On the mechanism of isomerization reactions in the esters of some simple α,β‐unsaturated carboxylic acids

Abstract It is shown from a detailed examination of first field free region metastable peak shapes that the molecular ion of the methyl ester of acrylic acid rearranges into 2‐ and 3‐butenoic acid ions prior to metastable fragmentations involving the losses of H 2 O, CH 3 ˙ and CO. The key intermediate ion in this ester‐acid isomerization is shown to be the enol form of ionized γ‐butyrolactone. The C‐5 homologues methylmethacrylate and …