The study of ion–molecule reactions in the gas phase using a triple quadrupole mass spectrometer. Part 1. The reactions of CH 3 + , CD 3 + , and C 2 H 5 + with simple olefins

A triple quadrupole mass spectrometer has been used to study the reactions of simple carbocations with low molecular weight olefins in the gas phase at relatively high pressures (10–3–10–4 Torr). In each case a high energy ‘addition complex’ is formed which fragments spontaneously to give daughter ions, the extent of fragmentation depending to some extent on the pressure and on the translational energy of the primary ions. Also formed are ‘second generation’ ions due to reactions of the predominant daughter ions with the olefin. Ions with the same mass as the high energy ‘addition complexes’ have been fragmented by collision (C.I.D.) with inert molecules (N2) to yield similar daughter ions to those found from the ‘addition complexes’. In the reactions, involving CD3+ ions, deuterium is widely, but not completely randomly, distributed among the daughter ions.