JPS61167636A - Production of vicinal diketone compound - Google Patents

Abstract

PURPOSE:To produce the titled compound useful as a food additive and industrial raw material, easily in high yield, by using a dihaloalkanone compound as a starting raw material, reacting with an alcoholic alkali metal compound, and contacting with water in the presence of an acid. CONSTITUTION:The dihaloalkanone compound of formula I (R1 and R2 are lower alkyl; X is halogen) is used as a raw material, and made to react with an alcoholic alkali metal compound at -10-100 deg.C, preferably 0-70 deg.C to obtain the dialkoxyalkanone compound of formula II (R3 is lower alkyl). The amount of the alkali metal compound is usually 1-10mol, preferably 1.5-4mol per 1mol of the compound of formula I. The produced compound of formula II is made to contact with water in the presence of an acid to obtain the objective compound of formula III. A concrete example of the compound of formula I used as a raw material is 3,3-dichlorobutanone.

Description

Detailed Description of the Invention (Industrial Field of Application) The present invention relates to a new method for producing a vicinal diketone compound, and more specifically, the present invention relates to a new method for producing a vicinal diketone compound, and more specifically, it uses a dihaloalkanone compound represented by the following general formula (1) as a raw material to produce a vicinal diketone compound using the following general formula (1) as a raw material. The present invention relates to a method for producing a vicinal diketone compound represented by the following general formula CIII) via a dialkoxyalkanone compound represented by Cn).

(In the formula, R1, R2 and R5 represent the same or different lower alkyl groups, and X represents a halodane atom.) (Prior art) A vicinal diketone compound represented by the above general formula [1 [1] represented by noacetyl. is a substance useful as a food additive or an industrial raw material.

As a method for producing such a vicinal diketone compound, for example, a method of oxidizing 2,3-butanediol with gold (Japanese Patent Application Laid-Open No. 1983-1999)
36467, etc.), and the method of oxidizing methyl ethyl ketone (Japanese Patent Application Laid-Open No. 132515/1989), etc., but the present inventors have been conducting intensive studies to develop all new synthetic methods different from these methods. As a result, we have discovered a method for efficiently producing all the vicinal diketone compounds represented by the above general formula (Ill) by using the dihaloalkanone compound represented by the above general formula (1) as a starting material, and have completed the present invention. .

(Means for Solving All Problems) Thus, according to the present invention, a dihaloalkanone compound represented by the following general formula (1) is reacted with an alcoholic alkali metal compound to form a dialkoxyalkyl compound represented by the following general formula (Cll). A method for producing a vicinal diketone compound represented by the following general formula [111], which comprises forming a canone compound and then contacting it with water in the presence of an acid.

(wherein R,, R2 and R3 are the same or different lower alkyl groups, and X represents a halodane atom).

In the present invention, first, the above general formula [! ] A dialkoxyalkanone compound represented by the above general formula (It) is formed from the dihaloalkanone compound represented by the above and the alcoholic alkali metal compound.

Specific examples of the /-roalkanone compounds used as raw materials include 3,3-dichlorobutanone, 3,3
-nopromoptanone, 3,3-dichloropentanone, etc., especially 3,3-dichloropentanone.

Butanone is used.

On the other hand, the alcoholic alkali metal compound used in the reaction refers to an alkali metal compound dissolved in alcohol as well as an alkali metal alcoholade, and specific examples thereof include sodium methylate, sodium ethylate, potassium methylate, sodium hydroxide, water Examples include potassium oxide, sodium carbonate, and potassium carbonate.

Specific examples of the alcohol used to dissolve the alkali metal compound include mineral alcohol, methanol, ethanol, and isoglobil alcohol.

The reaction temperature in the synthesis reaction is usually -10°C to 100°C,
Preferably 0 to 70°C, reaction pressure 0.5 to 10 atm,
The pressure is preferably selected from 1 to 3 atmospheres, and is appropriately determined by taking into account all the boiling points of the dihaloalkanone compound as a raw material. The amount of the alcoholic alkali metal compound used is usually 1 to 10 mol, preferably 1.5 to 4 mol, based on 1 mol of gold of the horn alkanone compound as a raw material.

The reaction is generally carried out in the presence of alcohol.

The alcohol used may be in the same range as those used to solubilize alkali metal compounds.

Further, the reaction format is not particularly limited, and may be a method of adding an alcoholic alkali metal compound to a dihaloalkanone compound, or the reverse method.

Even if inorganic salts are precipitated over time during the course of the reaction, there will be no particular adverse effect on the reaction, but it is necessary to ensure that stirring and other operations are not hindered.

