JP2006008979A - Process for producing polyphenylene ether - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for producing a linear polyphenylene ether which can be imparted with high heat resistance by introduction into a polyester resin, an epoxy resin, etc., has a reactive hydroxyl group, has a narrow molecular weight distribution, and is linear. thing.
SOLUTION: An alkali metal salt (a1) of 4,4′-dihydroxydiphenyl ether and 4,4′-dihalogenated diphenyl ether (a2) are reacted in an organic solvent (Y) in the presence of a transition metal catalyst (X). A process for producing polyphenylene ether, characterized in that
[Selection figure] None

Description

  The present invention relates to a method for producing polyphenylene ether that can be suitably used as an ultra-high heat resistant resin material.

  Polyphenylene ether, which is a polymer of 4,4'-dihydroxydiphenyl ether having a structure in which an unsubstituted aromatic ring is linked by an ether group, is a compound that is less susceptible to oxidative degradation and is expected as an ultra-high heat resistant resin material. Conventionally, as a production method for obtaining the polyphenylene ether, (1) a method in which 4,4′-dihydroxydiphenyl ether is oxidatively polymerized using a peroxide as an oxidizing agent in the presence of an iron complex catalyst (see, for example, Patent Document 1). ), (2) a method of oxidizing 4,4′-dihydroxydiphenyl ether in the presence of a transition metal complex catalyst and an oxidizing agent (see, for example, Patent Document 2), (3) p-halogenated phenol and 4,4′- A method of reacting dihydroxydiphenyl ether with a polar aprotic solvent in the presence of a Cu (I) halide is known (for example, see Patent Document 3).

  However, it is difficult to control the molecular weight of the polymer obtained by the method described in Patent Document 1 and only a polymer having a wide molecular weight distribution can be obtained. For example, the polymer synthesized in Example 5 of Document 1 is synthesized. The polyphenylene ether has a molecular weight distribution of 5.3 and is difficult to handle because it does not dissolve uniformly in an organic solvent. Further, in the method described in Patent Document 2, ortho-position branching occurs. For example, the ratio between the ortho-position bond and the para-position bond of the polyphenylene ether synthesized in the Example of the Document 2 is There is a problem that the amount of use is limited at the time of introduction into a polyester resin or an epoxy resin, and it is difficult to obtain a desired ultra-high heat resistance resin. Furthermore, in the technique described in Patent Document 3, the molecular weight distribution of the obtained polymer is wide, and it is difficult to adjust the molecular weight of these resins when introduced into a polyester resin or an epoxy resin. It was.

  That is, it has been difficult to obtain linear polyphenylene ether with a narrow molecular weight distribution by a conventionally provided method.

JP 2000-080162 A (Page 2-3 and Example 5) Japanese Patent Laid-Open No. 10-324743 (page 3) JP-A-2-214724 (page 2-3 and Examples 1 and 2)

  In view of the above circumstances, an object of the present invention is to provide a method for producing a linear polyphenylene ether having a narrow molecular weight distribution.

  As a result of intensive studies to solve the above problems, the present inventors have determined that an alkali metal salt of 4,4′-dihydroxydiphenyl ether and 4,4′-dihalogenated diphenyl ether in an organic solvent in the presence of a transition metal catalyst. It has been found that by reacting it, it is possible to obtain a linear polyphenylene ether having a narrow molecular weight distribution, and the present invention has been completed.

  That is, the present invention provides a method for producing a polyphenylene ether having a linear structure and a narrow molecular weight distribution.

  ADVANTAGE OF THE INVENTION According to this invention, the manufacturing method of polyphenylene ether which has a linear structure and narrow molecular weight distribution can be provided. In the present invention, those having a relatively low molecular weight can be efficiently produced, and since the resulting polyphenylene ether is soluble in an organic solvent, it is suitably used as a raw material for polyester resins and epoxy resins, and imparts ultrahigh heat resistance. Moreover, since it has the reactivity by the hydroxyl group of a terminal, it can be used suitably also as a functional resin raw material.

Hereinafter, the present invention will be described in detail.
In the production method of the present invention, 4,4′-dihydroxydiphenyl ether alkali metal salt (a1) and 4,4′-dihalogenated diphenyl ether (a2) are used as raw materials in the presence of a transition metal catalyst (X). There is no particular limitation other than obtaining polyphenylene ether by reacting in (Y), but high molecular weight polyphenylene ether is difficult to handle because it is difficult to dissolve in an organic solvent, and more likely to precipitate during the reaction. In view of the fact that the reaction yield is low, it is preferable to produce a polyphenylene ether having a number average molecular weight in the range of 300 to 1,000.

