JPS6125739B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to a method for purifying high molecular weight alkylene oxide polymers. In general, known methods for purifying alkylene oxide polymers include treatment with an adsorbent, neutralization of residual catalyst with various acids and filtration, and extraction method. These methods cannot be applied to coalescence because its viscosity is very high, the amount of catalyst used in the production process is very large, and large amounts of salts are produced. For example, in the method of adsorbing and removing the catalyst with a solid acid such as aluminum silicate, the amount of catalyst is large, so a large amount of solid acid is required for neutralization, and therefore a large amount of cake is produced. In addition, the overspeed is slow due to clogging caused by finely dispersed salts, and the yield is reduced due to polymer adhesion to the cake, so it is practically impossible. The same applies to the method of neutralizing the remaining catalyst and then filtering it; simply neutralizing the catalyst would result in clogging because the salt produced would be too fine.
Another possible method is to make the salt agglomerate and thicken to make it easier to process, but this is not easy due to the high viscosity of the system. Regarding the extraction method, even if you simply try to wash it with water, the polymer layer becomes completely creamy, and even if you dilute it with a solvent, it becomes an emulsion and cannot be separated. Considering the above points, the present inventors have developed a method for purifying high-molecular-weight alkylene oxide polymers by reducing the viscosity of the polymer layer with an appropriate solvent and then lowering the pH of the aqueous layer to approximately The present invention was achieved by discovering that when the ratio is set to 3 or less, the interface between the polymer layer and the water layer becomes very sharp and liquid separation becomes easy. That is, the present invention provides high molecular weight alkylene oxide polymers used in the production process and/or
or in removing the generated alkali metal compounds, diluting the polymer with a solvent so that the solution has a density substantially different from that of water;
Furthermore, this is a purification method in which extraction is performed while ultimately maintaining the pH of the aqueous layer at about 3 or less. The high molecular weight alkylene oxide polymer to which the present invention is preferably applied has a molecular weight of 3,000 to 12,000.
Unlike conventional alkylene oxide polymers, high molecular weight alkylene oxide polymers with a molecular weight exceeding 3000 are produced through a reaction for molecular weight jumping. Specifically, this is exemplified in Japanese Patent Application No. 52-45492 (Japanese Unexamined Patent Publication No. 53-129247) previously filed by the present inventors. That is, it essentially consists of chemically bonded structural units represented by the formula -R ^I -O- (1) (where R ^I represents a divalent alkylene group having 2 to 4 carbon atoms). This polyether is produced using cationic polymerization or anionic polymerization using raw materials such as ethylene oxide, propylene oxide, butene oxide, and tetrahydrofuran. The chemically bonded structural unit represented by formula (1) includes, for example,
−CH ₂ CH ₂ O−,

【formula】

Specific examples include [Formula] -CH ₂ CH ₂ CH ₂ CH ₂ O-. As polyether, not only one type of these structural units may be combined, but also two or more types of structural units may be combined in a mixed form, but in particular, polyether is produced using propylene oxide as a raw material. Polyethers are preferred. It is also necessary that the polyether be water-insoluble. In the anionic polymerization of alkylene oxide, polyhydric alcohols such as ethylene glycol, propylene glycol, glycerin, pentaerythritol, etc. are used as initiators, and the residues of these polyhydric alcohols form alkylene oxide polymers. It can be contained within the main chain. The polyether used may have a linear or branched structure, and has a molecular weight of 3,000 to 12,000. Formula CH ₂ =CH−R〓(−O−) _b (2) [In the formula, −R〓− is −R′−, −R′−O−R″−,

