| 摘要 |
- 9 - HOE 89/F 249 of the disclosure Process for the preparation of 2,6-dichloroquinoxaline A process for the preparation of 2,6-dichloroquinoxaline by hydrogenating 6-chloro-2-hydroxyquinoxaline-N-oxide in aqueous sodium hydroxide solution in the presence of about 0.001 to about 0.5 mol percent of a platinum shell catalyst, relative to 6-chloro-2-hydroxyquinoxaline-N-oxide employed, at temperatures of about 20 to about 120.degree.C at a hydrogen pressure of about 1 to about 100 bar, about 1 to about 3 equivalents of sodium hydroxide, relative to 6-chloro-2-hydroxyquinoxaline-N-oxide employed, being added, and after separating off the catalyst from the hot solution depositing the 6-chloro-2-hydroxyquinoxaline dissolved therein in the form of the sodium salt as crystals by cooling the reaction solution to a temperature of about 0 to about 20.degree.C, drying azaotropically with an inert solvent and chlorinating using a chlorinating agent in a customary manner to give 2,6dichloroquinoxaline.
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