Mononitration of p-Cymene

Mononitration of p-Cymene

“…Emulsification of the cymene was a factor of considerable importance. Kobe and Doumani (16,17) indicated that technical grade /?-cymene exhibited advantages in emulsion formation, over purified cymene, in agreement with Demonbreun and Kremers (5). The relative ease of nitration of other aromatics suggests either that they are more easily emulsified or that their reactions proceed smoothly regardless of the nature of the emulsion formed.…”

SIMULTANEOUS NITRATION AND PARTIAL DEALKYLATION OF p-CYMENE1

“…p-Cymene (500 g.) of b.p. 174.0-178.0°obtained from sulfite turpentine was nitrated according to our recommended conditions (1,15).…”

Anomalous Nitration Reactions.

“…The isopropyl group can be replaced with a nitro group or it can be oxidized to an acetyl group or to a carboxyl group, along with nuclear nitration. The nitration of p-cymene has been extensively studied in an effort to minimize side reactions and to improve the yield and purity of the 2-nitroand 2,6-dinitro-p-cymenes2 (1,43).…”

“…Since the isopropyl group is easily oxidized, it is not surprising that methyl p-tolyl ketone, p-toluic acid, 2-nitro-p-toluic acid, and 2,6-dinitro-p-toluic acid have been reported as by-products of the nitration of p-cymene. p-Nitrotoluene and 2,4-dinitrotoluene are the principal impurities in the 2-nitroand 2,6-dinitrocymene fractions, even when the nitration is carefully carried out at low temperatures (1,43,87).…”

“…the product is mainly mono-or dinitrocymene with varying amounts of p-nitrotoluene and 2,4-djnitrotoluene. Kobi and Doumani (43) report 90 per cent yields of mononitrocymene containing 8 per cent of p-nitrotoluene by carrying out the nitration at -10°C. with a mixture of glacial acetic acid, nitric acid, and sulfuric acid.…”