[expression] or

[Formula] (where R′ and R″ are divalent hydrocarbon groups having 1 to 20 carbon atoms)]] The polyether having a terminal olefin group has the final formula CH ₂ ＝CH−R〓 -Y (3) (wherein -R〓 is the same as above, Y is a halogen atom selected from chlorine, bromine, and iodine) It is produced by reacting an organic halogen compound having polyether with polyether. Specifically, the following production methods can be mentioned: (a) The terminal hydroxy group of a polyoxyalkylene polyol such as polyoxypropylene glycol, polyoxyethylene glycol, polytetramethylene glycol, etc. is treated with an alkali metal such as Na or K; metal hydrides such as;
Metal alkoxide such as NaOCH ₃ : It is converted into an alkoxide group by reacting with a caustic alkali such as caustic soda or caustic potash, and then reacted with an organic halogen compound represented by formula (3) to form an alkoxide group with an olefin group at the end. This is a method of obtaining polyether. In this method described above, a polyether having approximately the same molecular weight as the polyoxyalkylene glycol used as a starting material can be obtained, but if it is desired to obtain a polyether with a higher molecular weight, organic halogen of formula (3) Before reacting with a compound, the molecular weight can be increased by reacting with a polyvalent halogen compound containing two or more halogens in one molecule, such as methylene chloride, bis(chloromethyl)benzene, bis(chloromethyl)ether, etc. Then, by finally reacting with the organic halogen compound of formula (3), a polyether having a high molecular weight and having an olefin group at the end can be obtained. In the above reaction, Na metal was used as the reagent to convert the terminal hydroxyl group into an alkoxide group, allyl chloride was used as the organic halogen compound of formula (3), and 1
When methylene chloride is used as a polyvalent halogen compound containing two or more halogens in the molecule, it is illustrated as follows. (b) Using a caustic alkali such as caustic soda or caustic potash as a catalyst and in the presence of an alcohol such as allyl alcohol, propylene glycol, trimethylolpropane, etc., ethylene oxide,
Polymerize an alkylene oxide such as propylene oxide. Usually, caustic alkali is used in an amount of 0.1 to 1 wt% based on alkylene oxide, and a polymerization temperature of 80 to 160°C is used. Although some olefin ether groups are introduced at the ends of the polymer thus obtained, the majority are hydroxy end groups. This is a method in which the hydroxy terminal group is converted into an alkoxide group by the method shown in (a), and then reacted with an organic halogen compound of formula (3) to convert the terminal into an olefin group.
It is of course possible to obtain a polyether with a higher molecular weight by using a polyvalent halogen compound containing two or more halogens in one molecule, such as methylene chloride, in the same manner as in (a). (c) Using caustic potash as a catalyst, allyl alcohol,
An alkylene oxide such as propylene oxide is polymerized at low temperature in the presence of an alcohol such as propylene glycol, trimethylolpropane, etc. Caustic potash is used in an amount of 3 to 20wt% based on alkylene oxide, and the polymerization temperature is 20%.
Low temperatures of ~70°C are used. This method yields a polymer with a considerably larger molecular weight than the method (b), and by subsequent reaction with the organic halogen compound of formula (3), the terminal can easily be converted into an olefin group. A higher molecular weight product can be obtained by reacting with a polyvalent halogen compound containing two or more halogens in one molecule, such as methylene chloride, before reacting with the organic halogen compound of formula (3). In addition, in the above, polyether whose molecular weight has been increased using a polyvalent halogen compound having two or more halogens in one molecule is the residue obtained by removing halogen atoms from the polyvalent halogen compound in its main chain. Contains a group. In the organic halogen compound represented by formula (3), Y
is a halogen group selected from chlorine, bromine, and iodine. R〓 is the formula −R′−, −R′−O−R″−,

[expression] and

[Formula] (R′ and R″ are the divalent organic groups shown above,
R' and R'' are preferably an alkylene group, a cycloalkylene group, an arylene group, or an aralkylene group. Furthermore, R〓 has the formula -CH ₂ -,

[Formula] (R is a hydrocarbon group having 1 to 10 carbon atoms, or a carbon number 1 containing an ether bond.
~10 organic groups) and -R'-
A divalent group selected from OCH ₂ - is particularly preferred.
Specific examples of organic halogen compounds include allyl chloride, allyl bromide, vinyl (chloromethyl) benzene, allyl (chloromethyl) benzene, allyl (bromomethyl) benzene, allyl (chloromethyl) ether, allyl (chloromethoxy) benzene, Examples include 1-butenyl (chloromethyl) ether, 1-hexanyl (chloromethoxy) benzene, allyloxy (chloromethyl) benzene, and the like. Allyl chloride is particularly preferred because it is inexpensive and reacts easily. The polyvalent halogen compound having at least two halogen atoms in one molecule used to increase the molecular weight has the general formula

