Acidic groups in coal and coal-derived materials

The application of non-aqueous titrations to coal and coal-derived liquids is described to distinguish and determine carboxylic and phenolic groups in these materials. Such titrations have been applied to two coals, a subbituminous and a bituminous coal. For the subbituminous coal the amount of phenolic groups estimated from non-aqueous titrations is only about 30% of that estimated from acetylation studies, whereas both these methods give similar results for the bituminous coal. The lower values obtained by non-aqueous titrations, for the subbituminous coal, are due to proximal phenolic groups which are only partially titratable and alcohol groups which are non-titratable.