The formation of olefins and alkynes from the reaction of hydroxyl radical and carbonaceous material

Abstract

Using model systems and laser photolysis techniques, we have examined the mechanism of interaction of hydroxyl radicals with carbonaceous materials. The formation of ppb-level concentrations of methane, ethylene, acetylene, and propylene (prop-1-ene) was observed from interaction of ArF laser-generated hydroxyl radicals with activated carbon pellets in the temperature range of 200–500 °C. A maximum in the formation of olefins and acetylene is observed at 430–450 °C. A mechanism involving surface epoxide formation is postulated. These results support earlier hypotheses regarding the role of combustion generated hydroxyl radicals and light hydrocarbons in the catalytic formation of polychlorinated dibenzo-p-dioxins and -furans (PCDD/F) by the so-called “fast”de novo and extended precursor mechanisms.