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  • Author or Editor: B. Singh x
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Abstract  

Solid state reactivity between iron/II/oxalate dihydrate, i.e., FeC2O4.2H2O and para-chloro aniline hydrochloride, i.e., p-ClC6H4NH2.HCl has been studied at 373, 393 and 413 K. The reaction seems to follow the diffusion controlled mechanism. The product, [FeCl/oxH/.AN–Cl], has been characterized by elemental analysis, infrared and Mössbauer spectroscopic techniques, mass spectrometry and derivatographic methods /TG, DTA/.

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Thermal decomposition of bis 2-amino-5-phenyl-1,3,4-thiadiazole copper(II) sulphate has been studied by TG, DTA and DTG. The electrical conductivity of the compound in the solid state have also been measured at different temperatures. It is believed that decomposition is a nucleation controlled process and starts at the site of defects.

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Abstract  

Lead(II) complexes of reduced glutathione (GSH) of general composition [Pb(L)(X)]H2O (where L=GSH; X=Cl, NO3, CH3COO, NCS) have been synthesized and characterized by elemental analyses, infrared spectra and electronic spectra. Thermogravimetric (TG) and differential thermal analytical (DTA) studies have been carried out for these complexes. Infrared spectra indicate deprotonation and coordination of cysteinyl sulphur with metal ion. It indicates the presence of water molecule in the complexes that has been supported by TG/DTA. The thermal behaviour of complexes shows that water molecule is removed in first step-followed removal of anions and then decomposition of the ligand molecule in the subsequent steps. Thermal decomposition of all the complexes proceeds via first order kinetics. The thermodynamic activation parameters, such as E*, A, ΔH*, ΔS* and ΔG* have been calculated. The geometry of the metal complexes has been studied with the help of molecular modeling for energy minimization calculation.

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Abstract  

α-Hemihydrate was allowed to hydrate in the presence of tartaric, succinic, malic or citric acids at room temperature at a water/ binder ratio of 0.35. Hydration of hemihydrate leading to the crystallisation of calcium sulphate dihydrate is an exothermic process. The temperature rise during hydration was measured as a function of time using a semi-adiabatic method. The temperature rise–time curves are similar for all investigated systems but with different induction period. The results showed that calcium sulphate dihydrate crystallisation is a nucleation controlled process and different acids are chemisorbed at the surface of forming nuclei to different extent. Processes taking place during nucleation may control the morphology of resultant crystals. Infrared spectral and differential scanning calorimetric studies confirmed the adsorption of carboxylic acids at the surface of dihydrate crystals.

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Investigations of the thermal stability of detonating fuse containing 10 g pentaerythrol tetranitrate (PETN) revealed that the cord burnt under unconfinement at 403 K. Under confinement in a steel pipe or copper tube there was a partial detonation at 403 K. In order to characterize the thermal stability of PETN and pyrotechnic composition used in fuse head of electric detonators differential thermal analysis (DTA) was used.

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Abstract  

Mass attenuation coefficients of amino acids viz. glycine (C2H5NO2), l-Serine (C3H7NO3), l-Theronine (C4H9NO3), l-Proline (C5H9NO2), l-Valine (C5H11NO2) and l-Phenylalanine (C9H11NO2) in aqueous solutions have been determined at 81, 356, 511, 662, 1173 and 1332 keV by the gamma-ray transmission method in a narrow beam good geometry setup. Precisely measured densities of these solutions were used for the determination of these coefficients which varied systematically with the corresponding changes in the concentrations (g/cm3) of the solutions. Molar extinction coefficients of amino acids were then obtained at these energies and were found to be in good agreement with the theoretical results. In addition, total interaction cross sections of amino acids in aqueous solutions were also calculated.

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