The nitration of mono‐alkylbenzenes conformational analysis and steric hindrance: Part II: Secondary alkylbenzenes

Abstract The isomer distributions for the nitration of six secondary alkylbenzenes and the partial rate factors of three of these compounds have been determined. The steric hindrance of the nitration in the ortho‐position of isopropylbenzene is mainly of an enthalpic nature. The increase of this hindrance in the series of isopropylbenzene, s‐butylbenzene, (1‐ethylpropyl)benzene is of an entropic nature and can be explained from the conformational analysis of the initial states and the transition states. The steric hindrance in the ortho‐positions of (2‐methyl‐1‐ isopropylpropyl)benzene and (1‐t‐butyl‐2.2‐dimethylpropyl)benzene is very large.