JPH01149752A - Oxidation of (poly)oxyethylene alkyl ether compound - Google Patents

Abstract

PURPOSE:To obtain a (poly)oxyethylene alkyl ether acetic acid compound readily in high quality at low cost with slight decomposition, by oxidizing a (poly) oxyethylene alkyl ether compound by using a reactor of fixed bed. CONSTITUTION:A non-alkali aqueous solution of a (poly)oxyethylene alkyl ether compound shown by the formula R-O-(CH2CH2O)n-H (R is 1-30C alkyl, alkenyl, cycloalkyl, aryl or aralkyl; n is 2-100) and an oxygen-containing gas are passed through a reactor of fixed bed packed with granular platinum- palladium carbon catalyst and reacted at 30-90 deg.C. The catalyst is obtained by absorbing a water-soluble salt of Pt and Pd on granular active carbon in an aqueous solution at pH >=8 and reducing with a reducing agent (e.g., formalin). A (poly)oxyethylene alkyl ether acetic acid is useful as a surfactant, improver for functional high polymer, high polymer material for organisms, etc.

Description

Detailed Description of the Invention: Industrial Application Field - The present invention is based on the following general formula % (wherein R is an alkyl group having 1 to 30 carbon atoms, an alkenyl group, a cycloalkyl group, an aryl group, and an aralyl group). (n is an integer from 2 to 100);

(Poly)oxyethylene alkyl ether acetic acid is used as a surfactant, a modifier for functional polymer materials, and a polymer material for biological use.

It is already known that polyoxyethylene alkyl ether acetic acid can generally be produced by the following method.

■ (Poly)oxyethylene alkyl ether compound with permanate, potassium ganate, and ammonium vanadate.

A method of chemical oxidation with an oxidizing agent such as sodium hypochlorite (A, Fradat and E, Marech
al, Polymer Bulletin, L, 2
O5-210. (I981)) ■ A method of reacting a (poly)oxyethylene alkyl ether compound with a salt or ester of halogenated acetic acid. (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. (Japanese Unexamined Patent Publication No. 54-79229) Among these methods, methods ① and ③ inevitably involve a large amount of by-products and reaction raw materials, and the target product is a water-soluble polymer that is difficult to purify. Therefore, it can be said that industrial implementation is virtually impossible in terms of yield and production cost. ■The method is
Although it is a good method as the target product of relatively high purity can be obtained in the form of a free acid, it has the disadvantage that the substrate and the product have surface activity, which results in heavy foaming and makes it difficult to carry out the reaction. Furthermore, since it is a batch reaction, it has several drawbacks when considering industrial production. In other words, it takes a long time to complete the reaction, 8 to 12 hours, and when reacting a low molecular weight substrate, it is necessary to make the oxygen partial pressure higher than the air composition in order to increase the reaction rate, and the reaction concentration The catalyst is thin at around 20%, which requires a large reactor, the solubility of oxygen is low, so a large amount of stirring power is required to improve gas-liquid-solid contact, and the catalyst is in the form of a fairly fine powder. Therefore, the operation is quite troublesome when the catalyst is used repeatedly.

The present inventors have developed a method for oxidizing (poly)oxyethylene alkyl ether compounds that overcomes the drawbacks of such conventional methods and is suitable for industrial production. As a result of intensive research on
The inventors have discovered that (poly)oxyethylene alkyl ether acetic acid compounds can be produced continuously in a short period of time using a small reactor, and that the purity of the product can be improved, leading to the present invention.

4. In other words, in the present invention, the following general formula % formula % () (in the formula, R is a type of group 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 2 to 100. Characterized by flowing and reacting a non-alkaline aqueous solution of an ethylene alkyl ether compound with an oxygen-containing gas (poly)
This is a method for oxidizing oxyethylene alkyl ether compounds.

Continuous reactors generally used for catalytic reactions include a fixed bed type and a fluidized bed type. However, a characteristic of the (poly)oxyethylene alkyl ether compound oxidation reaction is that the unreacted (poly)oxyethylene alkyl ether compound and the (poly)oxyethylene alkyl ether acetic acid compound have similar properties, so separation and purification is almost impossible. Therefore, it is necessary to suppress unreacted substances and by-products in the reaction solution to a minimum amount. It is difficult to satisfy this condition using a fluidized bed method, and since this reaction does not generate much reaction heat, it can be said that a fixed bed method is suitable as a method for producing (poly)oxyethylene alkyl ether acetic acid compounds. .

