JPH04221339A - Production of (poly)oxyethylene alkyl ether acetic acid - Google Patents

Abstract

PURPOSE:To produce a highly pure (poly)oxyethylene alkyl ether acetic acid useful as a modifying agent for functional polymer materials and polymer materials used in living bodies in a process. CONSTITUTION:A (poly)oxyethylene alkyl ether compound is catalytically oxidized with oxygen or an oxygen-containing gas in the presence of a catalyst containing platinum and/or palladium as main components and further bismuth or lead as the second component under a pH of <=7 in an aqueous solution.

Description

[Detailed description of the invention]

0001

[Field of Industrial Application] The present invention relates to a method for producing (poly)oxyethylene alkyl ether acetic acid, which is useful as a surfactant, a modifier for functional polymer materials, a polymer material for biological use, etc. be.

0002

BACKGROUND OF THE INVENTION The following techniques are already known for producing (poly)oxyethylene alkyl ether acetic acid. ■ A method of chemically oxidizing (poly)oxyethylene alkyl ether compounds with oxidizing agents such as potassium permanganate, ammonium vanadate, and sodium hypochlorite. (A. Fradat and E.M.
arechal, Polymer Bulletin
, 4, 205-210 (1981)) ■ A method of reacting a (poly)oxyethylene alkyl ether compound with a halogenated acetate or ester. (Same as above)■
A method of oxidizing a (poly)oxyethylene alkyl ether compound in an aqueous solution with an oxygen-containing gas in the presence of a platinum-based catalyst. (Unexamined Japanese Patent Publication No. 54-79229) ■ (
A poly)oxyethylene alkyl ether compound in an aqueous solution in the presence of a catalyst containing platinum and/or palladium as a first component and one or more selected from selenium, tellurium, antimony, tin, bismuth, and lead as a second component. ,
A method of catalytic oxidation using an oxygen-containing gas while adjusting the pH of the reaction system to 7.5 or higher. (Unexamined Japanese Patent Publication No. 198641/1983)

[0003] However, methods ① and ②,
A large amount of inorganic salts and organic substances are mixed into the reaction product, making it quite difficult to obtain a pure reaction product. In method (2), (poly)oxyethylene alkyl ether acetic acid can be obtained in the form of free acid, but if the conversion rate of the reaction is increased to reduce the content of unreacted (poly)oxyethylene alkyl ether compound, Oxidative decomposition of the ether group occurs, making it impossible to obtain the target product with high purity. If the reaction temperature is lowered to suppress side reactions, the rate of the oxidation reaction will drop significantly and the reaction will take a long time. Also, ■
In this method, the product becomes 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 more steps are required, such as extraction after acid decomposition of the carboxylate salt. is necessary. Furthermore, the products obtained by this method inevitably undergo side reactions such as decomposition and esterification.
The limit is to obtain 93 to 94% purity, and more complex purification is required for applications that require higher purity, such as modifiers for biological polymer materials and functional polymer materials. There are problems such as the need for additional processes.

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 with high purity.

[0005]

[Means for Solving the Problems] That is, the present invention solves the problem by solving the following problems:
n −H (1)


(In the formula, R is one selected from the group consisting of an alkyl group having 1 to 30 carbon atoms, an alkenyl group, a cycloalkyl group, an aryl group, and an aralyl group, and n represents an integer of 1 to 100.) By oxidizing the compound shown, general formula (2)



R-O-(CH2 CH2 O)n-1 -CH2
When producing (poly)oxyethylene alkyl ether acetic acid represented by CCOOH (2) (in the formula, R and n are the same as above), platinum and/or palladium is used as the first component, and bismuth or lead is used as the second component. (Poly)oxyethylene represented by the general formula (2), which is catalytically oxidized with oxygen or an oxygen-containing gas in the presence of a catalyst contained as a component in an aqueous solvent under conditions where the pH is set to 7 or less This is a method for producing alkyl ether acetic acid.

The catalyst used in the present invention is a composite catalyst containing platinum and/or palladium as a first component and bismuth or lead as a second component, and is usually 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 can be 0.1 to 20% by weight, preferably 0.1 to 20% by weight.
5 to 10% by weight is good. The supported amount of the second component is 0.01
~10% by weight, preferably 0.05~5% by weight. The blending ratio of the first component and the second component is 0.005 in atomic ratio.
A range of 1.5 to 1.5 (second component/first component) is preferable.

