Structure and thermal characterization of tris-thallium(III) glycollate

Abstract

The thermal decarboxylation of TI(GLA)3 (where GLA stands for the anion ofglycollic acid) was studied by TG, DTG and DTA techniques. The results showed the escape of all three glycollic acid moieties in a single step. The I R spectra of the ligand and the complex indicated the bidentate character of carboxylate ion and the fact that the proton from the hydroxy group is not replaced during complex formation, The various kinetic and thermodynamic parameters were estimated from analysis of the TG, DTG and DTA curves of the sample, employing several computational methods. Precise results were then obtained by the method of least squares and are discussed.The thermal decomposition of metal carboxylates has attracted great interest during recent years [1,2]. However, work on the thermal decomposition of heavy metal carboxylates started only a short time ago [3]. Recently, we reported on the thermal dehydration and decomposition of metal complexes of salicylic and nuclear substituted salicylic acids [4][5][6][7][8][9]. The work on the thermal decomposition of metal complexes of hydroxy acids is very limited. As an extension of our previous studies [4][5][6][7][8][9], the present report deals with the thermal decarboxylation of TI(III) glycollate, with a view to understanding the mechanism of the decomposition and the nature of the decomposition products. The characterization ofTl(IlI) glycollate was carried out through elemental analysis, IR spectra, TG, DTG and DTA studies. Attempts were also made to estimate the kinetic parameters from thermal studies, employing different computational methods, e.g. the Horowitz-Metzger

Enthalpy-Entropy Compensation in Polyester Degradation Reactions

“…Mathematical analysis was performed on the TG data using the integral method of Coats and Redfern, [9] which has been used successfully for studies on the kinetics of decomposition of solid substances [10][11][12][13][14]. The activation energy (E) and 2 International Journal of Chemical Engineering the preexponential factor (A) for the degradation of PET, PTT, and PBT have been previously calculated from the TG curves.…”