FLY-ASH MEDIATED REACTIONS OF PHENOL AND MONOCHLOROPHENOLS - OXYCHLORINATION, DEEP OXIDATION, AND CONDENSATION

Monochlorophenols are smoothly oxidized to carbon dioxide and carbon m onoxide when vapors in air are passed over fixed beds of municipal was te incinerator fly ash at 625-725 K. Simultaneously polychlorinated be nzenes, monobenzofurans, and dibenzo-p-dioxins are formed with a large fraction of the original chlorine concentrated in these products. Fly ash catalyzed oxychlorination of phenol in the presence of HCl at 425 -725 K resulted in the formation of chlorinated phenols which, in turn , were converted above 625 K into mainly CO2 and the (poly)chloroarene s mentioned above. In contrast, under similar conditions, (chlorinated ) benzenes are inert. Deep oxidation and oxychlorination of phenol hav e also been studied using an oxidation catalyst (CuO on alumina) or a commercial oxychlorination catalyst (basically, CuCl2 on alumina). Res ults were comparable but, in neither case, chlorinated dibenzo-p-dioxi ns were detected. Kinetic data are presented and analyzed, and reactio n mechanisms and the practical relevance of our results are discussed.