Primary Steps in the Photolysis of CD3CHCl2

The photolysis of CH3CHCl2 and of CD3CHCl2 was studied at 25°C in the presence of iodine. Two series of experiments were carried out, one in which the initial pressure of 1, 1-dichloroethane was varied from 2.5 to 15.8 mm Hg and one in which nitrogen was used as an inert deactivator. The following reaction products were observed: hydrogen, acetylene, ethylene, vinyl chloride, 1, 1-dichloroethylene, 1, 1-chloroiodoethane, and iododichloroethane. The appearance of these products and their isotopic composition suggest that the following primary processes occur: CD3CHCl2* → CD3CHCl+ClCD2CHCl+DClCD2CCl2 + HDCD3CH+Cl2.Step (D) has been observed only below 2200 Å, Steps (A)-(C) occur also at wavelengths above 2200 Å. Primary steps (A)-(D) are discussed and compared with processes occurring during the photolysis of other ethanes.