JP2903187B2 - Method for producing (poly) oxyethylene alkyl ether acetic acid - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for producing (poly) oxyethylene alkyl ether acetic acid useful for applications such as surfactants, modifiers for functional polymer materials, and biopolymer materials. is there.

[0002]

2. Description of the Related Art With respect to a method for producing (poly) oxyethylene alkyl ether acetic acid, the following techniques are already known. A method of chemically oxidizing a (poly) oxyethylene alkyl ether compound with an oxidizing agent such as potassium permanganate, ammonium vanadate, and sodium hypochlorite. (A. Fradat and E. Marechal, Polymer Bul
letin, 4, 205-210 (1981)) A method of reacting a (poly) oxyethylene alkyl ether compound with a halogenated acetate or ester. (Id.) A method of oxidizing a (poly) oxyethylene alkyl ether compound with an oxygen-containing gas in an aqueous solution in the presence of a platinum-based catalyst. (JP-A-54-79229) A (poly) oxyethylene alkyl ether compound in an aqueous solution, platinum and / or palladium as a first component, and at least one selected from selenium, tellurium, antimony, tin, bismuth and lead The second
6. In the presence of the catalyst contained as a component, the pH of the reaction system is adjusted to 7.
A method of performing catalytic oxidation with an oxygen-containing gas while adjusting to 5 or more. (Japanese Patent Application Laid-Open No. Sho 62-198641)

[0003] However, in the methods (1) and (2), a large amount of inorganic salts and organic substances are mixed in the reaction product, and it is very difficult to obtain a pure reaction product. The method is
(Poly) oxyethylene alkyl ether acetic acid can be obtained in the form of a free acid, but if the conversion of the reaction is increased to reduce the content of unreacted (poly) oxyethylene alkyl ether compound, the oxidative decomposition of the ether group will inevitably occur. And a high-purity target product cannot be obtained.
When the reaction temperature is lowered to suppress side reactions, the rate of the oxidation reaction is remarkably reduced, and the reaction requires a long time. Also,
In the above method, the product is converted into a salt of (poly) oxyethylene alkyl ether acetic acid, and in order to obtain the desired product in the form of a free acid, several steps such as extraction after decomposing the carboxylate with acid are carried out. is necessary. Furthermore, the products obtained by this method cannot avoid side reactions such as decomposition and esterification,
The limit is to obtain a purity of 93-94% in purity. For applications such as biopolymer materials and functional polymer material modifiers requiring higher purity, more complicated purification is required. There is a problem that a process is required.

[0004]

SUMMARY OF THE INVENTION An object of the present invention is to efficiently produce (poly) oxyethylene alkyl ether acetic acid in the form of a free acid and of high purity.

[0005]

That is, the present invention provides a compound represented by the following general formula (1): R--O-(CH ₂ CH ₂ O) _n --H (1) wherein R is an alkyl group having 1 to 30 carbon atoms. , An alkenyl group, a cycloalkyl group, an aryl group, and an arallyl group, wherein n represents an integer of 1 to 100).
General formula (2) R—O— (CH ₂ CH ₂ O) _n-1 —CH ₂ COOH (2) (wherein R and n are as defined above) (poly)
When producing oxyethylene alkyl ether acetic acid, under the condition that the pH is 7 or less in an aqueous solvent in the presence of a catalyst containing platinum and / or palladium as a first component and bismuth or lead as a second component, General formula (2) characterized by catalytic oxidation with oxygen or an oxygen-containing gas
Is a method for producing a (poly) oxyethylene alkyl ether acetic acid represented by the formula:

[0006] The catalyst used in the present invention is a composite catalyst comprising platinum and / or palladium as a first component and bismuth or lead as a second component, and is usually used by being supported on a carrier. Activated carbon or alumina can be used as the carrier. The amount of platinum and / or palladium supported on the carrier may be 0.1 to 20% by weight, preferably 0.1 to 20% by weight.
5 to 10% by weight is good. The loading amount of the second component is 0.01
10 to 10% by weight, preferably 0.05 to 5% by weight. The mixing ratio of the first component and the second component is 0.00 in atomic ratio.
The range of 5 to 1.5 (second component / first component) is good.

[0007] The catalyst used in the present invention is produced by a conventional method. For example, in the case of a catalyst in which platinum and lead are supported on activated carbon, a predetermined amount of an aqueous solution of chloroplatinic acid and an aqueous solution of lead chloride are mixed, and the mixture is poured onto activated carbon dispersed in the aqueous solution to be adsorbed. It can be subjected to a reduction treatment with hydride, hydrogen, etc., sufficiently washed with water and dried, and then subjected to the present reaction.

