CJ-VOLUME 03 ISSUE 05 SEPTEMBER 2013


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Volume 3 Issue 5, September 2013

Chemistry Journal

ISSN

2049-954X

Publication Frequency

6 Issues per year

Pages

122-138

Publication History


Original Articles

Flotation-Spectrophotometric Investigations on an Ion-Association System Containing Zirconium (IV)

Galya K. Toncheva and Kiril B. Gavazov

Pages 122-127

Temperature Effects on the Rate of Reaction of Plasma Albumin with Formaldehyde in Water Solution and Ethanol-Water-Mixtures

J.T. Ugye, A. Uzairu, S.O. Idris and H.O. Kwanashie

Pages 128-132

Synthesis, Characterization and Study of the Effect of Yb3+ on MgAl2O4 Spinel Structure via Combustion Method

A.A. Ali, Bekir Karasu, M.R. Allazov and T.M. Ilyasli

Pages 133-138


Title

Flotation-Spectrophotometric Investigations on an Ion-Association System Containing Zirconium (IV)

Abstract

A system containing zirconium (IV), 4-(2-pyridylazo) resorcinol (PAR), 2,3,5-triphenyl-2H-tetrazolium chloride (TTC), acetate buffer, water and organic solvents was studied. The optimum conditions for zirconium (IV) flotation and spectroph-otometric determination as an ion-association complex were found: flotation solvent (chloroform), shaking time (2 min), pH (6.0-6.1, acetate buffer), concentration of the reagents (CPAR=2.8×10-4 mol L-1 and CTTC=2×10-4 mol L-1), sequence of their addition, dissolution solvent for the floated compound (dimethylsulphoxide) and its volume (4 mL). The molar ratio between Zr(IV), PAR and TTC in the floated compound was found to be 1:2:3. It could be regarded as an ion-associate between the triphenyltetrazolium cation (TT+) and an anionic chelate [Zr(OH)3–j(CH3COO)j(PAR)2]3– (most probably j=2 at the optimum conditions). The constant of association was calculated by two independent methods (Log b=12.8±0.2 and Log b=12.9±0.7). Some additional characteristics like conditional molar absorptivity, Sandell’s sensitivity, Beer’s law ran-ge, limit of detection, limit of quantification and relative standard deviation of the system for flotation-spectrophotometric determination of Zr(IV) were estimated. Beer’s law was obeyed for Zr(IV) concentrations up to 1.3 μg mL-1 at lmax=545 nm with a correlation coefficient of 0.9978. The conditional molar absorptivity was estimated to be e545=1.2×105 L mol-1 cm-1.

Keywords

Zirconium (IV), 4-(2-Pyridylazo) resorcinol, 2,3,5-Triphenyltetrazolium Chloride, Ion-Associate


Title

Temperature Effects on the Rate of Reaction of Plasma Albumin with Formaldehyde in Water Solution and Ethanol-Water-Mixtures

Abstract

The effects of temperature on the rate of reaction of plasma albumin and formaldehyde in water solution and in ethanol water mixtures (1-25%) were investigated under seven temperatures from 20-45 oC. The effects of the temperature variations on the reaction of plasma albumin with formaldehyde were then established from a plot of ln(At-A∞) against time at each of the varied temperatures. Also the Erying plots, logk2/T vs. 1/T as a function of different temperatures were plotted and the thermodynamic parameters were calculated from the relation ln(k2 / T) = - ΔH҂/RT + ΔS҂/ R + 23.8 while the activation energy was calculated by using the expression Ea = ΔH҂ + RT and the plot of lnk against 1/T according to the Arrhenius equation. The result of the temperature dependent study in water solution showed a mean second order rate constant k2=, 2.47 (±0.1) mol-1s-1, while that in ethanol-water-mixtures showed a mean value of (2.47 (±0.4). The rate constants of the reaction in both media were observed to have decreased steadily with increase in temperatures, it could then be asserted that the reaction was not favoured at high temperatures in both media.

Keywords

Temperature Effects, Water Solution, Ethanol-Water Mixtures, Reaction Rate, Plasma Albumin, Formaldehyde


Title

Synthesis, Characterization and Study of the Effect of Yb3+ on MgAl2O4 Spinel Structure via Combustion Method

Abstract

Nanoparticle doped YbxMg1-xAl2O4 (where x = 0.00, 0.05 and 0.01) synthesized through igniting a stoichiometric mixture of aluminum, magnesium and ytterbium nitrates with malonic acid dihydrazide as a solid fuel, followed by annealing at 800, 1000 and 1200 oC. The obtained samples were characterized by different tools as thermal analysis, X-ray diffractions, UV-Vis spectroscopy, transmission electron microscopy and infrared spectroscopy. Crystalline particle sizes were calculated from X-ray diffraction for Yb0.1Mg0.9Al2O4, Yb0.05Mg0.95Al2O4 and MgAl2O4 with a size of 12.3, 11.3 and 10.5 nm respectively, at 1000 oC in the same condition. Thermal analysis gives us that the crystalline phase of MgAl2O4 and doping materials are formed after annealing after 700 oC which agree with X-ray diffraction. TEM micrograph shows sheet and spherical shapes for Yb0.1Mg0.9Al2O4 and MgAl2O4 samples which are annealing at 1000 °C. The edges of bands were shifted to higher wavelength and band energies shifted to lower values as result of increasing the amount of Yb3+ in the lattice of MgAl2O4 and calcinations temperatures.

Keywords Spinel Structure, Nanomaterials,Transmission Electron Microscopy