JPS6016430B2 - Manufacturing method of benzimidazolone - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for producing benzimidazolones.

More details: A novel method for directly producing benzimidazolones by reacting dichlorobenzene, aqueous ammonia, and urea or ethylene carbonate under pressure in the presence of a monovalent or divalent copper compound. It is related to.

Traditionally, benzimidazo. The solution is to react the hydrochloride of ○-phenylenezamine with excess phosgene in toluene, or
Alternatively, it has been synthesized by a method in which 0-phenylenediamine and urea are reacted in an organic solvent or an aqueous solvent at a temperature of 80 to 1800°. The starting material for this known process, phenylenediamine, is obtained by nitrating chlorobenzene to obtain the corresponding compound. It was obtained by synthesizing lnitrobenzene and ammonolysis to synthesize nitroaniline, followed by reduction. However, these methods have drawbacks such as high manufacturing costs due to long steps.

In addition, in 112367 of 1983, ○-dichlorobenzenes, ammonia aqueous solution, carbonate or bicarbonate of alkali or alkali metal, monovalent copper salt and or metal steel catalyst composition were added. It has been described that benzimidazolones can be obtained by reaction under pressure.

The catalyst used here needs to be a monovalent copper salt, and for that purpose a mixture of metallic steel is used.

If metal steel is used for continuous reaction, it is difficult to continuously charge the catalyst, and when recovering the catalyst after the reaction, some of the monovalent copper salts or divalent copper salts are present, making it difficult to recycle the catalyst. remains.

Comparative experiments on sodium carbonate in the alkali metal carbonate used have shown that a large amount of decomposition products are generated and the yield is reduced.

Benzimidazolone is useful as an intermediate for dyes, pigments, etc., or as a raw material for resins, but the present inventors have found that benzimidazolone can be obtained in a higher yield than ○-dichlorobenzene, and that As a result of extensive research into an advantageous method for the cyclical use of copper compounds as catalysts, we have found that monovalent copper salts, divalent copper salts, or mixtures of monovalent and divalent copper compounds can be used as catalysts under specific conditions. The inventors have discovered that benzimidazolone can be obtained in high yield by carrying out the reaction, and have arrived at the present invention.

The catalyst used in the process of the invention can be any monovalent or divalent copper compound or a mixture thereof. Examples include cuprous chloride, cupric chloride, cuprous sulfate, cupric sulfate, cuprous oxide, sulfuric acid, and mixtures thereof. Although it is desirable to use a large amount of catalyst in order to increase the reaction rate,
There is no point in using more than a certain amount, and an appropriate amount is determined based on the convenience of reaction operations.

Generally, it is desirable that the amount is 0.1 to 1.0 moles relative to ◯-dichlorobenzene.

If the amount is too large, problems may occur such as the solubility in the reaction solution decreases and solids precipitate, making it difficult to mix.

On the other hand, if the amount is too small, the reaction rate becomes slow, which poses a problem in achieving a practically sufficient production. Recycling of catalysts is important as an industrial production method.

From this point of view, the fact that monovalent copper compounds, divalent copper compounds, or mixtures thereof can be used means that no matter how the catalyst is separated and recovered, it can be recycled as it is, making it suitable for industrial use. This is extremely advantageous. The amount of ammonia used must be at least the total amount of 2 moles of ○-dichlorobenzene and 4 times the mole of the copper compound, but it is generally preferable to use a large amount of ammonia.

However, it is practically meaningless to use more than 5 sonic moles of ammonia for a 5 M sonic mole steel catalyst for 0-dichlorobenzene.

The concentration of ammonia is preferably 5 to 80%, particularly 15 to 70%.

The appropriate amount of urea or ethylene carbonate used as the imidazolonating agent is 1 to 1 mol per ○-dichlorobenzene, and it is practically meaningless to use more than this.

The reaction pressure is carried out at the autogenous pressure at the reaction temperature, which is usually about 170-180 k9/gauge.

The reaction temperature is preferably 17,000 or higher. The reaction is carried out under these reaction conditions, and when the reaction is completed, the produced benzimidazolone is precipitated when it is cooled to room temperature, so it is taken out through a furnace, and ammonia is absorbed into the furnace liquid again to obtain a predetermined ammonia concentration. By recycling the ammonia and copper catalyst in the next reaction, it is possible to prevent loss of ammonia and copper catalyst, lower manufacturing costs, and reduce waste liquid treatment costs. According to the method of the present invention, highly pure benzimidazolones are obtained in high yields (75-80%). Next, the present invention will be explained in more detail with reference to Examples.

Example 1 36.8 tons of ○-dichlorobenzene, 256 tons of 50% ammonia water, 9.9 tons of cuprous chloride, and 30 tons of urea were charged into a 500 cc titanium autoclave, and the mixture was heated at 220 qo.
I reacted while worshiping the clock.

After the reaction is completed, the autoclave is cooled to room temperature, and the precipitated crystals are filtered and washed with water to obtain crude benzimidazolone.

Crude benzimidazolone in 5-7% caustic soda aqueous solution 3
The solution was dissolved at 8,000 yen and then filtered at room temperature to remove impurities, and the solution was made weakly acidic with hydrochloric acid to precipitate benzimidazolone, which was then filtered and washed with water.

When the crystals are dried at 80°C, they become almost pure, and the theoretical yield of benzimidazolone is 25.2 hours (theoretical yield of 0-dichlorobenzene is 7).
5.2%). Example 2 36.8 hours of 0-dichlorobenzene, 256 hours of 50% ammonia water, 13.4 hours of cupric chloride, and 30 hours of urea were charged into a 500cc titanium autoclave, and the mixture was heated at 220oo for 6 hours while praying. I reacted.

The reaction product was treated in the same manner as in Example 1 to obtain 25.8 hours of benzimidazolone (theoretical yield of dichlorobenzene: 77.0%). Example 3 Dichlorobenzene 36.8 times, 50% ammonia water 256 times, cuprous chloride 9.9 times, ethylene carbonate 44 times were mixed with titanium 5
I put it in a 00cc customer autoclave and reacted at 22,000 for 6 hours.

Benzimidazo by treating the reactants as in Example 1. 25.1 hours of water was obtained (theoretical yield of 0-dichlorobenzene: 75.0%). Comparative Example 0 - 36.8 hours of dichlorobenzene, 25 hours of 50% ammonia water, 9.9 hours of cuprous chloride, and 53.52 hours of soda carbonate were charged into a 500cc titanium autoclave, and 220q.
I reacted by languishing at o for 6 hours.

After the reaction is completed, the autoclave is cooled to room temperature, and the precipitated crystals are filtered and washed with water to obtain crude benzimidazolone.

Crude benzimidazolone in 5-7% caustic soda aqueous solution 3
The solution was dissolved at 8,000 yen and then filtered at room temperature to remove impurities, and the solution was made weakly acidic with hydrochloric acid to precipitate benzimidazolone, which was then filtered and washed with water.

Claims (1)

[Claims] 1 In the production of benzimidazolone represented by general formula (1) ▲There are mathematical formulas, chemical formulas, tables, etc.▼ O represented by general formula (2) ▲There are mathematical formulas, chemical formulas, tables, etc.▼ - A method for producing benzimidazolone, which comprises reacting dichlorobenzene, aqueous ammonia, urea or ethylene carbonate, and a monovalent or divalent copper compound or a mixture thereof under pressure in the presence of a monovalent or divalent copper compound or a mixture thereof.