JPS6024777B2 - Method for producing alkaline earth metal salt of aliphatic β-keto compound - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a process for preparing alkali metal salts of aliphatic 8-keto compounds.

More specifically, the present invention is characterized in that aliphatic 6-ketesters or B-diketones are treated with an alkali metal hydroxide without a solvent to obtain the corresponding alkali metal salts. - A method for producing an alkali metal salt of a keto compound.

Conventionally, alkali metal salts of aliphatic 8-keto compounds,
For example, acetoacetic acid ethyl ester and calcium salts of acetylacetone are widely used as non-toxic stabilizers when molding PVC. There are various methods for synthesizing them; for example, a method for synthesizing calcium salts of ethyl acetoacetate is [method of treating with metallic calcium in 1' absolute ethanol [Zh. 0bscheK
Him 42403 (1972)], '2} There is a method of processing with calcium carbide or calcium oxide in anhydrous benzene (J. Chem. SM 1951, 2505), and a method of synthesizing alkali metal salts of acetylacetone. '3} A method in which ketimine is formed using ammonia and then treated with a metal salt to replace it (Snake r.1, 0390
56), ■Method of treatment with metal hydroxide in an aqueous solvent [
Compt. To Rend 157, 50 (1913)]
Examples include.

However, each of these methods has its own drawbacks, and there are many disadvantages when producing on an industrial scale.

For example, method '1) uses expensive metallic calcium, which poses a cost problem, and method '2) uses calcium carbide, which makes it difficult to obtain high-purity calcium carbide and requires high hardness. However, the method using calcium oxide is the only industrially viable method, but the reaction progresses very slowly, gels as it progresses, and is colored yellow. There were drawbacks. On the other hand, if the method '2} is improved and treated with calcium hydroxide in benzene, the reaction will proceed easily, but the entire reaction solution will turn into a gel, and if the benzene is concentrated after the reaction, it will become a viscous product and crystallize. Only a colored product was obtained.
On the other hand, in recent years, regulations regarding pollution have become stricter, and it is desirable to keep the use of organic solvents, which tend to cause water pollution, to the minimum necessary, and it is also desirable to manufacture the above compounds under substantially solvent-free conditions. was desired. Under these circumstances, the inventor of the present invention has developed highly pure alkali metal salts of aliphatic 8-ketesters and aliphatic 8-diketones by a simple method using inexpensive raw materials in a substantially solvent-free environment. As a result of repeated research aimed at obtaining a product, the present invention was achieved. Thus, the method for preparing alkali metal salts of 8-keto compounds according to the present invention provides a method for preparing alkali metal salts of 8-keto compounds.
- The reaction is carried out by adding alkali metal hydroxide little by little to ketoesters and aliphatic 8-diketones in the absence of a solvent.

According to this method, the reaction proceeds extremely easily in the absence of a solvent, and the desired product can be obtained in high yield without generating heat that would induce hydrolysis. Further, if water or methanol is added after the reaction is substantially completed, there is an advantage that the target product can be easily collected. The aliphatic 8-ketesters and aliphatic 8-diketones used in this invention are:
The following general formula [1,:R, COCH2COR2
(1) (In the formula, R represents an alkyl group, and R2 represents an alkyl group or an alkyloxy group.

).

Particularly suitable compounds for use in the present invention are R, and R
2 is a lower alkyl group or a lower alkyloxy group having 1 to 3 carbon atoms. Among these, ethyl acetoacetate, methyl acetoacetate and acetylacetone are particularly preferred. Further, the alkali metal hydroxides include calcium hydroxide, magnesium hydroxide, and barium hydroxide. The ratio of the aliphatic P-keto compound to the alkali metal hydroxide is preferably 1:1. Since the reaction is somewhat exothermic, it is desirable to add the alkali metal hydroxide little by little to the aliphatic 8-keto compound at room temperature and carry out the reaction while appropriately maintaining the exothermic slope.

After the reaction is completed, there is no need for any special treatment, and the target product can be obtained in high yield and with high purity. Furthermore, if it is desired to obtain a product with higher purity, the reaction can be completed for a small amount of unreacted material by adding water or methanol, and collection of the target product can also be facilitated. In this case, the amount of water or methanol added is
- Preferably up to twice the weight of the keto compound used. The alkali metal salt of the aliphatic 8-keto compound thus obtained has no coloration and is of very high quality.
Next, the present invention will be explained by examples.

