Electron impact studies. CXIV —The occurance of metastable ions for two‐ and multi‐ stage decomposition of negative ions derived from p ‐nitrophenyl carboxylic acids

Pronounced metastable peaks are observed for the two‐stage decomposition and the multi ‐ stage elimination from p ‐NO 2 C 6 H 4 (CH 2 ) n CO 2 H (n>1). 2 H and 18 O labelling shows that each process involves elimination of atoms from both the nitro and carboxyl groups. A consideration of the spectrum of p ‐nitrophenylcyclohexane‐4‐carboxylic acid leads to the proposition that interaction between the two functional groups is not a necessary prerequisite for the elimination of HO⋅.