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Thermal analysis of some fly ashes

II. Self-hardening activity of fly ashes

Journal of Thermal Analysis and Calorimetry
Authors: Z. Adonyi and K. Mészáros Szécsényi

The self-hardening activity of fly ashes was investigated looking for the possibility of their chemical reactions with water without additives. A method had to be developed for separation of the structural water from the adsorbed or free one. The decomposition of the chemically bound water was measured by thermogravimetry. The‘I’ dimensionless number proved to be applicable for the quantitative characterisation of the measured data with more DTG peaks. The examined reaction depends on the chemical composition and the physical structure of the fly ashes and the time of interaction with water. The SO3 content seems important, but the characteristics of the formed compounds differ deeply from the CaSO4·2H2O. The observed and examined reaction is an important factor of the self-hardening process of fly ash deposits.

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Abstract  

A method is described for the microdistillation of liquids using quasi-isothermal quasi-isobaric thermogravimetry. The liquidus curve determined under quasi-equilibrium conditions gives useful information about the composition and some thermal properties of the sample. The method could be attractive for the mineral oil, lacquer, biological and organochemical industry.

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Abstract  

Manganese(II) chloride complexes with 3,4- and 3,5-lutidine have been prepared. The crystal symmetry and cell dimensions have been calculated on the basis of powder diffraction data. The compounds were characterised also by FT-IR spectrometry. The thermal decomposition of the complexes has been studied by thermogravimetry and DSC. By plotting densities vs. molar mass, the diagram obtained has correspondence to similar observations in other solid metal-lutidine complex systems.

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Abstract  

Compounds obtained by a solid–gas phase reactions between copper(II) chloride and bromide and 2,4-, 2,6- 3,4- and 3,5-lutidines were studied using thermogravimetry, far-infrared, electronic spectroscopy and X-ray diffraction. The results were compared with the corresponding data for the similar compounds with methylpyridines and 2,4,6-collidine. A special attention was paid to the host-guest phenomenon, a new structural feature of transition-metal halide complexes.

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Abstract  

We report the synthesis and the characterization (elemental analysis, FT-IR spectroscopy, thermal methods and molar conductivity measurements) of the mixed complexes of zinc with acetate and 3-amino-5-methylpyrazole, HL 1, [Zn(OAc)2(HL1)2], or 3-amino-5-phenylpyrazole, HL 2 [Zn(OAc)2(HL2)2], or 4-acetyl-3-amino-5-methylpyrazole, HL 3, [Zn(OAc)(L3)(HL3)]2, with isothiocyanate and HL 2 [Zn(SCN)2(HL2)2], or HL 3 [Zn(SCN)2(HL3)2], and with nitrate, isothiocyanate and 3,5-dimethyl-1-carboxamidinepyrazole, HL 4 [Zn(NO3)(NCS)(HL4)2]. The thermal decomposition of the complexes is generally continuous resulting zinc oxide as end product,except [Zn(OAc)(L3)(HL3)]2 in which case a well-defined intermediate was observed between 570–620 K. On the basis of the IR spectra and elemental analysis data of the intermediate a decomposition scheme is proposed.

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Transitionmetal complexes with pyrazole-based ligands

Part 21. Thermal decomposition of copper and cobalt halide complexes with 3,5-dimethyl-1-thiocarboxamidepyrazole

Journal of Thermal Analysis and Calorimetry
Authors: K. Mészáros Szécsényi, V. Leovac, A. Kovács, G. Pokol, and Ž. Jaćimović

Abstract  

The thermal decomposition of Cu2L2Cl4, Cu2L2Cl2, Cu2L2Br2 and Co2L2Cl4 complexes (L=3,5-dimethyl-1-thiocarboxamidepyrazole) is described. The influence of the central ion to ligand mole ratio on the course of complex formation is examined in reaction of L with copper(II) chloride. In Cu(II):L mole ratio of 1:1, in methanolic solution the reaction yields to yellow-green Cu2L2Cl4 crystals. In the filtrate a thermodynamically more stable orange Cu2L2Cl2 copper(I) complex is forming. With a Cu(II):L mole ratio of 1:2 only the latter compound is obtained. The composition and the structure of the compounds have been determined on the basis of customary methods. On the basis of FTIR spectrum of the intermediate which is forming during the thermal decomposition of Cu2L2Cl2 a decomposition mechanism is proposed.

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Abstract  

The coupling of a quadrupole mass spectrometer (QMS) via a heated capillary to a commercial thermogravimetric analyser is described. The amu and temperature ranges available were up to 1000 amu and 1500°C, respectively. The system was evaluated with test compounds, yielding gaseous species in the m/z range of 17-80, and then used for the study of thermal behaviour of scandium dipivaloyl methanate or Sc(thd)3 which is discussed in detail. Sc(thd)2 appears as the major Sc-containing species with m/z=411 in the gas phase at 200-300°C.

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Abstract  

Complexes represented by the general formula [MCl2L2] (M(II)=Zn, Mn, Co) and complexes of [Cu3Cl6L4] and CuSO4L24H2O, CoSO4L23H2O, [ZnSO4L3] where L stands for 3-amino-5-methylpyrazole were prepared. The complexes were characterized by elemental analysis, FT-IR spectroscopy, thermal (TG, DTG, DSC and EGA) methods and molar conductivity measurements. Except for the Zn-complexes, the magnetic susceptibilities were also determined. Thermal decomposition of the sulphato complexes of copper(II) and cobalt(II) and the chloro complexes of cobalt(II) and manganese(II) resulted in well-defined intermediates. On the basis of the IR spectra and elemental analysis data of the intermediates a decomposition scheme is proposed.

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Abstract  

The synthesis of copper(II) chloride complexes with 3,5-dimethylpyrazole, 1-carboxamidine-3,5-dimethylpyrazole, 5-amino-4-carboxamide-1-phenylpyrazole and 4-acetyl-3-amino-5-methylpyrazole is described. The compounds are characterized by elemental analysis, FT-IR spectroscopy, thermal methods, magnetic moment and molar conductivity measurements. Thermal decomposition of the dichloro-(3,5-dimethylpyrazole)-copper(II) complex results in an unstable intermediate with a stochiometric composition. The decomposition of the other compounds is continuous.

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