JPH05163199A - Production process for iodosobenzoic acid - Google Patents

Abstract

PURPOSE:To obtain the subject compound which is used as an oxidizing agent, a synthetic intermediate or a reagent for studying protein, by oxidizing an alkali iodobenzoate with an oxidizing agent such as alkali hypochlorite or bleaching powder or with chlorine in the presence of an alkali hydroxide. CONSTITUTION:Iodobenzoic acid such as o-iodobenzoic acid is dissolved using sodium hydroxide and water to form sodium iodobenzoate. The salt is oxidized with an alkali hypochlorite such as sodium hypochlorite or bleaching powder or with chlorine in the presence of an alkali hydroxide such as sodium hydroxide. Then, the reaction mixture is acidified by adding acetic acid or the like to precipitate solid, heated at 60 to 100 deg.C, the formed crystals are filtered off, rinsed with water, dried to give the objective iodosobenzoic acid in high yield.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for producing iodosobenzoic acid. Iodosobenzoic acid is a compound useful as various oxidizing agents, synthetic intermediates, and reagents for protein research.

[0002]

2. Description of the Related Art As a method for producing iodosobenzoic acid,
Oxidation of iodobenzoic acid with permanganate [Chem. Ber., 26, 1357, 1
893], oxidation method using fuming nitric acid and concentrated sulfuric acid [Journal of Organic Chemistry (J. Org. C
hem.), 29, 447, 1964] and the like.

Also known is a method in which iodobenzoic acid is chlorinated in chloroform to give iodobenzoic acid dichloride, which is then hydrolyzed with an aqueous alkali solution.

[0004]

The oxidation method using permanganate has poor production efficiency and has a problem in disposal of the manganese compound after the reaction. The oxidation method using fuming nitric acid and concentrated sulfuric acid has a large amount of nitrous acid. Compounds are by-produced. Further, in the method via iodobenzoic acid dichloride, the reaction has two steps, the operation is complicated, and the production efficiency is poor.

[0005]

Means for Solving the Problems As a result of intensive studies made by the present inventors to overcome the above-mentioned drawbacks of the reaction, the present invention has completed the method of the present invention having high production efficiency. That is, the present invention is characterized in that an alkali salt of iodobenzoic acid is oxidized with chlorine in the presence of alkali hypochlorite, a compound selected from bleaching powder and / or an alkali hydroxide, and is oxidized with chlorine. The present invention relates to a manufacturing method.

Examples of the alkali salt of iodobenzoic acid include lithium, sodium and potassium. The alkali salt of iodobenzoic acid can be prepared by reacting iodobenzoic acid with an equivalent amount or more of an alkali hydroxide such as lithium hydroxide, sodium hydroxide, potassium hydroxide, calcium hydroxide or barium hydroxide.

The alkali salt of iodobenzoic acid is preferably used as an aqueous solution, and the concentration of the aqueous solution is 3 to 2
5 weight percent, preferably 10 to 15 weight percent.

In the present invention, alkali hypochlorite oxidation, bleaching powder oxidation and chlorine oxidation can be carried out individually or in combination.

Examples of alkali hypochlorite include lithium hypochlorite, sodium hypochlorite, potassium hypochlorite, calcium hypochlorite and the like.

The amount of alkali hypochlorite and bleaching powder to be used is usually 1.9 to 2.1 equivalents, preferably about 2 equivalents, as effective chlorine with respect to the alkali salt of iodobenzoic acid.

If the amounts of alkali hypochlorite and bleaching powder used are insufficient, the alkali salt of iodobenzoic acid remains unreacted, and if it is excessive, iodooxybenzoic acid is produced.

Alkali hydroxides used in the method for producing chlorine-oxidized iodosobenzoic acid include lithium hydroxide, sodium hydroxide, potassium hydroxide, calcium hydroxide,
Examples include barium hydroxide.

The amount of alkali hydroxide used is usually 2 to 10 equivalents, preferably 3 to 5 equivalents, relative to the alkali salt of iodobenzoic acid.

Chlorine can be used as gas or liquid. The amount of chlorine used is usually 0.9 to 1.05 mol, preferably about equimolar to the alkali salt of iodobenzoic acid.

The reaction temperature is usually -5 to 60 ° C, preferably -5 to 20 ° C. When the reaction temperature is high, the disproportionation reaction of the iodosobenzoic acid produced occurs, and iodobenzoic acid and iodooxybenzoic acid are easily produced.

After the reaction, an acid is added to the reaction solution to precipitate the formed iodosobenzoic acid, which is then separated by filtration.

Examples of the acid include inorganic acids such as hydrochloric acid, sulfuric acid, nitric acid and phosphoric acid, and water-soluble organic acids such as acetic acid, propionic acid and lactic acid. When hydrochloric acid is used in excess, iodobenzoic acid dichloride is produced from the iodosobenzoic acid produced, so that only an amount necessary for neutralizing the alkali salt of iodosobenzoic acid and the excess alkali can be used.

