Isolation of prime value products from crude xylenol fraction of noncaking coal-derived tar acids

An efficient method for the separation of prime value products from crude xylenol fraction of noncaking coal-derived tar acids involving suitable distillation technique is described. The feed as well as the products was analysed by gas chromatography (G.C.). The crude xylenol comprising a number of close-boiling phenolic compounds was fractionated under reduced pressure to yield three cuts, viz. cresols (30.7%), xylenols (31.2%) and dihydric phenols (23.3%). The dihydric phenols fraction termed as high boiling tar acids (HBTA) was found to contain significant amounts of catechol (6.4%), methyl catechols (32.3%), resorcinol (12.7%) and methyl resorcinols (8.6%). Catechol together with its homologues and resorcinol with its homologues were isolated from the HBTA. These products, not available from the HBTA of metallurgical coke plants, have been shown to offer distinct marketing advantages. A conceptual scheme for the treatment of crude xylenol as well as application pattern of various products obtainable from the crude mixture is presented.