The (poly) oxyethylene alkyl ether compound represented by the general formula (1) used in the present invention is:
Specific examples include ethylene glycol monomethyl ether, diethylene glycol monomethyl ether, diethylene glycol phenyl ether, diethylene glycol monobutyl ether, polyethylene glycol monomethyl ether, polyethylene glycol lauryl ether, and polyethylene glycol nonyl phenyl ether. These (poly) oxyethylene alkyl ether compounds are subjected to the reaction as an aqueous solution, and the concentration varies depending on the compound, but can be set in the range of 5 to 50% by weight.

The (poly) oxyethylene alkyl ether acetic acid compound represented by the general formula (2) produced in the present invention is a compound in which a hydroxyl group of the above-mentioned starting material has been oxidized to a carboxyl group. Specific examples include methoxyacetic acid, methoxytoethoxyacetic acid, phenoxyethoxyacetic acid,
Butoxyethoxyacetic acid, methoxy-polyoxyethylene acetic acid, lauryl ether-polyoxyethylene acetic acid, nonylphenyl ether-polyoxyethylene acetic acid, and the like. All of the products of the present invention can be obtained in the form of free acid, and more than 97% pure,
This is a major feature of the present invention, and is an object of the present invention.

In oxidizing the (poly) oxyethylene alkyl ether compound of the general formula (1) in the aqueous solution while blowing an oxygen-containing gas in the presence of the above-mentioned catalyst in the method of the present invention, any alkali or acid is added at all. This is a feature of the present invention. Therefore, at the beginning of the reaction
Is about 7, but as the reaction proceeds, (poly) oxyethylene alkyl ether acetic acid is generated, so that the liquidity of the reaction gradually becomes acidic. Thus, the reaction always proceeds at a pH of 7 or less. As a result, although the oxidation reaction rate is reduced, side reactions can be extremely suppressed, and the (poly) oxyethylene alkyl ether acetic acid represented by the general formula (2) having good hue and having a purity of 97% or more can be obtained. Obtainable.

The amount of the catalyst in the oxidation reaction is not particularly limited, but in the case of a batch reaction system, it is 2 to 2 with respect to the substrate.
A range of 0% by weight is preferred. This amount can be arbitrarily selected depending on the required reaction time and catalyst cost. This reaction can be carried out not only in a batch system but also in a fixed bed continuous flow reaction. In the case of a fixed-bed type, the conversion can be controlled by the flow rate of the reactant and the reaction temperature to obtain the target purity.

The reaction of the present invention is carried out at a reaction temperature of 20 to 100.
C. and a reaction pressure of 1 to 10 kg / cm ² . Preferably, the reaction temperature is 30 to 80 ° C., and the reaction pressure is 5 to 8 kg / cm ^2.
Is good. The higher the reaction pressure, the more the oxygen-containing gas dissolves in the aqueous solution, and the higher the reaction rate. As the oxygen-containing gas, gas or air obtained by diluting oxygen with nitrogen can be used.

In the post-treatment of this reaction, a high-purity target product can be obtained only by a step of filtering the catalyst and a step of evaporating and removing the solvent under reduced pressure. In order to avoid incorporation of unreacted substances, it is sufficient to increase the conversion sufficiently, and there is almost no concern about side reactions. The filtered catalyst can be used repeatedly in the same reaction, and the method of the present invention exhibits remarkable performance as compared with the conventional method in which an alkali is added, even in the durability for maintaining the catalytic activity. I do.

The present invention will be described in more detail with reference to the following examples.

Example 1 An aqueous solution of palladium chloride hydrochloride containing 2.5 g of platinum and 0.75 g of palladium and an aqueous solution of lead chloride containing 1 g of lead were mixed with 95.8 of activated carbon.
g was suspended in 1 liter of water and stirred. After adsorption at room temperature for 24 hours, 0.5 N sodium carbonate was added to adjust the pH to 9. Next, 5 ml of a 38% formalin aqueous solution was added, and the mixture was reduced at 80 ° C. for 1 hour. After washing with water and drying, a platinum-palladium-lead-carbon catalyst was obtained.
1. With gas inlet, gas outlet, thermometer and stirrer
A 5-liter autoclave was charged with 1000 g of a 20% by weight aqueous solution of polyoxyethylene lauryl ether (n = 9) and 20 g of the above catalyst. Compressed air was introduced, air was discharged at a flow rate of 300 ml / min while maintaining the reaction pressure at 6 kg / cm ^2, and the reaction was carried out at 70 ° C. for 18 hours with stirring. The catalyst was filtered and concentrated to dryness under reduced pressure. The product is a colorless viscous liquid. As a result of analysis, the neutralization value is 95.3, the hydroxyl value is 0.5, and the hydroxyl value of the substrate is 95.8. Was 99.5%.