The reducing acid is difficult to use because iodobenzoic acid is produced from the iodosobenzoic acid produced.

Iodosobenzoic acid precipitated by adding an acid is usually fine crystals and has poor filterability and is difficult to wash with water.
At this time, the precipitated iodosobenzoic acid slurry liquid is usually added to 5
0 to 120 ° C., preferably 0.1 to 5 at 60 to 100 ° C.
When heated and stirred for a period of time and cooled, crystals of iodosobenzoic acid grow and the filterability is improved.

Iodosobenzoic acid precipitated using an inorganic acid may be colored, but a water-soluble organic acid is used.
Iodosobenzoic acid treated at 0 to 100 ° C. has large crystals and good color tone.

[0021]

According to the present invention, iodosobenzoic acid can be easily obtained in high yield from an alkali salt of iodobenzoic acid.

[0022]

EXAMPLES The present invention will be described in more detail below with reference to examples, but the present invention is not limited thereto.

Example 1 12.4 g of orthoiodobenzoic acid and 6 of sodium hydroxide
g and water (150 g) were mixed and dissolved, and sodium hypochlorite (70 g (active chlorine content: 5% by weight)) was added in an amount of 10 to 10.
The mixture was gradually added at 20 ° C. and stirred for 30 minutes. Next, 30 mL of acetic acid was added to precipitate a solid, followed by stirring at 80 ° C. for 1 hour and further at 30 ° C. for 1 hour. The formed crystals were separated by filtration, washed with water three times, dried, and then vacuum dried.
1.9 g of ortho-iodosobenzoic acid were obtained. The iodometric purity was 98%. Yield 90%.

Example 2 12.4 g orthoiodobenzoic acid, 9 sodium hydroxide
g and water 150g are mixed and dissolved, and chlorine gas 3.6g
Was added at 10 to 20 ° C. over 30 minutes and stirred for 30 minutes. Next, 30 mL of acetic acid was added to precipitate a solid, followed by stirring at 80 ° C. for 1 hour and further at 30 ° C. for 1 hour. The formed crystals were separated by filtration, washed 3 times with water, dried at room temperature, and then vacuum dried to obtain 12.2 g of iodosobenzoic acid. The purity was 98%. Yield 92%.

Example 3 Orthoiodobenzoic acid 12.4 g, sodium hydroxide 1
After mixing 5 g and 150 g of water and dissolving, chlorine gas 3.6
g was added at 5 to 15 ° C over 30 minutes and stirred for 30 minutes. Next, the reaction solution was added to 30 mL of acetic acid to make it acidic, and then the mixture was stirred at 80 ° C. for 1 hour and cooled. The precipitated crystals were separated by filtration, washed with water three times, dried at room temperature and then vacuum dried to obtain 11.9 g of pale yellow iodosobenzoic acid. The purity was 98%. Yield 90%.

Example 4 12.4 g orthoiodobenzoic acid, 8 sodium hydroxide
g and water 150g are mixed and dissolved, and chlorine gas 3.6g
Was added at 5 to 15 ° C over 30 minutes and stirred for 30 minutes. Next, 30 mL of a 30 weight percent sulfuric acid aqueous solution was added to make the solution acidic. The precipitated crystals were separated by filtration, washed with water three times, dried at room temperature and then vacuum dried to obtain 12.3 g of pale yellow iodosobenzoic acid. The purity was 99%. Yield 93%.

Example 5 12.4 g of orthoiodobenzoic acid and 6 of sodium hydroxide
g and water 150g are mixed and dissolved, then chlorine gas 3.0g
Was added at 5 to 15 ° C over 30 minutes and stirred for 30 minutes. Next, sodium hypochlorite (effective chlorine content 5
%) 12 g was further added and the reaction was carried out for 10 minutes. After the reaction was completed, 30 mL of a 30 wt% sulfuric acid aqueous solution was added to make the solution acidic. The precipitated crystals were separated by filtration, washed with water three times, dried at room temperature and then vacuum dried to obtain 12.3 g of pale yellow iodosobenzoic acid. The purity was 99%. Yield 93%.

Claims (5)

[Claims] 1. A method for producing iodosobenzoic acid, which comprises oxidizing an alkali salt of iodobenzoic acid with a compound selected from alkali hypochlorite and bleaching powder and / or oxidizing with chlorine in the presence of alkali hydroxide. Method. 2. After oxidizing the alkali salt of iodobenzoic acid,
The method for producing iodosobenzoic acid according to claim 1, wherein the method is acidic. 3. After oxidizing the alkali salt of iodobenzoic acid,
The method for producing iodosobenzoic acid according to claim 2, which is acidified and heated to 60 to 100 ° C. 4. The alkali salt of iodobenzoic acid is sodium iodobenzoate, the alkali hypochlorite is sodium hypochlorite, and the alkali hydroxide is sodium hydroxide. A method for producing iodosobenzoic acid. 5. The method for producing iodosobenzoic acid according to claim 2, wherein the water-soluble organic acid is used to make it acidic.