Method for producing polyoxyalkylene glycidyl ether

Abstract

To provide a method for producing a polyoxyalkylene glycidyl ether capable of improving a glycidyl etherification ratio of an oxyalkylene polymer having a hydroxy group and reducing an environmental load exerted on the waste water.SOLUTION: There is provided a method for producing a polyoxyalkylene glycidyl ether, comprising reacting an oxyalkylene polymer which has a hydroxy group having a water content of 100 mass ppm or less with an epihalohydrin in the presence of a metal alkoxide.SELECTED DRAWING: None

Description

[Technical field]

[0001] The present invention relates to a method for producing a polyoxyalkylene glycidyl ether having a polyoxyalkylene group and a glycidyl ether group. [Background technology]

[0002] Known methods for producing glycidyl ethers of alcohols include a two-stage method in which an alcohol and epihalohydrin are subjected to a ring-opening addition reaction in the presence of an acid catalyst to obtain a halohydrin ether, which is then ring-closed by dehydrohalogenation, and a one-stage method in which an alcohol and epihalohydrin are reacted using an aqueous alkali solution.

[0003] Although the two-stage method has a relatively high yield of glycidyl ether, dehydrohalogenation tends to be insufficient, and a large amount of halogen atoms remain in the product. Therefore, the glycidyl ether obtained by the two-stage method has problems such as a deterioration in electrical properties and a tendency to corrode electronic components, especially when used in electronic and electrical fields. On the other hand, in the one-stage process, a large amount of water is present in the reaction system, which results in a large amount of by-products due to cleavage of the epoxy ring and further addition of epihalohydrin to the glycidyl ether, resulting in a low yield of the desired glycidyl ether.

[0004] In response to this, for example, Patent Document 1 proposes a method for producing a glycidyl ether as an improved method for reducing by-products in a one-stage process, in which an alcohol and an epihalohydrin are reacted in the presence of a solid alkali metal hydroxide, and then water is added to dissolve the excess alkali metal hydroxide and the product salt, followed by liquid separation. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] JP 2005-29487 A Summary of the Invention [Problem to be solved by the invention]

[0006] However, in the production method described in Patent Document 1, although the amount of halogen elements remaining in the product is reduced, the improvement in the yield of the target glycidyl ether is not sufficient. In addition, in order to purify the product by removing excess alkali metal hydroxide and generated salt, it is necessary to use a large amount of water, the same amount or more as the crude product after the reaction, and the amount of wastewater in the purification is large, and the chemical oxygen demand (COD) of the wastewater is high, so that the method is not desirable from the viewpoint of environmental conservation.

[0007] Therefore, also in the production of polyoxyalkylene glycidyl ethers by reacting an oxyalkylene polymer having a hydroxyl group with an epihalohydrin, there is a demand for further improvement in the yield of the target polyoxyalkylene glycidyl ether and reduction in the environmental load caused by wastewater.

[0008] The present invention has been made to solve such problems, and has an object to provide a method for producing polyoxyalkylene glycidyl ether, which can improve the glycidyl etherification rate of an oxyalkylene polymer having a hydroxyl group and reduce the environmental load caused by wastewater. [Means for solving the problem]

[0009] The present invention is based on the discovery that by reacting an oxyalkylene polymer having a hydroxyl group, which has a water content of a predetermined value or less, with epihalohydrin in the presence of a metal alkoxide, it is possible to improve the glycidyl etherification rate of the oxyalkylene polymer and reduce the amount of wastewater during purification and the COD of the wastewater.

[0010] The present invention provides the following means. [1] A method for producing a polyoxyalkylene glycidyl ether, comprising reacting an oxyalkylene polymer having a hydroxyl group and having a water content of 100 ppm by mass or less with epihalohydrin in the presence of a metal alkoxide. [2] The method for producing a polyoxyalkylene glycidyl ether according to [1], wherein a glycidyl etherification rate (G), which indicates the proportion of hydroxyl groups in the oxyalkylene polymer that have been glycidyl etherified, is 70% or more. [3] The method for producing a polyoxyalkylene glycidyl ether according to [1] or [2], wherein the oxyalkylene polymer has 1 to 8 hydroxyl groups in one molecule. [4] The method for producing a polyoxyalkylene glycidyl ether according to any one of [1] to [3], wherein the oxyalkylene polymer has a hydroxyl value of 2 to 150 mg / KOH. [5] The method for producing a polyoxyalkylene glycidyl ether according to any one of [1] to [4], wherein the amount of alkoxy groups of the metal alkoxide is more than 1.0 mol and not more than 6.0 mol per 1 mol of hydroxyl groups of the oxyalkylene polymer. [6] The method for producing a polyoxyalkylene glycidyl ether according to any one of [1] to [5], wherein the metal alkoxide is an alkoxide of an alkali metal. [7] The method for producing a polyoxyalkylene glycidyl ether according to any one of [1] to [6], comprising reacting the oxyalkylene polymer with the epihalohydrin to obtain a crude product containing a by-product salt produced by a reaction of the epihalohydrin with the metal alkoxide and a polyoxyalkylene glycidyl ether, and then purifying the crude product. [8] The method for producing a polyoxyalkylene glycidyl ether according to [7], wherein the purification is carried out by separating the by-product salt from the crude product by crystallization. [9] The method for producing a polyoxyalkylene glycidyl ether according to [8], wherein the crystallization is carried out by adding water to the crude product, distilling off the water, and filtering and separating the granulated product of the by-product salt obtained.

