JPS6318966B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to a method for producing polyphenylene oxide. More specifically, without acid decomposition of the catalyst component in a polyphenylene oxide-containing reaction mixture prepared by contacting a phenolic monomer with oxygen in the presence of a catalyst and an amine in a basic reaction medium. , relates to an improved method for producing polyphenylene oxide by adding a non-solvent, precipitating polyphenylene oxide and a catalyst, and stirring the catalyst into the polyphenylene oxide. Conventionally, polyphenylene oxide has been produced by using phenolic monomers such as cuprous salt-tertiary amine (Japanese Patent Publication No. 36-18692), basic cupric salt-amine (Japanese Patent Publication No. 39-29373) ), manganese salt - tertiary amine (Special Publication No. 42-3195), manganese salt -
A polyphenylene oxide reaction mixture is produced by contacting with oxygen using a catalyst such as an alkali metal alcoholate (Japanese Patent Publication No. 47-619). For catalyst removal and purification, an acid such as hydrochloric acid or acetic acid is generally added to deactivate the catalyst system, and the catalyst metal is solubilized and separated by contacting with a non-solvent for the polymer, and the catalyst metal is removed. It depends on the method of precipitation and recovery of polyphenylene oxide. However, the method described above has the disadvantage that a large amount of organic solvent and waste water contaminated with the catalytic metal are produced, and therefore a huge amount of equipment for separating and recovering the catalytic metal is required. A method to overcome these disadvantages is to use highly active catalysts consisting of manganese() salts-ω-hydroxyoxime to reduce the amount of catalyst used and thereby reduce the amount of acid needed without adding acid to the polyphenylene oxide-containing reaction mixture. A method has been proposed in which, after separating the aqueous phase from the reaction mixture, a non-solvent such as methanol is added to precipitate the polyphenylene oxide and the catalyst, and the catalyst is stirred into the polyphenylene oxide and recovered. (Japanese Unexamined Patent Publication No. 52-98099). Although this method is extremely economical, it inevitably leaves catalyst residue in the resin, resulting in coloring and
This is not necessarily sufficient in terms of polymer deterioration. However, if catalyst residue is present in the resin, coloration may occur.
It is desirable that the amount of catalyst stirred is as small as possible, that is, the amount of catalyst used is as small as possible, as this may cause problems such as deterioration of the polymer. When precipitating the polymer, not only the catalyst residue but also some by-products and denatured low-molecular compounds are stirred together, which has a negative effect on the quality of the polyphenylene oxide obtained. The type of compound that is combined with and coordinated with the metal is also important. In view of these circumstances, the present inventors developed a method for producing polyphenylene oxide in which phenolic monomers are oxidatively reacted, and the reaction mixture is brought into contact with a non-solvent to precipitate polyphenylene oxide and a catalyst together. , by oxidative polymerization of a phenolic monomer in the presence of an amine using a manganese () salt and an orthohydroxyazo compound as a catalyst.
It was discovered that polyphenylene oxide of good quality that can be used as a molding resin composition can be obtained, and the present invention was completed. That is, the present invention provides manganese () salt and 1-
(2′-hydroxy-5′-sulfophenylazo)—
β-naphthol, 1-(1'-hydroxy-naphthyl-2'-azo)-4-sulfo-6-nitro-β-
A catalyst and an amine comprising at least one orthohydroxyazo compound selected from naphthol, 2-(2'-hydroxy-4'-sulfonaphthyl-1'-azo)-α-naphthol, and alkali metal salts thereof. The polyphenylene oxide is formed by contacting the phenolic monomer with oxygen in a basic reaction medium in the presence of a polyphenylene oxide, and then contacting the polyphenylene oxide-containing reaction mixture with a non-solvent without adding an acid. The present invention provides a method for producing polyphenylene oxide, which is characterized by precipitating polyphenylene oxide. The catalyst used in the present invention has high activity against the formation of polyphenylene oxide, so the amount used can be sufficiently reduced, and has high selectivity, which has an adverse effect on the coloring of the polymer during molding. The amount of by-product of diphenoquinone that exerts this effect can be reduced to a trace amount. Furthermore, the polyphenylene oxide of the present invention obtained by stirring the catalyst without adding an acid has a good coloring state after molding, and has the effect that it does not cause deterioration such as crosslinking or decomposition due to heating during molding. There is. Further, according to the method of the present invention, the reaction mixture and the non-solvent are brought into direct contact with each other, whether or not the aqueous phase is separated from the reaction mixture prior to contacting the reaction mixture with the non-solvent. It is also possible to obtain polyphenylene oxide of good quality simply by According to the method of the present invention, a known manganese () salt -
