Mixed ligand complexes of manganese(III) with dithiocarbamate and glycine/acetylacetone ligands: magnetic,spectral and thermal studies

Summary Mixed ligand complexes of Mn^III with morpholyl and piperidyldithiocarbamates (A) and glycine/acetylacetone (A) have been prepared with the general formule MnAA₂, MnA₂A and Mn(A)₃, and have been characterised by elemental analysis, magnetic susceptibility measurements, i.r. electronic and e.s.r. spectral techniques and by thermal analysis. The complexes exhibit magnetic moment in the 4.5–5.3 B.M. range. The ligands are bidentate. E.s.r. studies suggest that all the complexes have six-coordinate actahedral geometry. T.g.a. studies reveal one step decomposition of complexes and formation of manganese dioxide.     

4,4′-Bipyridyl complexes of iron: Magnetic,Mössbauer and other spectroscopic studies

Summary 4,4-Bipyridyl (4,4-bipy) complexes of ferrous salts of the Fe(4,4-bipy)_x(anion)_y type (where x or y=1 or 2) and of ferric salts of the Fe(4,4-bipy)_m(anion)_n type (where m=1 or 2 and n=3) have been synthesised. Elemental analyses, i.r. and electronic spectra, magnetic and Mössbauer studies have been performed to characterize the complexes. 4,4-Bipy and some anions are inferred to act as bridging ligands. The magnetic moments, electronic and Mössbauer spectra suggest that the complexes are of high spin type with distorted octahedral structures. The value of the isomer shift and quadrupole splitting are discussed in terms of bonding of the ligand and anions.     

Cobalt(II), nickel(II) and copper(II) complexes of bidentate bibenzimidazoles

Summary Complexes of cobalt(II), nickel(II) and copper(II) with novel bidentate bibenzimidazoles, [M(L-L)Cl₂], where L-L are methylenebis(1, 1-benzimidazole), methylenebis(2, 2-benzimidazole) and dimethylenebis(2, 2-benzimidazole) are described and characterized by different physical measurements. The four coordinate complexes have distorted tetrahedral or square coplanar structures. The bridging entity between the two donor groups apparently influences the ligand field strength and the ligands occupy a higher position than that of benzimidazole in the spectrochemical series.     

Studies on nitrile imines. Synthesis of some new five-membered heterocyclics via N-(2,4-dinitrophenyl)-C-alkyl nitrile imines

Reaction of N-(2,4-dinitrophenyl)-C-alkyl hydrazonyl chlorides with diverse dipolarophiles gave a variety of novel heterocyclics, which are expected to possess biological activities. The ring closure is brought about by a concerted process involving nitrile imine as an intermediate. The structures of the resulting products are supported by nmr and ir spectral data.     

Use of reciprocal temperature rise equation in analysis of non-isothermal kinetic data in general

Theoretical analysis of kinetic data obtained under increasing temperature conditions requires the solution of an exponential integral through various approximations. This paper shows that some common types of temperature variation approximating linear variation can be described, at least in limited temperature ranges, by a reciprocal temperature rise equation of the kind

where T is the absolute temperature, t is time and a and b are constants. Use of this equation leads directly to a simple and exact solution. A set of actual experimental data on the decomposition of CaCO₃ is analyzed to substantiate the approach proposed and demonstrate its usefulness.     

Liquid-liquid extraction and recovery of indium using Cyanex 923

The extraction of In(III) from HCl, H₂SO₄, and HNO₃ media using a 0.20 mol l⁻¹ Cyanex 923 solution in toluene is investigated. In(III) is quantitatively extracted over a fairly wide range of HCl molarity while from H₂SO₄ and HNO₃ media the extraction is quantitative at low acid concentration. The extracted metal ion has been recovered by stripping with 1.0 mol l⁻¹ H₂SO₄. The stoichiometry of the In(III): Cyanex 923 complex is observed to be 1:2. The extraction of In(III) is insignificantly changed in diluents namely toluene, n-hexane, kerosene (160-200 °C), cyclohexane, and xylene having more or less the same dielectric constants, whereas, it decreases with increasing polarity of diluents such as cyclohexanone and chloroform. The extractant is stable towards prolonged acid contact and there is a negligible loss in its extraction efficiency even after recycling for 20 times. The extraction behavior of some commonly associated metal ions namely V(IV), Ti(IV), Al(III), Cr(III), Fe(III), Ga(III), Sb(III), Tl(III), Mn(II), Fe(II), Cu(II), Zn(II), Cd(II), Pb(II), and Tl(I) has also been investigated. Based on the partition data the conditions have been identified for attaining some binary separations of In(III). These conditions are extended for the recovery of pure indium from zinc blend, zinc plating mud, and galena. The recovery of the metal ions is around 95% with purity approximately 99%.     

Determination of calcium in uranium by X-ray fluorescence

Summary An X-ray fluorescence method for the analysis of calcium in uranium in the range of 20 to 500 ppm is described. U₃O₈ samples are mixed with boric acid binder and double-layer pellets are prepared. The pellets are analysed using Philips PW 1220 semi-automatic X-ray spectrometer. Calculated lower limits of detection are better than 5 ppm for calcium in uranium.

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Bestimmung von Calcium in Uran durch Röntgenfluorescenz

Zusammenfassung Ein Verfahren für den Bereich von 20–500 ppm wird beschrieben. Die U₃O₈-Proben werden mit BorsÄure als Bindemittel vermischt zu Doppelschicht-Tabletten gepre\t, die mit Hilfe eines halbautomatischen Philips PW 1220 Röntgenspektrometers analysiert werden. Die untere Nachweisgrenze liegt bei 5 ppm Ca.

     

EFFECT OF INTERACTION BETWEEN SURFACTANTS,HLB AND ZETAPOTENTIAL IN EMULSIFICATION

Emulsification of xylene was carried out using mixed surfactant system. HLB concept was used to select the right surfactant mixture. Variation in the stability of emulsion with respect to HLB was investigated by studying interaction between mixed surfactant. The interaction was quantified interms of interaction parameter β. Exact location and nature of the interaction was (hydrophilic / hydrophobic) studied by 1H NMR spectroscopy. Charge present on emulsion droplet was calculated by zetapotential measurement.