[10] The method for producing a polyoxyalkylene glycidyl ether according to [9], wherein the water distilled off in the crystallization has an environmental load value (E) represented by the following formula (1) of 10 ppm or less. E = W × C / (Y × G / 100) (1) In formula (1), W is the amount of water distilled off [g], C is the chemical oxygen demand (COD) of the distilled water [ppm], Y is the yield of polyoxyalkylene glycidyl ether [g], and G is the glycidyl etherification rate [%].

[11] The method for producing a polyoxyalkylene glycidyl ether according to any one of [1] to

[10] , wherein the polyoxyalkylene glycidyl ether has a halogen atom content of less than 1,000 ppm by mass. Effect of the Invention

[0011] According to the process for producing polyoxyalkylene glycidyl ether of the present invention, it is possible to improve the glycidyl etherification rate of an oxyalkylene polymer having a hydroxyl group, and to reduce the amount of wastewater during purification and the COD of the wastewater. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0012] The definitions and meanings of the terms and expressions used in this specification are given below. "Glycidyl etherification rate" refers to the ratio of hydroxyl groups of a hydroxyl group-containing oxyalkylene polymer that have been glycidyl etherified, 1 It is determined from the ratio of the amount of glycidyl groups in the purified polyoxyalkylene glycidyl ether determined by H-NMR to the amount of hydroxyl groups in the oxyalkylene polymer. Specifically, it is determined by the method described in the Examples below. The water content of the oxyalkylene polymer having a hydroxyl group can be determined by measurement in accordance with JIS K1557-2:2007. The hydroxyl value of the oxyalkylene polymer having a hydroxyl group can be determined by measurement in accordance with JIS K1557-1:2007. The hydroxyl value-based molecular weight of the oxyalkylene polymer is a value calculated from the formula: 56100 / (hydroxyl value)×(number of hydroxyl groups in one molecule of the oxyalkylene polymer). The number of hydroxyl groups in one molecule of the oxyalkylene polymer is regarded as the number of active hydrogens of the initiator used in the production of the oxyalkylene polymer. Chemical oxygen demand (COD) is determined by measurements in accordance with JIS K0102:2016 "Oxygen consumption by potassium permanganate at 17.100°C". The halogen atom content in the polyoxyalkylene glycidyl ether is a measurement value of the content of halogen atoms mainly derived from epihalohydrin, and the measurement method is not particularly limited, and for example, a method of burning an oxyalkylene polymer and measuring by ion chromatography, etc. When epichlorohydrin is used as the epihalohydrin, the total chlorine value measured in accordance with JIS K7243-3:2005 is regarded as the halogen atom content.

[0013] The method for producing a polyoxyalkylene glycidyl ether of the present invention is characterized by reacting a hydroxyl-containing oxyalkylene polymer having a water content of 100 ppm by mass or less with epihalohydrin in the presence of a metal alkoxide. According to the method for producing polyoxyalkylene glycidyl ether of the present invention, the glycidyl etherification rate of the hydroxyl-containing oxyalkylene polymer as the raw material can be improved, and the amount of wastewater and the COD of the wastewater during purification of the crude product obtained by the reaction can be reduced.

[0014] According to the method for producing polyoxyalkylene glycidyl ether of the present invention, polyoxyalkylene glycidyl ether can be obtained with a high glycidyl etherification rate of preferably 70% or more, more preferably 80% or more, and even more preferably 90% or more.

[0015] [Oxyalkylene polymer having hydroxyl group] The oxyalkylene polymer having a hydroxyl group is a main raw material that becomes the main skeleton of polyoxyalkylene glycidyl ether (hereinafter, also referred to as the raw oxyalkylene polymer). As the raw oxyalkylene polymer, a compound obtained by ring-opening polymerization of an alkylene oxide with an initiator having an active hydrogen-containing group in the presence of a catalyst is preferable.

[0016] The raw material oxyalkylene polymer used in the method for producing polyoxyalkylene glycidyl ether of the present invention has a water content of 100 ppm by mass or less, preferably 80 ppm by mass or less, and more preferably 50 ppm by mass or less. When the water content is 100 ppm by mass or less, the reactivity of the oxyalkylene polymer having a hydroxyl group with epihalohydrin in the presence of a metal alkoxide becomes good, and a polyoxyalkylene glycidyl ether can be obtained at a high glycidyl etherification rate.

[0017] In the conventional one-stage method for producing polyoxyalkylene glycidyl ether, a large amount of water is present in the reaction system, which increases the amount of by-products due to the cleavage of epoxy rings and the further addition of epihalohydrin to glycidyl ether, making it difficult to improve the glycidyl etherification rate of oxyalkylene polymers having hydroxyl groups. In addition, since oxyalkylene polymers having hydroxyl groups have hydrophilic properties due to the hydroxyl groups, the water content in the atmosphere is usually more than 100 ppm by mass to several thousand ppm by mass, and they are directly subjected to the reaction. In contrast, the production method of the present invention focuses on the effect of water in the reaction system on the glycidyl etherification rate of an oxyalkylene polymer having a hydroxyl group, and is based on the discovery that a polyoxyalkylene glycidyl ether can be obtained with a high glycidyl etherification rate by adjusting the water content of the raw material oxyalkylene polymer to 100 ppm by mass.

[0018] The water content of the raw material oxyalkylene polymer can be reduced to 100 mass ppm or less by dehydration treatment. The method of dehydration treatment is not particularly limited, but for example, dehydration treatment can be performed by heating under reduced pressure in a nitrogen atmosphere.

[0019] The number of hydroxyl groups in one molecule of the raw material oxyalkylene polymer usually corresponds to the number of active hydrogens in the initiator, and is preferably 1-8, more preferably 1-7, and further preferably 1-6. If the number of hydroxyl groups is within the above range, the water content of the raw material oxyalkylene polymer can be easily reduced, and the production method of the present invention can provide a polyoxyalkylene glycidyl ether at a high glycidyl etherification rate.

