JP2870927B2 - Purification method of polyoxyalkylene alcohol - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a method for purifying polyoxyalkylene alcohol.

[Prior art] Polyoxyalkylene alcohol is a compound having an active hydrogen-containing functional group capable of reacting with an alkylene oxide such as a hydroxyl group, an amino group or a carboxyl group as an initiator (initiator) and ring-opening polymerization of the alkylene oxide. It is a compound that has an ether bond in the molecular chain and a hydroxyl group as a terminal group. Polyoxyalkylene alcohols having two or more hydroxyl groups (polyoxyalkylene polyols), also called polyether polyols, are one of the main raw material compounds in the polyurethane industry and the like, and are industrially important compounds. . In addition, polyoxyalkylene alcohols having one or more hydroxyl groups are widely used as surfactants, oils, and the like, or as raw materials thereof. By selecting an initiator having an arbitrary number of functional groups as the initiator, the polyoxyalkylene alcohol can have a corresponding arbitrary number of hydroxyl group terminals. The number of functional groups of the initiator is, in principle, any number of 1 or more, and is generally selected in the range of 1 to 8.

As described above, a typical example of the polyoxyalkylene alcohol in the present invention is a polyoxyalkylene alcohol having two or more hydroxyl groups, that is, a polyoxyalkylene polyol. Hereinafter, the present invention will be described mainly with reference to a polyoxyalkylene polyol, but the present invention does not exclude a polyoxyalkylene alcohol having one hydroxyl group, that is, a polyoxyalkylene monool.

As a method for producing a polyoxyalkylene alcohol by ring-opening polymerization of an alkylene oxide, a method using a double metal cyanide complex such as cobalt zinc cyanide-glyme as a catalyst is described in the following US Patent and EP283148.

USP 3278457, USP 3278458, USP 3278459, USP 3427256, USP 3427334, USP 3427335, USP 3829505, USP 3941849, USP 4355188, USP 4472560, USP 4721818 It is known that when a metal component such as the above-mentioned catalyst or a decomposition product thereof is present in the polyoxyalkylene polyol, allophanate bonds are increased in the reaction between the polyoxyalkylene polyol and the polyisocyanate, resulting in an undesirable result ( USP 4355188 and corresponding JP-B-59-153
No. 36). Therefore, in the method for producing a polyoxyalkylene polyol using a double metal cyanide complex as a catalyst, it is desirable to sufficiently remove the catalyst and catalyst decomposition products by purification. Japanese Patent Publication No. 59-15336 discloses a method of purifying a catalyst in a polyoxyalkylene polyol by decomposing a catalyst in a polyoxyalkylene polyol with a strong alkali metal or alkali metal hydroxide, and then removing the metal component with an ion exchange resin. Has been proposed. In addition, this Tokuno Sho 59
No. -15336 discloses that even when treated with ammonia water instead of treating the strongly alkaline catalyst-containing polyoxyalkylene polyol, the effect of removing the metal component is extremely low, and favorable results are obtained except under strongly alkaline conditions. Not been. Also, US Pat. No. 4,718,818 proposes a method of removing a metal component by decomposing the catalyst with an alkali metal hydride, adding a filter aid, and filtering. However, both methods have drawbacks in terms of safety and economy, such as the use of prohibitive raw materials such as alkali metals and alkali metal hydrides, which require careful handling, and the use of tetrahydrofuran as a solvent. It was not always satisfactory as a method for purifying oxyalkylene polyol.

[Problems to be Solved by the Invention] The present invention provides a method for producing a polyoxyalkylene alcohol by ring-opening polymerization of an alkylene oxide using a double metal cyanide complex as a catalyst. It is an object of the present invention to provide an efficient purification method using raw materials that can be easily handled.

[Means for Solving the Problems] The present invention basically provides the following purification method.

