JP2003267939A - Method for producing aminocarboxylic acid (salt) - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method for producing an aminocarboxylic acid or its salt, more improved in reactivity of amino-alcohol used as a raw material than ever, and improved in a yield of the aminocarboxylic acid or its salt, by using a catalyst having good moldability so as not to be restricted in reaction patterns. <P>SOLUTION: This method for producing the aminocarboxylic acid or its salt comprises oxidizing the amino-alcohol with oxygen-containing gas, wherein a gold catalyst which contains at least one kind of metal oxide selected from cobalt oxide, zirconium oxide, and zinc oxide is used as a catalyst for producing the aminocarboxylic acid or its salt. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a method for producing an aminocarboxylic acid or a salt thereof from an aminoalcohol as a raw material.

[0002]

2. Description of the Related Art Heretofore, there have been many reports on a method for producing an aminocarboxylic acid from amino alcohol as a raw material. In the old days, USP2,384,817, USP3,842,08
As described in No. 1, Japanese Patent Publication No. 1-53863, Japanese Patent Publication No. 1-53864, etc., oxidation was carried out using cadmium, copper, etc. as a catalyst. These are alkaline oxidations that generate hydrogen, and it is necessary to take explosion-proof measures for exhaust equipment. In addition, about 50% high concentration caustic 150-350
Corrosion of the reactor is severe because the reaction is performed at a high temperature of about ℃,
Not practical. To solve this problem, Japanese Patent Publication No. 56-2548 and Japanese Patent Publication No. 59-45666 disclose Pt.
It has been reported that the reaction proceeds even under mild conditions of 100 ° C. or lower by using / C or Pd / C catalyst and supplying oxygen-containing gas such as air into the reaction system. In this reaction, hydrogen atoms extracted from the raw material are oxidized by oxygen into water, so that hydrogen gas is not generated and there is no danger of explosion. Further, the alkali is added not as an oxidizing agent but for the purpose of neutralizing the generated carboxylic acid and keeping the pH on the alkaline side, and therefore, it may be added in an equivalent amount to the generated carboxylic acid. As described above, Pt / C or Pd /
Generation of hydrogen by using C catalyst and oxygen-containing gas,
Although the problem of container corrosion has been solved, the yield of the obtained aminocarboxylic acid may be as low as about 70% depending on the type of amino alcohol as a raw material.

On the other hand, Japanese Unexamined Patent Publication No. 2000-63338.
Discloses a method of improving the yield by using a catalyst in which gold is supported on a carrier. In this method, the target aminocarboxylic acid yield is improved by using a gold catalyst, but there is still room for improvement. Further, in the examples described in this publication, activated carbon is used as a catalyst carrier, but activated carbon has poor moldability of the catalyst as compared with other general catalyst carriers such as metal oxides, and has an arbitrary shape. Difficult to mold. Therefore, although there is no problem in using the powder state in a reactor such as a stirring bed system or a suspension bed system, it is difficult to use it as a pellet in a fixed bed reaction, and the reaction mode is limited.

The object of the present invention is to further improve the reactivity of amino alcohol and the yield of aminocarboxylic acid or its salt, and to use a catalyst which is not restricted in the reaction mode, that is, has good moldability. It is to provide an aminocarboxylic acid or a salt thereof.

[0005]

The present invention is a method for producing an aminocarboxylic acid or a salt thereof by oxidizing an aminoalcohol with an oxygen-containing gas, wherein the catalyst is selected from cobalt oxide, zirconium oxide and zinc oxide. A method for producing an aminocarboxylic acid or a salt thereof using a gold catalyst containing at least one metal oxide.

[0006]

BEST MODE FOR CARRYING OUT THE INVENTION The catalyst used in the present invention is a gold catalyst containing at least one metal oxide selected from cobalt oxide, zirconium oxide and zinc oxide,
A gold catalyst containing cobalt oxide and / or zinc oxide is preferable in terms of yield.

The gold catalyst of the present invention uses cobalt oxide, zirconium oxide and / or zinc oxide itself as a carrier, and even a catalyst in which gold is supported on the carrier, gold, cobalt oxide, zirconium oxide and / or oxidation is used. It may be a catalyst in which zinc is supported on a suitable carrier.