  Moreover, when using the obtained polyphenylene ether as a resin raw material, it is preferable that the terminal is a reactive hydroxyl group. By using the production method of the present invention, it is possible to efficiently produce polyphenylene ether having both molecular ends at hydroxyl groups and having a low molecular weight and soluble in an organic solvent.

  Examples of the alkali metal salt (a1) of 4,4′-dihydroxydiphenyl ether used in the present invention include 4,4′-dihydroxydiphenyl ether and alkali metal hydroxides such as sodium hydroxide, potassium hydroxide and lithium hydroxide. Can be easily obtained by reacting in a solvent.

  The 4,4′-dihydroxydiphenyl ether is not particularly limited as to its production method. For example, hydroquinone is dehydrated and dimerized in an organic solvent azeotropic with water in the presence of a catalyst, Examples thereof include a method of hydrolyzing 4′-dihalogenated diphenyl ether in the presence of a catalyst.

  The amount of the alkali metal hydroxide used is not particularly limited, but is 4,4′-dihydroxy because of its good reactivity with the 4,4′-dihalogenated diphenyl ether (a2) described later. It is preferable to use 60% or more of both terminal hydroxyl groups of diphenyl ether in an amount capable of forming an alkali metal salt. Specifically, it is used in the range of 2.0 to 4.0 moles per mole of 4,4′-dihydroxydiphenyl ether. It is preferable.

  As a solvent in the reaction of 4,4′-dihydroxydiphenyl ether and an alkali metal hydroxide, water or a lower alcohol such as methanol or ethanol is preferably used because it can dissolve the alkali metal hydroxide. Methanol is preferred because it is highly soluble in the alkali metal salt (a1) of 4,4′-dihydroxydiphenyl ether, which is a reactant, and can be easily removed after the reaction.

  The alkali metal salt (a1) of 4,4′-dihydroxydiphenyl ether obtained by the above reaction can be used for the reaction with 4,4′-dihalogenated diphenyl ether (a2) described later without isolation. In addition, after being isolated from the reaction solution, it may be used for the reaction with 4,4′-dihalogenated diphenyl ether (a2). In any case, there is no problem even if an unreacted alkali metal hydroxide remains, and it can be used as a raw material for the next step without being removed.

  When isolating the alkali metal salt (a1) of 4,4′-dihydroxydiphenyl ether from the reaction solution, for example, after completion of the reaction between 4,4′-dihydroxydiphenyl ether and an alkali metal hydroxide, the solvent is distilled off. And a method of drying the obtained solid under reduced pressure or normal pressure. The isolated alkali metal salt (a1) of 4,4'-dihydroxydiphenyl ether is stable in air and can be stored for a long period of time.

  Examples of the 4,4′-dihalogenated diphenyl ether (a2) used in the present invention include 4,4′-dichlorodiphenyl ether, 4,4′-dibromodiphenyl ether, 4,4′-diiododiphenyl ether, and the like. 4,4′-dibromodiphenyl ether is preferred because of its ease, cost, and industrial availability.

  The proportion of the alkali metal salt of 4,4′-dihydroxydiphenyl ether (a1) and 4,4′-dihalogenated diphenyl ether (a2) is appropriately selected depending on the molecular weight of the desired polyphenylene ether. When the purpose is a polyphenylene ether soluble in a solvent, it is preferable that a product having a number average molecular weight in the range of 300 to 1,000 is desired, the reaction proceeds rapidly and the yield is high, and From the point that the content of the halogen atom remaining by bonding to the terminal of the polyphenylene ether to be produced can be lowered, 4,4 ′ relative to 1 mol of 4,4′-dihydroxydiphenyl ether alkali metal salt (a1). -Using dihalogenated diphenyl ether (a2) in the range of 0.05 to 20 mol, especially 0.1 to 10 It is preferable.

  As the transition metal complex catalyst (X) used in the present invention, the reaction between the alkali metal salt of 4,4′-dihydroxydiphenyl ether (a1) and 4,4′-dihalogenated diphenyl ether (a2) can be promoted. Although not particularly limited as long as it is a transition metal complex, it is preferable to use a compound of a first series transition metal, particularly preferably a copper halide (x1), for example, cuprous chloride, odor Cuprous iodide, cuprous iodide, cuprous fluoride and the like.

  The amount of the transition metal catalyst (X) used includes the type of catalyst, the reaction temperature, the type of 4,4′-dihalogenated diphenyl ether (a2) used, and the alkali metal salt (a1) of 4,4′-dihydroxydiphenyl ether. Alkaline of 4,4′-dihydroxydiphenyl ether, although it varies depending on the ratio of use with 4,4′-dihalogenated diphenyl ether (a2), etc., in that an appropriate reaction rate is obtained and removal after the completion of the reaction is easy. It is 0.001-0.10 mol with respect to 1 mol of metal salts (a1), Preferably it is 0.005-0.05 mol.

