Abrégé

The present invention discloses a continuous-flow clean production process for pyrazolone series products, comprising reacting an aromatic amine with an aqueous sulfuric acid solution for 0.5-2 h to obtain an aromatic amine sulfate solution; simultaneously introducing the aromatic amine sulfate solution and a sodium nitrite into a pre-mixer solution for mixing, and then introducing the mixture into a continuous flow reactor for a diazotization reaction; adding the generated diazonium salt to an aqueous ammonium sulfite solution and an aqueous ammonium hydrogen sulfite solution in sequence for a reduction reaction; upon completion of the reduction reaction, adding a sulfuric acid solution for a hydrolyzation reaction at 70-120°C; carrying out neutralization after the hydrolyzation reaction, the pH being controlled between 2 and 5, and then carrying out a condensation reaction with diethylamine at 40-70°C for 1-3 h, cooling the solution to 10-40°C, followed by filtration and drying to give a pyrazolone product; and subjecting the mother liquor to extraction with a solvent or decolorization with activated carbon, followed by concentration by evaporation, gradient cooling at stages, and separation by crystallization, to give ammonium sulfate and sodium sulfate. The present invention has fewer side reactions, a high diazotization yield, and is capable of producing a series of products.

Classes IPC  ?

• C07D 231/26 - Phényl-1 méthyl-3 pyrazolones-5, non substituées ou substituées sur le cycle phényle
• C01C 1/24 - Sulfates d'ammonium
• C01D 5/00 - Sulfates ou sulfites de sodium, de potassium ou des métaux alcalins en général

Abrégé

A process for treating process wastewater produced in a production process of pyrazolone series products. The production process of the pyrazolone series products comprises steps of diazotization, reduction, hydrolysis, and condensation, an acid used in the diazotization process being a sulfuric acid solution. The process comprises: performing pre-treatment on process wastewater produced in the production process of pyrazolone series products using one or both of the following methods of decolorization with activated carbon or continuous extraction with an organic solvent, such that a COD is decreased; heating and evaporating a separated mother liquor obtained after the pre-treatment, cooling the residue to 40-80°C, and carrying out separation by crystallization to obtain ammonium sulfate meeting agricultural grade standards and a filtrate; adding a basic compound of sodium to the filtrate separated in the previous step, adjusting a pH value of the mixture, heating the mixture, cooling the residue to 0-40°C and carrying out separation by crystallization to give a sodium sulfate by-product. The process uses sulfuric acid instead of hydrochloric acid as a diazotized strong acid medium to treat process wastewater containing sodium sulfate and ammonium sulfate salts, such that the by-product produced after treatment is up to standard. The invention produces no salt-containing solid waste and achieves proper utilization of resources.

Classes IPC  ?

• C02F 9/10 - Traitement thermique
• C01C 1/24 - Sulfates d'ammonium
• C01D 5/00 - Sulfates ou sulfites de sodium, de potassium ou des métaux alcalins en général