【formula】

【formula】

【formula】

【formula】

【formula】

【formula】

[Formula] (In the formula, d is an integer of 0 to 2, h is an integer of 1 to 4,
l is an integer of 1 to 2, p is an integer of 2 to 4; R ⁵ is -
A monovalent organic group bonded to the C-Z _4-d group through a carbon atom and having no hydrogen atom on the carbon atom, or a hydrogen atom; R ⁶ is

[Formula] An h-valent organic group that is bonded to a group through a carbon atom and has no hydrogen atom on the carbon atom; R ⁷ is an h-valent organic group; R ³ is a p-valent organic group; Q ¹ is -O-, -S-,

【formula】 and

A divalent group selected from [Formula]; Q ² is an oxygen atom or a sulfur atom; Q ³ to ^{Q 6} are groups selected from a halogen atom, a hydrogen atom, and a monovalent organic group; Q ³ to Q At least two of ⁶ are halogen atoms; Z represents a halogen atom) A compound represented by the following formula is suitable. Specific examples of polyvalent halogen compounds include methylene chloride, chloroform, carbon tetrachloride, methylene bromide, methylene iodide, monochloromonobromomethane, 1.1
-dichloro-2,2-dimethylpropane, benzal chloride, benzal bromide, bis(chloromethyl)benzene, bis(bromomethyl)benzene, tris(chloromethyl)benzene, 4,4'-bis(chloromethyl)bisphenyl, 4・4'-Bis(chloromethyl)diphenyl ether, bis(chloromethyl)naphthane, bis(dichloromethyl)benzene, bis(chloromethyl)ether, bis(chloromethyl)thioether, bis(chloromethyl)
Ketone, bis(chloromethyl) formal, bis(chloromethoxy)benzene, tris(chloromethoxy)benzene, tetrachloroethylenetrichloroethylene, 1,1-dichloroethylene, 1.
Examples include 2-dichloroethylene, 1,2-dibromoethylene, phosgene, oxalic acid chloride, adipic acid chloride, and phthalic acid chloride. Therefore, the crude high molecular weight alkylene oxide polymer contains a large amount of an alkali metal compound such as caustic soda or common salt, usually in an amount of 1% by weight or more. This crude polymer, together with the high molecular weight of the polymer and the presence of a large amount of alkali metal compound moieties, makes it impossible to apply conventional fine assembly techniques. The solvent or solvent mixture is relatively inert towards water, alkali metal compounds and the high molecular weight alkylene oxide polymer, has a density substantially different from water, and is capable of dissolving the polymer. You can use whatever you have. For example, aliphatic, alicyclic, aromatic hydrocarbons, ketones, alcohols,
Ethers and their halides, specifically butanes, pentanes, hexanes, heptanes, octanes, nonanes, decanes, dodecanes, cyclohexane, cyclopentane, benzene, toluene, xylenes, acetone , methyl ethyl ketone, isopropanol, butanol, pentanol, methyl ether, ethyl ether,
Examples include isopropyl ether, methylene chloride, methyl chloroform, carbon tetrachloride, dichlorodifluoromethane, perchloroethylene, chloro, bromo, iodobenzenes and toluenes. These may be used alone or in combination. The amount of solvent used is sufficient to dissolve the high molecular weight alkylene oxide polymer and such that the density of the polymer solution after extracting and removing the alkali metal compounds is substantially different from the density of water. Must. The density difference between normal solution and water is
The amount is required to be 0.015 g/cm ³ or more, preferably 0.1 g/cm ³ or more. There is nothing wrong with using a larger amount, but considering the subsequent solvent recovery process,
As long as the amount satisfies the above-mentioned conditions, it is preferable that the amount be as small as possible. Practically speaking, the amount of solvent used for high molecular weight alkylene oxide polymers is 5 parts by weight to 500 parts by weight.
It is preferable to use within the range of parts by weight. The amount of water used, including the neutralization step, must be at least the amount that can ultimately dissolve the alkali metal compounds present in the system, but there is nothing wrong with using a larger amount. Practically speaking, it is preferably used in an amount of 100 parts by weight to 500 parts by weight per 100 parts by weight of the high molecular weight alkylene oxide polymer. Acids that can be used for the neutralization process and for maintaining the pH of the aqueous layer at about 3 or less include inorganic acids such as sulfuric acid, hydrochloric acid, and phosphoric acid, sodium sulfite, and sodium phosphite, which are acidic when dissolved in water. Acidic salts such as oxalic acid, acetic acid, citric acid, adipic acid, monovalent or divalent organic acids, and organic acid anhydrides such as acetic anhydride and maleic anhydride can be