Thermodynamic & Transport Properties of Aqueous Solutions of Fluoro-, Chloro-, Bromo-, & Iodoacetic, Propionic & Butyric Acids

91-9

Temperature of maximum density behaviour of SO₂, H₂S and CO₂ in water

114-118Temperatures of maximum density (TMD) of aqueous SO2, H2S and CO2 solutions at low concentrations (0.003-0.03 mol kg-1) have been measured to study the effects of these gases on the structure of water. Due to large degree of dissociation of SO2 in water yielding H+ and HSO ions, dissociation corrections are applied to evaluate the structural part (Δθ) of the change in TMD exclusively due to undissociated SO2 molecules. This correction is not found necessary for H2S and CO2 which on account of their small degree of dissociation produce very small number of ions. The structural part of the change in TMD (Δθ) at various concentrations for these gases has been used to evaluate the characteristic constant 'a' from the sign and magnitude of which the gases SO2, H2S and CO2 are shown to be water-structure stabilisers. This is corroborated by the positive ΔC for these gases dissolved in water. These findings are also supported by the formation of stable hydrates of SO2 and H2S from phase diagram and X-ray study respectively

Apparent Molal Volumes & Apparent Molal Compressibilities of Some Carbohydrates in Dilute Aqueous Solutions at Different Temperatures

6-1

Apparent Molal Compressibility Behaviour of Sodium Salts of Some Fatty Acids at Different Temperatures

12-1

Temperature of maximum density of aqueous solutions of aliphatic amines

942-945Temperature of maximum density (TMDs) in water at low concentrations for the seven amines: rnethyl-, ethyl-, n-propyl-, n-butyl-, t-butyl-, dimethyl-, and trimethyl amines have been measured and analyzed by applying hydrolysis correction to evaluate the structural part of the change in TMD (θstr) for the unhydrolysed amine molecules. A correction procedure is described for which additional experimental data on TMDs of corresponding amine hydrochlorides have been obtained. The results of amines studied in this work do not fit in the conventional straight line relation (θstr/x2) = a + bx2, which is obeyed by other non-electrolytes, like alcohols, which show positive intercepts (a) and negative slopes (b). The slopes of such plots for arnines are positive at low concentrations and negative at higher concentrations showing a broad maxima in between. The intercepts a which indicate the structure strengthening property of the solute are large negative for MeNH2 and EtNH2, slightly negative for n- PrNH2, and positive for the rest of the amines. Comparison of a values of alcohols and amines indicate the difference in the amine-water and alcohol-water interactions

Limiting compressibility and viscosity of alkylammonium hydrochlorides in dilute aqueous solutions at different temperatures

439-444Limiting apparent molal adiabatic compressibility and viscosity of MeNH3Cl, EtNH3Cl, n-PrNH3Cl, n-BuNH3Cl, t-BuNH3Cl, Me2NH2Cl, Me3NHCl and ammonium chloride in dilute aqueous solutions have been reported at 5°, 15°and 25°C.The results indicate that lower members possess structure breaking ability while higher members are structure-formers

Fabrication & Use of a Temperature of Maximum Density Apparatus for Investigating Structural Interactions in Aqueous Solutions

373-37

Temperature of maximum density of aqueous solutions of some <i>α</i>-amino acids

834-838Temperatures of maximum density (TMD) at different low concentrations of aqueous solutions of glycine, α-alanine, 1-serine, aspartic acid, asparagine, leucine and isoleucine have been reported. The changes in TMD with respect to that of water vary non-linearly with concentration of the amino acid. By subtracting from the observed change in TMD (∆θ), an ideal contribution evaluated numerically, it is possible to calculate the structural part ∆θstr. The quadratic dependence of ∆θstr on amino acid concentration is given by ∆θstr = ax + bx2 (x= mole fraction) thus enabling a graphical evaluation of the interaction parameters a (solute-solvent) and b (solute-solute). Evaluation of limiting expansibilities of the amino acids at 4°C also corroborate the findings based on a values

Hydrolysis Correction for Obtaining True Limiting Compressibilities of Amines in Aqueous Solutions

295-29

Viscosity B-Coefficients of Amines in Dilute Aqueous Solutions

937-94