Comparative Example 1 According to Example 1, a platinum-palladium-carbon catalyst from which lead was removed was prepared. In an autoclave, a 100% by weight aqueous solution of polyoxyethylene lauryl ether (n = 9) 100
0 g and platinum-palladium-carbon catalyst 20 g,
The reaction was carried out at 60 ° C. for 12 hours in the same manner as in Example 1. The neutralization number of the product is 98.0, the hydroxyl value is 5.0, and the purity of the product is calculated to be 95.1%. This was found to be due to oxidative elimination of a part of the lauryl group.

Example 2 Chloroplatinic acid containing 2.5 g of platinum and 0.75 g of palladium
And an aqueous solution of bismuth chloride containing 1 g of bismuth were added to water in which 95.8 g of crushed charcoal (20 to 50 mesh) was suspended, and immersed. After adsorption at room temperature for 24 hours, 0.5 N sodium carbonate was added to adjust the pH to 9. Next, 5 ml of a 38% formalin aqueous solution was added, and the mixture was reduced at 80 ° C. for 1 hour. After washing with water and drying, a platinum-palladium-bismuth-carbon catalyst was obtained. 40 g of this catalyst was filled in a stainless steel cylindrical reaction tube having an inner diameter of 28 mm and a height of 215 mm. Pressure gauge, thermometer,
A gas flow meter, a check valve, and a pressure regulating valve were attached, and a 10% by weight aqueous solution of diethylene glycol monomethyl ether was supplied at a rate of 2.2 × 10 ⁻³ mol / hr. Next, air was supplied from an air cylinder to increase the pressure to 6 kg / cm ^{2, and} then the temperature was raised to 70 ° C. in one hour while discharging 300 ml / min (normal pressure) air. After reaching steady state,
200 g of the reaction solution was collected, concentrated and dried to obtain 21.8 g of a colorless transparent liquid. The result of analysis by high performance liquid chromatography was as follows: unreacted substance 0.6%, methoxyethoxyacetic acid 9
7.2% and diglycolic acid 2.2%. Subsequently, the reaction was continued for 200 hours, but there was no change in the composition of the product, and no decrease in activity and selectivity was observed.

Comparative Example 2 A reaction was carried out at 50 ° C. in the same manner as in Example 2 except that a 10% aqueous solution of diethylene glycol monomethyl ether was replaced with an aqueous solution containing 1 mol of diethylene glycol monomethyl ether and 1 mol of sodium hydroxide in 1 kg. went. There was considerable exotherm from the reaction, which made it difficult to control the reaction. After reaching a steady state, the reaction solution was collected and analyzed by high performance liquid chromatography. As a result, 0.3% of unreacted substances, 90.2% of methoxyethoxyacetic acid, 5.6% of methoxyacetic acid, and 3.9% of an ester of methoxyacetic acid and diethylene glycol monomethyl ether were found. As a result of analysis by high performance liquid chromatography while continuing the reaction, unreacted substances gradually increased after 100 hours. It was found that the activity of the catalyst was reduced and the conversion was reduced.

[0018]

According to the method of the present invention, a free acid can be directly obtained, furthermore, the side reaction is very little, no ester is formed during the reaction, and high purity (poly) oxyethylene is obtained. Alkyl ether acetic acid can be produced. In addition, the catalyst of the present invention shows almost no deterioration in activity and selectivity when used repeatedly. Therefore, the method of the present invention is suitable for a fixed-bed continuous reaction, does not require a catalyst filtration step, and can be said to be an industrially advantageous production method.

Claims (1)

(57) [Claims] 1. A compound represented by the general formula (1): R—O— (CH ₂ CH ₂ O) _n —H (1) wherein R is an alkyl group having 1 to 30 carbon atoms, an alkenyl group, a cycloalkyl group, an aryl And n is an integer of 1 to 100. The compound represented by the general formula (2) R—O— (CH ₂ CH ₂ O) _n-1 —CH ₂ COOH (2) (wherein, R and n are as defined above) (poly)
In producing oxyethylene alkyl ether acetic acid, platinum and / or palladium as a first component, in the presence of a catalyst containing bismuth or lead as a second component, under a condition of adjusting the pH to 7 or less in an aqueous solvent, General formula (2) characterized by catalytic oxidation with oxygen or an oxygen-containing gas
A method for producing a (poly) oxyethylene alkyl ether acetic acid represented by the formula: