CN113149911A - Preparation method of high-purity 5-aminobenzimidazole ketone - Google Patents
Preparation method of high-purity 5-aminobenzimidazole ketone Download PDFInfo
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- C07D235/00—Heterocyclic compounds containing 1,3-diazole or hydrogenated 1,3-diazole rings, condensed with other rings
- C07D235/02—Heterocyclic compounds containing 1,3-diazole or hydrogenated 1,3-diazole rings, condensed with other rings condensed with carbocyclic rings or ring systems
- C07D235/04—Benzimidazoles; Hydrogenated benzimidazoles
- C07D235/24—Benzimidazoles; Hydrogenated benzimidazoles with hetero atoms or with carbon atoms having three bonds to hetero atoms with at the most one bond to halogen, e.g. ester or nitrile radicals, directly attached in position 2
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Abstract
The invention discloses a preparation method of high-purity 5-aminobenzimidazole ketone, relating to the technical field of 5-aminobenzimidazole ketone synthesis and comprising the following steps: 1) preparing a mixture of 5-nitrobenzimidazole ketone, a Pd/C catalyst and water; 2) adjusting the pH =8-9 of the mixture, conveying the mixture to a hydrogenation kettle, and performing continuous hydrogenation reaction at a hydrogenation temperature of 90-95 ℃ and a pressure of 0.2-0.4MPa after nitrogen replacement and hydrogen replacement; 3) after the hydrogenation is finished, the temperature is controlled at 120 ℃ under 115 ℃ and 0.8-0.9MPa, and the heat is continuously preserved for 1-2 h; 4) replacing the materials reacted in the step 3) with nitrogen, then pressing the filtrate obtained after solid-liquid separation of the materials into a closed crystallization kettle by using nitrogen, and reversely blowing the Pd/C catalyst into a batching kettle for repeated application after pressing; 5) cooling and separating out the materials in the crystallization kettle, and separating out mother liquor to enter a temporary storage tank; squeezing and air-blowing the filter cake to obtain a final product, namely 5-aminobenzimidazole ketone; the product produced by the method has few byproducts, high purity, high yield, almost no wastewater, environmental protection and energy conservation.
Description
Technical Field
The invention relates to the technical field of 5-aminobenzimidazole ketone synthesis, and particularly relates to a preparation method of high-purity 5-aminobenzimidazole ketone.
Background
The 5-aminobenzimidazole ketone is light yellow or white crystal, is prepared by deaminizing and cyclizing o-phenylenediamine and urea in a solvent phase at 140 ℃ and 150 ℃, is obtained by nitration and reduction, is mainly used for preparing yellow and orange organic pigments, and has wide application in the fields of medicine, pesticide, pigment and special material synthesis and the like.
At present, the method for producing 5-aminobenzimidazole ketone at home and abroad is mainly 5-nitrobenzimidazole ketone and is prepared by a Pd/C catalyst liquid phase catalytic reduction method, but the process has obvious defects, large amount of waste water and difficult application;
in view of this disadvantage, there is an urgent need for improvement of the conventional process.
Disclosure of Invention
The invention aims to provide a novel method for preparing environment-friendly 5-aminobenzimidazole ketone, which has the advantages of high product purity, high yield, almost no solid waste and cyclic mother liquor, and aims to overcome the defects in the prior art.
The technical scheme of the invention is as follows: a preparation method of high-purity 5-aminobenzimidazole ketone comprises the following steps:
1) preparing a mixture of 5-nitrobenzimidazole ketone, a Pd/C catalyst and water in a batching kettle;
2) adding an auxiliary agent into the mixture in the blending kettle in the step 1), adjusting the pH =8-9, conveying the mixture to a hydrogenation kettle, performing nitrogen replacement and hydrogen replacement, controlling the hydrogenation temperature at 90-95 ℃ and the pressure at 0.2-0.4MPa to perform continuous hydrogenation reaction, and stopping introducing hydrogen when the hydrogen is not consumed any more;
3) after the hydrogenation in the step 2) is finished, the temperature is controlled at 120 ℃ under 115 and 0.8-0.9MPa, and the temperature is kept for 1-2h to carry out deep hydrogenation reaction;
4) replacing the material reacted in the step 3) with nitrogen, then pressing the filtrate into a closed crystallization kettle after solid-liquid separation of the material by using 0.2-0.3Mpa nitrogen, and reversely blowing the Pd/C catalyst into a batching kettle for repeated application after pressing;
5) cooling and separating out materials in the crystallization kettle, separating by closed solid-liquid separation equipment, separating mother liquor, and recycling the mother liquor in a temporary storage tank; and squeezing and air-blowing the filter cake to obtain the final product 5-aminobenzimidazole ketone.
