Abstract

Hydrochlorofluorocarbons and hydrofluorocarbons are a harmful class of compounds for the atmosphere due to be phased out of use by 2020 in developed countries and 2030 in undeveloped countries via incineration by combustion chamber. This research is aimed at modeling the high energy decompositions of these molecules computationally using primarily DFT methods for optimization as well as CCSD(T) energy corrections and a combination of CASSCF and various model chemistries for calculations involving binding energy. A novel and interesting reaction pathway has been discovered through this research that involves the formation of a gas phase carbene-HX complex following 1,1-HX elimination. This complex can in some cases persist through subsequent isomerizations by providing a pathway with a lower threshold for activation. This type of reaction could potentially be relevant in systems studied by other groups, so it is important to investigate thoroughly. Currently, it has been found that this pathway is experimentally relevant in the molecule C2D5CHFCl following 1,1-HF elimination with the assisted isomerization proceeding at 3.9 kcal/mol lower threshold energy than the dissociation of the carbene complex. Other interesting results follow from studies into substituent effects on these carbene complexes. It has been found that resonance donation can strengthen the binding energy as in the case of 1-phenyl-1-chlorocarbene complexed to HF with a binding energy of 11.6 kcal/mol, stronger than the water-water H-bond. Substituent effects will continue to be studied as well as possible implications for nitrene complexes that may also prove relevant in some cases.

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