[0020] The hydroxyl value of the raw material oxyalkylene polymer is preferably 2 to 150 mgKOH / g, more preferably 3 to 120 mgKOH / g, and even more preferably 5 to 100 mgKOH / g, from the viewpoint of easily reducing the water content of the raw material oxyalkylene polymer and obtaining a polyoxyalkylene glycidyl ether at a high glycidyl etherification rate.

[0021] From the same viewpoint, the hydroxyl value-based molecular weight of the raw material oxyalkylene polymer is preferably 800 to 50,000, more preferably 900 to 30,000, and further preferably 1,000 to 20,000.

[0022] Examples of the active hydrogen-containing group of the initiator include a hydroxyl group, a carboxyl group, and an amino group, and a hydroxyl group is preferred, and an alcoholic hydroxyl group is more preferred. Examples of initiators include alcohols, phenols, carboxylic acids, amines, etc., and are preferably aliphatic alcohols. In addition, an oxyalkylene polymer having a hydroxyl group with a molecular weight lower than that of the raw material oxyalkylene polymer may be used as the initiator. Among these initiators, one type may be used alone, or two or more types may be used in combination. The aliphatic alcohol of the initiator preferably has 2-10 carbon atoms, more preferably 2-8 carbon atoms, and further preferably 2-6 carbon atoms.

[0023] Examples of the aliphatic alcohol initiator include methanol, ethanol, 2-propanol, n-butanol, isobutanol, 2-ethylhexanol, decyl alcohol, lauryl alcohol, tridecanol, cetyl alcohol, stearyl alcohol, oleyl alcohol, allyl alcohol, ethylene glycol, propylene glycol, 1,4-butanediol, 1,5-pentanediol, 3-methyl-1,5-pentanediol, neopentyl glycol, 1,6-hexanediol, glycerin, trimethylolethane, trimethylolpropane, pentaerythritol, sorbitol, 1,2,6-hexanetriol, diglycerin, dipentaerythritol, etc. Among these, n-butanol, propylene glycol, glycerin, pentaerythritol, and sorbitol are preferred from the viewpoint of availability, etc.

[0024] The number of carbon atoms of the alkylene oxide is preferably 2 to 4. Examples of the alkylene oxide include ethylene oxide, propylene oxide, 1,2-butylene oxide, and 2,3-butylene oxide, and the like may be used alone or in combination of two or more. Among these, from the viewpoint of availability, etc., ethylene oxide and propylene oxide are preferred, and it is also preferred to use ethylene oxide and propylene oxide in combination.

[0025] Known catalysts can be used for the ring-opening polymerization of alkylene oxide. For example, alkali catalysts such as potassium hydroxide, transition metal compound-porphyrin complex catalysts such as a complex obtained by reacting an organoaluminum compound with porphyrin, composite metal cyanide complex catalysts, catalysts made of phosphazene compounds, etc., are listed. Among these, composite metal cyanide complex catalysts are preferred from the viewpoint of uniforming the molecular weight distribution, for example, zinc hexacyanocobaltate complexes with tert-butanol as a ligand. The method for producing an oxyalkylene polymer having a hydroxyl group using a composite metal cyanide complex catalyst can be a known method. For example, production methods using catalysts disclosed in WO 2003 / 062301, WO 2004 / 067633, JP 2004-269776, JP 2005-15786, WO 2013 / 065802, JP 2015-010162, etc. can be used.

[0026] [Metal alkoxide] The metal alkoxide is used as an alcoholating agent for an oxyalkylene polymer having a hydroxyl group, that is, the hydroxyl group of the oxyalkylene polymer is converted into an alcoholate by converting the hydroxyl group of the oxyalkylene polymer into a metal alkoxide. By alcoholating an oxyalkylene polymer with a metal alkoxide and then glycidyl-etherifying the resulting polymer with epihalohydrin, a polyoxyalkylene glycidyl ether can be obtained at a high glycidyl-etherification rate. Metal alkoxides are highly reactive with water, and from this viewpoint as well, the lower the water content of the raw material oxyalkylene polymer, the more the alcoholation reaction is promoted, and accordingly the glycidyl etherification rate also increases.

[0027] In the production method of the present invention, an oxyalkylene polymer having a hydroxyl group is reacted with epihalohydrin in the presence of a metal alkoxide. The order of adding the metal alkoxide and epihalohydrin to the raw material oxyalkylene polymer is not particularly limited, and the metal alkoxide and epihalohydrin may be added to the raw material oxyalkylene polymer simultaneously, or one of them may be added first.

[0028] From the viewpoint of improving the glycidyl etherification rate of an oxyalkylene polymer having a hydroxyl group, it is preferable to produce a polyoxyalkylene glycidyl ether by, for example, adding a metal alkoxide to a raw material oxyalkylene polymer in an amount of more than 1.0 mole of alkoxy groups, i.e., an excessive amount, per mole of hydroxyl groups of the oxyalkylene polymer to effect alcoholation, and then adding epihalohydrin to effect glycidyl etherification.

[0029] From the viewpoint of sufficiently and efficiently promoting the alcoholation, the amount of metal alkoxide used is preferably an amount that provides more than 1.0 mole and not more than 6.0 moles of alkoxy groups per mole of hydroxyl groups of the oxyalkylene polymer, more preferably 1.5 to 5.0 moles, even more preferably 2.0 to 4.0 moles, and still more preferably 2.5 to 4.0 moles.

[0030] The alcoholation reaction with a metal alkoxide is preferably carried out in a nitrogen or inert gas atmosphere, and the reaction temperature and reaction time are preferably within the ranges of, for example, 100 to 150° C. and 0.5 to 24 hours.

