Thermal degradation of pesticides under oxidative conditions

The paper addresses thermal decomposition under oxidative conditions of 16 pesticides. Within the scope of the paper such 16 substances have been divided in four groups: (1) Pesticides with linear molecule belonging to the family of aldoxime carbamates. (2) Benzimidazolylcarbamates. (3) Pyrethroids. (4) Pesticides containing one aromatic (heterocyclic in one case) ring within their structure. The experimental work consists of non isothermal thermogravimetric analysis with 5% oxygen in helium, using a TG-DSC-MS system equipped with a Skimmer device that ensures the simultaneousness of thermogravimetric analysis with the analysis of evolved gas and rules out the possibility of secondary reactions in the gas phase. Results have been analyzed in order to highlight similarities and differences in the modes of decomposition of pesticides within and among the four mentioned groups. The influence of oxygen and the yield in gaseous products has also been addressed. (c) 2007 Elsevier B.V. All rights reserved.