CN1974559A - Skeleton nickel catalyzed 5-nitrobenzimidazole ketone reducing process for preparing 5-aminobenzimidazole ketone - Google Patents

Abstract

The invention discloses a method for preparing 5-aminobenzimidazolone by catalytically reducing 5-nitrobenzimidazolone with skeleton nickel, which belongs to the preparation technology of 5-aminobenzimidazolone. The process of the method comprises: adding nickel-aluminum alloy to a NaOH solution with a certain temperature and concentration, reacting for a certain period of time, and then filtering and washing with water and absolute ethanol several times to obtain the skeleton nickel and storing it in absolute ethanol for later use; mixing the skeleton nickel with 5 - Nitrobenzimidazolone and absolute ethanol are added into the autoclave according to a certain mass ratio, at a temperature of 80-120°C, a pressure of 1.0-6.0MPa, and a reaction time of 4-15 hours, take out the filtrate and remove the catalyst Afterwards, the filtrate was concentrated by distillation under reduced pressure, filtered with suction, and the filter cake was vacuum-dried to obtain 5-aminobenzimidazolone. The invention has the advantages of simple process, convenient reaction operation, low cost, product yield of 89.0%-94.0%, purity of 97.0%-99.8%, less "three wastes" and less environmental pollution.

Description

Method for preparing 5-aminobenzimidazolone by catalytic reduction of 5-nitrobenzimidazolone by skeleton nickel

Technical field

The invention relates to a method for preparing 5-aminobenzimidazolone through catalytic reduction of 5-nitrobenzimidazolone by skeleton nickel, which belongs to the preparation technology of 5-aminobenzimidazolone.

Background technique

5-Aminobenzimidazolone is an important pigment intermediate used in the preparation of high-grade organic pigments. 5-aminobenzimidazolone is usually prepared by reducing 5-nitrobenzimidazolone. The main reduction methods include iron powder reduction, hydrazine hydrate reduction and catalytic hydrogenation reduction. At present, the iron powder reduction method is mainly used in industry, the process is mature, the equipment investment is small, the price of iron powder is low, and the operation is simple, but a large amount of iron oxide sludge is produced in the process, and the post-treatment is complicated, causing serious pollution to the environment; hydrazine hydrate reduction method, low equipment investment, mild reaction conditions, good reduction effect, partial reduction can be carried out, and no waste gas and waste residue are produced, but it is only suitable for the synthesis of small batches and short-term aromatic amines, not suitable for large-scale industrial production; catalytic hydrogenation reduction method, complete reaction, few side reactions, high product quality and yield, less environmental pollution, Okujima et al. The yield of 5-aminobenzimidazolone is about 95% by using imidazolone, but the catalyst is expensive, recycling is difficult, and industrial production is difficult.

Contents of Invention

The purpose of the present invention is to provide a method for preparing 5-aminobenzimidazolone by catalytic reduction of 5-nitrobenzimidazolone by skeleton nickel, and the 5-aminobenzimidazolone prepared by this method has high yield and high quality. Well, easy to industrialize.

The present invention is achieved through the following technical solutions, a method for preparing 5-aminobenzimidazolone by catalytic reduction of 5-nitrobenzimidazolone with framework nickel, characterized in that it comprises the following process:

1. Preparation of skeleton nickel catalyst: using nickel-aluminum alloy as raw material, said nickel-aluminum alloy includes: binary alloy, wherein the mass fraction of nickel is 47%, and the mass fraction of aluminum is 53%; ternary alloy, wherein nickel The mass fraction of titanium is 46%, the mass fraction of titanium is 1-3%, and the rest is aluminum; the mass fraction of nickel is 46%, the mass fraction of chromium is 1%, and the mass fraction of iron is 1-3%. , and the rest is aluminum. Add the nickel-aluminum alloy to the NaOH solution with a temperature of 20-90°C and a mass concentration of 10-30%, and the reaction time is 1-15 hours, then wash with deionized water until there is no _NaAlO2 in the washing liquid, and then use no Water and ethanol were filtered and washed several times to remove water, and then stored in anhydrous ethanol solution for later use.

2. The process of liquid-phase catalytic hydrogenation reduction: based on 1g of 5-nitrobenzimidazolone, with absolute ethanol as solvent, the dosage is 5-10ml; the dosage of skeleton nickel is 5-nitrobenzimidazolone Add 3-10% of the mass of the autoclave into the autoclave, feed hydrogen, the reaction temperature is 80-120°C, the reaction pressure is 1.0-6.0MPa, the reaction time is 4-15 hours, the reaction solution is taken out, and after removing the catalyst , the filtrate was concentrated by distillation under reduced pressure, filtered with suction, and the filter cake was vacuum-dried to obtain 5-aminobenzimidazolone.

