Colored Charge-Transfer Complexes from N,N-Dimethyl-p-Toluidine

Abstract
Yellow mixtures form on adding essentially colorless N,N-dimethyl-p-toluidine (DMPT) to colorless methacrylate monomers containing phthalate, isophthalate, or terephthalate diester groups. The color-causing interactions between the amines and monomers were investigated using ultraviolet spectroscopy. Equations were derived for predicting interactions between formulation ingredients and DMPT that would lead to undesired color.