Substituent Effects in the Fragmentation of Benzyl Acetates

Abstract

Electron ionization mass spectra of substituted benzyl acetates [1] - [12] are measured. In general, the spectrum consists of four peaks: M⁺, [M-42]⁺, [M-59]⁺, and m/z 43 peak. A good Bursey-McLafferty correlation between log ([m/z 43]/[M]) and Hammett σ constants is found. The Einolf-Munson treatment of m/z 43 and [M-42] ions also gives an expected result. On the other hand, compounds [5] and [7] deviate considerably from the plott of log ([M-42]/[M]) vs. σ, and the Chin-Harrison analysis is applied to explain this discrepancy.