JPS61191651A - Recovery of catalyst for phenylpyruvic acid production - Google Patents

Abstract

PURPOSE:The reaction between benzyl chloride, carbon monoxide and an alkaline earth metal base is carried out in the presence of a catalyst of Co carbonyl, in the presence of water and a solvent hard soluble in water, then the titled product is separated from the solvent phase containing the catalyst whereby the catalyst is recovered. CONSTITUTION:The reaction between benzyl chloride, carbon monoxide and an alkaline earth metal base such as calcium hydroxide is carried out in the presence of a cobalt carbonyl catalyst such as dicobalt octacarbonyl to give the titled substance where water and a solvent hard soluble in water, preferably methyl isobutyl ketone or acetophenone is used and the reaction mixture is filtered to separated the solvent layer containing the catalyst, from which the catalyst is recovered. The solvent layer containing the catalyst can be reused directly in the following reactions. EFFECT:Since the alkaline earth metal salt of phenylacetic acid, as a by-product, is in the aqueous layer, it is easily separated from the catalyst.

Description

Detailed Description of the Invention (a) Industrial Application Field The present invention is a method for producing phenylpyruvic acid by reacting benzyl chloride and carbon monoxide in the presence of an alkaline earth metal base using a cobalt carbonyl compound as a catalyst. In the method, water and a poorly water-soluble solvent are added to the reaction system to cause a reaction, and after the reaction, the reaction product and a poorly water-soluble solvent layer containing a catalyst are separated. This invention relates to a catalyst recovery method.

Phenylpyruvic acid is an important starting material, for example, as a raw material for producing phenylalanine, which is a raw material for sweeteners.

(b) Prior art The method for producing phenylpyruvic acid by the reaction of benzyl chloride and carbon monoxide is known, for example, in Japanese Patent Publication No. 56-1
Publication No. 8587 and the like can be mentioned.

In Japanese Patent Publication No. 18587, benzyl chloride and carbon monoxide are reacted in a water/alcohol mixed solvent in the presence of an alkaline earth metal base using a metal carbonyl compound, particularly a cobalt carbonyl compound, as a catalyst. A method for producing phenylbilpic acid has been proposed.

(c) Problems to be solved by the invention However, in existing phenylpyruvic acid production methods such as the above-mentioned Japanese Patent Publication No. 56-18587, phenylpyruvic acid precipitates as a solid during the reaction. It can be easily obtained by treating an alkali metal salt or alkaline earth metal salt with an acid after filtration, but the alkali metal salt or alkaline earth metal salt of by-product phenylacetic acid and the cobalt carbonyl catalyst are dissolved in the reaction filtrate. Therefore, complicated steps are required to separate the by-product alkali metal salt or alkaline earth metal salt of phenylacetic acid from the cobalt carbonyl catalyst and to regenerate the cobalt carbonyl catalyst.

To regenerate the cobalt carbonyl catalyst, water/alcohol solvent etc. are removed from the reaction filtrate, and after treatment with mineral acid to recover by-product phenylacetic acid, the produced cobalt mineral salt is treated with, for example, alkali hydroxide, etc. After processing to produce cobalt hydroxide, the cobalt hydroxide is further reacted with high-temperature, high-pressure water gas to produce a cobalt carbonyl compound.

The present inventors have completed the present invention as a result of their earnest efforts and studies to improve these drawbacks.

(d) Means for solving the problems The present invention provides a method for producing phenylpyruvic acid by reacting benzyl chloride and carbon monoxide in the presence of an alkaline earth metal base using a cobalt carbonyl compound as a catalyst. A method for recovering a cobalt carbonyl catalyst, which is characterized by adding water and a poorly water-soluble solvent to the reaction system to cause a reaction, and after the reaction, separating the reaction product and a poorly water-soluble solvent layer containing the catalyst. It is related to.

Examples of the slightly water-soluble solvent in the present invention include benzene,
Aromatic hydrocarbons such as toluene, aliphatic hydrocarbons such as hexane and heptane, aliphatic and aromatic ethers such as diethyl ether, diisopropyl ether, diphenyl ether, methyl isobutyl ketone, acetophenone, diisopropyl ketone, methyl isopropyl ketone,
Aliphatic and aromatic ketones such as dibutyl ketone, diisobutyl ketone, and cyclopentanone are selected, and ketones such as methyl isobutyl ketone and acetophenone are particularly preferred.

The concentration of benzyl chloride in the reaction solvent is not particularly limited, but
It is generally used in an amount of 1 to 50% by weight based on the slightly water-soluble solvent.

The amount of water is generally 10 to 200% of the solvent that is poorly soluble in water.
% by weight used.

The alkaline earth metal base used in the present invention is generally selected from alkaline earth metal hydroxides, alkaline earth metal oxides and alkaline earth metal carbonates, but in particular alkaline earth metal hydroxides are used. Among them, calcium hydroxide is preferred.

