A Review of Oxidation of Aromatic Compounds

Abstract

Although the detailed oxidation chemistry of carbon monoxide, hydrogen and methane is understood, present understanding of the high temperature oxidation of more realistic fuels and fuels derived from the conversion of coal and other fossil forms is very limited. Studies are currently underway to elucidate oxidation mechanisms of the higher order aliphatics and olefins. However, less research is directed towards evaluating the detailed oxidation mechanisms of the aromatics. Fuels derived from coal and other fossil fuels characteristically have aromatic contents which vary from about 35 to 85 percent. Although under laboratory controlled conditions it should be possible to burn these fuels with respectable combustion efficiencies, it must be recognized that aromatics are notorious for soot and coke formation. Sooting can cause operational difficulties by increasing flame radiation to surfaces which must remain cool, as well as by coating surfaces and thus reducing overall heat transfer rates. Further, although it is expected that complex compounds can be formed during the oxidation of the aromatics, it is not known explicitly which compounds are formed, whether they can survive in cool zones of an actual combustion process, or whether they will be environmentally acceptable. As well as providing an extension of an earlier review (Minkoff and Tipper, 1962), the present communication is intended as a brief review of aromatic oxidation to aid researchers interested in the combustion problem posed by these compounds.