CARBONIUM-ION BEHAVIOR IN ALUMINUM BROMIDE-1,2,4-TRICHLOROBENZENE

Nmr spectroscopy was used to monitor the catalytic activity of the aluminum bromide-1,2,4-trichlorobenzene system andto study long-chain hydride-transfer reactions between paraffins and cations. Compounds containing tertiary C-H bonds generally participate in extremely rapid reactions converting all the paraffins into ions in moments. Rearrangement of the intermediates to ions with a different number of branches is slower and usually rate determining. Ionic rearrangements leading to similarly branched species, however, are fast and these studies do not distinguish between these rates and those of hydride transfer. Normal paraffins appear to react much more slowly, probably because both the rates of forming and rearranging secondary ions are slow. © 1969, American Chemical Society. All rights reserved.