JP2870926B2 - 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 U.S. Pat.
And so on.

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. As a method for such purification, JP-B-59-15336 discloses a method of decomposing a catalyst in a polyoxyalkylene polyol with a strong alkali metal, an alkali metal hydroxide, and then removing a metal component with an ion exchange resin. Has been proposed. In addition, this Tokuno Sho 59
No. -15336 discloses that the effect of removing metal components is extremely low even when treated with ammonia water instead of treating the catalyst-containing polyoxyalkylene polyol with a strong alkali, and preferable results are obtained under conditions other than strong alkali conditions. Not obtained. 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 non-water-soluble 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 oxyalkali 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 methods.

A polyoxyalkylene alcohol containing the catalyst 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 a pH buffer, and then the catalyst component and the treating agent component are treated. A method for purifying a polyoxyalkylene alcohol, comprising removing the polyoxyalkylene alcohol 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.

M _a [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, the double metal cyanide complex represented by the general formula (1) is composed of a metal salt MX _a (M, a is the same as described above, X is an anion forming a salt with M) and a polycyano metallate (salt) Z
_e [ _M'x (CN) _y ] _f (M ', x, y is the same as above. Z is hydrogen, alkali metal, alkaline earth metal, etc., e, f is Z, M'
Are mixed with each other or a solution in a mixture of water and an organic solvent, and the resulting double metal cyanide is brought into contact with the organic ligand R. , By removing excess solvent and organic compound R.

Polycyanometallate (salt) _Ze [M ' _x (CN) _y ]
_{For f} , various metals including hydrogen and alkali metals can be used for Z, but lithium salts, sodium salts, potassium salts, magnesium salts, and calcium salts are preferred. 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 monoepoxyside and initiator in the presence of a catalyst. Further, the reaction can be carried out while gradually adding monoepoxyside 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, and 30 to 1000 ppm based on the initiator used.
Is more preferred. The catalyst may be introduced into the reaction system in a lump at first, or may be divided and introduced sequentially.

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

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, the pH buffer is preferably used in combination with ammonia. In particular, it is used in combination with an aqueous ammonia solution having a pH of 9 or more. Most preferably, 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 examples of the ammonium 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.

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 magnesium aluminate (MgO.xAl ₂ O ₃ ) and magnesia silicate (MgO.xS
There are solid adsorbents such as iO ₂ ), aluminosilicate (Al ₂ O ₃ .xSiO ₂ ), zeolites and the like, and hydrates thereof. As the metal oxide, aluminum hydroxide [Al
(OH) ₃ ] and [Mg _a Al _b (OH) _c (CO ₃ ) .mH ₂ O] (a, b, c, and m have various values) known as hydrotalcite compounds There is a solid sorbent. In addition, a,
b, c, x are different from those 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. Is considered to have been removed by adsorption of the catalytic metal component by the solid adsorbent or ion exchange of the metal component by the ion exchange resin.

The polyoxyalkylene alcohol in the present invention is preferably a polyoxyalkylene polyol. The polyoxyalkylene polyol is obtained by sequentially subjecting an initiator having at least two hydroxyl groups to a ring-opening addition reaction of a monoepoxyside such as an alkylene oxide. 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, and pentaerythritol, diglycerin, dextrose, sorbitol and sucrose.
There are alcohols having a valency or higher, and polyoxyalkylene alcohols having a lower molecular weight than the target product obtained by reacting these alcohols with a monoepoxyside such as an alkylene oxide. Further, bisphenol A, resol, compounds having a phenolic hydroxyl group or methylol group such as novolak, ethanolamine, compounds having a hydroxyl group such as diethanolamine and other active hydrogen, and reacting these with a monoepoxy side such as an alkylene oxide. There is a polyoxyalkylene alcohol having a lower molecular weight than the obtained target product. Furthermore, there is a polyoxyalkylene alcohol having a molecular weight lower than that of a target product obtained by reacting a monoamine or a polyamine having at least two hydrogen atoms bonded to a nitrogen atom with a monoepoxyside 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 can also be applied to polyoxyalkylene monols obtained by subjecting a monovalent initiator to a ring-opening reaction with a monovalent initiator. 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 monoepoxyside such as an alkylene oxide. 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 one hydrogen atom bonded to a nitrogen atom with a monoepoxyside such as an alkylene oxide.

The monoepoxy side is a monoepoxy side 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 monoepoxysides such as ethylene oxide, styrene oxide, glycidyl ether and glycidyl ester. In the case of using two or more alkylene oxides or using an alkylene oxide and another monoepoxyside, 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 monoepoxyside per 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. When the hydroxyl value is expressed, it is suitably 200 or less, particularly 100 or less. 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. Other uses,
For example, the raw material of oil such as hydraulic oil is also preferably polyoxyalkylene poly (or mono) ol in the above range.

