JPH0597996A - Method for purifying polyethers - Google Patents

Abstract

PURPOSE:To purify a polyether containing an alkali metal halide. CONSTITUTION:A hydroxyl group-containing high-molecular weight polyether (polyether containing l-6 hydroxyl groups, having 1,000-50,000 molecular weight) is reacted with a halogenated hydrocarbon (e.g. allyl chloride) in the presence of an alkali metal or after the conversion of a basic alkali metal compound to convert the end hydroxyl group of the high-molecular weight polyether to an alkali metal alkoxide to give an alkali metal halide-containing polymer polyether, which is mixed with a nonionic surfactant (compound containing >=5wt.% oxyethylene chain in molecule) and water, dehydrated and the alkali metal halide is removed.

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION The present invention relates to a purification method for removing alkali metal halides from high molecular weight polyethers containing a small amount of alkali metal halides.

[0002]

2. Description of the Related Art High molecular weight polyethers (for example, polyoxyalkylene poly (or mono) ol and its derivatives) increase in viscosity as the molecular weight increases. When purifying high molecular weight polyethers to remove impurities contained therein, the higher the viscosity of the polyethers, the more difficult the purification treatment becomes. Also, the high viscosity of polyethers makes processing more and more difficult when impurities are small and must be removed satisfactorily.

When a terminal hydroxyl group of polyoxyalkylene poly (or mono) ol is converted into another organic group to produce a derivative, an alkali metal alkoxide is used as the hydroxyl group and an organic halide is reacted to produce the derivative. There is. Specifically, for example, when reacting allyl chloride as an organic halide to produce a derivative having a terminal allyl group, and when reacting with a polyhalogenated hydrocarbon such as methylene chloride to increase the amount of polyether, is there.

Alkali metal halides are by-produced in this process, and in most cases this derivative must be sufficiently removed from the derivative. However, removal of this by-product becomes extremely difficult when the derivative has a high viscosity.

As an example, the case of producing a polyether having a terminal alkenyl group will be specifically described below.

[0006] Polyethers having a terminal alkenyl group can be introduced into various functional groups by chemical modification such as addition reaction utilizing the olefin group thereof, and thus they are useful intermediates of functional group-containing polyethers. The synthetic method and the purification method have been studied so far. The method of reacting a hydroxyl group of a polyether polyol having a terminal hydroxyl group with an alkenyl chloride such as allyl chloride or methallyl chloride in the presence of a base to form an terminal alkenyl group is a well known method.

In this method, when an alkali metal hydroxide or sodium metal is used as a base during the reaction, an inorganic salt such as sodium chloride is by-produced. When such an inorganic salt produced as a by-product and an excess base are used, it is necessary to remove the remaining base. For this removal, generally, a method of treating with an appropriate adsorbent and filtering, a method of filtering a salt produced after neutralizing with various acids, a method of extracting and the like are known.

[0008]

However, as described above, high molecular weight polyethers are difficult to filter because of their high viscosity. Furthermore, in the case of high molecular weight polyethers, the salt produced by neutralization is finely dispersed and cannot be easily filtered. In addition, even with the extraction method, with high molecular weight polyethers, a simple water-washing method results in a creamy mixture in which the polymer layer and the water layer cannot be separated at all, and even if a solvent is used, it easily becomes an emulsion. It cannot be separated into two.

Dilute with a water-insoluble organic solvent and adjust the pH of the water layer.
Although a method of separating liquids by using a combination of the control of 1. and a surfactant is also known, it is practically difficult to use polyethers having high hydrophilicity, which is a major limitation. Therefore, it is desired to establish a highly general purification method for not only polyethers having a terminal alkenyl group but also high molecular weight polyethers having the above-mentioned properties.

[0010]

The present invention is the following invention to solve the above-mentioned problems. That is, a method for purifying polyethers, which comprises adding a surfactant and water to a high-molecular-weight polyether containing a small amount of an alkali metal halide, dehydrating it, and then removing the alkali metal halide. Is.

As the high molecular weight polyether containing a small amount of alkali metal halide, the high molecular weight polyether having a hydroxyl group as described above and a halogenated hydrocarbon can be prepared in the presence of an alkali metal or a basic alkali metal compound. Or a product obtained by reacting the terminal hydroxyl group of the high-molecular weight polyether with an alkali metal alkoxide, and then reacting is suitable. The alkoxide of the hydroxyl group of the high molecular weight polyether can be performed simultaneously with the reaction with the organic halide.

