Phenolic Structure and Colour in Mannich Reaction Products

Mannich reactions have been carried out with a variety of model alkylphenols and dimethylamine, methylamine, and diethylenetriamine to trace the origin of persistent coloured products occurring in related reactions with pentadeca(e)nylphenol and 4- tert-alkylphenols. It was found to be attributable to the presence of resorcinolic impurities.