THE PHOTOLYTIC AND PHOTOSENSITIZED DECOMPOSITION OF CHLOROFORM

Abstract

The photolysis of CHCl3, in the vapor phase, was carried out using the 1 849 Å line of Hg as the exciting radiation. The photosensitized reaction was also studied using benzene as a photosensitizer. In the latter case, the exciting wavelength was the 2 537 Å line of mercury, which CHCl3 does not absorb.The study was primarily concerned with establishing the initial steps of the direct photolysis and photosensitized reactions. Experimental observations rule out a molecular detachment of HCl in both the direct photolysis and photosensitized reactions at the wavelength used. The initial step of the photolysis appears to be a carbon–chlorine bond cleavage, but in the photosensitized reaction a carbon–hydrogen bond break is indicated as the primary step. It is concluded that in neither case does dissociation take place from the ground electronic state.