A polyoxyalkylene alcohol containing the catalyst component synthesized by ring-opening polymerization of an alkylene oxide in the presence of a double metal cyanide complex catalyst is treated with a treating agent comprising at least one selected from a pH buffer and an aqueous ammonia solution. A method for purifying a polyoxyalkylene alcohol, comprising treating and simultaneously or subsequently reacting a metal ion chelating agent, and then removing a catalyst component and a treating agent component from the polyoxyalkylene alcohol.

It is considered that the double metal cyanide complex in the present invention has a structure represented by the following general formula (1) as shown in the above-mentioned known examples.

Ma [M ′ _x (CN) _y ] _b (H ₂ O) _c (R) _d (1) where M is Zn (II), Fe (II), Fe (III), Co (I
I), Ni (II), Al (III), Sr (II), Mn (II), Cr
(III), Cu (II), Sn (II), Pb (II), Mo (IV), M
o (VI), W (IV), W (VI), etc., where M ′ is Fe (I
I), Fe (III), Co (II), Co (III), Cr (II), Cr
(III), Mn (II), Mn (III), Ni (II), V (IV),
V (V), etc., R is an organic ligand, a, b, x and y are positive integers depending on the valence and coordination number of the metal, and c and d are the coordination of the metal. It is a positive number that changes depending on the number.

M in the general formula (1) is preferably Zn (II), and M ′ is
Fe (II), Fe (III), Co (II), Co (III) and the like are preferable. Examples of the organic ligand include ketone, ether, aldehyde, ester, alcohol, and amide.

As described above double metal cyanide complex represented by the general formula (1) is a metal salt MX _a (M, a is as described above, X is forms a M and anions) and poly cyanometalate (salt) Ze
[M ′ _x (CN) _y ] _f (M ′, x, y is the same as above. Z is hydrogen,
E, f are positive integers determined by the valence and coordination number of Z, M ', such as alkali metals and alkaline earth metals), or a mixed solution of water and an organic solvent.
It is produced by bringing an organic ligand R into contact with the obtained double metal cyanide, and then removing excess solvent and the organic compound R.

Polycyanometallate (salt) _Ze [M ' _x (CN) _y ] _f is
As Z, various metals including hydrogen and alkali metals can be used, but lithium salts, sodium salts, potassium salts, magnesium salts, and calcium salts are preferable. Particularly preferred are ordinary alkali metal salts, that is, sodium salts and potassium salts.

The polyoxyalkylene alcohol is usually produced by reacting a mixture of monoepoxide and initiator in the presence of a catalyst. In addition, the reaction can be carried out while gradually adding monoepoxide to the reaction system. The reaction occurs at room temperature, but the reaction system can be heated or cooled if necessary. The amount of the catalyst used is not particularly limited, but is suitably about 1 to 5000 ppm, more preferably 30 to 1000 ppm, for the initiator used. The catalyst may be introduced into the reaction system in a lump at first, or may be divided and introduced sequentially.

When this double metal cyanide complex catalyst is used, it is possible to synthesize a polyoxyalkylene alcohol having a low content of unsaturated monool or an extremely high molecular weight having a low content of unsaturated monool.

The pH buffer used as a treating agent in the present invention is the pH of the solution.
Has the ability to keep a certain range. As the pH buffer, a salt of a weak base or a salt of a weak acid is used, and an acid or a base can be used together with these. Considering the easiness of removing the treating agent after the treatment, the base and the acid are preferably volatile. Therefore,
Ammonia (ammonium) is preferable as the base, and volatile organic acids such as acetic acid and formic acid are preferable as the acid. As the pH buffer, an ammonium salt, particularly an ammonium salt of acetic acid or formic acid, is preferably used. The pH buffer is usually used in an aqueous solution. The concentration is not particularly limited, but is suitably not more than the solubility of the pH buffer, particularly not more than 40 wt%. The lower limit is suitably 2 wt%, especially 5 wt%.

