KINETIC-STUDY OF ADDITION OF SUBSTITUTED AND UNSUBSTITUTED PHENYLTHIYL RADICALS TO AROMATIC OLEFINS - STERIC EFFECT ON REACTIVITIES OF MONOMERS CONTAINING BULKY GROUPS

For olefins containing aromatic groups such as naphthyl, monomer reactivities have been evaluated on the basis of the absolute rate constants and relative equilibrium constants which were determined by the flash photolysis method using phenylthiyl radicals as attacking radicals. The rate constant for addition of α-methyl-1-vinylnaphthalene is lower than that of α-methyl-2-vinylnaphthalene. This suggests that the aromatic π-orbitals of the 1-naphthalene derivative are twisted away from the olefinic π-orbital; in the transition state, the delocalization of the unpaired electron on the olefinic carbon into the naphthyl group is reduced by the angular structure.