Production process of 5-acetyl acetamino benzimidazolone

Abstract

The invention relates to a technology for producing 5-acetyl amido benzimidazolone. The condensation process is as follows: o-phenylendiamine, carbamide, water and concentrated sulfuric acid are added into a condensation reaction kettle step by step, the pH value is controlled to between 6 and 7, and benzimidazolone is obtained by drying the mixture; the nitration process is as follows: the benzimidazolone, chlorinated benzene and concentrated sulfuric acid are added into a nitration reaction kettle, the chlorinated benzene is reclaimed and purified by reduced pressure distillation and water boiling, and 5-nitryl benzimidazolone is obtained by drying the mixture; the reduction process is as follows: the 5-nitryl benzimidazolone, iron powder, hydrochloric acid and water are added into a reduction reaction kettle, the mixture is subject to suction filtering, cooling, crystallization and drying after the reaction for producing the 5-amino benzimidazolone; and the acetylization process is as follows: the 5- amino benzimidazolone, Diketene, phosphoric acid, caustic soda liquid and water are added into an acetylization kettle, the pressure inside the kettle is discharged in the temperature rising process, and the mixture is subject to suction filtering and drying to produce the 5-acetyl amido benzimidazolone. The process has the total yield coefficient up to 75 percent, purity quotient more than 99 percent and the product quality which meets the international standards of the same products at home and abroad.

Description

Production process of 5-acetoacetamidobenzimidazolone technical field The invention relates to a production process of chemical intermediate products, in particular to a production process of 5-acetoacetamido benzimidazolone. Background technique 5-Acetoacetamidobenzimidazolone (AABI) is an important chemical intermediate in medicine and pesticide. It is widely used in the field of dyeing pigments and special material synthesis, and is the key intermediate for the synthesis of high-performance pigment varieties - benzimidazolone series. The current production of 5-acetoacetamidobenzimidazolone (AABI for short) is made from o-phenylenediamine and urea through condensation, nitration, reduction and acetylation. This process mainly has the following problems. First, the nitration process does not have the recovery of chlorobenzene and boiling purification, which affects the product output efficiency; secondly, the reduction process adopts the conventional discharge mode wit...

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Problems solved by technology

This process mainly has the following problems. First, the nitration process does not have the recovery of chlorobenzene and boiling purification, which affects the product output efficiency; secondly, the reduction process adopts the conventional discharge mode with low production efficiency; finally, the acetylation process is due to The sealing performance of the reaction kettle is excellent, and the pressure generated during the reaction cannot be discharged, resulting in a high pressure in the reaction kettle, which makes the reaction difficult to control and has a low safety factor.