Cobalt oxide, zirconium oxide and / or
Alternatively, a catalyst in which zinc oxide itself is used as a carrier and gold is supported on the carrier is a conventional method for preparing a gold catalyst, for example, a precipitation-precipitation method (Japanese Patent No. 2615432), a coprecipitation method (JP-A-60-2).
38148) and the like. Also,
A method of supporting gold colloid particles prepared in advance in a suitable solvent on cobalt oxide, zirconium oxide and / or zinc oxide (hereinafter referred to as a gold colloid supporting method, J. Catal.
999, 181, 223., Gold Bull., 1999, 32, 96.) or an aqueous solution containing a water-soluble gold compound and impregnated with cobalt oxide, zirconium oxide and / or zinc oxide, and then a suitable formate salt or the like. It can also be prepared by a method of reducing a gold salt using a different reducing agent (JP-A 2000-63338). Among the above-mentioned preparation methods, in the coprecipitation method, the carrier cobalt oxide, zirconium oxide and / or zinc oxide is produced together with the fine gold particles in the catalyst preparation, but in other preparation methods, the carrier cobalt oxide, zirconium oxide and / or It is only necessary to prepare zinc oxide separately. Cobalt oxide, zirconium oxide and / or zinc oxide used here are washed and calcined by a conventional method, for example, by precipitation of an aqueous solution of cobalt salt such as nitrate or chloride, zirconium salt or zinc salt with an alkali. Can be prepared by Further, the above oxides are widely commercially available, and they can be used as they are. The specific surface area of the carrier is not particularly limited, but the specific surface area measured by the BET method is 1 m in order to support the gold particles on the carrier in a highly dispersed manner.
It is preferably ² / g or more. Although catalysts prepared by any of the preparation methods can be used in the present invention, in order to prepare a highly active catalyst in which gold is supported as particularly fine particles, precipitation precipitation method, gold colloid supporting method, The precipitation method is preferred.

The catalyst in which gold and cobalt oxide, zirconium oxide and / or zinc oxide are supported on a suitable carrier can be used for any carrier such as titania, alumina, silica, zeolite, carbon, etc. It can be prepared by loading zirconium and / or zinc oxide. The order of supporting gold and cobalt oxide, zirconium oxide and / or zinc oxide on the carrier is not particularly limited, and gold may be supported after supporting cobalt oxide, zirconium oxide and / or zinc oxide on the carrier. ,
Gold, cobalt oxide, zirconium oxide and / or zinc oxide may be simultaneously supported on the carrier.

Gold and cobalt oxide, zirconium oxide and
And / or the abundance ratio with zinc oxide is not particularly limited, but gold
From the viewpoint of dispersibility of these oxides (each Co₃O_Four, Z
rO ₂, As ZnO) 0.01 to 30 times gold
Amount% is preferable, and 0.1 to 10% by weight is particularly preferable.

The form of the catalyst used in the present invention is not particularly limited, and powders, molded products and the like may be used depending on the type of reactor. As a reactor type, a stirring tank system, a suspension bed system, a fixed bed system, or the like can be used.
Further, the catalyst amount is arbitrarily set according to the device.

The amino alcohol which is a raw material used in the present invention has an amino group and an alcoholic hydroxyl group, and for example, 2-aminoethanol (monoethanolamine), 2-methylaminoethanol, 2-ethylaminoethanol. , 2-phenylaminoethanol, 2-
Monoethanolamine derivatives such as dimethylaminoethanol, 2-diethylaminoethanol, 1- (2-hydroxyethyl) pyrrolidine, diethanolamine, N-
Examples thereof include diethanolamine derivatives such as methyldiethanolamine and N-ethyldiethanolamine, and triethanolamine. Monoethanolamine derivatives are preferable, and 2-dimethylaminoethanol is particularly preferable.

The aminocarboxylic acid or salt thereof obtained from the above raw materials in the present invention includes, for example, glycine,
Examples thereof include sarcosine, N, N-dimethylglycine, N, N-diethylglycine, N-carboxymethylpyrrolidine, iminodiacetic acid, nitrilotriacetic acid, or salts thereof, and alkyl-substituted glycine is preferable, and N, N-dimethyl is preferable. Glycine is particularly preferred.

In the present invention, the oxidation of amino alcohol can be carried out in the presence or absence of an alkali, depending on the state of the target aminocarboxylic acid or its salt. That is, when the target compound is an aminocarboxylic acid salt, the reaction may be carried out by adding an amount of alkali necessary for neutralizing the carboxylic acid formed, and the target compound is a free aminocarboxylic acid. When it is an acid, the reaction may be carried out without adding an alkali. Further, a mixture of an aminocarboxylic acid salt and a free aminocarboxylic acid can be obtained by arbitrarily setting the amount of alkali to be added to the carboxylic acid or its salt to be produced in the range of 0 to 1 equivalent. Examples of the alkali used in the present invention include caustic alkalis such as lithium hydroxide, sodium hydroxide, potassium hydroxide, calcium hydroxide and tetramethylammonium hydroxide, and carbonates such as sodium hydrogen carbonate, sodium carbonate and calcium carbonate. Salt, ammonia,
Although amines such as trimethylamine and triethylamine can be used, alkali metal hydroxides are preferable, and sodium hydroxide is more preferable from the viewpoint of availability.