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 uses zinc hexacyanocobaltate catalyst as the metal component
It contains 86 ppm and 35 ppm cobalt, which are hereinafter referred to as unpurified polyol. The method of purification using this unpurified polyol will be described below in Examples.

Example 1 A buffer solution A ^{* 1} 2.5 ml was added to 250 g of unpurified polyol, and the mixture was stirred at room temperature for 1 hour.
gO ・ 6SiO ₂ ) 2.5g and diatomaceous earth 2.5g were added, and deammonia 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 using a filter paper (No. 5C manufactured by Toyo Roshi Kaisha, Ltd .; the same applies hereinafter) (3 kg / cm ² N ₂ pressurization conditions, the same applies hereinafter) ) 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 2 A buffer solution A0.5 ml was added to unpurified polyol 250 g,
After stirring at 80 ° C for 3 hours in an autoclave, zeolite ^{* 2}
Was added, and deammonification and dehydration were performed at 110 ° C. under a reduced pressure of 1 mmHg for 3 hours, followed by filtration under pressure using filter paper to obtain a purified polyol.

^{* 2} Synthetic zeolite F-9, manufactured by Wako Pure Chemical Industries, Ltd. Example 3 To 250 g of unpurified polyol was added 0.5 ml of aqueous buffer solution B ^{* 3} , and the mixture was stirred at 80 ° C. for 3 hours in an autoclave, and then treated with aluminum magnesium hydroxide carbonate. [Mg ₆ Al ₂ (OH) ₁₆
CO ₃ ] was added thereto, deammoniaation and dehydration were performed at 110 ° C. under a reduced pressure of 1 mmHg for 3 hours, followed by filtration under pressure using filter paper to obtain a purified polyol.

^{* 1} 570 g concentrated ammonia water and 173 g ammonium sulfate dissolved in water to make 1 liter, pH10.

Example 4 A buffer solution C ^{* 4 (} 0.5 ml) was added to unpurified polyol (250 g), and the mixture was stirred at 80 ° C. for 3 hours in an autoclave, and then magnesium silicate (2.5 g) and diatomaceous earth (2.5 g) were added. , Dehydrate and finally 110
Dehydration operation under reduced pressure of 1 mmHg for 2 hours.
Pressure filtration was performed using a filter paper to obtain a purified polyol.

^{* 1} 570 g concentrated ammonia water and 101 g ammonium acetate dissolved in water to make 1 liter, pH10.

Example 5 Unpurified polyol was purified under the same conditions as in Example 4 except that aqueous buffer solution D ^{* 5} was used instead of aqueous buffer solution C.

^{* 5} 570g concentrated ammonia water and 82.5g ammonium formate dissolved in water to make 1 liter, pH10.

Example 6 A buffer solution (0.5 ml) was added to unpurified polyol (250 g),
After stirring at 80 ° C. for 3 hours in an autoclave, the mixture was cooled to room temperature. Water mixture - methanol (1: 1) solution 100ml were added, cation exchange resin (Mitsubishi Chemical Industries Co., Ltd. Diaion ^TM SK110), an anion exchange resin (Mitsubishi Chemical Industries Co., Ltd. Diaion ^TM PA316) Add 10g each, 25 ℃
Water and methanol were removed under reduced pressure from the filtered polyol mixture after filtration for 1 hour at 110 ° C.
After dehydration operation with Hg for 2 hours, pressure filtration was performed using filter paper 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 aqueous ammonia was added to 250 g of unpurified polyol, and the mixture was stirred at room temperature for 1 hour.
1) 100 ml of the solution was added, 10 g each of the same cation exchange resin and anion exchange resin as in Example 6 was added, and the mixture was stirred at 25 ° C. for 1 hour and filtered. Water and methanol are removed under reduced pressure from the polyol mixing section filtered off, and finally 110 ° C, 1 mmHg
, And then pressure filtration was performed using a 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 6 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 (6)

(57) [Claims] 1. A polyoxyalkylene alcohol containing a catalyst 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 a pH buffer, and then a catalyst component is prepared. And a treating agent component are removed from the polyoxyalkylene alcohol. 2. The method according to claim 1, wherein ammonia is used together with a pH buffer as a treating agent. 3. The method according to claim 1, wherein the pH buffer is an ammonium salt. 4. The method according to claim 1, wherein the treating agent is an aqueous solution containing an ammonium salt and ammonia. 5. A method for removing a catalyst component and a treating agent component,
The method according to claim 1, wherein the method is an adsorption removal method using a solid adsorbent.
Purification method of 3 or 4. 6. The method according to claim 1, wherein the volatile components are removed by reducing the pressure in addition to the adsorption removal.