Preparation method of 5-aminobenzimidazole

A technology of aminobenzimidazole and nitrobenzimidazolone is applied in the field of preparation of 5-aminobenzimidazole, can solve the problems of troublesome post-processing, less equipment investment, large environmental pollution and the like, and achieves less side reactions and higher quality Good, high-yield effect

Inactive Publication Date: 2011-04-06
张家港市蓝迪森新材料科技有限公司
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  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

The iron powder used in the iron powder hydrochloric acid reduction process is low in price, low in equipment investment, and mature in technology. It is the main method used in industry at present, but a large amount of iron sludge is generated during the reaction process, and post-processing is more troublesome, which causes greater environmental pollution.
Hydrazine hydrate reduction process has mild reaction conditions, high reduction yield, no waste gas and waste residue, but it is only suitable for small batch production

Method used

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  • Preparation method of 5-aminobenzimidazole
  • Preparation method of 5-aminobenzimidazole
  • Preparation method of 5-aminobenzimidazole

Examples

Experimental program
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Effect test

Embodiment 1

[0020] 1) Synthesis of 2,4-dinitroaniline:

[0021] In the autoclave, add 2,4-dinitrochlorobenzene (50.5g, 0.25mol), chlorobenzene (25mL) and 25-28wt.% ammonia water (50g), seal it, heat it to 145-150°C, and keep the temperature React at 145-150°C, 0.8-1.0Mpa for 1.5h, cool to room temperature, filter with suction, wash the filter cake with chlorobenzene (20mL) and water (50mL), recrystallize with ethanol, and dry to constant weight;

[0022] 2) Synthesis of 4-nitro-1,2-phenylenediamine:

[0023] In the reactor, add 2,4-dinitroaniline (42.1g, 0.23mol) and 35vol.% ethanol aqueous solution (500mL), stir, and heat to 65~70°C; at the same time, sodium sulfide nonahydrate (138.1g , 0.575mol) was dissolved in hot water (500mL) at 60°C, sodium bicarbonate (48.3g, 0.575mol) was added into the sodium sulfide solution and stirred to dissolve to obtain a mixed solution of sodium sulfide and sodium bicarbonate; sodium sulfide and Add the mixed solution of sodium bicarbonate dropwise int...

Embodiment 2

[0029] 1) Synthesis of 2,4-dinitroaniline:

[0030] In the autoclave, add 2,4-dinitrochlorobenzene (135.7g, 0.67mol), chlorobenzene (70mL) and 25-28wt.% ammonia water (400g), seal, heat to 150 ° C, and keep this temperature, 0.8~1.0Mpa, react for 1.5h, cool to room temperature, filter with suction, wash the filter cake with chlorobenzene (50mL) and water (50mL×2), recrystallize with ethanol, and dry to constant weight;

[0031] 2) Synthesis of 4-nitro-1,2-phenylenediamine:

[0032] In the reactor, add 2,4-dinitroaniline (115.4g, 0.63mol) and 50vol.% ethanol aqueous solution (1200mL), stir, and heat to 70°C; mol) was dissolved in water (3000mL) at 60°C, sodium bicarbonate (158.8g, 1.89mol) was added into the sodium sulfide solution and stirred to dissolve to obtain a mixed solution of sodium sulfide and sodium bicarbonate; sodium sulfide and sodium bicarbonate The mixed solution was added dropwise into the reactor, reacted at 65°C for 1h, cooled, diluted with water, filtered ...

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Abstract

The invention discloses a preparation method of 5-aminobenzimidazole, which comprises the following steps: 1) synthesis of 2,4-dinitroaniline; 2) synthesis of 4-nitro-1,2-phenylenediamine; 3) synthesis of 5-nitro benzimidazolone; and 4) hydrogenation reduction of the 5-nitro benzimidazolone. The preparation method of the 5-nitro benzimidazolone is a catalytic hydrogenation reducing process which has completed reaction and less side reaction, does not have pollution on the environment, and the product generated by the method has high quality and high yield, and is suitable for industrialized production.

Description

technical field [0001] The invention belongs to the field of organic synthesis, and in particular relates to a preparation method of 5-aminobenzimidazole. Background technique [0002] Benzimidazolone organic pigments belong to azo pigments in chemical classification, but their application performance and fastness are not comparable to other azo pigments. Benzimidazolone organic pigments get their name from the 5-amidobenzimidazolone group in the molecule. [0003] The benzimidazolone structure of the cyclic amido group (-NHCONH-) in the pigment molecule increases the polarity of the molecule and can form hydrogen bonds, which changes the aggregation state of the molecule, making the pigment have a higher melting point and can significantly reduce The solubility in the solvent makes the pigment have light fastness, weather fastness, solvent resistance, migration resistance and heat resistance stability. Because the color of benzimidazolone organic pigments is very strong, ...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C07D235/26
Inventor 钱建平
Owner 张家港市蓝迪森新材料科技有限公司
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