High-energy kinetic study of chemically activated 1,1-dichlorocyclopropane

1,1-Dichlorocyclopropane has been produced by addition of CH₂(¹A₁) to 1,1-dichloroethylene. CH₂(¹A₁) was generated by the photolysis of ketene at 277–334 nm. The 1,1-dichlorocyclopropane was formed in a chemically activated state, had an energy content between 386 and 400 kJ/mol, and reacted in two parallel channels to 2,3-dichloropropene and 1,1-dichloropropene. 1,1-Dichloropropene was also formed directly by insertion of CH₂(¹A₁) into the CH bond of 1,1-dichloroethylene. As secondary reactions elimination of HCl from chemically activated 2,3-dichloropropene occurred with 3-chloropropyne and chloroallene as products. In some of the experiments perfluoropropane was added as an inert gas. The apparent rate constants for the isomerization and elimination reactions are reported. The results of RRKM calculations including distribution functions for the activated 1,1-dichlorocyclopropane and a step-ladder model for the deactivation verify the proposed reaction scheme.