Production method and application of nitroso-sulfuric acid

Abstract

The invention provides a production method of nitroso-sulfuric acid, comprising the following steps: a, heating and dehydrating waste acid produced by diazotization deamination so as to obtain concentrated waste acid, and supplementing concentrated sulfuric acid to prepare mixed acid; b, introducing a gas mixture of exhaust gas produced by a nitrobenzene compound chloro-nitro reaction and the air into a mixed acid spray tower for absorption, detecting nitroso-sulfuric acid prepared in the spray tower and directly pumping qualified nitroso-sulfuric acid into a storage tank of nitroso-sulfuric acid; c, preparing a sodium hydroxide aqueous solution, absorbing tail gas which is not completely absorbed through the spray tower for the preparation of sodium nitrate and sodium chloride; d, adding nitric acid into the tail gas absorption liquid after tail gas absorption until pH of the solution is acidic, regulating pH to neutral level by the use of sodium hydroxide, heating and concentrating the absorption liquid, cooling for crystallization, precipitating out sodium nitrate solid, and continuously carrying out evaporative crystallization to obtain sodium chloride solid. The nitroso-sulfuric acid can be used as a diazotization reagent for the diazotization reaction of weak-base amine containing electron-withdrawing group and heterocyclic amine. The technology has advantages of reasonable design, low energy consumption and simple operation control.

Description

technical field [0001] The invention relates to the field of chemical production, in particular to a production method and application of phosphoric acid-containing nitrosyl sulfuric acid. Background technique [0002] Diazotization is an important reaction unit in organic synthesis, and sodium nitrite is a commonly used raw material for diazotization reaction. When there is an electron-withdrawing group on the benzene ring, the activity of the amino group is reduced, and a diazotization raw material with higher activity, nitrosylsulfuric acid, is needed. Compared with sodium nitrite, as a diazotization agent, nitrosyl sulfuric acid will not generate sodium sulfate salt during diazotization reaction, which is convenient for the concentrated recovery of dilute sulfuric acid in the subsequent process. [0003] Nitrosylsulfuric acid is a very unstable compound and usually needs to be dissolved in a certain concentration of sulfuric acid for safe storage and transportation. ...

AI Technical Summary

Problems solved by technology

The method is to firstly oxidize ammonia into nitrogen oxide gas, and then react with oleum in a concentrated sulfuric acid system to obtain nitrosyl sulfuric acid. This method requires a high level of production technology and is fully automated. Large production capacity, tail gas treatment is also relatively simple, the content of the obtained product nitrosyl sulfuric acid can reach more than 70%, but the production of nitrosyl sulfuric acid by direct absorption method is currently only available when the absorption pressure is 0.3MPa, and the use of sieve plate absorption Nitrosyl sulfuric acid is produced by tower absorption reaction. This technology is imported from abroad. There are problems such as difficult operation and adjustment, high energy consumption and unsatisfactory treatment of environmentally friendly nitrogen oxide gas.

[0008] In my country's industrial production, a large amount of industrial waste acid and industrial waste gas can be produced every year, especially the waste acid produced by diazotization deamination and the waste gas produced by the reaction of nitrobenzene compounds with chlorinated nitro groups. Among them, diazotization deamination The waste acid produced by the base mainly contains sulfuric acid, phosphoric acid and sodium bisulfate. This kind of industrial waste acid has a high acidity and is difficult to handle and utilize. The discharge of this industrial waste acid will cause environmental pollution and waste of resources.

The exhaust gas produced by the chlorinated nitro reaction of nitrobenzene compounds mainly contains nitrogen oxides and chlorine gas. Nitrogen oxides are one of the main pollutants in the atmosphere. Chlorine gas is extremely harmful to plants and is easy to form hydrochloric acid in contact with humid air. Smoke, hydrochloric acid fume contains irritating odor, this kind of waste gas is difficult to treat and utilize