Para-substituted Phenols Research Articles

Shift of Aromatic Band in Substituted Benzene

THE aromatic band1 found in benzene at 671 cm.-1 shifts as a consequence of mono-substitution (in benzene) to 740-760 cm.-1. In the case of di-substituted benzenes, there is a steady movement to higher frequencies in passing from the ortho- to the para-position ; whereas in the case of para-substituted phenols we find that increase in molecular weight of the para-substituent from methyl to octyl does not shift the absorption band, which is found in all these compounds at 825–830 cm.-1. Less extensive data on the ortho-phenols show no drift in the aromatic band at 750–755 cm as a result of change in the molecular weight of the substituent from methyl to isopropyl. m-Cresol and m-ethyl phenol absorb strongly at 780-785 cm.-1. It would appear that increasing molecular weight by aliphatic substituents does not shift the aromatic band in the mono-substituted phenols.

Shock, its mechanism and pathology: Moon, Virgil H.: Arch. Path. 24: 794, 1937

A modified version of the automated fluorometric determination of tyrosine by the nitrosonaphthol reaction is described, which was developed for the analysis of tyrosine in blood and tissues, and is simpler, more rapid, and more sensitive than earlier methods. Of the 50 compounds tested with this method, most of which were phenolic in structure, only para-substituted phenols with no other substituents in the aromatic ring, and 5-hydroxy indoles, gave appreciable fluorescence.