In the present invention, ammonia can be used instead of the above-mentioned pH buffer. Particularly, use of an aqueous ammonia solution having a pH of 9 or more is preferred. Most preferably, the above-mentioned pH buffer and ammonia are used in combination, and usually an aqueous ammonia-containing pH buffer solution obtained by dissolving a pH buffer in an aqueous ammonia solution is used. The pH of the aqueous solution is preferably 9 or more.

As described above, ammonium salts are preferred as the pH buffer. Specific ammonium salts include, for example, ammonium chloride, ammonium sulfate, ammonium phosphate, ammonium acetate, ammonium formate, and ammonium oxalate, and at least one selected from ammonium chloride, ammonium sulfate, ammonium acetate, and ammonium formate. Is particularly preferred.

In the treatment with the treatment agent, it is sufficient to simply add the treatment agent to the catalyst-containing polyoxyalkylene alcohol and hold it for a certain time. Preferably, the temperature is maintained for a period of time with stirring. Heating is not essential, but heating may be performed to increase the processing speed. Usually, stirring is performed at a temperature at which ammonia volatilization is low (about room temperature), or heating and stirring is performed in a closed container such as an autoclave. The holding time is not particularly limited, but is 10 minutes to several hours or longer. Although the processing time depends on the processing amount, usually 30 minutes or more is adopted. The amount of the treatment agent varies depending on the content of the catalyst.
When using the above ammonia-containing pH buffer aqueous solution,
0.001 based on catalyst-containing polyoxyalkylene alcohol
The addition of an aqueous solution of a pH buffer containing 〜10% by weight of ammonia is preferred. In particular, addition of 0.01 to 5 wt% is preferable.

In the present invention, simultaneously with the treatment with the treatment agent,
Alternatively, after the treatment, a treatment with a metal ion chelating agent is performed. The amount of the metal ion chelating agent to be added is preferably not less than the amount capable of chelating metals in the catalyst-containing polyoxyalkylene alcohol. Usually, it is used in an amount of 0.0001 to 1% by weight, especially 0.001 to 0.1% by weight, based on the catalyst-containing polyoxyalkylene alcohol.

The treatment with the metal ion chelating agent can be performed in the same manner as the treatment with a treating agent comprising a pH buffer or ammonia. For example, it is sufficient to simply add a metal ion chelating agent to a polyoxyalkylene alcohol containing the treating agent after the treatment with the treating agent comprising a pH buffer is completed, and hold for a certain period of time. Preferably, the temperature is maintained for a period of time with stirring. Heating is not essential, but may be. The holding time is not particularly limited, but is 10 minutes to several hours or longer. Processing time depends on processing volume, but usually 30
Minutes or more are employed. When the treatment with the metal ion chelating agent is performed simultaneously with the treatment with the treating agent comprising a pH buffer, the same conditions as those for the treatment with the treating agent comprising the pH buffer are employed.

As the metal ion chelating agent, a compound which coordinates with a metal ion to form a so-called chelate compound can be used. As the metal ion chelating agent, an aminocarboxylic acid polydentate ligand having a plurality of amino groups and carboxyl groups, or an alkali metal salt or an ammonium salt thereof is preferable. As the aminocarboxylic acid polydentate ligand,
For example, there are ethylenediaminetetraacetic acid, ethylenediaminediacetic acid, diethylenetriaminepentaacetic acid, triethylenetetraminehexaacetic acid, N- (2-hydroxyethyl) ethylenediaminetriacetic acid, and nitrilotriacetic acid. In particular, ethylenediaminetetraacetic acid, nitrilotriacetic acid, and alkali metal salts and ammonium salts thereof are preferable from the viewpoint of effect and economical reason.

