Kinetics of alpha‐methylstyrene oligomerization by catalytic chain transfer

Alpha‐methylstyrene (AMS) can be effectively dimerized by a free‐radical mechanism mediated by the catalytic chain transfer (CCT). Above the ceiling temperature of AMS, 61 °C, the dimer may become almost an exclusive product with only a small percentage of impurity of AMS trimer and tetramer. Kinetics of the AMS oligomerization has two characteristic features. First, the rate of the oligomerization increases with concentration of the CCT catalyst. Second, conversion reaches a plateau at 60–70%. A kinetic scheme explained both effects. Besides AMS, para‐ and methasubstituted AMS can also be dimerized. Orthosubstituted AMS's do not oligomerize. © 2002 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 40: 1366–1376, 2002