Activation energies for electrolyte diffusion of Zn(NO3)2, ZnBr2 and ZnI2 in 1% agar gel at different concentrations are determined by the least-squares fitting of the diffusion coefficient data obtained at various temperatures through the Arrhenius plots. Energy of activation is found to decrease with an increase in electrolyte concentration. This trend is explained by considering the changes in the physical properties of the solution with concentration at microscopic level, as envisaged in Wang's model.
Authors:J. Flieger, H. Szumiło, M. Tatarczak, and D. Matosiuk
The chromatographic behavior of several aromatic hydrocarbons with different functional groups — phenol, quinoline, and aniline derivatives — has been studied on thin layers of silica gel modified with zinc nitrate, bromide, chloride, acetate, and sulfate. Binary non-aqueous mixtures of 2-propanol or ethyl acetate with heptane were used mobile phases. Retention of the solutes is presented as relationships between
where subscripts ‘1’ and ‘2’ denote the two stationary phases correlated.Attempts have been made to explain the results in terms of intermolecular forces, especially with regard to complex formation. The effect of the type of anion as the ligand has also been studied. It should be stressed that modification of silica gel with zinc acetate leads to improvement of spot shape and separation selectivity, especially for quinoline derivatives. The effect of the nature of the anion on retention is most evident for quinolines and increases in the order bromide > sulfate > chloride > acetate > nitrate for ethyl acetate as mobile-phase modifier and bromide > nitrate > chloride > sulfate > acetate for 2-propanol as mobile-phase modifier.
The enthalpies of solution in water of L--methionine and its zinc complexes Zn(Met)Cl2, Zn(Met)2Cl2·2H2O, Zn(Met)(NO3)2·1/2H2O, Zn(Met)3(NO3)2·H2O and Zn(Met)SO4·H2O have been measured at 298.15 K. The standard enthalpy of formation of met(aq) has been calculated. The experimental results have been discussed.
The spontaneous deposition of Cu2+ from aqueous solutions on a hydrogen-saturated platinum surface as a possibility for the substoichiometric sampling of copper
is shown. A sensitive isotope dilution method has been developed for the determination of traces of copper in high purity
zinc making use of the spontaneous deposition of microquantities of Cu2+ from aqueous solutions of zinc salts on a cathodically polarized platinum surface. If the same platinum surface is used in
each run, the saturation values of the deposited copper are practically independent of the concentrations and contents of
copper and zinc in the solution. The copper traces were labelled with the product of the64Zn(n,p)64Cu nuclear reaction. A copper content of 0.18±0.03 ppm in zinc was determined by this method.
It was established by thermogravimetric measurements that the thermal decomposition of potassium benzoate in the presence of inorganic cadmium or zinc salts results in the formation of the easily decomposing cadmium or zinc benzoate. These carboxylates are presumably the catalysts of the transcarboxylation of potassium benzoate to terephthalate.
]. Gao et al. [ 10 ] have investigated the phase chemistry of the coordination behavior of zincsalts with l -α-methionine by the method of semi-micro phase equilibrium. The corresponding equilibrium phase diagram and refractive index diagram have been