Polyoxyalkylene poly (or mono) ol is preferable as the high molecular weight polyether having at least one hydroxyl group, which is a raw material of the polyethers in the present invention. The molecular weight is not particularly limited, but 1,000 or more is suitable. It is preferably 3000 to 50000. The number of hydroxyl groups is 1
It is above, 1-6 are suitable, Preferably it is 2-4.

The polyoxyalkylene poly (or mono) ol is preferably obtained by reacting an initiator with a monoepoxide, particularly an alkylene oxide having 3 to 6 carbon atoms, in the presence of a catalyst. The initiator is a compound having a reaction site (a hydrogen atom of a hydroxyl group or an amino group) corresponding to the number of hydroxyl groups, and examples thereof include monovalent or higher alcohols and phenols.

As the initiator, a dihydric to tetrahydric alcohol or an alkylene oxide adduct thereof (a polyoxyalkylene polyol having a lower molecular weight than the target) is used.
Is preferred.

Suitable initiators are 1- to 6-valent alcohols and phenols, but are not limited to these, and for example, 1- to 6-valent carboxylic acids, amines, thiols and the like can be used. When producing a polyether having a terminal alkenyl group, an initiator having an alkenyl group such as an alkenyl alcohol (eg, allyl alcohol) is preferable as the monovalent initiator. Two
Examples of the initiator having a valency or higher include the following compounds.

Ethylene glycol, diethylene glycol, propylene glycol, polypropylene glycol other than dipropylene glycol, butanediol, glycerin, trimethylolpropane, pentaerythritol, bisphenol A and alkylene oxide adducts thereof.

The monoepoxide particularly has 3 to 10 carbon atoms.
An alkylene oxide of 6 is preferred. Examples of the alkylene oxide having 3 to 6 carbon atoms include propylene oxide, butylene oxide, hexylene oxide and styrene oxide. Particularly preferably, propylene oxide alone or a small amount of propylene oxide and a small amount of other carbon atoms 3
It is a combination of the above alkylene oxides.

Alkali catalysts are well known as catalysts used in the production of polyoxyalkylene poly (or mono) ols. The alkali catalyst is usually composed of an alkali metal or a compound thereof, and it is considered that it effectively oxidizes a hydroxyl group and exerts a catalytic action.
However, when an alkali catalyst is used, the upper limit of the molecular weight of the polyoxyalkylene poly (or mono) ol obtained due to a side reaction is limited, and in the case of diol, it is at most about 4000.

In order to produce a higher molecular weight product,
It is preferable to use a double metal cyanide complex catalyst or a porphyrin metal complex catalyst. These complex catalysts are known as alkylene oxide addition catalysts.

As a method of reacting a halogenated hydrocarbon with a hydroxyl group of a high molecular weight polyether having at least one hydroxyl group, the hydroxyl group is an alkali metal such as sodium or potassium, an alkali metal hydride such as NaH, NaOR (R). Represents an alkyl group such as methyl, ethyl, propyl, isopropyl, butyl), or an alkali metal hydroxide such as sodium hydroxide or potassium hydroxide to form an alkoxide group and then halogenate. There is a method of causing a hydrocarbon reaction.

Alternatively, when a basic alkali metal compound such as an alkali metal hydroxide is used, a method of reacting with a halogenated hydrocarbon in the presence of such a compound can be used. Hereinafter, these alkali metals and their compounds are simply referred to as bases.

By this reaction, high molecular weight polyethers containing an alkali metal halide are obtained. The amount of alkali metal halide is usually smaller as the higher molecular weight polyethers are higher in molecular weight. Usually, the amount is not more than 5% by weight, and often not more than 2% by weight, based on the high molecular weight polyethers. The lower limit may vary depending on the need for purification, but in the normal case,
It is about 0.1% by weight.

The amount of the alkali metal halide in the polyethers purified by the present invention can also vary depending on the purpose, but it is preferably 1/10 or less of the unpurified amount, particularly It is preferably 1/10 or less of the unpurified amount and less than 0.1% by weight. In many cases, the above-mentioned base is contained in the unpurified polyethers,
This base is also removed by the purification of the present invention.

