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Method for preparing benzimidazolone

A technology of benzimidazolone and o-phenylenediamine, which is applied in the field of chemical intermediate preparation, can solve the problems of high risk of pressurization process, large human injury, complicated waste liquid in the process, etc., and achieves easy absorption and utilization and material cost saving. , the effect of reducing side effects

Inactive Publication Date: 2018-04-20
SHANDONG HUIHAI PHARMA & CHEM
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0008] 1. Phosgene is highly dangerous, and the reaction by-product hydrogen chloride seriously corrodes equipment and is not suitable for industrial production;
[0009] 2. The organic solvents used are harmful to the human body, and the process is complicated and accompanied by a large amount of waste liquid;
[0010] 3. Water is used as a solvent to pressurize or adjust acid. The pressurized process is dangerous and the yield is slightly low. A large amount of inorganic salts are produced in acid adjustment, and the reaction is unstable, resulting in unstable product yield and quality.

Method used

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  • Method for preparing benzimidazolone

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0025] In a 1000ml three-necked flask equipped with electric stirring, reflux condenser and thermometer, add 100g of urea, 100g of o-phenylenediamine, 200g of water and 10g of alkaline solvent, the pH value is 11, start the stirring and continue to heat up to 105°C, and keep the reaction temperature React for 4 hours. After the reaction, 100 g of water was distilled, cooled to room temperature, filtered, washed with water, and dried to obtain a white product with a yield of 99.6% and a purity of 99.5%. The mother liquor is recycled mechanically, and the product yield and the purity obtained after applying mechanically 4 times are as follows:

[0026] Apply times

[0027] As can be seen from the above table, the application of mother liquor has little impact on the purity and yield of the product. The solvent can be directly applied multiple times.

Embodiment 2

[0029] In a 1000ml three-neck flask equipped with electric stirring, reflux condenser and thermometer, add 130g of urea, 100g of o-phenylenediamine, 300g of water and 6g of alkaline solvent. React for 8 hours. After the reaction was completed, 210 g of water was distilled, cooled to room temperature, filtered, washed with water, and dried to obtain a white product with a yield of 99.3% and a purity of 99.4%.

Embodiment 3

[0031] In a 1000ml three-necked flask equipped with electric stirring, reflux condenser and thermometer, add 120g of urea, 100g of o-phenylenediamine, 100g of water and 7g of alkaline solvent, the pH value is 10, start the stirring and continue to heat up to 100°C, and keep the reaction temperature React for 10 hours. After the reaction was completed, 30 g of water was distilled, cooled to room temperature, filtered, washed with water, and dried to obtain a white product with a yield of 99.2% and a purity of 99.5%.

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Abstract

The invention relates to a method for preparing benzimidazolone. The method comprises the following steps: carrying out cyclization reaction on o-phenylenediamine and urea under the alkaline condition; after the reaction is ended, distilling out part of solvent, then cooling to room temperature, filtering and drying to obtain the benzimidazolone; mechanically applying a reaction mother solution. According to the method disclosed by the invention, by using the urea as a cyclizing agent, a generated byproduct is easy to absorb and utilize and no wastewater is generated; reaction materials are sufficiently mixed in a homogeneous phase reaction system; reaction temperature is constant and reaction is easy to control; solvent water is mechanically applied for multiple times, so that green synthesis is realized, the yield of a product reaches 99 percent and the purity reaches 99.0 percent.

Description

technical field [0001] The invention belongs to the field of preparation of chemical intermediates, in particular to a method for preparing benzimidazolone. Background technique [0002] Benzimidazolone is an important organic intermediate, especially used in the fields of medicine, pigment and pesticide. [0003] J.Am.Chem.Soc.80,1657 (1958) discloses a method for preparing benzimidazolone by reacting o-phenylenediamine and phosgene. However, the phosgene used in this method is highly dangerous, and the by-product hydrogen chloride generated by the reaction is highly corrosive to equipment. [0004] In US-4138568, o-phenylenediamine compounds react with urea and urea derivatives in a water-insoluble organic solvent at a temperature of 100°C to 200°C to obtain benzimidazolone, and then undergo a complicated purification process, solvent consumption Large, producing a large amount of waste liquid. [0005] In DE2052026, water is used as the reaction medium, o-phenylenediam...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C07D235/26
CPCC07D235/26
Inventor 李华振侯利国李保铃殷福东孙蒂王磊
Owner SHANDONG HUIHAI PHARMA & CHEM
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