[0031] Examples of the metal alkoxide include alkoxides of various metals, and one type may be used alone or two or more types may be used in combination. From the viewpoints of availability and reactivity, etc., it is preferable to use an alkoxide of an alkali metal. Examples of alkali metal alkoxides include sodium methoxide, sodium ethoxide, sodium propoxide, sodium isopropoxide, sodium tert-butoxide, potassium methoxide, potassium ethoxide, potassium propoxide, potassium isopropoxide, potassium tert-butoxide, etc. Among these, sodium methoxide and sodium ethoxide are preferred from the viewpoint of availability, etc. In addition, since the alkoxide of an alkali metal is easily hydrolyzed by moisture in the air, an alcohol solution is usually used. After reacting an oxyalkylene polymer having a hydroxyl group with a metal alkoxide, the alcohol is preferably distilled off under reduced pressure at a temperature equal to or higher than the boiling point of the alcohol. From the viewpoint of improving the distillation efficiency, it is more preferable to perform the distillation under reduced pressure while bubbling nitrogen or an inert gas into the reaction solution.

[0032] [Epihalohydrin] Examples of epihalohydrin include epichlorohydrin, epibromohydrin, epiiodohydrin, β-methylepichlorohydrin, β-methylepibromohydrin, etc., and may be used alone or in combination of two or more. From the viewpoints of availability and wastewater treatment, etc., epichlorohydrin is preferably used.

[0033] The amount of epihalohydrin used is preferably more than 1.0 mol and not more than 10.0 mol, more preferably 2.0 to 8.0 mol, and even more preferably 3.0 to 7.0 mol, per mol of hydroxyl groups of the oxyalkylene polymer having hydroxyl groups.

[0034] The glycidyl etherification reaction with epihalohydrin is preferably carried out in a nitrogen or inert gas atmosphere, and the reaction temperature and reaction time are preferably within the ranges of, for example, 60 to 140° C. and 0.5 to 8 hours. After the reaction, the reaction system is depressurized to distill off unreacted epihalohydrin, thereby obtaining a polyoxyalkylene glycidyl ether.

[0035] [purification] In one embodiment of the method for producing a polyoxyalkylene glycidyl ether of the present invention, it is preferable to obtain a crude product containing a polyoxyalkylene glycidyl ether and a by-product salt produced by the reaction of epihalohydrin with a metal alkoxide in the reaction of an oxyalkylene polymer having a hydroxyl group with epihalohydrin, and then purify the crude product. In the production method of the present invention, a salt, which is a by-product of the reaction between epihalohydrin and a metal alkoxide, is also produced as a by-product, and the polyoxyalkylene glycidyl ether is obtained as a crude product containing this by-product salt, so it is preferable to carry out a purification step to remove the by-product salt.

[0036] The purification is preferably carried out by separating by-product salts from the crude product by crystallization. The by-product salt is a metal chloride, for example, when the epihalohydrin is epichlorohydrin and the metal alkoxide is sodium alkoxide, the by-product salt is sodium chloride. The by-product salt in the crude product of the polyoxyalkylene glycidyl ether can be efficiently separated and removed by crystallization.

[0037] The crystallization is preferably carried out by adding water to the crude product of the polyoxyalkylene glycidyl ether, and then distilling off the water to obtain granulated by-product salt, which is then separated by filtration. The by-product salt in the crude product exists as fine particles with a particle size of less than about 100 μm, and is not easily separated from the polyoxyalkylene glycidyl ether. Therefore, after adding water to make an aqueous solution, the water is slowly distilled off to recrystallize the salt, and the salt is granulated to a particle size of about 100 μm or more, preferably about 500 μm. The purified polyoxyalkylene glycidyl ether can be easily obtained by filtering and separating the granulated product.

[0038] The amount of water to be added to the crude product is an amount that can sufficiently extract and dissolve the by-product salt, and in consideration of the distillation efficiency, is preferably 3 to 20 parts by mass, more preferably 5 to 18 parts by mass, and even more preferably 10 to 15 parts by mass, relative to 100 parts by mass of the crude product.

[0039] When water is added to the crude product, it is preferable to add an acidic neutralizing agent from the viewpoint of sufficiently neutralizing the crude product and improving the efficiency of purification by crystallization. Examples of acid neutralizing agents include mineral acids such as hydrochloric acid, sulfuric acid, sulfurous acid, nitric acid, phosphoric acid, and hypophosphorous acid; phosphates such as sodium hypophosphite and sodium acid pyrophosphate; organic acids (monobasic acids) such as formic acid, acetic acid, and octylic acid; and dibasic acids such as adipic acid and fumaric acid. The amount of the acidic neutralizer to be added should be an amount sufficient to neutralize the crude product. For example, when sodium acid pyrophosphate is added, the amount is preferably 5 parts by mass or less, more preferably 3 parts by mass or less, and even more preferably 1 part by mass or less, per 100 parts by mass of the crude product.

[0040] After adding water and, if necessary, an acidic neutralizing agent to the crude product, it is preferable to heat the crude product in a sealed state in order to sufficiently extract the by-product salt, for example, at 50 to 90°C for 1 to 10 hours in a sealed state.

[0041] It is preferable to slowly remove water in order to make the granules by recrystallization large enough. Then, it is preferable to reduce the pressure and remove water sufficiently. For example, it is preferable to remove water at 50 to 90°C for 3 to 18 hours while introducing nitrogen or an inert gas, and then dehydrate at 50 to 90°C for 1 to 5 hours under reduced pressure.

