylic acids (malic, citric, and tartaric) in water were determined in the 278.15 to 338.15 K temperature range.

Solubility of ascorbic, 2-furancarboxylic, glutaric, pimelic, salicylic, and o-phthalic acids in water from 279.15 to 342.15 K, and apparent molar volumes of ascorbic, glutaric, and pimelic acids in water at 298.15 K

Abstract The solubilities of ascorbic, 2-furancarboxylic, glutaric, pimelic, salicylic, and o -phthalic acids in water in the 279.15 to 342.15 K temperature range and the apparent molar volumes of ascorbic, glutaric, and pimelic acids in water at 298.15 K have been determined.

Dissociation constants and limiting conductances of organic acids in water

Determination of the dissociation constants of organic acids in aqueous solutions by the conductometric method during a period of nearly 120 years is discussed. Electrical conductivities available in the literature were reexamined to yield a reliable and consistent set of the limiting conductances of organic anions λ0 and the dissociation constants K of 250 organic acids at T = 298.15 K. Also, presented are coefficients of the Quint-Viallard conductivity equation which permit to evaluate conductances of these acids in dilute solutions (c ≤ 10−2 mol·dm−3). The experimental conductances were analyzed in terms of dissociation steps of carboxylic acids, the Onsager conductivity equation for neutral sodium or potassium salts, the Quint-Viallard conductivity equation for unsymmetrical electrolytes (monobasic and polybasic acids) and the Debye-Huckel equation for activity coefficients.

An assessment of thermodynamic consistency tests for vapor-liquid equilibrium data

Consistency tests are techniques that allow, in principle, the assessment of experimental vapor-liquid equilibrium data on the basis of the Gibbs-Duhem equation. Much empiricism and arbitrariness is frequently observed in the analysis and application of consistency tests, a situation that may question their usefulness. Perfect data satisfy exactly the Gibbs-Duhem relation, but acceptable data obey it within a tolerable limits (consistency criteria) which does not give a unique answer, regarding the quality of the data, when different consistency procedures are used. As with any approximation, application of consistency tests requires rigour, reasonable assumptions and models, and an examination of the data and results of the test. In this work, a set of guidelines that allow a critical interpretation of consistency analysis is proposed and special attention is given to the point-to-point test which is extensively used today in data evaluation.

Conductivity of Phosphoric Acid, Sodium, Potassium, and Ammonium Phosphates in Dilute Aqueous Solutions from 278.15 K to 308.15 K

Precise conductivity measurements on aqueous solutions of phosphoric acid, sodium dihydrogen phosphate, potassium dihydrogen phosphate, ammonium dihydrogen phosphate, disodium hydrogen phosphate, dipotassium hydrogen phosphate, diammonium hydrogen phosphate, sodium phosphate, and potassium phosphate were performed from 5 to 35°C. Data analysis was executed by the use of the Quint–Viallard equation for unsymmetrical electrolytes. Equations are given for the concentration dependence of electrolyte and single-ion conductivities at all temperatures.

Apparent molar volumes of organic acids and salts in water at 298.15 K

Abstract Apparent molar volumes of citric, oxalic and lactic acids and di-sodium hydrogen citrate, tri-sodium citrate, tri-potassium citrate, sodium hydrogen tartrate, di-sodium tartrate, potassium tartrate, ammonium tartrate, dl -di-sodium malate, di-sodium maleate, di-sodium oxalate and sodium lactate were determined in aqueous solutions at 298.15 K. For these organic acids and salts the partial molar volumes at infinite dilution and the conventional partial molar volumes of single-, double- and triple-charged ions were derived or estimated. It was observed that in ternary system the Young rule for the mean apparent molar volumes can be applied to citric acid-potassium chloride solutions but not to citric acid—tri-sodium citrate solutions.

Thermodynamics of acetone—chloroform mixtures

Abstract Apelblat, A., Tamir, A. and Wagner, M., 1980. Thermodynamics of acetone—chloroform mixtures. Fluid Phase Equilibria , 4: 229–255. The excess thermodynamic functions G E , H E , S E , C p E and V E and the vapour—liquid equilibria at constant temperature, at constant pressure and azeotropic behaviour are satisfactorily described for the acetone + chloroform system using the ideal association model of the type A + B + AB + AB 2 . Existing data in the literature for the system were supplemented by determination of vapour pressures at 25.0° and 35.17°C, excess volumes of mixing at 35°C and excess heat capacities at 30°C.

Apparent molar volumes of citric, tartaric, malic, succinic, maleic, and acetic acids in water at 298.15 K

Apparent molar volumes of acids in aqueous solutions were determined at 298.15 K. Derived from the density measurements, the partial molar volumes V2∞ at infinite dilution are 112.44 cm3·mol−1 for citric acid; 82.23 cm3·mol−1 for tartaric acid; 88.22 cm3·mol−1 for mallic acid; 82.75 cm3·mol−1 for succinic acid; 75.65 cm3·mol−1 for maleic acid; and 51.66 cm3·mol−1 for acetic acid.

Mass transfer with a chemical reaction of the first order: Analytical solutions

Abstract The problem of mass transfer coupled with an irreversible chemical reaction of the first order in plug flow, in Couette flow, in Couette flow with a moving interface, and in fully developed boundary layer flow is investigated. Analytical solutions and asymptotic expressions are proposed for homogeneous and heterogeneous chemical reactions. Some extensions for mass transfer in non-Newtonian liquids, or in the case of permeable surfaces, are also presented.

The vapour pressures of water over saturated aqueous solutions of barium chloride, magnesium nitrate, calcium nitrate, potassium carbonate, and zinc sulfate, at temperatures from 283 K to 313 K

Vapour pressures of saturated aqueous solutions of BaCl2, Mg(NO3)2, Ca(NO3)2, K2CO3, and ZnSO4 were measured in the 283 K to 313 K temperature range using evaporimetric technique and compared with the literature values. From the vapour pressures, the water activities, osmotic coefficients, and molar enthalpies of vaporization and solution at saturation were evaluated.