Authors:J. Zsakó, G. Liptay, Cs. Várhelyi, Cs. Novák, and I. Ganescu
Nineteen salts of hexachloroplatinic acid with monovalent metals, aromatic and heterocyclic amines and phosphine were obtained and characterized by chemical analysis. The thermal decomposition of these complexes was studied by means of derivatograph and differential scanning calorimetry. The nature of the pyrolysis processes is discussed. From the TG curves, kinetic parameters were derived for different stages of the thermal decompositions.
Authors:M. Maneva, D. Rizova, L. Genov, and G. Liptay
The DTA method has been used in studying the thermal dehydration and decomposition of NiSO4.nH2O, accordingly of NiSO4.nD2O, (atn=7, 6, 4, 1) in a temperature interval of 20 to 900°C, at a heating rate of 10 deg/min. The endoeffects observed show in all cases partial dehydration to monohydrate and evolution of the last molecule of hydrate water at a high temperature Tmax ∼-360°C for the hydrates and Tmax ∼ 360-335°C for the deuterates. At NiSO4.6H2O (6D2O) and NiSO4.4D2O there occurs stepwise dehydration before the monohydrate as well. Decomposition of the anhydrous NiSO4 takes place at higher temperature which depends on whether it had been obtained from the respective deuterate ordinary hydrate. The one obtained from the deuterate undergoes decomposition at relatively lower temperature.
Authors:J. Zsakó, Cs. Várhelyi, Gh. Marcu, and G. Liptay
14 mixed Co(III) dioximine chelates of the types [Co(DioxH)2(amine)2]X (X = Br, I, NO3, ClO4) and H[Co(DioxH)2(N3)2], respectively (DioxH2-1,2-cyclohexane dione dioxime (nyoxime), 1,2-cycloheptane dione dioxime (heptoxime) 1,2-cyclooctane dione dioxime (octoxime)
were obtained and their thermal decompositions were studied in an argon atmosphere. After the dehydration of the crystallohydrates,
both types of complexes exhibit 3 decomposition stages. For the [Co(DioxH)2(amine)2]X type complexes (X = Br, I) the first endothermal stage is the substitution of an amine molecule for the external sphere
anion and this process is followed by two exothermal decomposition stages. With H[Co(DioxH)2(N3)2] type complexes the first and third processes are relatively slow, but the second process is very fast, corresponding to
a vertical portion of the TG curves. From the TG curves kinetic parameters were derived for 11 processes and the validity
of a non-linear compensation law was observed.
Authors:S. Békássy, T. Cseri, G. Kenessey, G. Pokol, K. Tomor, and G. Liptay
Montmorillonite-supported iron(III) nitrate and copper(II) nitrate reagents, and other supported metal nitrates prepared in
the same way, were investigated by thermal and X-ray powder diffraction methods. The metal nitrates are present on the support
in the form of crystalline hydrate and not as acetone solvate as supposed earlier. Thermal decomposition of metal nitrates
that are active in model reactions proceeds in a different way from that of the practically inactive nitrates. In the former
case, water release and nitrate decomposition itself are simultaneous process. These and other results contributed to determination
of suitable reaction conditions for the montmorillonite-supported reagents.
Authors:Cs. Várhelyi Jr., G. Pokol, Á. Gömöry, A. Gănescu, P. Sohár, G. Liptay, and Cs. Várhelyi
chelates of the type [Ni(II)(Diox.H)2], ((Diox.H)2:
various α-dioximes) have been studied by means of FTIR, NMR, MS data
and various thermoanalytical methods (TG, DTA, DTG, DSC). In some cases kinetic
parameters of the thermal decomposition of the complexes were also calculated
using Zsak’s ‘nomogram method’. The mechanism of
the decomposition processes was characterised on the basis of mass spectra.
Authors:J. Zsakó, G. Pokol, Cs. Novák, Cs. Várhelyi, A. Dobó, and G. Liptay
A number of 30 [Co(en)3 ]Y3 , [Co(en)2 X2 ]Y and [Co(en)2 X(amine)]Y2 type complexes (X =Cl, Br; Y =Cl, Br, I, NCO, NCS, NO3 , ClO4 , etc.; amine =aromatic and alkylamines) were obtained from trans-[Co(en)2 Cl2 ]Cl by double decomposition and by substitution reactions, respectively. The structure of the complexes was proved by means
of far and middle FTIR spectra. The thermal decomposition was studied by TG, DTA and DSC measurements. Mass spectra were also
recorded. In the case of [Co(en)3 ]Y3 complexes the nitrate, perchlorate and dimesoperiodates decompose suddenly, frequently explosion like. The halides and thiocyanates
seem to substitute an ethylenediamine ligand, yielding a rather unstable intermediate. The pyrolysis of [Co(en)2 X2 ]Y type derivatives yields no relatively stable intermediates, but the decomposition temperatures may be correlated with
the nature of Y and with the cis or trans configuration of the compound. With the [Co(en)2 X(amine)]Y2 type complexes one observes the formation of [Co(en)2 XY]Y as intermediate product. From the TG curves kinetic parameters were derived for some dehydration and deamination processes,
by using the nomogram method. The validity of a non-linear kinetic compensation law was observed.
Authors:K. Mészáros Szécsényi, T. Wadsten, B. Carson, É. Bencze, and G. Liptay
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.