As mentioned above, as the halogenated hydrocarbon in the present invention, a polyhalogenated hydrocarbon having 4 or less carbon atoms or a monohalogenated hydrocarbon having 8 or less carbon atoms is suitable.

Chlorine or bromine is suitable as the halogen. Particularly, a dichlorohydrocarbon having 1 to 2 carbon atoms or a monochlorohydrocarbon having 6 or less carbon atoms is preferable.
As mentioned above, most preferred are alkenyl halides, especially alkenyl chlorides. As the alkenyl halide, allyl chloride and methallyl chloride are particularly preferable.

The amount of the alkenyl halide used can be arbitrarily changed depending on the percentage of the total amount of hydroxyl groups in the high molecular weight polyether having hydroxyl groups to be converted into alkenyl groups. Although any equivalent can be used with respect to the hydroxyl groups of the high molecular weight polyether having at least one hydroxyl group, when all the hydroxyl groups are converted into alkenyl groups, it is generally used in excess equivalent to the hydroxyl groups. The appropriate upper limit of the equivalent is about 1.3.

The number of alkenyl groups per molecule in the obtained high molecular weight polyethers is 1.6 to.
6, especially 1.8-3 are preferable. Of course, the obtained high molecular weight polyethers may have a hydroxyl group which is not converted into an alkenyl group.

Further, in the production of polyoxyalkylene monool, an initiator having an alkenyl group such as allyl alcohol and methallyl alcohol is used to produce polyoxyalkylene monool, and the hydroxyl group thereof is alkenyl by the above method. It is also possible to produce high molecular weight polyethers having more than 1 alkenyl group.

In the present invention, in order to remove an alkali metal halide (hereinafter also referred to as a salt) from a high molecular weight polyether containing an alkali metal halide, a surfactant and water are added to the polyether, Extraction of alkali metal halides in high molecular weight polyethers with water,
The salt is precipitated by dehydration to obtain a salt crystal having a size that can be easily removed.

The use of this water is particularly effective when the base may be partially precipitated depending on the content of the base in the high molecular weight polyether to be purified and the polarity of the high molecular weight polyether. That's the method.

In the present invention, the use of surfactant is essential. As the surfactant used in the present invention, those generally known as nonionic surfactants are particularly preferable. In the present invention, a compound having 5% by weight or more of oxyethylene chain in the molecule is particularly preferable among the nonionic surfactants.

Specific compounds include polyoxyethylene aliphatic alkyl ether, polyoxyethylene polyoxypropylene aliphatic alkyl ether, polyoxyethylene alkylphenyl ether, polyoxyethylene monoaliphatic carboxylic acid ester, sorbitan mono or poly. Aliphatic ester, polyoxyethylene sorbitan monofatty acid ester, polyoxyethylene oxypropylene block polymer, oxyethylene or polyoxyethylene aliphatic amine, fatty acid dialkanolamide, glycerol monofatty acid ester, polyglycerin fatty acid ester, propylene glycol fatty acid ester, Examples thereof include, but are not limited to, pentaerythritol fatty acid ester.

The amount used is preferably 0.01 to 5 parts by weight, more preferably 0.1 to 1 part by weight, relative to 100 parts by weight of the mixture.

When the amount of the surfactant is less than 0.01 part by weight, the salt may remain in the polyether even if the salt precipitated later is removed, or the salt is finely dispersed. Therefore, it becomes very difficult to remove the salt from the polyethers. Further, when the amount of the surfactant is more than 5 parts by weight, a large amount of the surfactant remains in the purified polyethers, which is not preferable.

The amount of water used in the present invention may be 1 to 50 parts by weight, preferably 5 to 30 parts by weight, based on 100 parts by weight of high molecular weight polyethers. If the amount of water is less than 1 part by weight, the salt that precipitates after dehydration will not become sufficiently large, so if the amount of water is difficult to remove, and if it is more than 50 parts by weight, the time and heat required for the dehydration step are large and it is not economical. ..

As a method for removing salt, a generally known method can be used. Specific examples of such a method include a filtration method and a centrifugation method. When removing salts from high molecular weight polyethers, it is also possible to dilute with a solvent as needed. Such a method is effective when the high molecular weight polyether compound has a large molecular weight and therefore has a large viscosity. In that case, as the solvent that can be used, it is essential that the salt is not dissolved,
There are no other restrictions.