Further, the mass ratio of the 5-nitrobenzimidazole ketone, the Pd/C catalyst and the water in the mixture in the step 1) is 1 (0.02-0.03) to (12-16).
Further, the auxiliary agent in the step 2) is an ionic membrane caustic soda auxiliary agent.
Further, in the step 2), nitrogen gas replacement is carried out for 2-3 times, and hydrogen gas replacement is carried out for 2-3 times.
Further, the solid-liquid separation equipment in the step 4) is a titanium rod filter.
Further, the crystallization kettle and the temporary storage tank are sealed by nitrogen to isolate air.
Further, 0.5-1 per mill of antioxidant is added into the crystallization kettle in advance before material pressing in the step 4), and 0.5-1 per mill of antioxidant is added into the temporary storage tank in the step 5) in each batch.
Further, the antioxidant is hydrazine hydrate.
Compared with the prior art, the invention has the following advantages:
(1) the environment-friendly 5-aminobenzimidazole ketone preparation method provided by the invention has the advantages of few by-products, high purity, high yield, almost no wastewater generation, environmental protection and energy conservation;
(2) the appearance of the product produced by the method is white spherical crystals, the product appearance is good, the yield reaches more than 98%, and the product purity reaches more than 99%;
(3) the crystallization kettle and the mother liquor tank are sealed by nitrogen to isolate air, so that the materials are prevented from being oxidized and deteriorated; the invention adopts hydrazine hydrate to replace sodium bisulfite as an antioxidant so as to improve the stability of the 5-aminobenzimidazole ketone.
Detailed Description
In order to make the objects, technical solutions and advantages of the present invention more apparent, the present invention is further described in detail below with reference to the following embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the invention and are not intended to limit the invention.
Example one
A preparation method of high-purity 5-aminobenzimidazole ketone comprises the following steps:
1) preparing a mixture of 5-nitrobenzimidazole ketone, a Pd/C catalyst and water in a batching kettle, wherein the mass ratio of the 5-nitrobenzimidazole ketone, the Pd/C catalyst and the water in the mixture is 1:0.02: 12;
2) adding 0.5 per mill ionic membrane caustic soda auxiliary agent of the solvent amount into the mixture in the batching kettle in the step 1), adjusting the pH =8, conveying the mixture to a hydrogenation kettle by using a pump, replacing the mixture for 2 times by using 0.3MPa nitrogen and replacing the mixture for 2 times by using 0.3MPa hydrogen, controlling the hydrogenation temperature to be 90 ℃, carrying out continuous hydrogenation reaction at the pressure of 0.2MPa, and stopping introducing hydrogen when the hydrogen is not consumed any more;
3) after the hydrogenation in the step 2) is finished, continuously preserving heat for 1h at the temperature of 115 ℃ and the pressure of 0.8MPa to carry out deep hydrogenation reaction;
4) replacing the materials reacted in the step 3) with nitrogen, performing solid-liquid separation on the materials by a titanium rod filter with 0.2Mpa nitrogen, pressing filtrate into a closed crystallization kettle, and performing back flushing on a Pd/C catalyst to a batching kettle for repeated application after pressing;
5) cooling and separating out materials in the crystallization kettle, separating by closed solid-liquid separation equipment, separating mother liquor, and recycling the mother liquor in a temporary storage tank; and squeezing and air-blowing the filter cake to obtain the final product 5-aminobenzimidazole ketone.
The product in the embodiment is white spherical crystal in appearance, the product appearance is good, the yield reaches 98.41%, and the product purity reaches 99.08%.