The amount of alkaline earth metal base used should generally be at least 1 mol per mol of benzyl chloride, and at least 1.1 to 2.0 mol per mol of benzyl chloride.
Preference is given to using moles.

As the catalyst, cobalt carbonyl compounds, especially dicobalt octacarbonyl, are preferred.

The cobalt carbonyl compound/benzyl chloride (molar ratio) of the catalyst is generally used in a range of 1/1 to 1/1000, but a range of 1/30 to 1/200 is particularly preferred.

Carbon monoxide does not need to be of high purity, and water gas or the like can also be used. - Carbon oxide pressure is 0°5 to 200 to -C
A range of kg/cd is adopted, preferably 5 to 50
A range of kg/cJ is good.

The reaction temperature is preferably 20 to 150°C, preferably 40 to 100°C.
Good temperature.

Generally, the reaction is carried out until absorption of carbon monoxide stops;
The reaction solution is treated as follows to recover the target product phenylpyruvic acid, by-products phenylacetic acid and cobalt carbonyl catalyst.

That is, by filtering the reaction solution, the solid portion consisting of the alkaline earth metal salt of phenylpyruvic acid precipitated as a solid during the reaction, the aqueous layer portion containing the alkaline earth metal salt of phenylacetic acid, and the cobalt carbonyl catalyst are removed. It can be separated into a solvent layer that is poorly soluble in the water it contains.

Subsequently, the alkaline earth metal salt of phenylpyruvic acid separated by the filtration operation is acidified with an aqueous mineral acid solution, for example, a dilute aqueous hydrochloric acid solution, and the resulting aqueous solution is extracted with a suitable organic solvent, such as diethyl ether. Phenylpyruvic acid can be obtained by removing the organic solvent.

Similarly, the aqueous layer containing the alkaline earth metal salt of phenylacetic acid is acidified with an aqueous mineral acid solution, for example, a dilute aqueous hydrochloric acid solution, and the resulting aqueous solution is extracted with a suitable organic solvent, such as diethyl ether. By removing , the by-product phenylacetic acid can be recovered.

Further, the solvent layer portion containing the cobalt carbonyl catalyst and poorly soluble in water can be recycled to the reaction system as it is without any treatment and can be reused.

(E) Effects of the Invention According to the present invention, the alkaline earth metal salt of by-product phenylacetic acid and the cobalt carbonyl catalyst can be easily separated from each other, and the cobalt carbonyl catalyst can be recycled to the reaction system and reused as it is. Furthermore, phenylpyruvic acid can be produced in high yield.

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

Example) Example 1 In a 300++ liter stainless steel autoclave, 75 ml of methyl isobutyl ketone and T5 tal of water were added.

18.6 g (0,251 mol) of calcium hydroxide, 15.4 g (0,122 mol) of benzyl chloride, and 1.2 g (0,0035 mol) of dicobalt octacarbonyla were charged.

After washing the inside of the autoclave with carbon monoxide, the pressure of -carbon oxide was set to 10 kg/Cl11 and the temperature was raised while stirring. - The reaction was carried out at a carbon oxide pressure of 10 kg/cd and a temperature of 70° C. for 6 hours until absorption of carbon monoxide stopped. After the reaction, the reaction mixture was separated from the autoclave into a solid, an organic layer, and an aqueous layer through a pressure filter using carbon monoxide pressure.

Transfer the resulting solid to a 500 ml flask and add 10%
Hydrochloric acid aqueous solution 270+lIl and diethyl ether 150ml
j+ was added and stirred until the solid was completely dissolved. After separating the diethyl ether layer, the aqueous layer was further diluted with diethyl ether 1
Treated twice with 00I111. These diethyl ether layers were combined, washed with water, and then dried over sodium sulfate. After drying, diethyl ether is distilled off, phenylpyruvic acid 14.
7 g was obtained, and the sheet weight was 73.5%.

The aqueous layer of the reaction filtrate was treated with 70mj of 10% aqueous hydrochloric acid solution! The mixture was acidified and extracted three times with 100 mf of diethyl ether. These diethyl ether layers were combined, dried over sodium sulfate, and the diethyl ether was distilled off, leaving only phenylacetic acid.
．． 5 g was obtained, and the sheet weight was 15.0%.

In addition to the cobalt carbonyl catalyst, a small amount of benzyl alcohol was present in the organic layer of the reaction filtrate.

Example 2 Water 25mA! , 6.2 g of calcium hydroxide, 5.1 g of benzyl chloride, and methyl isobutyl ketone containing the cobalt carbonyl catalyst of Example 1 were added to machine layer 2511+1.
The mixture was placed in an oOmN stainless steel autoclave, and the reaction and treatment were carried out in the same manner as in Example 1. The weight of phenylpyruvic acid is 73.0%, and the weight of phenylacetic acid is 15.2.
%Met.

