| 摘要 |
Quinacridones optionally bearing 1 or 2 halogen, C1- 3 alkyl or C1- 3 alkoxy substituents are made by oxidizing the corresponding dihydroquinacridone or its halogen, alkyl and alkoxy derivatives of general formula <FORM:1091027/C2/1> where X is halogen, lower alkyl or lower alkoxy radical of up to 3 carbon atoms and n is 0 to 2 by the following steps: (a) heating the dihydroquinacridone or its derivative to an elevated temperature with a mixture of a strong alkali, water and tetramethylene sulphone, dimethyl sulphoxide, N-methyl pyrrolidine or the monobutyl ether of diethylene glycol, (b) introducing into the solution less than the stoichiometric quantity of a polycyclic quinone compound such as 2-chloroanthraquinone, (c) blowing a gas containing elemental oxygen such as air, through the reaction mixture, (d) subsequently diluting the mixture with water suitably by rapid addition of the reaction mixture to a large volume of cold water with prolonged stirring to yield a less stable b -crystal phase or by slow addition of water to the hot reaction mixture with continued heating to yield the most stable g -crystal phase, and (e) recovering the quinacridone from the reaction mixture. |