As a method for removing impurities such as the double metal cyanide complex catalyst component decomposed in the above treatment and the metal component of the ionized catalyst, several methods can be considered,
Adsorption removal by the adsorbent is the simplest method because of the ease of operation, that is, only the addition and filtration of the adsorbent,
This is the most preferred method in the present invention. In addition, the removal of volatile components together with the adsorption removal is performed under reduced pressure,
It can be performed by an inert gas blowing treatment or the like. This volatile component removal processing may be performed together with the adsorption removal processing, or may be performed before or after the adsorption removal processing. The volatile components include ammonia and water.

As adsorbents, including metal oxides and metal hydroxides,
Commonly known solid adsorbents can be used. The solid adsorbents can be used alone or in combination of two or more. Examples of the metal oxide include magnesium oxide (MgO),
Composites containing these, such as aluminum oxide (Al ₂ O ₃ ) and silicon oxide (SiO ₂ ), such as magnesia aluminate (MgO · xAl ₂ O ₃ ), magnesia silicate (MgO · xSiO
₂ ) There are solid adsorbents such as aluminosilicate (Al ₂ O ₃ .xSiO ₂ ), zeolite, etc., and hydrates thereof. As the metal hydroxide, aluminum hydroxide [Al
(OH) ₃ ] and [Mg _a Al _b (OH) _c (CO ₃ ) · mH ₂ O] (a, b, c, m take various values) known as hydrotalcite compounds There is a solid sorbent. Note that a, b, c, x
Is different from that in the description of the double metal cyanide complex.

The solid adsorbent is added to the polyoxyalkylene alcohol which has been treated with the treating agent, and is usually left for a while under stirring to sufficiently adsorb the adsorbed components and then removed by a filtration operation. . A generally known filter aid may be optionally added to improve the filterability during the filtration operation.

An ion exchange resin can also be used as a solid adsorbent. In this case, ion-exchanged water or a solvent is added to the polyoxyalkylene alcohol which has been treated with the treating agent, if necessary, and the mixture is passed through a column filled with a cation exchange resin or an anion exchange resin. Dehydration and desolvation are performed below to obtain a purified polyol.

In the polyoxyalkylene alcohol purified according to the present invention, the residual amount of metal derived from the catalyst is reduced to such an extent that it is not detected by ICP emission analysis. In the present invention, the double metal cyanide complex catalyst contained in the polyoxyalkylene alcohol is decomposed by the action of a pH buffer, particularly an ammonia-containing pH buffer, and is converted into an ionic metal complex compound. Are removed by chelation with a metal chelating agent, adsorption of a catalytic metal component or a chelated metal component by a solid adsorbent, or ion exchange of the metal component by an ion exchange resin.

The polyoxyalkylene alcohol in the present invention is preferably a polyoxyalkylene polyol. The polyoxyalkylene polyol is obtained by sequentially performing a ring-opening addition reaction of a monoepoxide such as an alkylene oxide to an initiator having at least two hydroxyl groups.
As the initiator, a polyhydroxy compound having 2 to 8 hydroxyl groups is particularly preferable. Examples of the polyhydroxy compound include dihydric alcohols such as ethylene glycol and propylene glycol, trihydric alcohols such as glycerin, trimethylolpropane, and hexanetriol; tetrahydric or higher such as pentaerythritol, diglycerin, dextrose, sorbitol, and sucrose. And polyoxyalkylene alcohols having a lower molecular weight than the target product obtained by reacting these alcohols with a monoepoxide such as an alkylene oxide. Compounds having a phenolic hydroxyl group or a methylol group such as bisphenol A, resole and novolak, compounds having a hydroxyl group such as ethanolamine and diethanolamine and other active hydrogens, and compounds obtained by reacting these with a monoepoxide such as an alkylene oxide. There is a polyoxyalkylene alcohol having a lower molecular weight than the intended product. Further, there is a polyoxyalkylene alcohol having a molecular weight lower than that of a target product obtained by reacting a monoamine or polyamine having at least two hydrogen atoms bonded to a nitrogen atom with a monoepoxide such as an alkylene oxide. In addition, phosphoric acid, its derivatives, and other polyhydroxy compounds can also be used. These polyhydroxy compounds may be used in combination of two or more.

