NEWLY IDENTIFIED PRODUCTS OF BENZENE DROPLET COMBUSTION: POLYCYCLIC AROMATIC HYDROCARBONS OF THREE TO TEN RINGS

Abstract

In order to investigate further the polycyclic aromatic hydrocarbons (PAH) produced by benzene droplet combustion, we have obtained and analyzed a highly-concentrated benzene droplet combustion sample, using high pressure liquid chromatography (HPLC) with diode-array ultraviolet-visible (UV) absorbance spectroscopy. In addition to benzo[k]fluoranthene, we have identified ten large (5- to 10-ring) PAH never before reported as products of benzene pyrolysis or combustion: dibenz[a,c]anthracene, indeno[1,2,3-cd]fluoranthene, anthanthrene, cyclopenta[cd]benzo[ghi]perylene, coronene, dibenzo[a,i]pyrene, cyclopenta[bc]coronene, benzo[a]coronene, naphtho[8,1,2-abc]coronene, and ovalene. In this sample we have also identified three smaller PAH, benz[f]indene, 2-ethynylanthracene, and benzo[c]phenanthrene, never before reported as products of benzene pyrolysis or combustion. In order to document the unequivocal identification of these compounds as benzene droplet combustion products, we present the UV absorbance spectrum of each newly identified benzene product, along with the matching UV spectrum of the respective PAH reference standard. Several of the identifications have required the acquisition of specially synthesized reference standards. Combined with our previous results, the present findings show that 50 individual PAH (and related compounds), of up to 10 rings in size, are produced during benzene droplet combustion.