■l.Halogenation +Br2 hv B HBr anhy.AICla Highly selective:bromination of 3 C CH3 CH3 CH3- C-H Br2 hv> CH3一C-Br+ HBr CH3 CH3 90% Highly selective: bromination of 3 C 90% CH3 C + HBr CH3 CH3 Br h CH3 C + Br2 CH3 CH3 H RH + Cl2 RCl + HCl u.v. Cl Cl 2 anhy. AlCl3  1. Halogenation + HBr H Br h + Br2 H H