used alone or in combination. However, from an economical point of view, sulfuric acid, hydrochloric acid, etc. are preferable. The specific operating procedure is to dissolve and disperse an unpurified high molecular weight alkylene oxide polymer (hereinafter referred to as crude polyether) in a solvent, then add water so that the pH of the aqueous layer is finally 3 or less. The method of adding and stirring an acid is preferable, but it is also possible to prepare the crude polyether, solvent, and water at the same time and add a predetermined amount of acid for treatment, or the acid may be dissolved in water from the beginning. You can leave it there. Furthermore, after neutralizing the crude polyether with an acid, with or without dissolving it in a solvent, water and a predetermined amount of acid, and if necessary, a solvent can be added. In either method, it is necessary that the pH of the aqueous layer is maintained at least 3 or less at the time the extraction of the alkali metal compounds in the crude polyether is completed, and if the PH exceeds 3 and is 6 or less. The aqueous layer and polyether layer are separated, but they are not separated as clearly as when the pH is below 3. Therefore, in order to obtain sufficiently purified polyether, the polyether layer near the interface is not used, so the polyether layer is separated. Recovery rate decreases. If the pH exceeds about 6, the interface between the aqueous layer and the polyether layer will not be sharp, which will impede the subsequent separation operation. Separation of the polyether layer and aqueous layer is done by centrifugation,
All methods commonly used for liquid-liquid separation, such as decantation, are effective. The separated polyether layer can be concentrated as is, but in order to remove the trace amount of water dissolved in the polyether layer and the trace amount of acid contained therein, it is necessary to perform a secondary treatment before concentration. You can also do it. For example, for dehydration, treatment with anhydrous mirabilite, passing through a column of molecular sieves,
In order to adsorb and remove trace amounts of acid, it can be treated with a solid base or passed through a column of basic packing material. Furthermore, in order to improve the quality of the product, it is also possible to perform operations such as decolorization and deodorization treatment in between. The high-molecular alkylene oxide polymer having an olefin group at the terminal end obtained in this manner can be used in a wide range of applications as a so-called liquid rubber by taking advantage of its viscosity and the reactivity of the olefin group at the terminal end. For example, it can be used as it is as a high molecular weight plasticizer, or by copolymerizing with a reactive vinyl monomer to modify the physical properties of plastics. This will be specifically explained below with reference to Examples. Reference example 1 320.0 g of polyoxypropylene glycol (manufactured by Sanyo Chemical: PP-400) with a viscosity average molecular weight of 3200
was placed in a pressure-resistant reaction vessel equipped with a stirrer and purged with nitrogen. Next, add powdered caustic soda (98% purity).
After adding 40.8g, raise the temperature to 60℃. Thereafter, 7.76 g of bromochloromethane was added and the reaction was carried out at 60°C for 10 hours. Subsequently, the temperature of the reaction system was lowered to 50°C, 9.2g of allyl chloride was added, and the reaction was carried out at 50°C for 10 hours. Crude polyether A is obtained by the above operations. Reference Example 2 Polyoxyethylene glycol (average molecular weight:
After taking 14.7 g of 200) and 5.0 g of caustic potassium (purity 85%), the temperature was raised to 120°C and the reaction was carried out under reduced pressure for 2 hours. Subsequently, the temperature is lowered to 90° C., propylene oxide is added at an additional rate of 34.6 g/hr, and polymerization is carried out for 20 hours. After the addition was completed, polymerization was continued for another 2 hours. At this point, a propylene oxide polymer with an average molecular weight of 3900 is obtained. followed by powdered caustic soda (98% purity) into the reactor
and 12.4 g of bromochloromethane, and heated to 60℃.
Carry out the reaction for 12 hours. Furthermore, the temperature of the reaction system is
Lower the temperature to 80℃, add 30.0g of allyl chloride,