The present invention is also applicable to polyoxyalkylene monols obtained by subjecting a monovalent initiator to a ring-opening reaction of monoepoxide. Monovalent initiators include, for example, methanol, ethanol, butanol, hexanol, other monols, phenol,
There are phenol derivatives such as alkyl-substituted phenols, and polyoxyalkylene alcohols having a lower molecular weight than the target product obtained by reacting these with a monoepoxide such as an alkylene oxide. Furthermore, there is a polyoxyalkylene alcohol having a molecular weight lower than that of a target product obtained by reacting a monoamine or polyamine having one hydrogen atom bonded to a nitrogen atom with a monoepoxide such as an alkylene oxide.

The monoepoxide is a monoepoxide having 2 or more carbon atoms, particularly preferably an alkylene oxide having 2 or more carbon atoms. More preferably, alkylene oxides having 3 to 4 carbon atoms such as propylene oxide, 1,2-butylene oxide, 2,3-butylene oxide, and epichlorohydrin are preferable, and propylene oxide is most preferable. The alkylene oxides having 3 to 4 carbon atoms can be used alone or in combination of two or more thereof, or in combination with other monoepoxides such as ethylene oxide, styrene oxide, glycidyl ether, and glycidyl ester. When two or more alkylene oxides are used or when an alkylene oxide and another monoepoxide are used, they can be mixed and added or sequentially added to form a random polymerized chain or a block polymerized chain.

The molecular weight of the polyoxyalkylene alcohol in the present invention is not particularly limited. However, products that are liquid at room temperature are preferred in terms of their use. The reaction amount of monoepoxide with respect to 1 mol of the initiator is preferably at least about 10 mol, and more preferably at least about 50 mol. More preferably, polyoxyalkylene alcohols obtained by reacting an average of at least about 10 molecules, particularly at least about 30 molecules per hydroxyl group of the initiator are preferred. Also, if expressed in terms of hydroxyl value, it is 200 or less, especially 100
The following are appropriate: For example, as a raw material for polyurethane, a liquid polyoxyalkylene polyol having a hydroxyl value of about 5 to 200, particularly 5 to 60 is preferable. Polyoxyalkylene poly (or mono) ol in the above range is also preferable for other uses, for example, oil raw materials such as hydraulic oil.

The polyoxyalkylene polyol obtained by the present invention is most useful as a polyol for a polyurethane raw material used alone or in combination with other polyols. The polyoxyalkylene poly (or mono) ol obtained according to the present invention is also used as a raw material of synthetic resins other than polyurethane and as an additive.
In addition, as lubricating oil, insulating oil, hydraulic oil, and other oils,
Alternatively, it can be used as a raw material. further,
The polyoxyalkylene alcohol obtained according to the present invention can be converted into other compounds such as alkyl ether compounds and acyl compounds to be used for various purposes.

Hereinafter, the present invention will be described with reference to examples, but the present invention is not limited thereto.

Example A polyether polyol containing a double metal cyanide complex catalyst was produced according to a known method. Using zinc hexacyanocobaltate / glyme as a catalyst and 1,2,3-tris (2-hydroxy-propoxy) propane as an initiator, polymerizing propylene oxide gives a number average molecular weight of about 6000 (hydroxyl value 28.6). )) Was obtained. This polyol contains zinc hexacyanocobaltate catalyst as a metal component and contains 86 ppm of zinc and 35 ppm of cobalt.
It is called unpurified polyol. The purification method using this unpurified polyol will be described below in Examples.

