JPH0637428B2 - Method for producing pyruvic acid ester - Google Patents

Description

TECHNICAL FIELD The present invention relates to a method for producing a pyruvic acid ester by oxidizing a methacrylic acid ester with hydrogen peroxide, and more specifically to a methacrylic acid ester and a peroxide. The present invention relates to a novel method for producing a pyruvic acid ester by reacting hydrogen under a metal catalyst.

Pyruvate obtained by hydrolyzing a pyruvate ester is a highly reactive compound and is easily used as a raw material for various synthesis because it easily reacts with phosphorus, nitrogen, chlorine compounds, aldehydes and the like. For example, as a drug, L-tryptophan, L-cystine,
As synthetic raw materials for amino acids such as L-tyrosine and L-doper, quinophene, calcium isoniazidopyrupate, hormones, etc., α-cyanoacrylate and an industrially valuable α-cyanoacrylate in the plastic industry, textile industry, adhesives field, etc. It is a promising product as an intermediate for the synthesis of monomers such as α-acyloxy acrylate, and further, its application and development as a raw material for the synthesis of fragrances and agricultural chemicals is underway.

(Prior art and its problems) Conventionally, as a method for producing a pyruvic acid ester, a method of dry distillation of tartaric acid in the presence of potassium hydrogen sulfate (Org.Syn,
Coll. Vol. 1475, 1941), a method of reacting sodium cyanide with acetyl chloride to synthesize acetyl cyanide and hydrolyzing it, and a method of oxidizing acetone with selenium dioxide (Patent Publication No. 54-81221). ), A method of air-oxidizing hydroxyacetone under a metal catalyst (Patent Publication No. 54-39016), and a method of oxidizing mesityl oxide with a peroxide (Patent Publication No. 56-120634).
No.), a method for producing metal oxides by reacting oxaloacetate in the presence of protein (Patent Publication No. 51-70724).
No.), a method of oxidizing a lactate ester with potassium permanganate (Org, Syn, 31 , 59, 1959), a method of producing a lactic acid ester by an enzymatic method, a method of air-oxidizing a lactate ester under a metal catalyst, etc. Proposed.

However, the method (1) has a drawback that the raw material tartaric acid is expensive and uses a large amount of potassium hydrogen sulfate as a by-product, and the method (1) is expensive, the yield is low, and a large amount of by-products are separated and purified. Is difficult, and the method of using an expensive catalyst, there is a drawback that the yield is low, further,
It is difficult to obtain raw materials by the methods of and.

At present, pyruvic acid itself is expensive and its application range is limited because raw material lactic acid is expensive even by the method which is industrially adopted.

An object of the present invention is to provide a novel method for producing an inexpensive pyruvic acid ester, which overcomes the above-mentioned drawbacks of the conventional method.

(Means for Solving Problems) As a result of various studies on the method for producing a pyruvic acid ester, the present inventors have found that methacrylic acid ester is reacted with hydrogen peroxide under a certain metal catalyst. Surprisingly, they have found that the double bond at the α-position of methacrylic acid ester is not epoxidized and undergoes oxidative cleavage to produce pyruvic acid ester, and thus completed the present invention.

That is, the present invention is to produce a pyruvic acid ester by reacting a methacrylic acid ester with hydrogen peroxide in the presence of an organic complex compound of chromium or vanadium.

The methacrylic acid ester, which is a raw material of the method of the present invention, has the general formula (1) (However, R is an ester residue, and is exemplified by methyl, ethyl, isopropyl, n-butyl, cyclohexyl, glycidyl, etc.).

These methacrylic acid esters, especially methacrylic acid methyl esters, are produced in large quantities by the direct oxidation method of isobutylene or a C ₅ fraction containing isobutylene, and can be industrially obtained at a very low cost. Therefore, according to the method of the present invention, a pyruvic acid ester can be produced from a methacrylic acid ester in a high yield in a single step in a good yield, and the pyruvic acid ester can be industrially inexpensively obtained without the drawbacks of the conventional method. be able to.

The method of the present invention is a method for producing a pyruvic acid ester by oxidizing a methacrylic acid ester with hydrogen peroxide in the presence of a chromium or vanadium catalyst, and is a methacrylic acid such as acetonitrile commonly used in an oxidation reaction. A substance that is well miscible with the ester and hydrogen peroxide is used as a solvent, which is added to the methacrylic acid ester and reacted with hydrogen peroxide.

In the method of the present invention, specific examples of the organic complex compound of chromium or vanadium used as the catalyst include an acetylacetone complex salen complex of chromium or vanadium or a compound of tributyltin oxide, and more specifically, trisacetylacetate. Examples include natochrome, trisacetylacetonatovanadium, chromium / salen complex, vanadium / salen complex, bis (tri-n-butyltinoxy) chromic acid, and bis (tri-n-butyltinoxy) vanadic acid. These catalysts can be easily synthesized by known methods.

If a catalyst in the form of a simple oxide or halide is used, hydrogen peroxide is preferentially decomposed and the intended reaction occurs only partially.

In the method of the present invention, commercially available reagents or industrial chemicals can be used as they are as hydrogen peroxide, and the concentration of hydrogen peroxide is not particularly limited.

The reaction between the methacrylic acid ester and hydrogen peroxide is carried out at room temperature to 80 ° C. under normal pressure, but usually 40
Frequently used temperatures of ℃ to 60 ℃.

Hereinafter, the present invention will be described in more detail with reference to Examples.
The invention is in no way limited by these examples.

(Example) Example-1 5 ml of methacrylic acid ester was added to 10 ml of acetonitrile.
l and trisacetylacetonatochrome 3.0 × 10 ^-2 mmol
Is dissolved, the reaction vessel is placed in a constant temperature water bath, and the mixture is stirred with stirring 6
20 mmol of 0% H ₂ O ₂ was added. After adding hydrogen peroxide, the reaction was carried out for 8 hours while stirring. The temperature during the addition of hydrogen peroxide and during the reaction was kept at 50 ° C.

The conversion of methacrylic acid ester and the selectivity of methyl pyruvate were measured by gas chromatography analysis of the reaction solution. The results of the reaction are shown in Table 1.

Example-2 Bis (tri-n-butyltinoxy) chromic acid was used as a catalyst in place of trisacetylacetonatochromium at 3.0 × 10 ^-2.
The reaction was performed in the same manner as in Example 1 except that mmol was used. The results of the reaction are shown in Table 2.

Example 3 Trisacetylacetonato vanadium was used as a catalyst in place of trisacetylacetonatochromium at 3.0 × 10 ⁻² mmo.
The reaction was carried out in the same manner as in Example-1 except that it was used. The results of the reaction are shown in Table 3.

Example-4 A reaction was carried out in the same manner as in Example-1 except that 3.0 × 10 ^-2 mmol of chromium / salen complex was used instead of trisacetylacetonatochromium as a catalyst. The results of the reaction are shown in Table 4.

Claims (1)

[Claims] 1. A method for producing a pyruvic acid ester by oxidizing a methacrylic acid ester, wherein the methacrylic acid ester is oxidized with hydrogen peroxide in the presence of an organic complex compound of chromium or vanadium. Method for producing ester.