An extensive theoretical study of the thermal decomposition of alkyl- and phenylureas, which are widely used in the pesticides, pharmaceuticals, and materials industries, has been carried out using electronic structure calculations and reaction rate theories. Enthalpies of formation and bond dissociation energies (BDE) of 11 urea derivatives have been calculated using different levels of theory (CBS-QB3, CCSD(T)/CBS//M06-2X/6-311++G(3df,2pd), and CBS-QM062X) according to the size of the system. Potential energy surfaces for the unimolecular decomposition pathways of these urea derivatives were also systematically computed for the first time.
View Article and Find Full Text PDFThe chemistry underlying liquid-phase oxidation of organic compounds, the main cause of their aging, is characterized by a free-radical chain reaction mechanism. The rigorous simulation of these phenomena requires the use of detailed kinetic models that contain thousands of species and reactions. The development of such models for the liquid phase remains a challenge as solvent-dependent thermokinetic parameters have to be provided for all the species and reactions of the model.
View Article and Find Full Text PDFA theoretical study of the thermal decomposition of β-1,4-xylan, a model polymer of hemicelluloses, is proposed for the first time. A mechanism based on unimolecular concerted reactions is elaborated in a comprehensive way. Elementary reactions, such as dehydrations, retro-aldol, retro Diels-Alder, retro-ene, glycosidic bond fissions, isomerizations, etc.
View Article and Find Full Text PDFOrganoarsenic compounds have been widely used as pesticides and chemical agents. Lewisite (CHAsCl), a blister agent, is a model of such compounds. A comprehensive detailed kinetic mechanism of combustion has been developed based on theoretical investigations.
View Article and Find Full Text PDFGuaiacol or 2-methoxy phenol is one of the main primary tars produced during lignin pyrolysis. Tar conversion in the gas phase influences the production of gaseous and condensable products, and is also responsible for PAH and soot formation during biomass and bio-oil gasification or combustion. Guaiacol pyrolysis and oxidation under stoichiometric conditions were studied in a jet stirred reactor between 623 and 923 K for a residence time of 2 s and under a pressure of 800 Torr (106.
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