  As the organic solvent (Y) used in the present invention, the alkali metal salt (a1) of 4,4′-dihydroxydiphenyl ether and 4,4′-dihalogenated diphenyl ether (a2) of the raw material compound can be uniformly dissolved, Although it will not be restrict | limited especially if it does not participate in reaction, From the point which is excellent in the solubility of polyphenylene ether obtained, it is preferable to use a water-soluble polar organic solvent (y1), for example, tetrahydrofuran, dimethylformamide, dimethyl sulfoxide, sulfolane. And aprotic polar solvents such as N-methylpyrrolidone.

  The reaction temperature during the reaction varies depending on the catalyst to be used, the organic solvent, the use ratio of the reaction raw materials, the molecular weight of the target polyphenylene ether, etc., but is usually 50 to 300 ° C., preferably 100 to 200 ° C.

  In order to adjust the molecular weight of the polyphenylene ether obtained in the present invention, in particular, the use ratio of 4,4′-dihydroxydiphenyl ether alkali metal salt (a1) and 4,4′-dihalogenated diphenyl ether (a2), reaction temperature It is preferable to set the reaction time appropriately.

  The method for isolating and purifying the produced polyphenylene ether after completion of the reaction is not particularly limited, and various techniques can be used. For example, the reaction mixture is poured into an acidic aqueous solution, and the precipitated solid is washed and dried. Polyphenylene ether can be obtained in high yield.

  The polyphenylene ether in the present invention can be used as a raw material or additive for various resins. For example, by using the polyphenylene ether of the present invention as a part or all of the dihydroxy compound that is a raw material for polyester, polyether ether ketone, and polyether sulfone, it has excellent heat resistance, low dielectric properties, and low water absorption. A resin is obtained. In particular, in the case of liquid crystalline polyester having a very high molding temperature, by using the polyphenylene ether in the present invention as a part of the dihydroxy compound that is a raw material, the melting point is lowered without impairing the heat resistance and the moldability is improved. Can do. Moreover, by using the polyphenylene ether in the present invention as part or all of the dihydroxy compound that is a raw material of the epoxy resin, an epoxy having excellent heat resistance, low dielectric constant, moisture resistance, flexibility, moldability, and anticorrosion performance A resin is obtained. Moreover, the resin excellent in heat resistance and abrasion resistance is obtained by using the polyphenylene ether in the present invention as a part or all of the dihydroxy compound of polycarbonate. Further, when used as a developer for thermal paper, thermal paper excellent in light resistance, sensitivity, and storage stability can be obtained. Further, a resin excellent in heat resistance, flexibility, low moisture absorption and dimensional stability can be obtained by adding a small amount of the polyphenylene ether particles in the present invention at the time of polymerization or kneading of polyester, polyamide and polyphenylene sulfide. In addition, by adding the polyphenylene ether of the present invention to a film or sheet of a resin used for optical applications such as cycloolefin polymer, polyethylene terephthalate, triacetyl cellulose, polycarbonate, etc., optical properties such as moisture permeation resistance and birefringence Control or improvement in strength is manifested.

  Although the manufacturing method of the polyphenylene ether of this invention is demonstrated concretely using an Example and a comparative example below, the following Examples do not limit the method of this invention.

Synthesis example 1
Synthesis of 4,4′-dihydroxydiphenyl ether Into a 1000 ml four-necked flask equipped with a water separator and a thermometer, hydroquinone 100 g (0.91 mol), mesitylene 200 g, and activated clay K-500 (Japan activated clay) 17 g) was added, and the mixture was stirred at 160 ° C. for 4 hours while dehydrating, and a dehydration dimerization reaction was performed.

  After completion of the dehydration reaction, 200 g of water at 60 ° C. was added, and the system was heated to 80 ° C. with stirring to dissolve unreacted hydroquinone and the reaction product, followed by filtration at 80 ° C. to separate active clay. The filtrate was cooled to 20 ° C. The precipitated crystals were collected by filtration, washed with water, and then dried under reduced pressure to obtain 4,4'-dihydroxydiphenyl ether. The conversion rate of hydroquinone measured by gas chromatography was 56.4 mol%, and the selectivity of 4,4'-dihydroxydiphenyl ether was 87.6%.

  45.4 g of butyl acetate and 90.8 g of xylene were added to 45.4 g of the unpurified 4,4'-dihydroxydiphenyl ether obtained above, and the mixture was heated to 80 ° C for dissolution, and then cooled to 20 ° C. The precipitated 4,4′-dihydroxydiphenyl ether crystals were collected by filtration and then purified by drying under reduced pressure. The yield of 4,4′-dihydroxydiphenyl ether obtained was 44.6 g (yield 48.5 mol%, purity 99.3% by weight: GPC method). Moreover, hydroquinone content was 800 ppm (GC method).

