Abstract

A series of phenolic sulphonic acids have been prepared and the ¹³C chemical shifts of the aromatic carbon atoms compared with those calculated using the principle of chemical shift additivity. In most cases good agreement was found but in some cases the chemical shift parameter employed requires modification to enable complete assignments to be made. Despite this limitation it should be possible to identify the site or sites of sulphonation for sulphonated novolacs of the type employed as synthetic tanning materials.