Thermal ion—molecule reactions in oxygen-containing molecules. Condensation—elimination reactions in n-propyl formate

Abstract

The condensation—elimination reactions involving CH 2OH + and CH 2CHCH 3 + in n-propyl formate have been studied using a time-of-flight mass spectrometer. CH 2OH + reacts with the neutral molecule to form HCOOC 3H 7H +, HCOOC 3H 7CH + and HCOOC 3H 7CHO +; CH 2CHCH 3 + reacts to form HCOOC 3H 7H + and HCOOC 3H 7CH 2CHCH 2 +. The condensation—elimination reactions leading to the formation of these ions were studied using n-propyl formate- d. The product ions are formed by the dissociation of the intermediate complex in which extensive scrambling does not take place. The rate constants for the product ions resulting from the condensation—elimination and dimerization reactions were obtained. The rate constant of the proton transfer reaction by CH 2OH + is larger than that by CH 2CHCH 3 +, and thus it was found that the proton donor activity of an oxonium ion such as CH 2OH + is greater than that of a carbonium ion such as CH 2CHCH 3 +.