Example 3 Example 1 except that acetophenone was used as a poorly soluble solvent in water and the carbon monoxide pressure was 50 kg/crA.
The reaction and treatment were carried out in the same manner as above. The shedding rate of phenylpyruvic acid was 72.5%, and the sheet weight of phenylacetic acid was 12.4%.

Example 4 Water 25mj! , 100 m of acetophenone organic 1125 IIll containing 6.2 g of calcium hydroxide, 5.1 g of benzyl chloride, and the cobalt carbonyl catalyst of Example 3.
j! Example 3
The reaction and treatment were carried out in the same manner as above.

The weight of phenylpyruvic acid was 74.2%, and the weight of phenylacetic acid was 14.0%.

Patent Applicant: Nissan Chemical Industries, Ltd. Procedural Amendment (Voluntary) July 6, 1937 Director General of the Patent Office Mr. Michibe Uga 1 Indication of the Case 1985 Patent Application No. 33194 2 Name of the Invention Catalyst for the Production of Phenylpyruvic Acid Recovery method 3 Relationship with the case of the person making the amendment Patent applicant address 3-7-14 Kanda Nishiki-cho, Chiyoda-ku, Tokyo 0101
Claims column and Detailed Description of the Invention column 5 of the specification to be amended Contents of the amendment ■: The claims of the specification are corrected as shown in the attached sheet.

2. Page 6 of the specification, lines 8 to 10, “0°5 to 20
A range of 0 kg/- is adopted, but preferably 5 to 50
A range of kg/aJ is good. ” is r O, 5~2
A range of 00 kg/aJ is adopted. ” he corrected.

3. The text "rroomJJ" on page 10, line 7 and page 11, line 1 of the specification is corrected to "135m7!J".

4. On page 11 of the specification, after the 5th line, insert a line break and write ``Example 5 In a 500 mJ glass autoclave, 100 ml of methyl isobutyl ketone, 50 ml of water, 9.3 g (0,126 mol) of calcium hydroxide % , benzyl chloride7.
7 g (0,061 mol) and 1.2 g (0,0035 mol) of dicobalt octacarbonyl were charged.

After washing the inside of the autoclave with carbon monoxide, carbon monoxide was blown into the autoclave at normal pressure, and the temperature was raised while stirring.

- The reaction was carried out at a temperature of 50° C. for 20 hours until the absorption of carbon oxide stopped. After the reaction, the same treatment as in Example 1 was carried out, and the weight of phenylpyruvic acid was 71.0%, and the weight of phenylacetic acid was 22.2%.

Example 6 Water 25mm! , 50 n/l of methyl isobutyl ketone organic layer containing 4.7 g of calcium hydroxide, 3.8 g of benzyl chloride and the cobalt carbonyl catalyst of Example 5 was added to 13
The mixture was charged into a 5 ml stainless steel autoclave, and the reaction and treatment were carried out in the same manner as in Example 5.

The weight of phenylpyruvic acid was 71.5%, and the weight of phenylacetic acid was 22.0%.

Example 7 The reaction and treatment were carried out in the same manner as in Example 5, except that acetophenone was used as a poorly water-soluble solvent. The weight of phenylpyruvic acid is 71.2%, and the weight of phenylacetic acid is 2.
It was 1.7%.

Example 8 25 mf of water, 4.7 g of calcium hydroxide, 3.8 g of benzyl chloride, and 50 Ill of an acetophenone organic layer containing the cobalt carbonyl catalyst of Example 7 were charged into a 135 mA stainless steel autoclave, and reacted and carried out in the same manner as in Example 7. processed.

The weight of phenylpyruvic acid was 72.0%, and the weight of phenylacetic acid was 21.2%. ” to join.

2. Claims l A method for producing phenylpyruvic acid by reacting benzyl chloride and carbon monoxide in the presence of an alkaline earth metal base using a cobalt carbonyl compound as a catalyst, including water and a poorly water-soluble solvent. 1. A method for recovering a cobalt carbonyl catalyst, which comprises adding to a reaction system to cause a reaction, and after the reaction, separating a reaction product and a solvent layer containing the catalyst that is sparingly soluble in water.

2. The dish Ll according to claim 1, wherein the solvent poorly soluble in water is a ketone.

3. The double plate according to claim 1, characterized in that the ketone is methyl isobutyl ketone or acetophenone.

Claims (1)

[Scope of Claims] 1. In a method for producing phenylpyruvic acid by reacting benzyl chloride and carbon monoxide in the presence of an alkaline earth metal base using a cobalt carbonyl compound as a catalyst, water and a poorly water-soluble solvent are used. 1. A method for recovering a cobalt carbonyl catalyst, which comprises adding to a reaction system to cause a reaction, and after the reaction, separating a reaction product and a solvent layer containing the catalyst that is sparingly soluble in water. 2. The manufacturing method according to claim 1, wherein the solvent that is poorly soluble in water is a ketone. 3. The manufacturing method according to claim 1, wherein the ketone is methyl isobutyl ketone or acetophenone.