The catalyst used in the present invention is produced by a commonly used method. For example, in the case of a catalyst in which platinum and lead are supported on activated carbon, a predetermined amount of a chloroplatinic acid aqueous solution and a lead chloride aqueous solution are mixed, and this is poured onto activated carbon dispersed in the aqueous solution to adsorb it, followed by formalin, formic acid, and sodium chloride. After reduction treatment with hydride, hydrogen, etc., thorough washing with water, and drying, it can be subjected to this 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 nonylphenyl ether. These (poly)oxyethylene alkyl ether compounds are subjected to the reaction as an aqueous solution, and the concentration thereof 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 the hydroxyl group of the above-mentioned starting material is oxidized to a carboxyl group. Specific examples include methoxyacetic acid, methoxyethoxyacetic acid, phenoxyethoxyacetic acid,
Examples include butoxyethoxyacetic acid, methoxy-polyoxyethylene acetic acid, lauryl ether-polyoxyethylene acetic acid, nonylphenyl ether-polyoxyethylene acetic acid, and the like. The products of the present invention can all be obtained in the form of free acids with a purity of 97% or more, which is a major feature and objective of the present invention.

In the method of the present invention, when the (poly)oxyethylene alkyl ether compound of general formula (1) is oxidized in an aqueous solution while blowing an oxygen-containing gas in the presence of the above-mentioned catalyst, no alkali, acid, etc. are added. It is a feature of the present invention that this is not the case. Therefore, at the beginning of the reaction, the pH
is approximately 7, but as the reaction progresses, (poly)oxyethylene alkyl ether acetic acid is produced, so the liquid nature of the reaction gradually becomes acidic. Therefore, the reaction always proceeds at a pH of 7 or less. As a result, although the oxidation reaction rate is slow, side reactions can be extremely suppressed, and (poly)oxyethylene alkyl ether acetic acid represented by the general formula (2) with a good color and a purity of 97% or more can be produced. Obtainable.

[0011] The amount of catalyst in the oxidation reaction is not particularly limited, but in the case of a batch reaction, it is 2 to 2
A range of 0% by weight is preferred. The amount used can be arbitrarily selected depending on the required reaction time and catalyst cost. This reaction can be carried out not only in a batchwise manner but also in a fixed bed continuous flow reaction. In the case of a fixed bed type, the conversion rate can be controlled by the flow rate of the reactants and the reaction temperature to obtain the desired purity.

[0012] The reaction of the present invention is carried out at a reaction temperature of 20 to 100°C.
The reaction can be carried out at a reaction pressure of 1 to 10 kg/cm2. Preferably, the reaction temperature is 30-80°C and the reaction pressure is 5-8k.
g/cm2 is good. The higher the reaction pressure, the more oxygen-containing gas is dissolved in the aqueous solution, and the reaction rate becomes faster. As the oxygen-containing gas, a gas prepared by diluting oxygen with nitrogen or air can be used.

[0013] As for the post-treatment of this reaction, the target product of high purity can be obtained by only the steps of filtering the catalyst and removing the solvent by evaporation under reduced pressure. In order to avoid contamination of unreacted substances, it is sufficient to sufficiently increase the conversion rate, and there is almost no concern about side reactions. The filtered catalyst can be used repeatedly for the same reaction, and the method of the present invention exhibits remarkable performance in terms of durability in maintaining catalytic activity compared to conventional methods that involve adding alkali. do.

[Examples] The present invention will be explained in more detail with reference to Examples below.

Example 1 Chloroplatinic acid containing 2.5 g of platinum, palladium chloride hydrochloric acid aqueous solution containing 0.75 g of palladium, and lead chloride aqueous solution containing 1 g of lead were mixed with activated carbon at 95.5 g.
8g was added to 1 liter of suspended water and stirred. After adsorption at room temperature for a day and night, 0.5N sodium carbonate was added to adjust the pH to 9. Next, 5 ml of 38% formalin aqueous solution was added, and the mixture was kept at 80° C. for 1 hour for reduction. After washing with water and drying, a platinum-palladium-lead-carbon catalyst was obtained. 1. Equipped 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. Introducing compressed air and increasing the air flow to 300ml/m2 while maintaining the reaction pressure at 6kg/cm2.
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, and 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, the purity of the product is 99.5
%Met.