The environment-friendly 5-aminobenzimidazole ketone preparation method provided by the invention has the advantages of few by-products, high purity, high yield, almost no wastewater generation, environmental protection and energy conservation.
Example two
As a preferred embodiment of the present invention, in this embodiment, on the basis of the first embodiment, the crystallization kettle and the temporary storage tank in step 4) and step 5) are optimally set, specifically: the crystallization kettle and the temporary storage tank are sealed by nitrogen to isolate air, so that the materials in the container are prevented from being oxidized and deteriorated.
EXAMPLE III
As a preferred embodiment of the present invention, the present embodiment is different from the first embodiment in that: in the embodiment, 0.5-1 per mill of antioxidant is added into a crystallization kettle in advance before material pressing in the step 4), and 0.5-1 per mill of antioxidant is added into a temporary storage tank in the step 5) in batches; the antioxidant is hydrazine hydrate, and is used for improving the stability of 5-aminobenzimidazole ketone.
Example four
A preparation method of high-purity 5-aminobenzimidazole ketone comprises the following steps:
1) preparing a mixture of 5-nitrobenzimidazole ketone, a Pd/C catalyst and water in a batching kettle, wherein the mass ratio of the 5-nitrobenzimidazole ketone to the Pd/C catalyst to the water in the mixture is 1:0.025: 14;
2) adding 0.53 per thousand ionic membrane caustic soda additive in the solvent amount into the mixture in the batching kettle in the step 1), adjusting the pH to be 8.5, conveying the mixture to a hydrogenation kettle by using a pump, replacing the mixture for 3 times by using 0.3MPa nitrogen and replacing the mixture for 3 times by using 0.3MPa hydrogen, controlling the hydrogenation temperature to be 93 ℃, carrying out continuous hydrogenation reaction at the pressure of 0.3MPa, and stopping introducing hydrogen when the hydrogen is not consumed any more;
3) after the hydrogenation in the step 2) is finished, continuously preserving heat for 1.5h at the temperature of 117 ℃ and the pressure of 0.86MPa to carry out deep hydrogenation reaction;
4) replacing the materials reacted in the step 3) with nitrogen, pressing the filtrate obtained after solid-liquid separation of the materials by a titanium rod filter with 0.3Mpa nitrogen into a closed crystallization kettle, adding 0.7 thousandth of hydrazine hydrate into the crystallization kettle in advance before material pressing, and performing back flushing on the Pd/C catalyst to a material preparation kettle for repeated use after material pressing;
5) cooling and separating out materials in the crystallization kettle, separating by a closed solid-liquid separation device, separating mother liquor, feeding the separated mother liquor into a temporary storage tank, adding 0.5 per mill of hydrazine hydrate into each batch of the temporary storage tank, and recycling the recovered mother liquor for cyclic utilization; and squeezing and air-blowing the filter cake to obtain the final product 5-aminobenzimidazole ketone.
The product in the embodiment is white spherical crystal in appearance, the product appearance is good, the yield reaches 98.53%, and the product purity reaches 99.07%.
EXAMPLE five
A preparation method of high-purity 5-aminobenzimidazole ketone comprises the following steps:
1) preparing a mixture of 5-nitrobenzimidazole ketone, a Pd/C catalyst and water in a batching kettle, wherein the mass ratio of the 5-nitrobenzimidazole ketone, the Pd/C catalyst and the water in the mixture is 1:0.03: 16;
2) adding 0.6 per mill ionic membrane caustic soda auxiliary agent of the solvent amount into the mixture in the batching kettle in the step 1), adjusting the pH =9, conveying the mixture to a hydrogenation kettle by using a pump, replacing the mixture for 3 times by using 0.3MPa nitrogen and replacing the mixture for 3 times by using 0.3MPa hydrogen, controlling the hydrogenation temperature to be 95 ℃, carrying out continuous hydrogenation reaction under the pressure of 0.4MPa, and stopping introducing hydrogen when the hydrogen is not consumed any more;
3) after the hydrogenation in the step 2) is finished, continuously preserving heat for 2h at the temperature of 120 ℃ and the pressure of 0.9MPa for deep hydrogenation reaction;
4) replacing the materials reacted in the step 3) with nitrogen, pressing the filtrate obtained after solid-liquid separation of the materials by a titanium rod filter with 0.3Mpa nitrogen into a closed crystallization kettle, adding 1 thousandth of hydrazine hydrate into the crystallization kettle in advance before material pressing, and performing back flushing on the Pd/C catalyst after material pressing until a material mixing kettle is used repeatedly;
5) cooling and separating out materials in the crystallization kettle, separating by a closed solid-liquid separation device, separating mother liquor, feeding the separated mother liquor into a temporary storage tank, adding 1 per mill of hydrazine hydrate into each batch of the temporary storage tank, and recycling the recovered mother liquor for cyclic utilization; and squeezing and air-blowing the filter cake to obtain the final product 5-aminobenzimidazole ketone.
