Thermal ion-molecule reactions in oxygen-containing molecules. Proton and acetyl ion transfer reactions in n-Propyl acetate-acetaldehyde mixtures

Abstract

Thermal ion-molecule reactions in n-propyl acetate-acetaldehyde mixtures have been studied using a time-of-flight mass spectrometer. As cross-reaction product ions, CH 3CHOH +, CH 3COOC 3H 7H +, and CH 3CHOCH 3CO + were observed. CH 3COOH 2 + and CH 3CO + from n-propyl acetate undergo proton and acetyl ion transfer reactions in which CH 3COOH 2 + leads to the formation of CH 3CHOCH 3CO + by condensation-elimination reaction via a homo-elimination mechanism. The rate constants for the formation of CH 3CHOCH 3CO + by both CH 3COOH 2 + and CH 3CO + from n-propyl acetate were larger than those for CH 3COOC 3H 7CH 3CO + by a factor of four. CH 3CHO + and CH 3CO + from acetaldehyde did not participate in the acetyl ion transfer reaction leading to the formation of CH 3COOC 3H 7CH 3CO +.