Reactive oxygen groups in low-temperature tars from low-rank coal

Abstract

Two Polish brown coals and two low-rank bituminous coals were subjected to low-temperature rapid pyrolysis to obtain tars. The reactive (phenolic, carbonyl and carboxyl) oxygen groups in the oils, asphaltenes and preasphaltenes of the tars were quantified. The amount of reactive oxygen groups in the bituminous coal tars was twice that in the brown coal tars. Phenolic groups predominated. Reactive oxygen in the oil fractions of the bituminous coal tars represented 80% of the total oxygen, and in the asphaltenes 90–100%. Non-reactive oxygen occurred in greater proportions in the preasphaltenes.