[0042] The water distilled off during crystallization preferably has an environmental load value (E) represented by the following formula (1) of 10 ppm or less. E = W × C / (Y × G / 100) (1) In formula (1), W is the amount of water distilled off [g], C is the COD of the distilled water [ppm], Y is the yield of polyoxyalkylene glycidyl ether [g], and G is the glycidyl etherification rate [%].

[0043] The distilled off water is water that is condensed and collected outside the vessel in which crystallization is carried out, and is collected, for example, in a trap tube cooled with dry ice. The amount of water distilled off (W) is usually about 85 to 95% by mass of the amount of water added during purification. The environmental load value (E) is an index of the amount of water distilled off during purification, i.e., the amount of wastewater, and the amount of organic matter, which is an oxidizable substance, contained in the wastewater, per unit amount of the desired polyoxyalkylene glycidyl ether. A larger value indicates a larger amount of wastewater and a larger load on the environment caused by the wastewater. The environmental load value (E) is preferably 10 ppm or less, more preferably 8 ppm or less, and further preferably 5 ppm or less, from the viewpoint of reducing the environmental load caused by wastewater in the production of polyoxyalkylene glycidyl ether.

[0044] Furthermore, from the viewpoint of improving the filtration efficiency of the granulated product and improving the purity of the purified polyoxyalkylene glycidyl ether, it is preferable to carry out a preliminary treatment for filtration when filtering and separating the granulated product of the by-product salt. In the preliminary treatment, for example, an anion adsorbent such as hydrotalcite, a filter aid such as perlite or diatomaceous earth, etc. can be appropriately added to the crude product containing the granules. In this case, it is preferable to perform a dehydration treatment under reduced pressure on the crude product after the addition in order to remove moisture caused by the anion adsorbent, the filter aid, etc.

[0045] From the viewpoint of increasing filtration efficiency, the filtration and separation of the granulated product is preferably carried out by vacuum filtration or pressure filtration, and more preferably by pressure filtration.

[0046] In the filtration, from the viewpoint of increasing the filtration efficiency, an organic solvent may be appropriately added as a viscosity reducer depending on the viscosity of the crude product to be filtered. The organic solvent is preferably a hydrocarbon solvent having a boiling point of 80° C. or less at 1 atmospheric pressure, from the viewpoint of insolubility of the granulated product and ease of distillation from the filtrate. Furthermore, from the viewpoint of safety of the filtration operation, the boiling point of the organic solvent at 1 atmospheric pressure is preferably 40 to 75° C., more preferably 50 to 70° C. Specific examples of such an organic solvent include normal hexane and isohexane, and normal hexane is preferred. The amount of the solvent used is appropriately adjusted depending on the viscosity of the crude product, but taking into consideration the efficiency of distillation from the filtrate, it is preferably 0 to 30 parts by mass, more preferably 0 to 25 parts by mass, and even more preferably 0 to 20 parts by mass relative to 100 parts by mass of the crude product.

[0047] By the above-mentioned filtration operation, a purified polyoxyalkylene glycidyl ether is obtained as a filtrate. When an organic solvent is added as a viscosity reducing agent, the organic solvent is distilled off from the filtrate by heating under reduced pressure, etc., to obtain a purified polyoxyalkylene glycidyl ether. For example, when normal hexane is added as a viscosity reducing agent, it is preferable to distill off normal hexane by heating at 80 to 110°C under reduced pressure for 1 to 5 hours.

[0048] The polyoxyalkylene glycidyl ether obtained by the production process of the present invention has a halogen atom content of preferably less than 1000 ppm by mass, more preferably 800 ppm by mass or less, and even more preferably 500 ppm by mass or less. By having the halogen atom content within the above range, the polyoxyalkylene glycidyl ether is unlikely to suffer from deterioration of electrical properties or corrosion of electronic components due to the contained halogen atoms when used in applications such as electronic and electrical fields, etc. Therefore, the polyoxyalkylene glycidyl ether obtained by the production method of the present invention can be suitably used in the electronic and electrical fields, etc.

[0049] The polyoxyalkylene glycidyl ether obtained by the production method of the present invention has high purity and can be suitably used in the fields of electronics and electricity, as well as paints, adhesives, and the like, for example, as a modifier for epoxy resins and an intermediate for various function-imparting agents for other resins. EXAMPLES

[0050] The present invention will be described in detail below with reference to examples, but the present invention is not limited to the following examples.

[0051] [Measurement and evaluation method] The methods for measuring and evaluating the physical properties of the raw oxyalkylene polymer in each example, the COD of the distillate or wastewater when obtaining the purified polyoxyalkylene glycidyl ether from the crude product (during purification), and the physical properties of the purified polyoxyalkylene glycidyl ether are as follows. Table 1 shows the measurement and evaluation results of each of the above examples. Examples 1 to 12 are working examples, and Examples 13 to 16 are comparative examples.

[0052] [Hydroxyl value] The hydroxyl value of the raw material oxyalkylene polymer was measured in accordance with JIS K1557-1:2007, Method B (automatic potentiometric titration method). [Hydroxyl value calculated molecular weight] The hydroxyl value-based molecular weight of the raw material oxyalkylene polymer (number of hydroxyl groups in one molecule: n) was determined by calculating 56100×n / V using the hydroxyl value (V [mgKOH / g]) measured as described above. [Water content] The water content of the raw material oxyalkylene polymer was measured in accordance with Method B of JIS K1557-2:2007.

[0053] [COD] The COD of the distillate (wastewater) during purification was measured in accordance with JIS K0102:2019 "Oxygen consumption by potassium permanganate at 17.100°C."

