Formation of the 3-Pentanone ion from ionized propyl propanoate through Ion-Neutral complexes.

Formation of the 3-pentanone ion (3) from ionized propyl propanoate through the complex [C2H5CO(+) (•)OC3H7] is proposed based on data obtained by photoionization. The threshold and energy dependence for forming 3 relative to those for related processes support this proposal. The threshold for forming 3 coincides with that predicted for forming [CH3CH2CO(+) (•)CH2CH3], suggesting that that complex is also an intermediate in the pathway to 3. 3-Pentanone ion formation is important much further above threshold than is alkane elimination through [RCO(+) (•)R] complexes. This adds to evidence that reactions between the partners in ion-dipole complexes take place over a wider energy range than do such reactions in complexes containing nonpolar neutral partners.