In the present invention, an oxygen-containing gas is used as the oxidizing agent. Examples of the oxygen-containing gas include oxygen, air,
A mixed gas of oxygen and an inert gas such as nitrogen having any composition,
A mixed gas of oxygen and air having an arbitrary composition may be used. Among these, oxygen gas is preferable from the viewpoint of reaction rate,
On the other hand, from the viewpoint of economy, air is preferable, and the oxidizer can be selected according to the purpose. The pressure of the oxygen-containing gas is not particularly limited, but it is normal pressure to 10MP from the viewpoint of equipment of the device.
It is preferable to use a.

The oxidation reaction of the present invention is carried out by dissolving the starting material amino alcohol in a suitable solvent. The solvent used is not particularly limited, but water is preferable from the viewpoint of safety and economy. The concentration of the amino alcohol can be set arbitrarily, but from the viewpoint of obtaining a good reaction rate and the desired selectivity of the aminocarboxylic acid, it is preferably 40% by weight or less, more preferably 20 to 35% by weight. .

In the present invention, the reaction temperature is arbitrarily set according to the reactivity of the starting amino alcohol.
From the viewpoint of accelerating the reaction rate and suppressing the amount of by-products to improve the selectivity of the target product, preferably 0 to 100 ° C.,
More preferably, it is 10 to 80 ° C.

[0018]

EXAMPLES The reaction rate (conversion rate of raw materials), yield and selectivity in each of the following examples are calculated based on quantitative values by ¹ H-NMR internal standard method (internal standard: sodium acetate), It is expressed in mol%. Further, the average particle size of the gold fine particles in each catalyst is calculated from the peak half width of the Au [111] plane in a transmission electron microscope (TEM) or X-ray diffraction (XRD).

Catalyst Preparation Example 1 Ion-exchanged water 2 to 400 g of cobalt (II) nitrate hexahydrate
114.4 g was added and dissolved at room temperature with stirring. Sodium carbonate 190.68g is added to this with ion-exchanged water
A solution dissolved in 45.46 g was added, and the generated precipitate was filtered and washed with water. This was dried at 50 ° C. under reduced pressure and then calcined in air at 400 ° C. for 4 hours to obtain 98.12 g of cobalt oxide. The specific surface area of this cobalt oxide was 70 m ² / g.

A 3 L separable flask was charged with 0.628 g of chloroauric acid tetrahydrate and 2400 mL of distilled water, and the temperature was raised to 70 ° C. with stirring. After adjusting the pH to 7.5 with a 0.1N aqueous sodium hydroxide solution, the above Co ₃
30 g of O ₄ was added, and the mixture was stirred at 70 ° C. for 1 hour. After allowing to cool, the suspension was filtered, and the obtained catalyst was washed with water until the washing liquid became cloudless with the silver nitrate aqueous solution. The catalyst was dried under reduced pressure at 50 ° C and then dried in air at 400 ° C for 4 hours.
An Au / Co ₃ O ₄ catalyst was obtained by calcining for a time.
As a result of the analysis, the Au content of the catalyst was 0.84%, TEM
The average particle size of the Au fine particles as analyzed was 4 nm.

Catalyst Preparation Example 2 A 2L beaker was charged with a 0.2N aqueous sodium hydroxide solution 44.
22 g and 1370 g of distilled water were charged, and 29.06 g of a 1% tetrakis (hydroxymethyl) phosphonium chloride aqueous solution was added with stirring at room temperature. After hydrolysis for 2 minutes, an aqueous solution in which 0.628 g of chloroauric acid tetrahydrate was dissolved in 34.83 g of distilled water was added, and reduction was carried out at room temperature for 1 hour. 1% sulfuric acid was added to the obtained gold colloid solution to adjust the pH to 6, and ZnO (manufactured by Sakai Chemical Co., Ltd., specific surface area 9
m ² / g) (30 g) was added and the gold fine particles were immobilized overnight at room temperature. The obtained suspension was treated in the same manner as in Catalyst Preparation Example 1 to obtain an Au / ZnO catalyst. As a result of the analysis, the Au content of this catalyst was 0.97%, and the average particle size of the Au fine particles by TEM analysis was 5 nm.