The catalyst used in the present invention is a catalyst supported on granular activated carbon containing platinum and palladium as essential components. but,
Among these, the catalyst produced by the method described in Japanese Patent Publication No. 60-40453 is particularly excellent in its high activity. That is, 5~
Approximately 50 mesh of granular activated carbon is seeded in water, an alkali is added to it to raise the pH to 8 or higher, and a mixed aqueous solution of water-soluble salts of platinum and palladium is added dropwise under stirring to adsorb platinum and palladium onto the activated carbon. Next, a reducing agent such as formalin, formic acid, or sodium borohydride is added to reduce the platinum and palladium salts to their respective metals, followed by sufficient water washing and the reaction is carried out as is or after drying.

Examples of the (poly)oxyethylene alkyl ether compound used in the present invention include ethylene glycol monomethyl ether, diethylene glycol phenyl ether, diethylene glycol monobutyl ether, polyethylene glycol monomethyl ether, polyethylene glycol lauryl ether, and polyethylene glycol nonylphenyl ether. It will be done. In this way, the poly(oxyethylene alkyl ether compound) is subjected to the reaction as an aqueous solution. Its concentration varies depending on the molecular weight, but is preferably 10 to 50% by weight. If the concentration is too low, production efficiency will deteriorate, and if the concentration is too high, it will be difficult to remove the reaction heat and control the reaction temperature will become difficult.

In the present invention, "non-alkaline" means that the reaction proceeds without adding an acid or alkali at the beginning of the reaction, and without adding an alkali during the reaction.

The fixed bed reactor used in the present invention is a so-called concentrated liquid packed column reactor that is widely employed in the petrochemical industry. In other words, gas-liquid phases flow between a fixed bed filled with relatively small porous particles, and a gas-liquid-solid reaction progresses.The fluid flow within the device is close to an extrusion flow, increasing the reaction rate. You can take it. The direction of flow of both gas and liquid phases can be upward cocurrent flow, downward cocurrent flow, or countercurrent flow, but downward cocurrent flow is most preferred from the viewpoint of flooding and pressure loss problems. The reactor is basically equipped with a raw material liquid inlet, an oxygen-containing gas inlet, a reaction liquid outlet, and a jacket for heating or cooling.

The reaction is carried out under normal pressure or increased pressure. When the reaction pressure is high, the amount of dissolved oxygen increases and the reaction speeds up, but for industrial production it is preferable to carry out the reaction at 4 to 10 kg/cra2, so the reactor must be constructed to withstand that much pressure. There must be. Other auxiliary equipment required include liquid metering pumps, gas pressure regulating valves, check valves, pressure gauges, thermometers, and gas flow meters.

In the reaction method of the present invention, an aqueous solution of a (poly)oxyethylene alkyl ether compound at a concentration of 10 to 50% is passed through a reactor filled with a catalyst by a wet method. When the poly)oxyethylene alkyl ether compound has a molecular weight of 750 or less, the flow rate (mole amount per unit time) is F, catalyst,! i(g)
When W is W, W/F is 2 x 103hr, g-c
At/mo1 or more, if the molecular weight is 750 or more, W/mo
It is preferable to supply the raw material aqueous solution at a rate such that F is 4×10'hr, g-cat/mo1 or more. 6 ml/min per gram of catalyst while raising the temperature at the same time (converted to normal pressure)
Supply air while purging at a flow rate of 4 to 1
Maintain pressure at 0 kg/cm2. The higher the oxygen partial pressure in the gas composition at this time, the more advantageous the reaction is, but in the method of the present invention, the reaction proceeds sufficiently with an air composition. In addition, the supply speed of liquid and gas is controlled so that the flow of gas and liquid remains in the state of #liquid flow. The reaction temperature is preferably maintained at 30 to 90°C, preferably 40 to 80°C. Normally, 0.5 to 3 hours after reaching the reaction temperature, unreacted substances are no longer detected and a steady state is reached, and the catalyst can be continuously (
Poly)oxyethylene alkyl ether acetic acid compounds can be extracted.

Hereinafter, the present invention will be explained in more detail with reference to Examples.