The invention has the advantages of simple process, convenient reaction operation, low cost, product yield of 89.0%-94.0%, purity of 97.0%-99.8%, less "three wastes" and less environmental pollution.

Detailed ways

Example 1 Add 30 g of nickel-aluminum alloy (binary) to a NaOH solution with a mass concentration of 19% and a volume of 200 ml, stir, the feeding temperature is 10-15° C., the feeding time is 2 hours, and then the temperature is raised to 20-25° C. , reacted for 9 hours, then used deionized water and absolute ethanol to filter and wash several times, and stored the obtained skeleton nickel in absolute ethanol for subsequent use, and marked it as W-1-(two) type.

Take 18g of 5-nitrobenzimidazolone, 80ml of absolute ethanol, and 1.8g of W-1-(two)-type skeleton nickel into the autoclave, feed hydrogen gas to a pressure of 2MPa, heat up to 85°C, and react for 6 hours. The catalyst was removed by liquid filtration, the filtrate was concentrated, filtered with suction, and the filter cake was dried in vacuum to obtain 14.0 g of 5-aminobenzimidazolone with a yield of 93.2%, a purity of 97.2%, and a melting point of 248-251°C.

Example 2 Add 40 g of nickel-aluminum alloy (binary) to a 10% NaOH solution with a volume of 600 ml, stir, the feeding temperature is 85-90° C., the feeding time is 1.5 hours, and the temperature is raised to 90-95° C. React for 1 hour, then use deionized water and absolute ethanol to filter and wash several times, store the prepared skeleton nickel in absolute ethanol for later use, and mark it as T-1-(two) type.

Take 18g of 5-nitrobenzimidazolone, 100ml of absolute ethanol, and 1.8g of T-1-(two) skeleton nickel into the autoclave, feed hydrogen gas to a pressure of 3MPa, heat up to 85°C, and react for 5 hours. The catalyst was removed by liquid filtration, the filtrate was concentrated, filtered with suction, and the filter cake was dried in vacuum to obtain 14.0 g of 5-aminobenzimidazolone with a yield of 93.1%, a purity of 98.8%, and a melting point of 248-251°C.

Example 3 Add 30 g of nickel-aluminum alloy (ternary) to a NaOH solution with a concentration of 19% and a volume of 200 ml, stir, the feeding temperature is 10-15° C., the feeding time is 2 hours, and the temperature is raised to 20-25° C., and the reaction After 9 hours, use deionized water and absolute ethanol to filter and wash several times, and store the obtained skeleton nickel in absolute ethanol for later use, and mark it as W-1-(III) type.

Take 18g of 5-nitrobenzimidazolone, 120ml of absolute ethanol, and 1.5g of W-1-(three)-type skeleton nickel into the autoclave, feed hydrogen gas to a pressure of 4MPa, heat up to 85°C, and react for 7 hours. The catalyst was removed by liquid filtration, the filtrate was concentrated, filtered with suction, and the filter cake was dried in vacuum to obtain 13.9 g of 5-aminobenzimidazolone with a yield of 92.5%, a purity of 98.8%, and a melting point of 249-251°C.

Example 4 Add 40 g of nickel-aluminum alloy (ternary) to a NaOH solution with a concentration of 10% and a volume of 600 ml, stir, the feeding temperature is 85 to 90° C., the feeding time is 1.5 hours, and the temperature is raised to 90 to 95° C., and the reaction After 1 hour, filter and wash several times with deionized water and absolute ethanol, and store the obtained skeleton nickel in absolute ethanol for later use, and mark it as T-1-(three) type.

Take 18g of 5-nitrobenzimidazolone, 120ml of absolute ethanol, and 0.9g of T-1-(three)-type skeleton nickel into the autoclave, feed hydrogen gas to a pressure of 2MPa, heat up to 90°C, and react for 10 hours. The catalyst was removed from the filtrate, the filtrate was concentrated, filtered with suction, and the filter cake was dried in vacuum to obtain 13.7 g of 5-aminobenzimidazolone with a yield of 91.6%, a purity of 99.1%, and a melting point of 249-251°C.

Take 25g of 5-nitrobenzimidazolone, 200ml of absolute ethanol, and 1.0g of T-1-(three)-type framework nickel into the autoclave, feed hydrogen gas to a pressure of 3MPa, heat up to 90°C, and react for 10 hours. The catalyst was removed by liquid filtration, the filtrate was concentrated, filtered with suction, and the filter cake was dried in vacuum to obtain 19.4 g of 5-aminobenzimidazolone with a yield of 93.3%, a purity of 99.0%, and a melting point of 250-253°C.