The product in the embodiment is white spherical crystal in appearance, the product appearance is good, the yield reaches 98.58%, and the product purity reaches 99.05%.
The present invention is not limited to the above-described embodiments, and various changes can be made within the knowledge of those skilled in the art without departing from the gist of the present invention, and the contents of the changes still fall within the scope of the present invention.
Claims (8)
1. A preparation method of high-purity 5-aminobenzimidazole ketone is characterized by comprising the following steps:
1) preparing a mixture of 5-nitrobenzimidazole ketone, a Pd/C catalyst and water in a batching kettle;
2) adding an auxiliary agent into the mixture in the blending kettle in the step 1), adjusting the pH =8-9, conveying the mixture to a hydrogenation kettle, performing nitrogen replacement and hydrogen replacement, controlling the hydrogenation temperature at 90-95 ℃ and the pressure at 0.2-0.4MPa to perform continuous hydrogenation reaction, and stopping introducing hydrogen when the hydrogen is not consumed any more;
3) after the hydrogenation in the step 2) is finished, the temperature is controlled at 120 ℃ under 115 and 0.8-0.9MPa, and the temperature is kept for 1-2h to carry out deep hydrogenation reaction;
4) replacing the material reacted in the step 3) with nitrogen, then pressing the filtrate into a closed crystallization kettle after solid-liquid separation of the material by using 0.2-0.3Mpa nitrogen, and reversely blowing the Pd/C catalyst into a batching kettle for repeated application after pressing;
5) cooling and separating out materials in the crystallization kettle, separating by closed solid-liquid separation equipment, separating mother liquor, and recycling the mother liquor in a temporary storage tank; and squeezing and air-blowing the filter cake to obtain the final product 5-aminobenzimidazole ketone.
2. The method according to claim 1, wherein the preparation method of high-purity 5-aminobenzimidazole ketone comprises the following steps: the mass ratio of the 5-nitrobenzimidazole ketone, the Pd/C catalyst and the water in the mixture in the step 1) is 1 (0.02-0.03) to (12-16).
3. The method according to claim 1, wherein the preparation method of high-purity 5-aminobenzimidazole ketone comprises the following steps: the auxiliary agent in the step 2) is an ionic membrane caustic soda auxiliary agent.
4. The method according to claim 1, wherein the preparation method of high-purity 5-aminobenzimidazole ketone comprises the following steps: and in the step 2), replacing nitrogen for 2-3 times and replacing hydrogen for 2-3 times.
5. The method according to claim 1, wherein the preparation method of high-purity 5-aminobenzimidazole ketone comprises the following steps: the solid-liquid separation equipment in the step 4) is a titanium rod filter.
6. The method according to claim 1, wherein the preparation method of high-purity 5-aminobenzimidazole ketone comprises the following steps: the crystallization kettle and the temporary storage tank are both sealed by nitrogen to isolate air.
7. The method according to claim 1, wherein the preparation method of high-purity 5-aminobenzimidazole ketone comprises the following steps: 0.5-1 per mill of antioxidant is added into the crystallization kettle in advance before material pressing in the step 4), and 0.5-1 per mill of antioxidant is added into each batch of the temporary storage tank in the step 5).
8. The method according to claim 7, wherein the preparation method comprises the following steps: the antioxidant is hydrazine hydrate.
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