Authors:G. Liptay, T. Wadsten, and A. Borbély-Kuszmann
The stepwise thermal decomposition of [Ni(py)4]Cl2 was studied by means of a derivatograph. The stepwise mode of thermal decomposition allowed the preparation of new complexes. X-ray powder diffraction and IR methods were used to study the structures of the decomposition intermediates. [Ni(py)4]Cl2 was applied as a model substance. The decompositions of a great number of complex compounds of similar type have been reported, but only a few of them have been investigated structurally by single-crystal X-ray diffraction techniques due to the difficulty of obtaining large single-crystals.
Authors:J. Zsakó, Cs. Várhelyi, G. Liptay, and A. Borbély-Kuszmann
Twelve new complexes NH4[Co(DH)2(SO3)(amine)]·t H2O (DH2=dimethylglyoxime) have been synthesized and characterized. Their i.r. spectra show the SO3 to be co-ordinated to the Co atom through the S atom. The thermal decompositions of a series of derivatives of this type have been investigated with a derivatograph. The first process is an endothermic dehydration reaction, occurring in a single stage or in two successive ones. The loss of the crystallization water is followed by another endothermic reaction, without a clear stoichiometry, which is referred to as “deamination”. At higher temperatures, exothermic pyrolysis processes occur. From the TG curves, kinetic parameters have been derived for the dehydration and deamination reactions.
Authors:G. Liptay, A. Borbély- Kuszmann, T. Wadsten, and J. Losonczi
The thermal decomposition of theα, β andγ- picoline complexes of cadmium were studied by means of TG-DTG-DTA. In connection with the preparation of the complex compounds, it was established that the ligand number was influenced by the reaction medium. The thermal decomposition took place stepwise, and intermediates were formed which could be isolated with a derivatograph by the “freezing-in” method. The structures and properties of these previously unknown compounds were investigated by far-IR spectroscopy and X-ray powder diffraction.
Authors:A. Borbély-Kuszmann, E. Brandt-Petrik, G. Liptay, and J. Nagy
Cellulose substituted by organosilicon groups represents a new type of modified cellulose. The silylation changes the physical and chemical properties of cellulose drastically. The thermoanalytical investigation of differently trimethylsilylated cellulose derivatives was carried out under static conditions in air atmosphere. The DTA curves of the cellulose used as starting material are different from those of its silylated derivatives. In the latter a new characteristic exothermic peak appears in the range 320–370°. The value of this maximum depends on the grade of silylation, being shifted towards higher temperatures with higher degrees of substitution.