Specific examples of the solvent which can be used in the present invention include aliphatic hydrocarbon solvents such as hexane, heptane and octane, alicyclic hydrocarbon solvents such as cyclohexane and methylcyclohexane, benzene, toluene and xylene. Examples of the aromatic hydrocarbon solvent include, but are not limited to, halogenated hydrocarbon solvents such as dichloromethane, trichloroethylene and tetrachloroethylene, and halogenated aromatic solvents such as chlorobenzene and dichlorobenzene.

In the present invention, the basic compound contained in the high-molecular weight polyether containing the alkali metal halide to be purified can be neutralized with an acid, which is generally preferred.

As the acid that can be used for neutralization, any of an organic acid, an inorganic acid and a solid acid can be used. In the case of an organic acid, the organic acid salt produced by the neutralization is dissolved in a high molecular weight polyether. In some cases, inorganic acids and solid acids are preferred.

Examples of the inorganic acid which can be used in the present invention include hydrochloric acid, sulfuric acid, nitric acid, phosphoric acid, boric acid, perchloric acid and the like, and solid acids include activated clay, magnesia silicate, aluminosilicate and hydrochloric acid. Adsorbents and the like, which are also known as solid ion exchangers such as talcite, can be exemplified, but not limited to these.

When the base in the high molecular weight polyether containing the alkali metal halide is neutralized, it should be added before adding the surfactant and water to the high molecular weight polyether containing the alkali metal halide. , The time of addition is good.

[0042]

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

Reference Example 1 Polyoxypropylene triol having a molecular weight of 30,000 obtained by polymerizing propylene oxide in the presence of a catalyst using glycerin as an initiator was reacted with 1 equivalent of NaH with respect to the hydroxyl group at 60 ° C. in a nitrogen atmosphere. After making it a sodium alkoxide, 1.05 equivalent of allyl chloride was added and reacted at 60 ° C.,
Unreacted allyl chloride was distilled off under reduced pressure to produce a terminally allylated polyether compound containing sodium chloride (hereinafter referred to as unpurified polyether A).

Reference Example 2 Propylene oxide was polymerized in the presence of a catalyst using ethylene glycol as an initiator to a molecular weight of 15,000, and then ethylene oxide was further polymerized to a molecular weight of 18,000 in a polyether diol under a nitrogen atmosphere and powdered hydroxide. Sodium was added in an amount of 1.5 equivalents to the polyether diol, 1.05 equivalents of methallyl chloride were further added, and the mixture was reacted at 60 ° C., and then unreacted methallyl chloride was distilled off under reduced pressure. An end-alkenylated polyether compound containing sodium chloride and sodium hydroxide (hereinafter referred to as unpurified polyether B) was produced.

[Reference Example 3] Propylene oxide was polymerized in the presence of a catalyst using butanol as an initiator to give a molecular weight of 4000.
After that, 1.0 equivalent of metallic sodium was added to the polyether polyol in a nitrogen atmosphere with respect to the hydroxyl group, and the mixture was reacted at 120 ° C. for 3 hours. After further adding 1.1 equivalents of allyl chloride and reacting at 60 ° C., the unreacted allyl chloride was distilled off under reduced pressure to give a terminal alkenylated polyether compound containing sodium chloride (hereinafter,
A crude polyether C) was produced.

Example 1 10 parts of unpurified polyether A was used.
It was placed in a glass reactor equipped with a 0 g stirrer, and a polyoxyethylene propylene block copolymer (molecular weight 10,000,
1 g of oxyethylene chain (containing 12% by weight) and 20 g of an aqueous hydrochloric acid solution containing 1.05 equivalents of hydrogen chloride with respect to the alkaline compound contained in the unpurified polyether A, and the mixture was heated at 60 ° C.
Stir for hours. The mixture was heated to 80 ° C. and nitrogen gas was passed to remove water. Add 100 g of hexane and mix at room temperature for 3
After stirring for 0 minutes, it was filtered using filter paper precoated with Celite. The solvent was distilled off from the filtrate under reduced pressure to obtain a pale yellow transparent oily substance (polyether A).

