Studies on Phenols The Steric Effect

If both or o-positions of phenol are substituted by t-butyl groups, the reactivity of the compound is reduced regardless of the individual features of the system considered. This decrease in the reactivity of 2,6-di-t-butylphenols as compared to other phenols having similar Zo+ values may be attributed mainly to steric effects. These compounds, 

As an interpretation of the constancy of the p/pst ratio, it was suggested that the O—H bond could be twisted out of the plane of the ring (Simonyi et al., 1967b) and that the decreased p value was an apparent consequence of decreased substituent effects. 

Radical Medium t°C No. of compounds used in calculations pat P pat Reference 

Polyvinyl acetate Vinyl acetate 50 3 -110 1-38 Simonyi el al. (1967b) 

It is perhaps not yet possible to give a final conclusion of this problem. It is, however, undoubtedly proved from infrared measurements that 

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