Aqueous High-Temperature Chemistry of Carbo- and Heterocycles. 29. 1 Reactions of Aryl Hydrocarbons, Aryl N- Oxides, and Aryl Carbonyl Compounds in Supercritical Water at 460 °C

• Published in: Energy & fuels Vol. 11; no. 1; pp. 160 - 173
• Main Authors: Katritzky, Alan R, Ignatchenko, Elena S, Allin, Steven M, Barcock, Richard A, Siskin, Michael, Hudson, Carl W
• Format: Journal Article
• Language: English
• Published: American Chemical Society 21.01.1997
• ISSN: 0887-0624; 1520-5029
• DOI: 10.1021/ef9600725

A series of aryl hydrocarbons, aryl N-oxides, and aryl carbonyl compounds were subjected to thermolysis at 460 °C in water alone, in 15% aqueous formic acid, in 15% aqueous sodium formate, and, for comparison of purely thermal reactions, in cyclohexane. The runs were carried out initially for 7 min and, in most cases, also for 1 h. The aryl carbonyl substrates underwent mainly carbonyl reduction mainly under reducing conditions, with ring opening only observed in significant amounts for 1,4-naphthoquinone and 3,4-benzocoumarin. The arenes produced mainly reduction products with only low yields of ring-opened products observed. Aryl oximes underwent significant denitrogenation and subsequent reduction with only very little cleavage to simpler aromatic systems. The N-oxides underwent deoxygenation, and in the case of isoquinoline, ring opening of the heterocycle was prevalent. 2-Aminobiphenyl was denitrogenated and cleaved to simpler systems in cyclohexane, but in the aqueous systems it underwent mainly cyclization to yield carbazole with only low yields of denitrogenated products. 2-Phenylphenol was unreactive under aqueous conditions with only low yields of deoxygenated products observed.