Comparative Example 1 According to Example 1, a platinum-palladium-carbon catalyst excluding lead was prepared. 100% by weight aqueous solution of polyoxyethylene lauryl ether (n=9) in an autoclave
0g and 20g of platinum-palladium-carbon catalyst,
The reaction was carried out in the same manner as in Example 1 at 60°C for 12 hours. The neutralization value 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 portion of the lauryl group.

Example 2 Chloroplatinic acid containing 2.5 g of platinum and 0.75 g of palladium
An aqueous solution of palladium chloride in hydrochloric acid containing 1 g of bismuth 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 therein. After adsorption at room temperature for a day and night, 0.5N sodium carbonate was added to adjust the pH to 9. Next, 5 ml of 38% formalin aqueous solution was added, and the mixture was kept at 80° C. for 1 hour for reduction. After washing with water and drying, a platinum-palladium-bismuth-carbon catalyst was obtained. 40g of this catalyst has an inner diameter of 28mm and a height of 215mm.
The mixture was filled into a stainless steel cylindrical reaction tube. A pressure gauge, a thermometer, a gas flow meter, a check valve, and a pressure regulating valve were installed, and a 10% by weight aqueous solution of diethylene glycol monomethyl ether was supplied at a rate of 2.2 x 10-3 mol/hr. Next, air is supplied from an air cylinder and the pressure is increased to 6k.
After raising the temperature to g/cm2, the temperature was raised to 70° C. in 1 hour while discharging air at a rate of 300 ml/min (converted to normal pressure). After reaching a steady state, 200 g of the reaction solution was collected and concentrated to dryness to obtain 21.8 g of a colorless and transparent liquid. The high performance liquid chromatography analysis results showed that unreacted matter was 0.6%;
Methoxyethoxyacetic acid 97.2%, diglycolic acid 2.
It was 2%. The reaction was continued for 200 hours, but there was no change in the composition of the product, and no decrease in activity or selectivity was observed.

Comparative Example 2 In Example 2, the reaction was carried out at 50°C in the same manner as in Example 2, except that the 10% aqueous solution of diethylene glycol monomethyl ether was replaced with an aqueous solution containing 1 mole of diethylene glycol monomethyl ether and 1 mole of sodium hydroxide in 1 kg. went. There was considerable heat generated by the reaction, making it difficult to control the reaction. After reaching 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 ester of methoxyacetic acid and diethylene glycol monomethyl ether were found. As a result of analysis by high performance liquid chromatography while the reaction continued, the amount of unreacted substances gradually increased over the course of 100 hours. It was found that the activity of the catalyst decreased and the conversion rate decreased.

[0018]

Effects of the Invention According to the method of the present invention, free acid can be obtained directly, and there are very few side reactions, no ester is produced during the reaction, and highly pure (poly)acid can be obtained.
Oxyethylene alkyl ether acetic acid can be produced. Moreover, the catalyst of the present invention shows almost no deterioration in activity and selectivity even after repeated use. Therefore, the method of the present invention is suitable for fixed bed continuous reaction, does not require a step of filtering the catalyst, and can be said to be an industrially advantageous production method.

Claims (1)

[Claims] [Claim 1] General formula (1) R-O-(CH2 CH2 O)
n −H (1)
(In the formula, R is one selected from the group consisting of an alkyl group having 1 to 30 carbon atoms, an alkenyl group, a cycloalkyl group, an aryl group, and an aralyl group, and n is 1 to 1
Represents an integer of 00. ) by oxidizing the compound represented by the general formula (2)
R-O-(CH2CH2O)n-1-
When producing (poly)oxyethylene alkyl ether acetic acid represented by CH2COOH (2) (in the formula, R and n are the same as above), platinum and/or palladium is used as the first component, and bismuth or lead is used as the first component. (Poly)oxy represented by the general formula (2), which is catalytically oxidized with oxygen or an oxygen-containing gas in the presence of a catalyst contained as two components in an aqueous solvent under conditions where the pH is set to 7 or less. A method for producing ethylene alkyl ether acetic acid.