Catalyst Preparation Example 3 Instead of ZnO, ZrO ₂ (manufactured by Daiichi Rare Element Chemical Industry,
An Au / ZrO ₂ catalyst was obtained in the same manner as in Catalyst Preparation Example 2 except that 30 g of a specific surface area of 88 m ² / g) was used and the pH of the gold colloid solution was adjusted to 2. As a result of the analysis, the Au content of this catalyst was 0.88%, and the average particle size of the Au fine particles by TEM analysis was 5 nm.

Comparative Catalyst Preparation Example 1 A 20 L poly bucket was charged with 3.00 g of chloroauric acid tetrahydrate and 12.38 kg of distilled water, and 44.48 g of a 2% aqueous polyvinyl alcohol solution was added with stirring at room temperature. Three
After 0 minutes, 292.09 g of 0.1 M NaBH ₄ aqueous solution was added, and reduction was performed at room temperature for 3 hours. After reduction, activated carbon (manufactured by Takeda Yakuhin, specific surface area 879 m ^{2 /} g) 142.04
g and stirred at room temperature overnight. The obtained suspension was treated in the same manner as in Catalyst Preparation Example 1 to obtain an Au / C catalyst. As a result of the analysis, the Au content of this catalyst was 0.94%,
The average particle size of the Au fine particles as determined by XRD analysis was 6 nm.

Comparative Catalyst Preparation Example 2 TiO ₂ (manufactured by Nippon Aerosil, specific surface area 49
except using m ² / g), by performing the catalyst preparation by the method of Catalyst Preparation Example 1 to obtain the Au / TiO ₂ catalyst. As a result of the analysis, the Au content of this catalyst was 0.93%, and the average particle size of the Au fine particles by TEM analysis was 8 nm.

Example 1 25 g of 2-dimethylaminoethanol, 5 g of 1% Au / Co ₃ O ₄ catalyst prepared in Catalyst Preparation Example 1, 12.34 g of sodium hydroxide, and 4 parts of distilled water were placed in a 1 L 5-necked flask.
75 g was charged and the temperature was raised to 30 ° C. with stirring. Then, use a sparger to add oxygen at 209 mL / min (2-
The reaction was performed by blowing at a flow rate of 2 equivalents per hour with respect to dimethylaminoethanol. The reaction was terminated after 10 hours, and the catalyst was removed by filtration to obtain an aqueous solution of N, N-dimethylglycine sodium salt. Table 1 shows the results of analysis of the obtained aqueous solution of N, N-dimethylglycine sodium salt.

Example 2 The reaction was carried out according to the method of Example 1 except that 1% Au / ZnO prepared in Catalyst Preparation Example 2 was used as the catalyst and the reaction time was 7 hours. Table 1 shows the results of analysis of the obtained aqueous solution of N, N-dimethylglycine sodium salt.

Example 3 1% Au / ZrO ₂ prepared in Catalyst Preparation Example 3 as a catalyst
Was used and the reaction was carried out according to the method of Example 1 except that the reaction time was 10 hours. Table 1 shows the results of analysis of the obtained aqueous solution of N, N-dimethylglycine sodium salt.

Comparative Examples 1-2 As catalysts, 1% A prepared in Comparative Catalyst Preparation Examples 1 and 2
The reaction was carried out according to the method of Example 1 except that u / C catalyst or 1% Au / TiO ₂ catalyst was used and the reaction time was changed as shown in Table 1. The results are shown in Table 1.

[0029]

[Table 1]

[0030]

According to the method of the present invention, the reaction rate is higher than that in the case of using the activated carbon-supported gold catalyst (Comparative Example 1) and the like, and the metal catalyst containing cobalt oxide or zinc oxide is particularly high in yield. The target aminocarboxylic acid or salt thereof can be obtained.

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Claims (3)

[Claims] 1. A method for producing an aminocarboxylic acid or a salt thereof by oxidizing an amino alcohol with an oxygen-containing gas, wherein at least one metal oxide selected from cobalt oxide, zirconium oxide and zinc oxide is used as a catalyst. A method for producing an aminocarboxylic acid or a salt thereof using a gold catalyst contained therein. 2. The production method according to claim 1, wherein the oxidation of amino alcohol is carried out in the presence of an alkali. 3. The method according to claim 1, wherein the amino alcohol is 2-dimethylaminoethanol and the aminocarboxylic acid is N, N-dimethylglycine.