20039-23-0Relevant articles and documents
Electrophilic Aromatic Substitution. Part 33. Kinetics and Products of Aromatic Nitrations in Solutions of Dinitrogen Pentaoxide in Nitric Acid
Moodie, Roy B.,Stephens, R. John
, p. 1059 - 1064 (2007/10/02)
The kinetics and/or products of reaction, in nitric acid containing 0-5 mol dm-3 of dinitrogen pentaoxide, of phenyltrimethylammonium perchlorate, 1,2-dichloro-4-nitrobenzene, 2,4-dinitrotoluene, 1,4-dichloro-2-nitrobenzene, 1,2,4-trichloro-5-nitrobenzene, 1,2,4,5-tetrachlorobenzene, pentachlorobenzene, 1,2,3-trichlorobenzene, 1,3,5-trichloro-2-nitrobenzene, 1,2-dichloro-3-nitrobenzene, 1,2,3,4-tetrachlorobenzene, and 1,3-dichloro-2-nitrobenzene, have been studied.For each substrate investigated kinetically, rate coefficients for nitration in solutions containing more than ca. 2 mol dm-3 dinitrogen pentaoxide increase more quickly than the concentration of nitronium ion.In the cases of 1,2,4,5-tetrachlorobenzene, 1,4-dichloro-2-nitrobenzene, and 1,2,4-trichloro-5-nitrobenzene, but not with the other substrates, there was evidence for the formation of, in addition to expected aromatic nitroproducts, unstable cyclohexadiene products.Those from 1,2,4-trichloro-5-nitrobenzene were identified as a diastereomeric pair of 3,5,6-trichloro-2,4-dinitrocyclohexa-2,5-dienyl nitrates.A mechanism for the formation of these products is proposed.
