The mechanism of formaldehyde loss from the oxonium ions CH₃CH₂CH₂CHO⁺CH₃and CH₃CH₂CH₂CH₂⁺OCH₂

Abstract

In contrast to CH3CH2(CH3)CO+CH3 and (CH3)2CHCHO+CH3, which in slow dissociations lose mainly CH3OH, metastable CH3CH2CH2CHO+CH3 exples predominantly CH2O by isomerising to CH3CH2CH2CH2+OCH2, probably via two 1,2-H shifts and a subsequent 1,5-H shift; CH3CH2CH2+OCH2 undergoes limited interconversion with CH3+CHCH2CH2OCH3, prior to CH2O elimination, via a 1,5-H shift.