Example 1 1.25 g of concentrated aqueous ammonia was added to 250 g of unpurified polyol, and the mixture was stirred at room temperature for 1 hour. Then, 10 ml of an aqueous solution containing 90 mg of disodium ethylenediaminetetraacetate was added, and the mixture was further stirred at room temperature for 1 hour. Alumina (200 mesh) 5.0 for the mixture
g, and deammoniaation and dehydration are performed under reduced pressure while raising the temperature. Finally, dehydration operation is performed at 110 ° C. under a reduced pressure of 1 mmHg for 2 hours. Then, filter paper (No. 5C manufactured by Toyo Roshi Kaisha, Ltd.) ) To obtain a purified polyol (under pressure of 3 kg / cm ² N ₂ , the same applies hereinafter).

Example 2 To 250 g of unpurified polyol, 2.5 ml of an aqueous buffer solution A ^{* 1} was added and stirred at room temperature for 1 hour. Then, 10 ml of an aqueous solution containing 90 mg of disodium ethylenediaminetetraacetate was added, and the mixture was further stirred at room temperature for 1 hour. 2.5 g of aluminum magnesium magnesium carbonate [Mg ₆ Al ₂ (OH) ₁₆ CO ₃ ] was added to the mixture, deammoniaization and dehydration were performed under reduced pressure while heating, and finally at 110 ° C. under reduced pressure of 1 mmHg for 2 hours. After performing a dehydration operation, pressure filtration was performed using a filter paper to obtain a purified polyol. ^{* 1} 570 g concentrated ammonia water and 70 g ammonium chloride dissolved in water to make 1 liter, pH10.

Example 3 A buffer solution (A2.5 ml) was added to unpurified polyol (250 g),
After stirring at room temperature for 1 hour, 10 ml of an aqueous solution of 90 mg of disodium ethylenediaminetetraacetic acid was added, and the mixture was further stirred at room temperature for 1 hour. Magnesia silicate (2MgO ・ 6Si)
O ₂ ) 2.5 g was added, deammoniaation and dehydration were performed under reduced pressure while raising the temperature, and finally dehydration operation was performed at 110 ° C. and 1 mmHg under reduced pressure for 2 hours, followed by pressure filtration using filter paper. And a purified polyol was obtained.

Example 4 An aqueous solution in which 1.25 g of concentrated aqueous ammonia and 90 mg of ethylenediaminetetraacetic acid were dissolved in 20 ml of water was added to 250 g of unpurified polyol, and the mixture was stirred at room temperature for 2 hours. 2.5 g of magnesia aluminate (2.5 MgO.Al ₂ O ₃ ) was added to the mixture, and deammoniaration and dehydration were performed under reduced pressure while raising the temperature.
After performing a dehydration operation under a reduced pressure of 1 mmHg for 2 hours, pressure filtration was performed using a filter paper to obtain a purified polyol.

Example 5 A buffer solution (A2.5 ml) was added to unpurified polyol (250 g),
After stirring at room temperature for 1 hour, nitrilotriacetic acid disodium salt 80
10 ml of an aqueous solution of mg was added, and the mixture was further stirred at room temperature for 1 hour.
5 g of zeolite ^{* 2} was added to the mixture, and deammoniaation and dehydration were performed under reduced pressure while heating, and finally 110 ° C, 1 mmHg
After performing a dehydration operation under reduced pressure for 2 hours, filtration under pressure was performed using a filter paper to obtain a purified polyol. ^{* 2} Synthetic zeolite F-9, manufactured by Wako Pure Chemical Industries, Ltd. Example 6 To 250 g of unpurified polyol was added 2.5 ml of aqueous buffer solution B ^{* 3,} and the mixture was stirred at room temperature for 1 hour, and then an aqueous solution of 90 mg of disodium ethylenediaminetetraacetic acid was added. 10 ml was added, and the mixture was further stirred at room temperature for 1 hour. To the mixture was added 2.5 g of aluminum magnesium hydroxide, deammoniaization and dehydration were performed under reduced pressure while heating, and finally dehydration was performed at 110 ° C. and 1 mmHg under reduced pressure for 2 hours. Pressure filtration was performed to obtain a purified polyol. ^{* 3} 570 g concentrated ammonia water and 101 g ammonium acetate dissolved in water to make 1 liter, pH10.

