| abstract |
The present invention relates to a process for the preparation of nitro-armstrong acid, which is characterized in that naphthalene is sulfonated in a reaction-poor organic solvent with liquid sulfur trioxide, the reaction mixture obtained is a mixture consisting of approximately equal parts of 100% sulfuric acid and fully reacted crude Nitriding mass from the nitration of a previous batch of nitration is added, resulting in a two-phase system, from which the upper organic solvent phase is decanted and the rest of the remaining organic solvent is removed from the AS-AN acid slurry by distillation, after which the residue for nitriding the required amount of nitric acid is added at a temperature between 10 and 60 ° C. and the resulting 3-nitronaphthalene-1,5-disulfonic acid is isolated by precipitation and filtration. |