A model for the prediction of biologically mediated reductive dechlorination pathways

Graduation date: 1990The environment has been exposed to a number of hazardous chlorinated\ud organic compounds. These compounds may be anaerobically biotransformed by\ud sequential reductive dechlorination reactions in which the chlorine atoms are\ud replaced with hydrogen atoms. Because reductive dechlorination processes may\ud occur very slowly in the environment and chlorine position affects the fate and\ud toxicity of the compound in the environment, it is desirable to develop a model to\ud predict the products of these reactions.\ud This project was designed to examine the reductive dechlorination pathways\ud of various chlorinated aromatic compounds in relation to additional substituents on\ud the ring and to develop an empirical model to predict these pathways. The model\ud is based on the structural properties of the compound. Molecular structures and\ud properties such as net atomic charges were calculated using the published semiempirical\ud MNDO (Modified Neglect of Differential Overlap) method, Versions\ud 4.01 and 5.01 at the Cornell National Supercomputer Facility.\ud Net carbon-chlorine bond charges are compared for chlorinated positions on\ud the ring or aliphatic chain. These data provide a means for correlating charge\ud with the position of dechlorination. The pathways predicted from this model\ud agreed well with experimentally determined pathways for several classes of\ud chlorinated organic compounds including: phenols, dihydroxybenzenes, benzoic\ud acids, and anilines