| 摘要 |
These known substances are obtained by catalytic hydrogenation of the corresponding dinitronaphthalenes. While it was previously necessary to employ pure dinitro compounds because the technical-grade crude products are only hydrogenated slowly and incompletely, it is now possible to prepare them starting from crude dinitro compounds. These compounds are first treated with water or an aqueous solution with an alkaline reaction, if appropriate with addition of a solvent which is not miscible with water, such as benzene, naphthalene or halohydrocarbons, at a temperature between 0 DEG C and the boiling point of the mixture, the aqueous, or aqueous/organic, solvent phase is then separated off, and the product is subjected to conventional catalytic hydrogenation. |