[0054] 〔viscosity〕 The viscosity of the purified polyoxyalkylene glycidyl ether was measured in accordance with 6.2.3 of JIS K1557-5:2007. [Glycidyl etherification rate] A solution sample was prepared by mixing and stirring approximately 100 mg of purified polyoxyalkylene glycidyl ether (A [mg]), approximately 50 mg of benzyl alcohol (molecular weight 108.14) (B [mg]), and approximately 3 g of deuterated chloroform. 1 H-NMR was measured. Obtained 1 The integral value (SA ) and the integral value (S B ) and the amount of glycidyl groups in the purified polyoxyalkylene glycidyl ether (E [mmol / g]) was calculated according to the following formula (2). E = (B / 108.14) × (2 × S A / S B )×1000 / A (2) The glycidyl etherification rate (G [%]) of the purified polyoxyalkylene glycidyl ether was calculated according to the following formula (3). G = E / (V / 56.1) × 100 (3) In the formula (3), V is the hydroxyl value [mgKOH / g] of the raw material oxyalkylene polymer. [Halogen atom content (total chlorine value)] The total chlorine value of the purified polyoxyalkylene glycidyl ether was measured in accordance with JIS K7243-3:2005.

[0055] [Environmental impact value] The environmental load value (E [ppm]) of the distillate or wastewater during purification was calculated according to the following formula (1'). E = = W × C / (Y × G / 100) (1') In formula (1'), W is the mass [g] of the distillate or wastewater, C is the COD [ppm] of the distillate or wastewater, Y is the yield [g] of the purified polyoxyalkylene glycidyl ether, and G is the glycidyl etherification rate [%]. Formula (1') is substantially the same as formula (1), with some differences in the explanation of the symbols.

[0056] [Example 1] In a 5L reactor equipped with a stirrer, stirring blades, a heating jacket, a cooling coil, a nitrogen inlet pipe, and a pressure reducing pipe, 3500 g of polyoxypropylene glycol (hydroxyl value 9.6 mgKOH / g, hydroxyl value calculated molecular weight 11688, water content 210 mass ppm) obtained by ring-opening polymerization of propylene oxide (hereinafter abbreviated as "PO") using propylene glycol (number of hydroxyl groups in one molecule: 2) as an initiator was charged as the raw oxyalkylene polymer (M1), the inside of the reactor was replaced with nitrogen, and the reactor was heated at 130 ° C. for 2 hours under a reduced pressure of -0.1 MPaG to perform a dehydration treatment. The water content after the dehydration treatment was 23 mass ppm. Next, 462 g (4.0 moles of NaOMe per mole of hydroxyl group in polyoxypropylene glycol) of 28% by mass sodium methoxide (NaOMe) methanol solution (manufactured by Fujifilm Wako Pure Chemical Industries, Ltd.; special grade; the same applies below) was added as an alcoholating agent, and the temperature was raised to 130°C while bubbling with nitrogen and reacted for 4 hours. After that, the mixture was subjected to devolatilization at 130°C for 20 hours under a reduced pressure of -0.1 MPaG to distill off the methanol and alcoholate the polyoxypropylene glycol. Into a reactor, 332 g of epichlorohydrin (6.0 mol per mol of hydroxyl groups of polyoxypropylene glycol) was added and mixed with stirring at 80°C for 7 hours. After that, the mixture was subjected to devolatilization at 130°C for 2 hours under a reduced pressure of -0.1 MPaG to distill off unreacted epichlorohydrin, thereby obtaining 3,373 g of a crude product of polyoxypropylene diglycidyl ether.

[0057] To this crude product, 32.4 g of sodium acid pyrophosphate (0.96 parts by mass relative to 100 parts by mass of the crude product) and 405 g of pure water (12 parts by mass relative to 100 parts by mass of the crude product) were added, and the mixture was stirred and mixed at 85°C for 5 hours in a sealed state to neutralize and extract the by-product salt sodium chloride. Nitrogen was then introduced into the gas phase at 85°C for 11 hours to distill off the water. The water was collected in a trap tube cooled with dry ice. After 11 hours of nitrogen flow, the water content of the crude polyoxypropylene diglycidyl ether was 13,000 ppm. The water was then dehydrated at 85°C for 3 hours under reduced pressure of -0.1 MPaG, and the water was collected in a trap tube cooled with dry ice. The total amount of water distilled off was 364 g, and the COD was 5 ppm. To the crude product of this polyoxypropylene diglycidyl ether, 16.2 g of an anion adsorbent (hydrotalcite "Kyoward (registered trademark) 500SN", manufactured by Kyowa Chemical Industry Co., Ltd.) (0.48 parts by mass relative to 100 parts by mass of the crude product) and 33.7 g of a filter aid (perlite) (1 part by mass relative to 100 parts by mass of the crude product) were added, and the mixture was dehydrated by stirring at 85 ° C. for 1 hour under a reduced pressure of -0.1 MPaG. After lowering the temperature to 60 ° C., 675 g of normal hexane (20 parts by mass relative to 100 parts by mass of the crude product) was added as a viscosity reducer, stirred for 30 minutes, and pressure filtered at 0.2 MPaG. The obtained filtrate was heated at 100 ° C. for 3 hours under a reduced pressure of -0.1 MPaG, and normal hexane was distilled off to obtain 3103 g of polyoxypropylene diglycidyl ether as a purified polyoxyalkylene glycidyl ether (P1).

[0058] [Example 2] As the raw material oxyalkylene polymer (M2), polyoxyethylene polyoxypropylene glycol (hydroxyl value 28.9 mg KOH / g, hydroxyl value calculated molecular weight 3882, EO / (PO+EO) 24 mass%) obtained by ring-opening polymerization of PO and ethylene oxide (hereinafter abbreviated as "EO") in this order using propylene glycol as an initiator was used, and the same operation as in Example 1 was carried out to obtain a diglycidyl ether as a purified polyoxyalkylene glycidyl ether (P2). During pressure filtration, no viscosity reducing agent was added.

