JPH0616589A - Production of sodioformylacetone - Google Patents

Abstract

PURPOSE:To produce sodioformylacetone in high yield while extremely suppressing the production of by-products by using sodium methoxide in the form of a methanol solution and carrying out a liquid-phase reaction while restricting the concentration of acetone in the liquid in the course of reaction. CONSTITUTION:Sodioformylacetone is produced by using acetone, methyl formate and sodium methoxide as raw materials. The sodium methoxide is used in the form of a methanol solution, acetone and methyl formate are supplied at the same time to the solution in the form of a mixture or as separate flows and the obtained mixture is thoroughly mixed for a prescribed period to effect the reaction of the components and obtain the objective sodioformylacetone.

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION The present invention relates to a method for producing sodioformylacetone. Sodioformylacetone is a compound containing a ketone and an aldehyde group in its molecule and useful as a raw material for organic synthesis, and a compound neutralized and acetalized by itself is a drug,
Used as a raw material for agricultural chemicals.

[0002]

2. Description of the Related Art A method for producing sodioformylacetone from acetone, methyl formate and sodium methoxide as raw materials is described in U.S. Pat. S. Patent 2,
760,985, solid sodium methoxide in powder form is used as a raw material in this method, and sodium methoxide in powder form reacts with oxygen and is decomposed by moisture in the air humidity. , There is a loss of expensive sodium methoxide,
It is not satisfactory in terms of manufacturing cost. Also,
If sodium methoxide adheres to human skin, it may cause a sanitary hindrance such as chemical injury, so handling with powder is complicated, and the reaction liquid during the reaction also becomes a slurry with an extremely high viscosity, There are problems in industrialization such as difficulty in mixing in a reaction tank for carrying out the reaction.

As described above, in the method for producing sodioformylacetone using acetone, methyl formate and sodium methoxide as raw materials, the conventionally known method of reacting sodium methoxide in a solid state is a solid-phase contact reaction by powder. However, the reproducibility is poor and the operability is complicated as compared with the liquid-liquid reaction, so that there is a problem that it is not sufficient as an industrial production method and the yield is not sufficient.

[0004]

DISCLOSURE OF THE INVENTION An object of the present invention is to produce sodioformylacetone from acetone, methyl formate and sodium methoxide as raw materials by a liquid-liquid reaction in order to facilitate industrial operation. It is an object of the present invention to provide an industrial method for producing sodioformylacetone that can obtain high-purity sodioformylacetone in a high yield with a possible simplified production process.

[0005]

In order to overcome the above-mentioned problems in the conventionally known method for producing sodioformylacetone, the present inventors have added sodium methoxide to carry out the reaction in the liquid phase, An intensive study was conducted on a method of producing sodioformylacetone by supplying it in a liquid phase of a methanol solution. The present invention uses acetone, methyl formate and sodium methoxide as raw materials in a method for producing sodioformylacetone, wherein sodium methoxide is used as a methanol solution, and acetone and methyl formate are added to the methanol solution of sodium methoxide. The present invention relates to a method for producing sodioformylacetone, which comprises simultaneously supplying a mixed solution or each solution separately, and sufficiently mixing and reacting while supplying acetone so as not to become excessive over a certain period of time.

The reaction of the present invention is a reaction for producing methanol, and the higher the initial methanol concentration, the slower the reaction rate (represented by formula (1)). Further, since this reaction is a reaction in strong alkali, as is known, acetone undergoes a dimerization reaction in a strong alkali to become a compound of diacetone alcohol (represented by formula (2)), or As the reaction proceeds, a methyl ether form of diacetone alcohol is produced (represented by formula (3)). Each reaction step can be described by the chemical formula as follows.

Therefore, when the production rate of the main reaction (1) becomes slower due to the above reaction mechanism, relative (2),
As the side reaction of the formula (3) progresses, the ratio of diacetone alcohol and the by-product which is a methyl ether of diacetone alcohol increases, and the reaction yield of the target product, sodioformylacetone, decreases and is obtained. It became clear that the quality of sodioformylacetone also deteriorates. Therefore, the inventors of the present invention have established a condition in which the reaction of the formula (1) can be optimally promoted by limiting the concentration of acetone in the liquid during the reaction so that a solution using sodium methoxide as a methanol solution can be used. Through a phase reaction, a method for producing high-purity sodioformylacetone with high yield and extremely low by-products was established.