Example 7 Unpurified polyol was purified under the same conditions as in Example 6, except that an aqueous buffer solution C ^{* 4} was used instead of the aqueous buffer solution B. ^{* 4} 570g concentrated ammonia water and 82.5g ammonium formate dissolved in water to make 1 liter, pH10.

Example 8 A buffer solution (A2.5 ml) was added to unpurified polyol (250 g),
After stirring at room temperature for 1 hour, 10 ml of an aqueous solution of 90 mg of disodium ethylenediaminetetraacetic acid was added, and the mixture was further stirred at room temperature for 1 hour. Cation exchange resin (Diaion ^TM SK 110 manufactured by Mitsubishi Kasei Kogyo Co., Ltd.) and anion exchange resin (Diaion ^TM PA manufactured by Mitsubishi Kasei Kogyo Co., Ltd.)
316), 10 g of each was added, the polyol obtained from below was passed through the polyol mixture from above, and subsequently the dehydration treatment was performed at 110 ° C. under a reduced pressure of 1 mmHg to obtain a purified polyol.

Comparative Example 1 1.25 g of concentrated aqueous ammonia was added to 250 g of unpurified polyol, and the mixture was stirred at room temperature for 1 hour.
After adding 5 g and stirring at 25 ° C. for 1 hour, dehydration operation was performed at 110 ° C. under a reduced pressure of 1 mmHg for 2 hours, followed by pressure filtration using filter paper to obtain a polyol.

Comparative Example 2 1.25 g of concentrated aqueous ammonia was added to 250 g of unpurified polyol, and the mixture was stirred at room temperature for 1 hour. Then, water-methanol (1: 1) was added.
100 ml of the solution was added, 10 g of each of the same cation exchange resin and anion exchange resin as in Example 8 were added, and the mixture was stirred at 25 ° C. for 1 hour and filtered. Water and methanol were removed from the polyol mixture filtered off under reduced pressure.
After performing the dehydration operation for a time, pressure filtration was performed using filter paper to obtain a purified polyol.

Comparative Example 3 2.5 g of magnesia silicate was added to 250 g of unpurified polyol, stirred at room temperature for 1 hour, dehydrated at 110 ° C. and 1 mmHg for 2 hours, and filtered under pressure using filter paper to obtain a polyol. Was.

The analysis values of the purified polyols obtained in Examples 1 to 8 and Comparative Examples 1 to 3 are shown in Table 1.

[Effects of the Invention] The present invention is a method for efficiently and sufficiently removing a metal component of a double metal cyanide complex catalyst from a polyoxyalkylene alcohol. Various inconveniences can be eliminated. Therefore, a particularly useful polyoxyalkylene polyol can be obtained according to the present invention in the production of a polyoxyalkylene polyol used as a raw material for a polyurethane in which a metal component in the polyoxyalkylene polyol tends to cause a problem.

Claims (5)

(57) [Claims] 1. A polyoxyalkylene alcohol containing a catalyst component synthesized by ring-opening polymerization of an alkylene oxide in the presence of a double metal cyanide complex catalyst, is prepared from at least one selected from a pH buffer and ammonia. A method for purifying a polyoxyalkylene alcohol, comprising treating the polyoxyalkylene alcohol with a metal ion chelating agent simultaneously or subsequently, and then removing the catalyst component and the processing agent component from the polyoxyalkylene alcohol. 2. The method according to claim 1, wherein the pH buffer is an ammonium salt. 3. The method according to claim 1, wherein the treating agent is an aqueous solution containing an ammonium salt and ammonia. 4. A method for removing a catalyst component and a treating agent component,
4. The purification method according to claim 1, wherein the method is an adsorption removal method using a solid adsorbent. 5. The method according to claim 1, wherein volatile components are removed by reduced pressure together with adsorption removal.