反应详情

5.00 kg of this dinitroanthraquinone mixture (consisting of 41.2% of 1,5-dinitroanthraquinone, 39.6% of 1,8-dinitroanthraquinone, 8.9% of 1,6-dinitroanthraquinone and 9.5% of 1,7-dinitroanthraquinone) together with 49.04 kg of 97 percent strength by weight nitric acid (molar ratio 45) continuously flow, per hour, onto the fourth tray of a 5-tray rectifying column at about 55° C. 29.65 kg/hour of 99 percent strength by weight nitric acid is taken off at the head of the column at a reflux ratio of reflux/take-off of 0.4. The column is operated under a head pressure of 200 mm Hg, a head temperature of about 50° C. being set up. 19.29 kg/hour of 70 percent strength by weight nitric acid are continuously added to the sump of the column at a temperature of about 70° C. The dinitro-anthraquinone mixture to be crystallised, in which the molar ratio of nitric acid to organic products is 30:1 and the nitric acid concentration is 82 percent by weight (weight ratio 7.7), is removed at the sump of the column at a temperature of about 70° C. 3.8 kg per hour of a dinitroanthraquinone mixture having a composition of 53.2% of 1,5-dinitroanthraquinone, 44.6% of 1,8-dinitroanthraquinone, 0.3% of 1,6-dinitroanthraquinone and 1.8% of 1,7-dinitroanthraquinone is isolated from the mixture thus obtained, by cooling to room temperature (25° to 30° C.), separating off by filtration the solid which has precipitated and then drying it.

1. customat about 55° C
2. customa head temperature of about 50° C.
3. customThe dinitro-anthraquinone mixture to be crystallised, in which the molar ratio of nitric acid to organic products
4. customthe nitric acid concentration is 82 percent by weight (weight ratio 7.7), is removed at the sump of the column at a temperature of about 70° C