The method of the present invention will be described in detail below. First, regarding the usage ratio of the raw materials used in this reaction, sodium methoxide was used as a methanol solution to give 10
The reaction is carried out in the liquid phase by using a concentration of -40%, preferably 20-30%. Acetone preferably has a molar ratio of 0.9 to sodium methoxide.
1.2, but particularly preferably 0.95 to 1.
Use 1. As mentioned above, outside this reaction range, excess acetone causes a side reaction, and when the reaction amount ratio of acetone is small, sodium methoxide remains and decomposes the main product, sodioformylacetone. This is because the reaction yield is reduced.

Next, the molar ratio of methyl formate to sodium methoxide is preferably 1 to 10, and preferably 1 to 3 is used. As described above, one of the methods for suppressing the side reaction is to increase the main reaction rate, and therefore, it is preferable that methyl formate is in excess for this purpose. However, from an economic perspective, the boiling point of methyl formate is 32.
Since it is as low as ℃, it is quite difficult to separate and recover it from methanol. Therefore, in order to reduce the raw material cost, it is preferable that the excess amount is as small as possible. Therefore, the reaction is particularly preferably carried out in the range of 1.5 to 2.5.

Acetone and methyl formate are added to the charged methanol solution of sodium methoxide, but acetone and methyl formate may be added separately or as a mixed solution. However, as mentioned above, as the concentration in acetone becomes higher, the side reaction is more likely to occur. Therefore, acetone is supplied over a period of time so that the reaction rate of acetone in the reaction solution remains at 3% or less. It is preferable to react. When the reaction is carried out at the above molar ratio, the reaction time is 1 hour or longer, preferably 2 hours or longer, and there is no particular upper limit, but it is usually 10 hours or shorter in view of productivity in industrial production.

On the other hand, for methyl formate, the concentration in the liquid should be high in order to increase the main reaction rate, but since the reaction liquid is strongly alkaline and the decomposition reaction of methyl formate also occurs, this is also supplied at the same time as acetone. Preferably
The above raw material ratio is fed into a methanol solution of sodium methoxide. That is, for example, it is preferable to supply twice the molar amount of methyl formate to the charged sodium methoxide and equimolar amount of acetone at the same time into the methanol solution of sodium methoxide over 3 hours or more. As mentioned above, the molar ratio of acetone to methyl formate is 1.5 to 3.0 for methyl formate to acetone.
Is preferred.

The reaction can be carried out in either a batch system or a continuous system. In the case of the batch system, the reaction is carried out under the conditions of the above reaction amount ratio, and in the case of the continuous system, sodium methoxide, acetone and methyl formate are used. Mix and react at the above ratio,
The reaction is carried out by simultaneously supplying so that the residence time is, for example, 3 hours or more. Since it is desirable to carry out sufficient stirring when carrying out the reaction, a device capable of performing sufficient mixing by selecting the shape of the stirring blade and the reactor capable of performing sufficient reaction in batch or continuous reaction is preferred.

The reaction temperature is determined by selecting the temperature at which the yield of the main reaction is highest due to the competition between the reaction rates of the main reaction and the side reaction. The reaction temperature at the starting material molar ratio under the above conditions is It can be carried out at 10 ° C to 60 ° C, preferably 25 ° C to 50 ° C, and most preferably 35 ° C to 45 ° C. The reaction pressure is not particularly limited, but since the compound to be handled has a low boiling point, it is slightly pressurized from normal pressure (1-2 kg / cm ² G) in order to prevent evaporation of the raw materials from the reaction system. It is preferable to carry out. Further, when the reaction is carried out at normal pressure, it is preferable to install a condenser in the reactor, condense the evaporated component with cold water, and sufficiently reflux methyl formate.

