Thermal Decomposition Kinetics of Some Di‐ and Triorganotin(IV) Carboxylates Derived from para‐Nitrophenylethanoic Acid

Abstract

Thermogravimetric (TG) investigations of organotin(IV) carboxylates with the general formula R m SnL 4-m (where R＝CH 3 , C 2 H 5 , n-C 4 H 9 , C 6 H 5 , cyclo-C 6 H 11 , n-C 8 H 17 , m＝2, 3, and L＝para-nitrophenylethanoate anion) have been performed. Derivative thermogravimetry (DTG) and differential thermal analysis (DTA) techniques, Horowitz-Metzger method and the fundamental thermodynamic relations are used to evaluate the thermokinetic parameters of each thermal degradation pattern. Results reveal that the thermal stability is functional to Sn-C and Sn-O bonds. In the case of R 2 SnL 2 , activation energy, reaction order and pre-exponential factor associated with the bulk degradation processes increase as the alkane chain length increases. Hence, Oct 2 SnL 2 is thermally more stable than Bu 2 SnL 2 , which in turn is more resistant to thermal dissociation than Et 2 SnL 2 . The same phenomenon is not observed for R 3 SnL compounds because their degradation is highly irregular. Furthermore, R 2 SnL 2 has larger values of kinetic parameters than those of corresponding triorganotin(IV) para-nitrophenylethanotes. Thermodynamic parameters of these compounds also reinforce the above facts.