Perform a time reaction. Crude polyether B is obtained by the above operations. Example 1 600 g of crude polyether A and 1.8 kg of n-hexane are placed in an 8-separable flask equipped with a stirrer and stirred to sufficiently disperse the caustic soda and salts. Next, add 1.8 kg of 3wt% sulfuric acid water, stir for 1 hour, and after confirming that the pH is approximately 1.5, stop stirring (the amount of sulfuric acid required for neutralization is 50.4 kg as in Comparative Example 1).
g). When left to stand for about 1 hour, both the water layer and the polyether layer become transparent, and there is almost no foam at the interface between the polyether layer and the water layer, and the interface becomes sharp. The polyether layer is separated by decantation, and n-hexane is removed using an evaporator to obtain transparent purified polyether _A1 .
The analytical values of purified polyether A ₁ are shown in Table 1. Similar treatments were carried out in cases where the pH was set to 2.5 and when the pH was set to 1, but the interfacial state between the aqueous layer and the polyether layer was the same as in the case of pH 1.5. Example 2 600 g of crude polyether A and 600 g of toluene were placed in an 8-separable flask equipped with a stirrer and stirred to sufficiently disperse the caustic soda and salts. Next, add 59.3 g of 85% sulfuric acid aqueous solution (as sulfuric acid) required for neutralization.
50.4g) and stir thoroughly to neutralize. Furthermore,
Add 1.8 kg of hydrochloric acid aqueous solution with pH 2 and 1.2 kg of toluene, stir for about 1 hour, and then leave it for 1 hour. Both the water layer and the polyether layer are transparent, and there are almost no bubbles at the interface between the polyether layer and the water layer. The interface is sharp. The polyether layer is separated by decantation and toluene is removed by an evaporator to obtain transparent purified polyether _A2 . The analytical values are shown in Table 1. Example 3 600g of crude polyether B, 1.8Kg of cyclohexane, and 1.8Kg of water in an 8-separable flask equipped with a stirrer.
and stir for about 30 minutes. At this point, the water layer
When the pH is 13 or higher, the interface between the polyether layer and water layer cannot be distinguished. Next, 450 g of 10% aqueous hydrochloric acid solution was added, stirred for about 1 hour, and then left to stand for about 1 hour. The pH was below 1. Both the water layer and polyether layer are transparent and the interface is sharp. Separate the polyether layer by decantation and remove cyclohexane with an evaporator to obtain purified polyether.
Got _B3 . The analytical values are shown in Table 1. Example 1 600 g of crude polyether A and 1.8 kg of n-hexane were placed in an 8-separable flask equipped with a stirrer and stirred to sufficiently disperse the caustic soda and salts. Subsequently, 1.8 kg of water in which the amount of sulfuric acid (50.4 g) necessary to neutralize the remaining caustic soda in 600 g of crude polyether A was dissolved was added and stirred. When stirring was stopped every 30 minutes and the system was allowed to stand still to observe the state of the system, it was found that both the water layer and the polyether layer were cloudy, and the interface between the two was not sharp, making it impossible to separate the layers. water layer
When I measured the pH, it was 7.3. Comparative Example 2 The same treatment as in Example 1 was performed except that the pH of the aqueous layer was adjusted to 5 and 6. After standing for 1 hour, the water layer and polyether layer were separated, but there was some turbidity, although not as turbid as in Example 1, and foam-like substances were present at the interface between both layers. . Comparative Example 3 The same treatment as in Example 2 was carried out except that 1.8 kg of an aqueous hydrochloric acid solution with a pH of 3.5 was used. Water layer after standing for 1 hour,
Although the polyether layers were transparently separated, a small amount of foam was present at the interface between both layers, although not as much as in Comparative Example 2.

【table】

Claims (1)

[Claims] 1. A crude water-insoluble alkylene oxide polymer having a terminal olefin group and having a molecular weight of 3,000 to 12,000, obtained by reacting a water-insoluble alkylene oxide polymer having a hydroxyl group at the end with the hydroxyl group in the presence of an equivalent or more alkaline catalyst. To remove an alkali metal compound from a molecular weight alkylene oxide polymer, the polymer is treated with a solvent to form a solution with a density substantially different from that of water, and further treated with an aqueous solution to reduce the pH of the aqueous layer to 3 or less. A method for purifying a crude high molecular weight alkylene oxide polymer, characterized by retention and extraction.