The Structure of Hexane Soot I: Spectroscopic Studies

Soot produced from the combustion of fossil fuels, widely distributed in the atmosphere, is significantly different from most carbons for which the surface structure and/or reactivity have been studied. The composition and surface structure of soot derived from the combustion of n-hexane have been examined by FT-IR, Raman, U C CP/MAS NMR, and EPR spectroscopies as well as through desorption measurements. Carbon-oxygen functionalities on the fresh carbon surface include acid anhydride, a carbonyl conjugated with an aromatic segment, an alkyl-ketone, and aryl ether linkages. Also present, confirmed by isotopic substitution, is a quantity of unsaturated C-H, dependent upon the combustion conditions. The degree of aromaticity and the graphitic nature of this soot have been determined.