Theoretical study on the thermal decomposition of pyridine

Semi-empirical PM3 molecular orbital calculations have been used to investi gate the reaction pathways of pyrolysis of pyridine. All the transition sta tes and intermediates of the reaction path were optimized. The probable pat hways are estimated from the activation energies calculated and compared wi th known experimental results. The heats of formation of pyridine radicals are calculated to be 76.1, 80.6, and 79.5 kcal/mol for 2- (2A), 3- (3A) and l-pyridyl radicals (3A), respectively. The weakest bonds on the radicals w ere assumed to be broken and gave thr decomposition fragments successively. (C) 2000 Elsevier Science Ltd. All rights reserved.