Cause of the red Color of Aqueous Extracts and Emulsions of Low-Temperature Tars

Phenols in Low-Temperature Tar

“…of the homologs of catechol (4,IS,14), but ratios of the dihydric to the monohydric phenols produced during carbonization have not been reported. This paper describes a method by which this ratio, or, more specifically, the average number of hydroxyl groups per molecule of the phenols of a tar, may be determined, and gives the results obtained by applying it to the tars produced by carbonizing several bituminous coals at temperatures from 400°to 600°C.…”