Nitration by nitrogen dioxide

In a solution containing oxygen, photolysis yields a mixture of 6,12-, 1,6-, and 3,6-diones. Nitration by nitrogen dioxide forms 6-nitro-, 1-nitro-, and 3-nitrobenzo[a]pyrene. When benzo [a] pyrene in methanol (1 g/L) was irradiated at 254 nm in a quartz flask for 1 h, the solution turned pale yellow. After 2 h, the solution turned yellow and back to clear after 4 h of irradiation. After 4 h, 99.67% of benzo[a]pyrene was converted to polar compounds. One of these compounds was identified as a methoxylated benzo[a]pyrene (Lu et al, 1977). A carbon dioxide yield of 26.5% was achieved when benzo [a] pyrene adsorbed on silica gel was irradiated with light (A, >290 nm) for 17 h (Freitag et al, 1985). 

For aliphatic hydrocarbons in the medium range (7-12 carbon atoms), which are not satisfactorily amenable to either the Hass or the Grundmann method, Geiseler154 has described a process of nitration by nitrogen dioxide under pressure, for which the overall reaction is ... 

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