THE PHOTOINITIATED ADDITION OF MERCAPTANS TO OLEFINS: II. THE KINETICS OF THE ADDITION OF n-BUTYL MERCAPTAN TO 1-PENTENE

The detailed kinetics involved in the photoinitiated addition of n-butyl mercaptan to 1-pentene is presented. It has been shown that side reactions such as propagation and α-dehydrogenation are relatively negligible and the principal mechanism comprises attack by thiyl radical followed by transfer with mercaptan by the alkyl radical. The velocity constant of the attack step is estimated to be 7 × 106 and that of the transfer step 1.4 × 106 liters/mole-sec. These values together with approximate termination velocity constants are shown to explain the kinetics over a wide range of concentration.