Crystallise the pale green p-dimethylaminobenzophenone from EtOH. Dissolve 100g in 600mL of boiling EtOH, add 5g of charcoal, cool, isolate the solid by centrifugation and similarly wash the pale crystals with ice-cold EtOH. When filtered by suction, EtOH solution remains on the crystals and turns deep green in air. Dry it in a vacuum and store it in the dark. The hydrazone has m 128-130o and forms a ketyl with potassium. [Hurd & Webb Org Synth Coll Vol I 217 1941, Beilstein 14 H 82, 14 I 288, 14 III 218, 14 IV 248.]
