A process for converting an arylamine into an arylamine derivative, includes (i) providing a first arylamine compound; (ii) formylating the first arylamine compound to form a formyl substituted arylamine compound, where the first arylamine compound is not a formyl substituted arylamine compound; and (iii) acidifying the formyl substituted arylamine compound, in the presence of a solvent and a solid organic catalyst, to convert formyl functional groups into acid functional groups to form an acidified compound.