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Journal of Thermal Analysis and Calorimetry
Authors:
B. Avid
,
B. Purevsuren
,
M. Born
,
J. Dugarjav
,
Ya. Davaajav
, and
A. Tuvshinjargal

Abstract  

The coal sample of the Shivee Ovoo deposits has been non-isothermally pyrolysed in a thermogravimetric analyser to determine the influence of temperature, heating rate and purge gas employed on the thermal degradation of the sample. The heating rates investigated in the TG were 10–50 K min–1 to final temperature of 1000C. N2or CO2 were employed as well as type of purge gas on the process of thermal degradation of the coal sample. The coal was also investigated in a fixed bed reactor to determine the influence of temperature and heating rate of the pyrolysis on the yield of products and composition of the gases evolved. The main gases produced were H2, CH4, C2H2, C2H4, C2H6, C3H6 and C3H8 and also minor concentrations of other gases.

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Abstract  

Complexes of lanthanide(III) (La–Lu) and Y(III) with 1-hydroxy-2-naphthoic acid were obtained as crystalline compounds with a general formula Ln[C10H6(OH)COO]3nH2O:n=6 for La–Tm and Y, n=2 for Yb and n=0 for Lu. IR spectra of the prepared complexes were recorded, and their thermal decomposition in air were investigated. Spectroscopic data suggest that in the coordination of metal-organic ligand only oxygen atoms from the carboxylate group take part. When heated, the complexes decompose to the oxides Ln2O3, CeO2, Pr6O11 and Tb4O7 with intermediate formation of Ln(C11H7O3)(C11H6O3).

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Abstract  

Several two and three parameter analytical functions were fitted to the measured detection efficiencies () of a Ge detector for a Marinelli beaker filled with samples up to different heights (H). From these, the expression =308E –0.82/((H–6.1)2+107), gave the best fit. The measured and calculated efficiencies were compared and for 70 determinations, a relative standard deviation of only 7.6% was obtained.

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Abstract  

The rigid dopamine analogue (+/-) 6,7-ADTN was originally synthesized to probe the geometrical constraints of the dopamine receptor family and [3H] (+/-) 6,7-ADTN was required for receptor binding assay. The radioligands was prepared by means of catalytic tritium dehalogenation of a suitable dibromo precursor and characterized by HPLC and tritium NMR. It has proven very useful as a tool to study dopaminergic receptors.

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Abstract  

A preconcentration method combined with neutron activation technique for the analysis of organic and inorganic mercury in waste water samples at ppb levels is presented. The inorganic mercury is extracted in CCl4 solution with lead diethyldithiocarbamate reagent and the organic mercury is extracted in C6H6 solution. Interfering activities of sodium and bromine are removed from the irradiated samples by this procedure. Two different solvent extraction procedures are also described in detail.

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Abstract  

The extraction of iodine and bromine under various conditions from their saturated aqueous solutions by CCl4, C6H6 and o-xylene has been studied. The data obtained from the experiments carried out at various temperatures, for H2O(I2)−CCl4 and H2O(I2)−C6H6 systems, exhibit an Arrhenius behaviour. The overall activation energy calculated for the extraction in the H2O(I2)−CCl4 system, 650±50 cal·mol−1 is lower than that of H2O(I2)−C6H6, 3600±300 cal·mol−1. The use of the solubility parameter for the interpretation of the data in the extraction of iodine is investigated. The data obtained in multiple extractions are treated by using the analogy between extraction and radioactive decay. The half number of extraction for each system is determined. The complex curves obtained in the H2O(I2)−CCl4 and H2O(I2) −Br2)−CCl4 systems are resolved into two components.

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Six adducts of the tctrakis(8-hydroxyquinolinato) complex of thorium(IV) with 8-hydroxyquinoline, pyridine, urea, dimethylsulphoxide, dimethylformamide and 1,10-phenanthroline were prepared and characterized, the infrared bands for the room-temperature forms are given and their particular thermal properties are reported. The thermal analyses were performed mostly in the presence of air, but in some cases an argon atmosphere was used for comparison. The adducts were lost from the principal complex at temperatures varying between 110 and 290°. Intermediate oxygenated complexes were formed in each case at about 400°. The thermal data suggest the standardization of a procedure for the formation of Th(C9H6NO)4.

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Abstract  

This work describes the synthesis, IR and UV-Vis spectroscopic characterization as well the thermal behavior of the [NiCl2(HIPz)4]⋅C3H6O (1), [Ni(H2O)2(HIPz)4](NO3)2 (2), [Ni(NCS)2(HIPz)4] (3) and [Ni(N3)2(HIPz)4] (4) (HIPz=4-iodopyrazole) pyrazolyl complexes. TG experiments reveal that the compounds 14 undergo thermal decomposition in three or four mass loss steps yielding NiO as final residue, which was identified by X-ray powder diffraction.

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Abstract  

Thermal treatment of SiO2-aerogel in inert atmosphere, in contrary to oxidizing atmosphere, yields a series of gas products with great range of mole masses (12–154 g mol–1) and every product has specific way of evolving. These substances are represented by CO, CO2, CH4, CH3OH, C2H6, C2H4 and aromates. Part of evolving products, which are formed during catalytic condensation, is trapped under the surface and after carbonisation it causes opacity of surface layer of aerogel.

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Journal of Thermal Analysis and Calorimetry
Authors:
E. M. Schwartz
,
I. M. Vitola
,
G. S. Sergeiyeva
,
G. O. Piloyan
, and
O. V. Drozdova

The thermal decompositions of dicitratoborates M1[B(C6H6O7)2]·nH2O (n=0–2, M1=Rb, K, Li, NH4) and M11[B(C6H6O7)2]2·8H2O (M11=Co, Ni, Mn, Cu, Zn, Cd) were investigated by means of TG, DTA and DTG methods. It was found that these thermal decompositions involve three successive stages: dehydration, the endothermal decomposition of the ligand, and oxidation of the residual organic component. The volatile products of decomposition in each stage were detected by means of gas chromatography. The method of TG-curve transformation into the curvedm/d T vs.m, wherem is the loss of weight at each moment of time, was used for a more detailed study of dehydration. The optimal conditions for TG-curve modification were found.

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