Electrophilic aromatic reactivities via pyrolysis of 1-arylethyl acetates. Part XI. The σ+ value for the m-methyl substituent

Abstract

The rates of gas-phase elimination of acetic acid from 1-(m-methylphenyl)ethyl acetate together with that of 1-phenylethyl acetate acetate between 613.8 and 666.1 K have been determined. From these data a new value of σ⁺_m-Me of –0.098 is obtained. This gives a much better correlation of the effect of the m-methyl substituent in electrophilic substitutions in solution than does the existing value of –0.066 which is considerably in error. The new value shows that there is a significant relay of polarisability effects to the meta-position in toluene and derivatives.