[0059] [Example 3] As the raw material oxyalkylene polymer (M3), polyoxyethylene polyoxypropylene triol (hydroxyl value 17.5 mgKOH / g, hydroxyl value calculated molecular weight 9617, EO / (PO+EO) 12% by mass) obtained by ring-opening polymerization of PO and EO in this order using glycerin (number of hydroxyl groups in one molecule: 3) as an initiator was used, and the same operation as in Example 2 was carried out to obtain a triglycidyl ether as a purified polyoxyalkylene glycidyl ether (P3).

[0060] [Example 4] As the raw material oxyalkylene polymer (M4), polyoxyethylene polyoxypropylene triol (hydroxyl value 28.2 mgKOH / g, hydroxyl value calculated molecular weight 5968, EO / (PO+EO) 8% by mass) obtained by ring-opening polymerization of PO and EO in this order using glycerin as an initiator was used, and the same operation as in Example 2 was carried out to obtain a triglycidyl ether as a purified polyoxyalkylene glycidyl ether (P4).

[0061] [Example 5] As the raw material oxyalkylene polymer (M5), a polyoxyalkylene triol (hydroxyl value 55.7 mgKOH / g, hydroxyl value calculated molecular weight 3022, EO / (PO+EO) 13% by mass) obtained by ring-opening polymerization of PO and EO in this order using glycerin as an initiator was used, and the same operation as in Example 2 was carried out to obtain a triglycidyl ether as a purified polyoxyalkylene glycidyl ether (P5).

[0062] [Example 6] As the raw material oxyalkylene polymer (M6), 2900 g of polyoxyalkylene tetraol (hydroxyl value 28.6 mg KOH / g, hydroxyl value calculated molecular weight 7846, EO / (PO+EO) 13% by mass) obtained by ring-opening polymerization of PO and EO in this order using pentaerythritol (number of hydroxyl groups in one molecule: 4) as an initiator was used, and the same operation as in Example 2 was carried out to obtain a tetraglycidyl ether as a purified polyoxyalkylene glycidyl ether (P6).

[0063] [Example 7] As the raw material oxyalkylene polymer (M7), polyoxyethylene polyoxypropylene hexaol (hydroxyl value 35.8 mgKOH / g, hydroxyl value calculated molecular weight 9402, EO / (PO+EO) 13% by mass) obtained by ring-opening polymerization of PO and EO in this order using sorbitol (6 hydroxyl groups per molecule) as an initiator was used, and the same operation as in Example 2 was carried out to obtain a hexaglycidyl ether as a purified polyoxyalkylene glycidyl ether (P7).

[0064] [Example 8] As the raw material oxyalkylene polymer (M8), polyoxypropylene monol (hydroxyl value 11.2 mgKOH / g, hydroxyl value calculated molecular weight 5009) obtained by ring-opening polymerization of PO using n-butanol (1 hydroxyl group per molecule) as an initiator was used, and the same operation as in Example 2 was carried out to obtain a monoglycidyl ether as a purified polyoxyalkylene glycidyl ether (P8).

[0065] [Example 9] Using 231 g of a 28% by mass sodium methoxide methanol solution (2.0 moles of NaOMe per mole of hydroxyl group of polyoxypropylene glycol) as an alcoholating agent, the same procedure as in Example 1 was carried out to obtain polyoxypropylene diglycidyl ether as a purified polyoxyalkylene glycidyl ether (P9).

[0066] [Example 10] As the raw material oxyalkylene polymer (M9), polyoxypropylene glycol (hydroxyl value 112, hydroxyl value calculated molecular weight 1002) obtained by ring-opening polymerization of PO using propylene glycol as an initiator was used, and the same operation as in Example 2 was carried out to obtain polyoxypropylene diglycidyl ether as purified polyoxyalkylene glycidyl ether (P10).

[0067] [Example 11] As the raw material oxyalkylene polymer (M10), polyoxypropylene glycol (hydroxyl value 115 mgKOH / g, hydroxyl value calculated molecular weight 1463) obtained by ring-opening polymerization of PO using glycerin as an initiator was used, and the same operation as in Example 2 was carried out to obtain polyoxypropylene triglycidyl ether as purified polyoxyalkylene glycidyl ether (P11).

[0068] [Example 12] Using 815 g of a 20% by mass sodium ethoxide (NaOEt) ethanol solution (manufactured by Tokyo Chemical Industry Co., Ltd.) (4.0 mol of NaOEt per mol of hydroxyl group of polyoxypropylene glycol) as an alcoholating agent, the same operation as in Example 1 was carried out to obtain polyoxypropylene diglycidyl ether as a purified polyoxyalkylene glycidyl ether (P12).

