Abstract

Elimination reactions are a possible degradation pathway of haloalkanes during their destruction in high temperature environments. Elimination reactions occur in two different pathways: a 1,2 elimination where a halogen and a hydrogen are eliminated from two different carbon atoms, or a 1,1 elimination where a halogen and a hydrogen are eliminated from the same carbon atoms. The highly multireference character of the 1,1 eliminations make it difficult to study these reactions using conventional Density Functional Theory (DFT) calculations, therefore the CASSCF, or Complete Active Space Self Consistent Field level of theory is utilized to optimize two propane molecules, 1,1 dichloro and 1,1 difluoropropane. Results are presented as transition state geometries with consideration of the optimum active space for generating reliable geometries and vibrational frequencies, and found that the 1,1 difluoropropane 1,1 HF elimination pathway had a threshold energy of 70.1 kcal/mol and matches with experimental data. However, the 1,1 HCl elimination transition state geometry from 1,1 dichloropropane produced a threshold energy of 121.6 kcal/mol which is too high of an energy for this reaction to take place. More research has been done on the 1,1 HCl elimination pathway including chloroform HCl elimination and 1,1 dichloroethane 1,1 HCl elimination in order to find a more reasonable transition state for 1,1 dichloropropane.

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