Example 1 Ethyl acetoacetate calcium salt 3 390 ml of ethyl acetoacetate and 20 ml of calcium hydroxide are added to the ground mixture to start the process.

The reaction begins after about 1 minute, followed by calcium hydroxide 10
When adding Tazu every 2 to 3 minutes, the reaction solution becomes a gel. Further addition was continued, reaching the maximum temperature (approximately 40°C) after approximately 70 evenings. Add calcium hydroxide until the total amount becomes 111, react for 40 to 50 minutes, and then dry at 7 and 0 for 3 hours to obtain pale pink ethyl acetoacetate calcium salt 44.
Get 4 evenings. (Yield: 99.3%) mP21pi○ (decomposition) Example 2 Methyl acetoacetate calcium salt 3 Add 80% of methyl acetoacetate and 20% of calcium hydroxide to the grinder and react in the same manner as in Example 1. A white methylcalcium acetoacetate salt 369 was obtained.

(Yield: 91.1%) ○ (decomposition) at mP22 Example 3 Acetylacetone calcium salt 3 Grinding machine 300 g of acetylacetone and 209 g of calcium hydroxide are added and reacted in the same manner as in Example 1 to produce white acetylacetone calcium. Salt powder crystal 312
Get the evening.

(Yield: 87.2%) mP26.8qo (decomposition) Example 4 Magnesium acetylacetone salt 3 Add 300 g of acetylacetone and 10 g of magnesium hydroxide to the grinder and start grinding.

The reaction starts after about 1 minute, and then 5 tons of magnesium hydroxide is added every 2 to 3 minutes, and the reaction solution turns into a gel and boils. Further addition was continued until the maximum temperature (7 pi○) was reached after about 60 days. Magnesium hydroxide was added until the total amount reached 87.6 mm, and the mixture was reacted for about 1 hour, and then dried at 8°C for 3 hours to obtain 309 mm of white acetylacetone magnesium salt powder crystals. (Yield: 0.7%) mP 154°C (decomposition) Example 5 Ethyl acetoacetate magnesium salt 3 To the grinder were added 390 g of ethyl acetoacetate and 102 g of magnesium hydroxide, and the reaction was carried out in the same manner as in Example 4.

Drying at 80 quarts (maximum temperature 70° C.) yields 367 white powder crystals of ethylmagnesium acetoacetate. (Yield: 865%) mP244qo (decomposition) Example 6 Ethyl calcium acetoacetate The reaction was carried out according to the method of Example 1, and the total amount of calcium hydroxide was added, and after about 3 minutes of reaction, methyl alcohol was added to complete the reaction. Add 220 ml of ethyl acetate and continue to stir for 10 to 20 minutes, then filter under suction and dry the crystals at 70°C to obtain ethyl acetoacetate calcium salt 396 ml.

(Yield: .6%) mP220qo (decomposition) Example 7 Acetylacetone calcium salt The reaction was carried out according to the method of Example 3, the total amount of calcium hydroxide was added, and after about 30 minutes of reaction, 300 g of distilled water was added to complete the reaction. After adding water and continuing the stirring for 10 to 2 minutes, the crystals are dried at 70 qo after suction filtration to obtain 304.4 qo powder crystals of acetylacetone calcium salt.

Claims (1)

[Scope of Claims] 1. An aliphatic compound characterized in that an aliphatic β-ketoester or β-diketone is treated with an alkaline earth metal hydroxide without a solvent to obtain the corresponding alkaline earth metal salt. A method for producing an alkaline earth metal salt of a β-keto compound. 2. The method according to claim 1, wherein the aliphatic β-ketoester is ethyl acetoacetate or methyl acetoacetate. 3. The method according to claim 1, wherein the aliphatic β-diketone is acetylacetone. 4. The method according to any one of claims 1 to 3, wherein the alkaline earth metal hydroxide is calcium hydroxide, magnesium hydroxide, or barium hydroxide. 5. The method according to any one of claims 1 to 4, wherein water or methanol is added after substantially the reaction has taken place.