[0069] [Example 13] A polyoxyalkylene glycidyl ether was produced in the following manner using the raw material oxyalkylene polymer (M1) described in Example 1 of Patent Document 1 in a manner similar to that of Example 1 of Patent Document 1. A 5L reactor equipped with a stirrer, stirring blade, heating jacket, cooling coil, nitrogen inlet pipe and pressure reducing pipe was charged with 2430g of raw material oxyalkylene polymer (M1) (polyoxypropylene glycol; water content 210 mass ppm), and 77.6g of epichlorohydrin (2.0 moles per mole of hydroxyl group of polyoxypropylene glycol), 126g of cyclohexane, and 0.7g of 50% by mass aqueous solution of benzyltrimethylammonium chloride were added and mixed with stirring. While bubbling with nitrogen, 27.7g of granular potassium hydroxide (KOH) (1.2 moles of KOH per mole of hydroxyl group of polyoxypropylene glycol) was added little by little over 9.5 hours at 25°C, and the mixture was allowed to react at 25°C for 5 hours. The inside of the reactor was cooled to 15°C, and 1380 g of pure water at 25°C was added at a temperature range of 20 to 28°C and stirred for 0.5 hours, then allowed to stand at 17°C for 0.5 hours, and the lower layer (aqueous layer) was taken out. The emulsion portion that was not separated into oil and water was treated as wastewater together with the aqueous layer. 23.9 g of an alkali adsorbent ("Kyoward (registered trademark) 600", manufactured by Kyowa Chemical Industry Co., Ltd.) was added to the separated upper layer (organic layer), and the temperature was raised while reducing the pressure, and the mixture was devolatilized at 121°C for 2 hours under a reduced pressure of -0.1 MPaG to distill off unreacted epichlorohydrin and cyclohexane. The residue was filtered and circulated using a diatomaceous earth filter aid ("Radiolite #700", manufactured by Showa Chemical Industry Co., Ltd.) to obtain polyoxypropylene diglycidyl ether as a purified polyoxyalkylene glycidyl ether (P13).

[0070] [Example 14] Using 141 g (4.0 mol of KOH per mol of hydroxyl group of the raw material oxyalkylene polymer) of granular KOH (purity 95%) as an alcoholating agent, the same operation as in Example 1 was carried out to obtain polyoxypropylene diglycidyl ether as a purified polyoxyalkylene glycidyl ether (P14).

[0071] [Examples 15 and 16] After the raw material oxyalkylene polymer (M1) (polyoxypropylene glycol) was charged, the same operation as in Example 1 was carried out except that the dehydration treatment was not carried out, thereby obtaining polyoxypropylene diglycidyl ethers as purified polyoxyalkylene glycidyl ethers (P15) and (P16), respectively.

[0072] [Table 1]

[0073] As can be seen from the results shown in Table 1, when the water content of the raw material oxyalkylene polymer was low, at 100 ppm by mass or less, and a metal alkoxide was used as the alcoholating agent (Examples 1 to 12), the glycidyl etherification rate of the obtained purified polyoxyalkylene glycidyl ether was high, at 70% or more, and the environmental load value of the production process was also low. On the other hand, when a metal hydroxide was used as the alcoholating agent (Examples 13 and 14) or when the water content of the raw oxyalkylene polymer exceeded 100 mass ppm (Examples 15 and 16), the glycidyl etherification rate of the purified polyoxyalkylene glycidyl ether obtained was low at less than 70%. In addition, when a metal hydroxide was used as the alcoholating agent and the reaction system contained a lot of water (Example 13), the amount of wastewater increased when obtaining the purified polyoxyalkylene glycidyl ether from the crude product, and the COD of the wastewater was high, and the environmental load value in the production process was also very high.

Claims

1. A method for producing a polyoxyalkylene glycidyl ether, comprising reacting an oxyalkylene polymer having a hydroxyl group and having a water content of 100 ppm by mass or less with an epihalohydrin in the presence of a metal alkoxide.

2. The method for producing a polyoxyalkylene glycidyl ether according to claim 1, wherein a glycidyl etherification rate (G), which indicates the proportion of hydroxyl groups of the oxyalkylene polymer that have been glycidyl etherified, is 70% or more.

3. 3. The method for producing a polyoxyalkylene glycidyl ether according to claim 1, wherein the oxyalkylene polymer has 1 to 8 hydroxyl groups in one molecule.

4. The method for producing a polyoxyalkylene glycidyl ether according to any one of claims 1 to 3, wherein the oxyalkylene polymer has a hydroxyl value of 2 to 150 mg / KOH.

5. The method for producing a polyoxyalkylene glycidyl ether according to any one of claims 1 to 4, wherein the amount of alkoxy groups of the metal alkoxide is more than 1.0 mole and not more than 6.0 moles per mole of hydroxyl groups of the oxyalkylene polymer.

6. The method for producing a polyoxyalkylene glycidyl ether according to any one of claims 1 to 5, wherein the metal alkoxide is an alkoxide of an alkali metal.

7. The method for producing a polyoxyalkylene glycidyl ether according to any one of claims 1 to 6, wherein a crude product containing a by-product salt produced by a reaction between the epihalohydrin and the metal alkoxide and a polyoxyalkylene glycidyl ether is obtained by the reaction of the oxyalkylene polymer with the epihalohydrin, and the crude product is then purified.

8. The method for producing a polyoxyalkylene glycidyl ether according to claim 7, wherein the purification is carried out by separating the by-product salt from the crude product by crystallization.

9. The method for producing a polyoxyalkylene glycidyl ether according to claim 8, wherein the crystallization is carried out by adding water to the crude product, distilling off the water, and filtering and separating the granulated product of the by-product salt obtained.

10. The method for producing a polyoxyalkylene glycidyl ether according to claim 9, wherein the water distilled off in the crystallization has an environmental load value (E) represented by the following formula (1) of 10 ppm or less. E=W×C / (Y×G / 100) (1) In formula (1), W is the amount of water distilled off [g], C is the chemical oxygen demand (COD) [ppm] of the distilled off water, Y is the yield of polyoxyalkylene glycidyl ether [g], and G is the glycidyl etherification rate [%] which represents the proportion of hydroxyl groups of the oxyalkylene polymer that have been glycidyl etherified.

11. The method for producing a polyoxyalkylene glycidyl ether according to any one of claims 1 to 10, wherein the halogen atom content in the polyoxyalkylene glycidyl ether is less than 1000 ppm by mass.

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