In the present invention, the desired vinyl diketone compound is formed by bringing the thus synthesized dialkoxyalkanone compound into contact with water in the presence of an acid.

Specific examples of acids used include hydrochloric acid, sulfuric acid, phosphoric acid,
Examples include inorganic acids such as nitric acid, boric acid, and heteropolyacids, and organic acids such as p-toluenesulfonic acid and acetic acid.
It is used as a 5-30% by weight aqueous solution. Further, a solid acid such as a strong acid type cation exchange resin can also be used.

The amount of acid used is usually 0.05 to 5 mol, preferably 0.05 to 5 mol, based on 1 mol of the dialkoxyalkanone compound.
It is selected in the range of 1 to 1 mol. When using an acid monoaqueous solution, there is no need to supply water again, but anhydrous tl
When used for water, it is necessary to coexist with a small amount of water.

The temperature in this treatment is usually selected from O to 100°C, preferably 20 to 60°C, and the pressure is selected from O, S to 10 atm, preferably 1 to 3 atm. Alternatively, the desired vinyl diketone compound is formed by continuously passing the dialkoxyalkanone compound together with gold water through a packed tower filled with a solid acid such as a strong acid type cation exchange resin.

The vinal diketone 218 compound thus formed can be obtained by distillation after distilling off the alcohol gold, but it is recommended that the alcohol gold be distilled off under atmospheric pressure or reduced pressure before the complete hydrolysis. This is preferable for increasing the purity of the compound.

(Effects of the Invention) Thus, the present invention provides an extremely
An easy and practical method is provided.

(Example) The present invention will be further explained in detail by way of Examples below.

Note that parts and parts in the examples are based on weight unless otherwise specified.

Example 1 (1) Synthesis of 3.3-dimethoxy-2-butanone 3.3
-141 parts of dichloro-2-f-tanone and 700 parts of methanol
(1) 1100 parts of a 10% methanol solution of IJ ummetherate was added over 2 hours while stirring while keeping the contents at 40°C. After addition, stirring was continued for 30 minutes at the same temperature. After stirring, the reaction solution t
The precipitated sodium chloride was removed by filtration under reduced pressure of 100 mHH.

As a result of gas chromatographic analysis of P solution, 112 parts (molar yield 85 parts) of 3,3-dimethoxy-
It was found that 2-butanone had been produced and that unreacted 3,3-fuchloro-2-butanone was only a trace.

Next, this F solution was heated under atmospheric pressure at a temperature of 80 to 90°C, 11,600 parts of methanol was recovered from the solution, and the filtrate was concentrated. Sodium chloride, which had been dissolved in methanol, precipitated in the concentrate, so it was decanted and the solution was subjected to the next hydrolysis reaction.

(2) Synthesis of Noacetyl Concentrate containing 112 parts of 3,3-dimethoxy-2-butanone (approximately 220 parts)? Place in a four-loop flask equipped with a stirrer and a cooling reflux device, immerse in a warm bath, and bring the contents to a temperature of 4.
180 parts of a 15% aqueous solution of sulfuric acid was added over 15 minutes while stirring at 0°C, and after the addition, the solution was added at the same temperature for 3
Stirring was continued for 0 minutes. At this time, - of the reaction solution was 0.7.

Analysis of the reaction solution by gas chromatography revealed that 73 parts of diacetyl were produced in the reaction solution, and that diacetyl was produced almost quantitatively from nomethoxypumenon by hydrolysis.

Example 2 A reaction was carried out in the same manner as in Example 1 except that 1100 parts of a 7.4% methanol solution of arsenic hydroxide was used in place of the methanol solution of sodium methylate used in Example 1, and a gas chroma Analyze with tograph and get 7 as a result,
The molar yield of 3,3-dimethoxy-2-butanone is 82%
It was found that the reaction from nomethoxybutanone to diacetyl was almost quantitative.

Claims (1)

[Claims] 1. A dihaloalkanone compound represented by the following general formula [I] is reacted with an alcoholic alkali metal compound to form a dialkoxyalkanone compound represented by the following general formula [II], and then an acid A method for producing a vicinal diketone compound represented by the following general formula [III], which comprises contacting with water in the presence of. ▲There are mathematical formulas, chemical formulas, tables, etc.▼...[I] ▲There are mathematical formulas, chemical formulas, tables, etc.▼...[II] ▲There are mathematical formulas, chemical formulas, tables, etc.▼...[III] (Formula (wherein, R_1, R_2 and R_3 are the same or different lower alkyl groups, and X represents a halogen atom)