Example 1 5.0 g of platinum and 1.5 g of palladium were dissolved in 2O1 of aqua regia, and the remaining acid was evaporated to dryness.The obtained chloroplatinic acid and palladium chloride were dissolved in 1001 of a 5% aqueous hydrochloric acid solution. 95 g of commercially available crushed activated carbon (particle size 20 to 48 mesh) was suspended in a 0.25N aqueous sodium carbonate solution IC, and the entire amount of the chloroplatinic acid and palladium chloride aqueous solution was added dropwise thereto over 10 minutes with stirring. Then at room temperature 1
The temperature was further heated to 80 ± 5°C and stirring was continued for 2 hours to completely adsorb chloroplatinic acid and palladium chloride to the crushed charcoal. Then, 38% formalin aqueous solution 101 was added to the crushed charcoal.
After being reduced by maintaining the temperature at 80±5° C. for a period of time, the mixture was filtered, washed with water, and dried to obtain a platinum-palladium carbon catalyst.

Commercially available polyethylene glycol monomethyl ether (manufactured by Aldrich, average molecular weight 750, hydroxyl value 80.1)
40 g of the above catalyst was suspended in 200 ml of a 2O superimposed aqueous solution of 2 O, and the catalyst was filled into a cylindrical reaction tube with an inner diameter of 28 mm and a height of 215 nn+. A pressure gauge, a thermometer, a gas flow meter, a check valve and a pressure regulating valve were installed, and the above 20% polyethylene glycol monomethyl ether aqueous solution was continuously added at 5.0 x 10''3 mol/hr using a metering pump.
was supplied at a rate of

The W/F at this time was 8. OX 10'hr, g-c
At/mol was 0. Next, air was supplied from an air cylinder and the pressure was raised to 6 kg/Cm2, then 600 ml.
/ll1in (normal pressure equivalent) while purging air.
The temperature was raised to 70°C over an hour. Sequential samples were taken and analyzed by high performance liquid chromatography. One hour after the temperature reached 70°C, no unreacted substances were detected, and a steady state was reached. After reaching a steady state, 500 g of the reaction solution was collected and concentrated to dryness to obtain 100 g of a colorless and transparent liquid. Is this thing neutralizing value? 9. It had a hydroxyl value of O, and high-performance liquid chromatography analysis revealed that it was polyethylene glycol monomethyl ether acetic acid with a purity of 100%.

Example 2 40 g of the catalyst obtained in Example 1 was suspended in a 20% by weight aqueous solution of commercially available polyethylene glycol monomethyl ether (manufactured by Aldrich, average molecular weight 2000, hydroxyl value 29.1), and a reaction tube was prepared in the same manner as in Example 1. The same aqueous solution was filled with a OX 10-'m using a metering pump.
It was fed continuously at a rate of ol/hr. W/F at this time
5. OX 10'hr, g-cat/+ol. When the reaction was carried out in the same manner as in Example 1, 55
Unreacted substances are no longer detected in 2 hours after reaching °C.
It became steady state. Thereafter, 500 g of the reaction solution was collected and concentrated to dryness to obtain 100 g of a white solid. This product had a neutralization value of 29.9 and a hydroxyl value of O, and analysis by high performance liquid chromatography revealed that it was polyethylene glycol monomethyl ether acetic acid with a purity of 100%.

The present invention makes it easier to produce a foamable (poly)oxyethylene alkyl ether acetic acid compound, and produces a high-quality, low-cost (poly)oxyethylene alkyl ether acetic acid compound with less decomposition. Obtainable.

Claims (1)

[Claims] 1. In a fixed bed reactor filled with granular platinum-palladium carbon catalyst, the following general formula (I) R-O-(CH_2CH_2O)n-H(I) (where R is carbon (Poly)oxyethylene is a group selected from the group consisting of alkyl groups, alkenyl groups, cycloalkyl groups, aryl groups, and aralyl groups of numbers 1 to 30, where n represents an integer of 2 to 100. A method for oxidizing a (poly)oxyethylene alkyl ether compound, which comprises reacting a non-alkaline aqueous solution of an alkyl ether compound with an oxygen-containing gas. 2. A platinum-palladium carbon catalyst is obtained by adsorbing water-soluble salts of platinum and palladium on granular activated carbon in an aqueous solution with a pH of 8 or higher, and then reducing the mixture with a reducing agent selected from formalin, formic acid or sodium borohydride. platinum
The manufacturing method according to claim 1, which is a palladium carbon catalyst.