Reactions of tert-C4H9+, tert-C5H11+, and CH3-cy-C5H9+ ions with pentenes

Total reaction rate constants for the disappearance of tert-C 4 H 9 + ions with five C 5 H 10 unsaturated hydrocarbons were determined by comparing the rate of formation of isobutane in the radiolysis of neopentane in the presence of various additives. These rate constants are of the order of 5 to 1.35 × 10 −10  cm 3 molecule −1 s −1 depending upon the olefin under investigation. The hydride transfer reaction from 3-methyl-1-butene and trans-2-pentene toward the tert-C 4 H 9 + ion was also observed, as was the proton transfer reaction from the tert-C 4 H 9 + ion toward 2-methyl-2-butene and 2-methyl-1-butene. In the latter two cases, a significant isomerization of methylbutene is noticed: an isomerization mechanism based upon the reactions of tert-C 5 H 11 + ions is tentatively suggested. Finally, the transfer reaction of an hydrogen molecule between the CH 3 -cy-C 5 H 9 + ion and the methylbutenes is observed during the radiolysis of methylcyclopentane.