Biacetyl, atmosphere

Photolytic. Major products reported from the photooxidation of butane with nitrogen oxides under atmospheric conditions were acetaldehyde, formaldehyde, and 2-butanone. Minor products included peroxyacyl nitrates and methyl, ethyl and propyl nitrates, carbon monoxide, and carbon dioxide. Biacetyl, tert-butyl nitrate, ethanol, and acetone were reported as trace products (Altshuller, 1983 Bufalini et al, 1971). The amount of sec-butyl nitrate formed was about twice that of n-butyl nitrate. 2-Butanone was the major photooxidation product with a yield of 37% (Evmorfopoulos and Glavas, 1998). Irradiation of butane in the presence of chlorine yielded carbon monoxide, carbon dioxide, hydroperoxides, peroxyacid, and other carbonyl compounds (Hanst and Gay, 1983). Nitrous acid vapor and butane in a smog chamber were irradiated with UV light. Major oxidation products identified included 2-butanone, acetaldehyde, and butanal. Minor products included peroxyacetyl nitrate, methyl nitrate, and unidentified compounds (Cox et al., 1981). 

Usually collection of about 200-300 ml. of distillate is sufficient. The distillate is extracted with two 100-ml. portions of ether, and the extracts are combined with the dimethylfurazan obtained by direct distillation (Note 4). The ether solution is dried for a short time over anhydrous magnesium sulfate. The drying agent is removed by filtration, and the ether is evaporated on a steam bath. The residue is distilled at atmospheric pressure through a short column, and after a fore-run, consisting chiefly of biacetyl, the dimethylfurazan distils at 154-159° as a colorless liquid, 1.4234-1.4243, m.p. —7.2 to —6.6°. The yield is 59-63 g. (60-64%). 

Not as much work has been reported on atmospheric ketone concentrations. Acetone was present at 0.001 ppm in the air at Point Barrow, Alaska (Cavanagh et al., 1969) and also, at half that concentration or less, in air over the Atlantic (Penkett, 1982 Zhou and Mopper, 1990) it is also present at higher elevations (Arnold et al., 1986). Phenyl and higher cyclic ketones, a few Cg-Cig aliphatic ketones, butanone, biacetyl and 4-methyl-2-pentanone have also been identified in ambient air (Kawamura and Kaplan, 1983 Ramdahl, 1983 Zhou and Mopper,... 

Biacetyl is a major product of the atmospheric oxidation of many aromatic compounds, e.g., toluene, o-xylene, 1,2,3- and 1,2,4-trimethylbenzene. Its photochemistry is of interest to atmospheric scientists since it is a likely source of free radicals within the troposphere. The absorption of biacetyl extends well into the visible region of the sunlight see figure IX-F-14. The analysis of the absorption bands of biacetyl have been studied and rationalized theoretically (e.g., see Brand and Mau, 1974) Huang et al., 2005). The photochemistry of biacetyl in the absence of oxygen has been the subject of numerous studies since the early 1940s (e.g., see Henriques and Noyes, 1940 Roof and Blacet, 1941 Anderson and RoUefson, 1941 Blacet and Bell, 1953 Bell and Blacet, 1954 Sheats and Noyes, 1955a, b Ausloos and Steacie, 1955 Okabe and Noyes, 1957 Heicklen, 1959 Noyes et al., 1962 Parmenter and Poland, 1969 Caro et al., 1969 Abuin et al., 1971 Horowitz and Calvert, 1972 Sidebottom et al.. 

Several experiments have been made that relate more directly to photodecomposition of biacetyl in the atmosphere (Taylor and Blacet, 1956b Padnos and Noyes, 1964 ... 

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