Example 1
A 300 ml four-necked flask was charged with 22.4 g (0.4 mol) of potassium hydroxide and 89.8 g of ethanol and stirred. After the exothermic reaction, it was completely dissolved after 20 minutes. To this solution, 40.4 g (0.2 mol) of 4,4′-dihydroxydiphenyl ether synthesized in Synthesis Example 1 was added and heated to reflux for 1 hour.

  The residue obtained by distilling off ethanol and water was dried at 80 ° C. overnight to obtain 55.7 g (yield 100%) of potassium salt of 4,4′-dihydroxydiphenyl ether.

  Subsequently, the potassium salt of 4,4′-dihydroxydiphenyl ether obtained by the above reaction, 19.7 g (0.06 mol) of 4,4′-dibromodiphenyl ether obtained by the above reaction, and 0.198 g of cuprous chloride were added to a 300 ml four-necked flask. (0.002 mol) and 120 g of N-methylpyrrolidone were added, and the mixture was stirred at 140 ° C. for 3 hours while introducing nitrogen into the system at a rate of 20 ml / min. After the reaction, the reaction mixture was cooled to 40 ° C. or lower and added dropwise to 243 g of 6% aqueous hydrochloric acid. After dropping, the mixture was stirred at room temperature for 1 hour, and then the precipitated solid was collected by filtration, washed with 200 ml of water, and dried under reduced pressure to obtain 27.5 g of polyphenylene ether. Table 2 shows the composition ratio of the obtained polyphenylene ether.

Examples 2-7
Using the potassium salt of 4,4′-dihydroxydiphenyl ether obtained in Example 1, the use ratio of 4,4′-dihydroxydiphenyl ether and 4,4′-dibromodiphenyl ether shown in Table 1, catalyst compound (0.002 mol) ) And 120 g of solvent were used, and the experiment was performed in the same manner as in Example 1. The results are shown in Tables 1 and 2.

Footnotes in Table 1 DHDE: 4,4′-dihydroxydiphenyl ether DBDE: 4,4′-dibromodiphenyl ether NMP: N-methylpyrrolidone DMSO: dimethyl sulfoxide

Footnotes in Table 2
The numerical values in the table represent the area% of each component in the GPC spectrum.
Mw: weight average molecular weight Mn: number average molecular weight

Comparative Example 1 (Trace experiment in Patent Document 3)
25.95 g (0.15 mol) of p-bromophenol, 7.58 g (0.0375 mol) of 4,4′-dihydroxydiphenyl ether, 80 g of N, N-dimethylimidazolidin-2-one, 100 ml of toluene and 40% water 31.56 g (0.22 mol) of an aqueous potassium oxide solution was placed in a 500 ml four-necked flask equipped with a stirrer, a thermometer, a water separator and a reflux condenser under a nitrogen atmosphere and dehydrated by refluxing for 4 hours. After adding 120 mg of cuprous chloride at 150 ° C., the mixture was reacted with stirring at 195 ° C. for 4 hours. After cooling to room temperature, 300 ml of 5% aqueous hydrochloric acid solution was added to precipitate a solid. The solid was collected by filtration, washed with water until the washing solution became neutral, and then dried under reduced pressure. The obtained solid was 40.5 g, the weight average molecular weight was 777, the number average molecular weight was 613, and at least 10 types of products having different molecular weights were recognized by GPC measurement.

2 is a GPC spectrum of the polyphenylene ether obtained in Example 1. 2 is a GPC spectrum of polyphenylene ether obtained in Comparative Example 1.

Claims (6)

Characterized in that an alkali metal salt of 4,4′-dihydroxydiphenyl ether (a1) and 4,4′-dihalogenated diphenyl ether (a2) are reacted in an organic solvent (Y) in the presence of a transition metal catalyst (X). A method for producing polyphenylene ether. The method for producing a polyphenylene ether according to claim 1, wherein the reaction temperature is 50 to 300 ° C. The method for producing a polyphenylene ether according to claim 2, wherein 0.05 to 20 mol of 4,4'-dihalogenated diphenyl ether (a2) is used per 1 mol of the alkali metal salt (a1) of 4,4'-dihydroxydiphenyl ether. The method for producing a polyphenylene ether according to claim 2, wherein the 4,4'-dihalogenated diphenyl ether (a2) is 4,4'-dibromodiphenyl ether. The process for producing a polyphenylene ether according to claim 1, wherein the transition metal catalyst (X) is a copper halide (x1). The method for producing a polyphenylene ether according to any one of claims 1 to 5, wherein the organic solvent (Y) is a water-soluble polar organic solvent (y1).

Images