The sodioformylacetone thus produced is industrially known as a unit operation, which is a unit operation known as a crystallization operation such as a concentration cooling method or a solution evaporation method. It can be obtained in high yield. The high-purity sodioformylacetone obtained by this method is very useful when it is used as a raw material for pharmaceuticals, and the obtained sodioformylacetone is subjected to various further reactions. Sum and acetalize to 4,
When 4-dimethyl-2-butanone is obtained, it can be used as a methanol solution as it is, so that the step of separating and recovering methanol can be omitted, which is very useful when industrially carried out.

[0015]

EXAMPLES Next, the method of the present invention will be described in more detail by way of examples, but these do not limit the method of the present invention in any way. Example 1 A 2 l four-necked flask equipped with a thermometer, dropping funnel, Dimroth condenser, stirrer, and exhaust pipe to the draft was placed in a 28% sodium methoxide methanol solution 579.
g (3.0 mol) was added, this was heated to 40 ° C., methyl formate 540 g (9.0 mol) and acetone 191 g
A mixed solution of (3.3 mol) was added dropwise over 3 hours. During the reaction, the liquid temperature was kept at 40 ° C. and the mixture was sufficiently stirred.

After continuing the stirring for 1 hour after dropping, quantitative analysis of sodioformylacetone by liquid chromatography revealed that 302 g (2.8 mol) of sodioformylacetone was produced ( 93.3% yield based on sodium methoxide). In addition, the by-product diacetone alcohol methyl ether body is about 8 g (0.06
Mol).

Example 2 Example 1 was repeated except that the amount of acetone used was 174 g (3.0 mol). As a result of the analysis, the amount of sodioformylacetone produced was 292 g (2.7 mol).
(90% yield based on sodium methoxide).
In addition, the methyl ether form of diacetone alcohol as a by-product was about 5 g (0.04 mol).

Comparative Example 1 (Additional Reference to Reference) In the same apparatus as in Example 1, 180 g of methyl formate (3.0 g) was used.
162 g (3.0 mol) of powdery sodium methoxide was slowly added under cooling, and after heating and refluxing for 15 minutes, 192 g (3.3 mol) of acetone was added dropwise over 15 minutes. After dropping, continue stirring for 1 hour and heat.
After performing reflux, when analyzed in the same manner as in Example,
The amount of sodioformylacetone produced is about 60 g (0.55
Mol) (18.3% yield based on sodium methoxide)
Met. The reaction liquid was a slurry having a very high viscosity.

Comparative Example 2 540 g (9.0 mol) of methyl formate and 191 g of acetone
The same procedure as in Example 1 was repeated, except that the mixed solution (3.3 mol) was added dropwise for 30 minutes. As a result, the amount of sodioformylacetone produced was 185 g (1.7 mol).
(56.6% yield based on sodium methoxide). In addition, the by-product diacetone alcohol methyl ether form was about 55 g (0.51 mol).

Examples 3 to 9 Using the same apparatus as in Example 1, 579 g (3.0 mol) of 28% sodium methoxide methanol solution was added,
This was heated up to 40 ° C., and a mixed solution in which 191 g (3.3 mol) of acetone and an amount of methyl formate were changed was added dropwise over 3 to 10 hours to react. During the reaction, the liquid temperature was kept at 40 ° C. and the mixture was sufficiently stirred. After the reaction, the reaction solution was quantitatively analyzed for sodioformylacetone by liquid chromatography. The reaction results are shown in Table 1 with the yield of sodioformylacetone (based on sodium methoxide) and the amount of by-product methyl ether form of diacetone alcohol.

[0021]

[Table 1]

Claims (1)

[Claims] 1. A method for producing sodioformylacetone using acetone, methyl formate and sodium methoxide as starting materials, wherein sodium methoxide is used as a methanol solution, and acetone and methyl formate are added to the methanol solution of sodium methoxide. The method for producing sodioformylacetone, which comprises simultaneously supplying the mixed solution or the respective solutions at the same time and thoroughly mixing them while supplying them so that the acetone does not become excessive over a certain time.