Example 5 Add 30 g of nickel-aluminum alloy (quaternary) to a concentration of 19%, and a volume of 200 ml of NaOH solution, stir, the feeding temperature is 10-15 ° C, the feeding time is 2 hours, the temperature is raised to 20-25 ° C, and the reaction After 9 hours, use deionized water and absolute ethanol to filter and wash several times, and store the prepared skeleton nickel in absolute ethanol for subsequent use, and mark it as W-1-(four) type.

Take 18g of 5-nitrobenzimidazolone, 120ml of absolute ethanol, and 0.9g of W-1-(four)-type skeleton nickel into the autoclave, feed hydrogen gas to a pressure of 2MPa, heat up to 90°C, and react for 7 hours. The catalyst was removed by liquid filtration, the filtrate was concentrated, filtered with suction, and the filter cake was dried in vacuum to obtain 13.5 g of 5-aminobenzimidazolone with a yield of 90.1%, a purity of 98.7%, and a melting point of 248-251°C.

Example 6 Add 40 g of nickel-aluminum alloy (quaternary) to a concentration of 10% and a volume of 600 ml of NaOH solution, stir, the feeding temperature is 85 to 90° C., the feeding time is 1.5 hours, the temperature is raised to 90 to 95° C., and the reaction After 1 hour, use deionized water and absolute ethanol to filter and wash several times, and store the obtained skeleton nickel in absolute ethanol for later use, and mark it as T-1-(four) type.

Take 18g of 5-nitrobenzimidazolone, 120ml of absolute ethanol, and 0.7g of T-1-(tetra)skeleton nickel into the autoclave, feed hydrogen gas to a pressure of 3MPa, heat up to 90°C, and react for 12 hours. The catalyst was filtered off, the filtrate was concentrated, filtered with suction, and the filter cake was dried in vacuum to obtain 13.7 g of 5-aminobenzimidazolone with a yield of 91.3%, a purity of 99.3%, and a melting point of 250-253°C.

Take 25g of 5-nitrobenzimidazolone, 200ml of absolute ethanol, and 1.0g of T-1-(tetra)skeleton nickel into the autoclave, feed hydrogen gas to a pressure of 2MPa, heat up to 90°C, and react for 14 hours. The catalyst was removed, the filtrate was concentrated, filtered with suction, and the filter cake was dried in vacuum to obtain 19.3 g of 5-aminobenzimidazolone with a yield of 92.8%, a purity of 99.0%, and a melting point of 250-253°C.

Take 30g of 5-nitrobenzimidazolone, 250ml of absolute ethanol, and 0.9g of T-1-(tetra)skeleton nickel into the autoclave, feed hydrogen gas to a pressure of 2MPa, heat up to 95°C, and react for 13 hours. The catalyst was filtered off, the filtrate was concentrated, filtered with suction, and the filter cake was dried in vacuum to obtain 23.4 g of 5-aminobenzimidazolone with a yield of 93.5%, a purity of 99.4%, and a melting point of 249-252°C.

Claims (1)

1. a skeleton nickel catalyzed reduction 5-nitrobenzimidazole ketone prepares the method for the amino benzimidazolone of 5-, it is characterized in that comprising following process:

(1) preparation of skeletal nickel catalyst: with the alumel is raw material, and described alumel comprises: binary alloy, and wherein the massfraction of nickel is 47%, the massfraction of aluminium is 53%; Ternary alloy, wherein the massfraction of nickel is 46%, and the massfraction of titanium is 1～3%, and all the other are aluminium; Quad alloy, the massfraction of nickel is 46%, the massfraction of chromium is 1%, the massfraction of iron is 1～3%, all the other are aluminium, and it is 20～90 ℃ that alumel is joined temperature, and mass concentration is in 10～30% the NaOH solution, reaction times is 1～15 hour, and being washed till with deionized water does not then have NaAlO in the washings ₂Till, remove for several times with the dehydrated alcohol diafiltration again and anhydrate, after deposit in the ethanol solution standby;

(2) liquid phase catalytic hydrogenation reductive process: the 5-nitrobenzimidazole ketone with 1g is benchmark, with the dehydrated alcohol is solvent, consumption is 5～10ml, the skeleton nickel consumption be 5-nitrobenzimidazole ketone quality 3～10%, they are joined in the autoclave, feed hydrogen, temperature of reaction is 80～120 ℃, reaction pressure is 1.0～6.0MPa, and the reaction times is 4～15 hours, and reaction solution is taken out, after removing catalyzer, the filtrate decompression distillation concentrates, and suction filtration obtains the amino benzimidazolone of 5-with filter cake vacuum-drying.