CALORIMETRIC COMPARISONS OF THE INTERACTIONS OF 7 COALS AND THEIR DERIVED LIQUIDS WITH 13 ACIDS

Heats of interaction for samples of Wyoming-Dakota subbituminous, Illinois no. 6 bituminous, Pittsburgh no. 8 bituminous and Utah Black Thunder subbituminous coals with 13 acids (carboxylic, sulfonic and boron trichloride) are reported at 25-degrees-C by titration and immersion calorimetry. These acids are considerably stronger than the phenols used previously to study hydrogen-bonding interactions in coals and their derived liquids. The coals are compared to each other and to polyvinylpyridine as a prototype solid base. Considerable differentiation is found between the coals, primarily in terms of their ranks and aromatic content. Titrametric heats of reaction were also determined for the acids with liquids derived from several of the coals. In all cases reactions with the coal-derived liquids were more exothermic than with the parent coals and there were several examples of parallel response by liquid systems and their solid precursors, although such correlations were by no means general.