Example 2 10 parts of unpurified polyether B was used.
Put in a glass reactor equipped with a 0 g stirrer, and add cetyl alcohol ethylene oxide adduct (NONION P-
208, containing 15% by weight or more of oxyethylene chain) 0.2
g and 10 g of an aqueous hydrochloric acid solution containing 1.02 equivalents of hydrogen chloride with respect to the alkali compound contained in the unpurified polyether B, and the mixture was stirred at 60 ° C. for 2 hours. The mixture was heated to 80 ° C. and nitrogen gas was passed to remove water. After adding 50 g of toluene and stirring at room temperature for 30 minutes, it was filtered using a filter paper precoated with topcoperlite. The solvent was distilled off from the filtrate under reduced pressure to obtain a pale yellow transparent oily substance (polyether B).

Example 3 10% of unpurified polyether C was used.
It was placed in a glass reactor equipped with a 0 g stirrer, and a polyoxyethylene propylene block copolymer (molecular weight 10,000,
0.1 g of oxyethylene chain (containing 12% by weight), 0.5 g of magnesia silicate and 5 g of water were added, and the mixture was stirred at 60 ° C. for 2 hours. The mixture was warmed to 80 ° C. and nitrogen gas was passed through to remove water. Filtration was performed using a filter paper precoated with Celite to obtain a pale yellow transparent oily substance (polyether C).

[Comparative Example] Unpurified polyether was replaced with A100.
In a glass reactor equipped with a stirrer, 20 g of a hydrochloric acid aqueous solution containing 1.05 equivalents of hydrogen chloride was added to the alkaline compound contained in the unpurified polyether A, and the mixture was stirred at 60 ° C. for 2 hours. The mixture was heated to 80 ° C. and nitrogen gas was passed to remove water. After adding 100 g of hexane and stirring at room temperature for 30 minutes, filtration was performed using a filter paper precoated with Celite, but the filterability was remarkably poor as compared with Example 1 and the entire amount could not be filtered. The solution that could be filtered was evaporated under reduced pressure to give a cloudy oil.

Regarding the above examples, the results of analyzing the obtained purified products are summarized in Table 1. In addition, (1) in Table 1
The pH value, (2) Cl ⁻ ion, and (3) Cl ⁻ removal rate are as follows.

(1) p when 10 g of polyether was dissolved in 60 cm ³ of isopropyl alcohol-ion exchanged water (mixed solvent of volume ratio 60/40) adjusted to pH = 7
H value (2) Chloride ion amount (mmol / g) per 1 g of polyether determined by titration with an aqueous silver nitrate solution using potassium chromate as an indicator (3) Chloride ion contained in the initial mixture could be removed by several% after purification It shows

[0052]

[Table 1]

[0053]

As shown in the examples, the present invention provides polyethers having a low chloride ion content (that is, a low alkali metal halide content).

Claims (9)

[Claims] 1. A polyether which comprises adding a surfactant and water to a high molecular weight polyether containing a small amount of an alkali metal halide, dehydrating the mixture, and then removing the alkali metal halide. Purification method. 2. A high molecular weight polyether containing a small amount of an alkali metal halide, a high molecular weight polyether having a hydroxyl group and a halogenated hydrocarbon in the presence of an alkali metal or a basic alkali metal compound, or The purification method according to claim 1, which is a product obtained by reacting a terminal hydroxyl group of a high-molecular weight polyether with an alkali metal alkoxide. 3. The purification method according to claim 2, wherein the halogenated hydrocarbon is an alkenyl halide. 4. The purification method according to claim 3, wherein the alkenyl halide is allyl chloride or methallyl chloride. 5. A high molecular weight polyether having a hydroxyl group,
The purification method according to claim 2, which is a polyether having a hydroxyl group number of 1 to 6 and a molecular weight of 1,000 to 50,000. 6. The method according to claim 5, wherein the polyether is a polyoxyalkylene polyol obtained by reacting an initiator having a valency of 1 to 4 with an alkylene oxide having a carbon number of 3 to 6 in the presence of a catalyst. 7. The purification method according to claim 6, wherein the alkylene oxide having 3 to 6 carbon atoms is at least one selected from propylene oxide, butylene oxide and hexylene oxide. 8. The purification method according to claim 1, wherein the surfactant is a nonionic surfactant. 9. The purification method according to claim 8, wherein the nonionic surfactant is a compound having 5% by weight or more of an oxyethylene chain in the molecule.