Thermogravimetric （TG） investigations of organotin（IV） carboxylates with the general formula RmSnL4-m （where R=CH3, C2H5, n-C4H9, C6H5, cyclo-C6H11, n-C8H17, m=2, 3, and L=para-nitrophenylethanoate anion） have b...Thermogravimetric （TG） investigations of organotin（IV） carboxylates with the general formula RmSnL4-m （where R=CH3, C2H5, n-C4H9, C6H5, cyclo-C6H11, n-C8H17, 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 pa- rameters of each thermal degradation pattern. Results reveal that the thermal stability is functional to Sn--C and Sn--O bonds. In the case of R2SnL2, activation energy, reaction order and pre-exponential factor associated with the bulk degradation processes increase as the alkane chain length increases. Hence, Oct2SnL2 is thermally more stable than Bu2SnL2, which in turn is more resistant to thermal dissociation than Et2SnL2. The same phenomenon is not observed for R3SnL compounds because their degradation is highly irregular. Furthermore, R2SnL2 has larger values of kinetic parameters than those of corresponding triorganotin（IV） para-nitrophenylethanotes. Thermodynamic parameters of these compounds also reinforce the above facts.展开更多
文摘Thermogravimetric （TG） investigations of organotin（IV） carboxylates with the general formula RmSnL4-m （where R=CH3, C2H5, n-C4H9, C6H5, cyclo-C6H11, n-C8H17, 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 pa- rameters of each thermal degradation pattern. Results reveal that the thermal stability is functional to Sn--C and Sn--O bonds. In the case of R2SnL2, activation energy, reaction order and pre-exponential factor associated with the bulk degradation processes increase as the alkane chain length increases. Hence, Oct2SnL2 is thermally more stable than Bu2SnL2, which in turn is more resistant to thermal dissociation than Et2SnL2. The same phenomenon is not observed for R3SnL compounds because their degradation is highly irregular. Furthermore, R2SnL2 has larger values of kinetic parameters than those of corresponding triorganotin（IV） para-nitrophenylethanotes. Thermodynamic parameters of these compounds also reinforce the above facts.