It is characterized in that the colored state of the molded product is much better when the same amount of catalyst is used than when a catalyst consisting of ω-hydroxyoxime is used. The phenolic polymer used in the present invention has the formula (In the formula, X is a member selected from hydrogen, chlorine, bromine, and iodine, and Q is an alkyl group, an alkoxy group, and at least two carbon atoms between the halogen atom and the phenol nucleus. a monovalent substituent selected from halogenated alkyl groups and halogenated alkoxy groups having is one member selected from the groups and hydrogen atoms listed for '). Specific examples of the phenolic monomer used in the present invention include 2,6-dimethylphenol, 2,6-diethylphenol, 2,6-dibutylphenol, 2,6-dilaurylphenol, and 2,6-dimethylphenol. Propylphenol, 2,6-diphenylphenol, 2,6-dimethoxyphenol, 2,3,6-trimethylphenol, 2,
3,5,6-tetramethylphenol, 2,6-
Diethoxyphenol, 2-ethyl-4-stearyloxyphenol, 2,6-di(chlorophenoxy)phenol, 2,6-dimethyl-3-chlorophenol, 2,6-dimethyl-4-chlorophenol, 2,6- Dimethyl-3-chloro-5
- Bromophenol, 2,6-di(chloroethyl)phenol, 2-methyl-6-isobutylphenol, 2-methyl-6-phenylphenol, 2,6-dibenzylphenol, 2,6-ditolylphenol, 2 , 6-di(chloropropyl)phenol, 3-methyl-6-tert-butylphenol, and the like. these are,
Each of them can be used alone, or can be used together with other phenolic monomers to produce a copolymer. Among these, 2,6-dimethylphenol is particularly preferably used. In carrying out the method of the present invention, a catalyst consisting of a manganese () salt and an orthohydroxyazo compound represented by the following general formula is used. Manganese () salts used in the present invention include manganese () halides, such as manganese () chloride, manganese () bromide, and manganese () iodide, as well as other manganese () compounds,
For example, manganese carbonate ( ), manganese oxalate ( ), manganese sulfate ( ), manganese nitrate ( ), manganese phosphate ( ), manganese acetate ( ), etc., and hydrates of these manganese ( ) compounds are also included. Among these, manganese chloride, manganese sulfate, and manganese acetate are preferably used, and manganese chloride is particularly preferably used. The orthohydroxyazo compound used in the present invention has the general formula (In the formula, A and B are the same or different arylene rings, and are at least a divalent arylene ring having a hydroxyl group and an azo group directly bonded to the arylene ring carbon atom at the ortho position.) It is. Within the range of formula (1), A and B each range from about 6 to about
Included are compounds selected from the group of monocyclic and polycyclic organic groups having 30 carbon atoms. Among these monocyclic and polycyclic organic groups, preferred are phenylene groups, naphthylene groups, and substituted derivatives thereof.
Any type of substituent can be selected. For example, hydroxyl group, sulfonic acid group or its salt, carboxylic acid group or its salt, nitro group, carboxylic acid ester group, amino group, amide group, alkyl group, alkoxy group,
Examples include allyl group, arylazo group, halogen group, and sulfonamide group. Among these, alkali metal salts of sulfonic acid are preferred in terms of improving solubility. The orthohydroxyazo compounds used in the present invention include 1-(2'-hydroxy-5'-sulfophenylazo)-β-naphthol, 1-(1'-hydroxy-naphthyl-2'-azo)-4- Surho
It is an alkali metal salt of 6-nitro-β-naphthol and 2-(2'-hydroxy-4'-sulfonaphthyl-1'-azo)-α-naphthol. A catalyst consisting of a manganese () salt and an orthohydroxyazo compound can be prepared by combining them in any proportion. For effective preparation, a solvent is used in which both the manganese() salt and the orthohydroxyazo compound are at least partially dispersible or soluble.
Suitable solvents are used, such as methanol, chlorobenzene, toluene and xylene, etc. or mixtures thereof. A more basic inorganic base can be added to this solvent. Generally, manganese() salt and orthohydroxyazo compound can be combined in any amount, but
Preferably about 1 mole of manganese() salt
More than a molar amount, particularly preferably about 2 times the molar amount, of the orthohydroxyazo compound is used. The structure of the catalyst consisting of manganese() salt and orthohydroxyazo compound is unknown, but it is presumed that it forms a complex of manganese()-orthohydroxyazo compound in solution. Therefore, divalent manganese ions are also included in manganese() salt. Therefore, by using the above-mentioned catalyst, the amount of by-products such as diphenoquinone can be reduced, and therefore the coloration during molding of polyphenylene oxide can be improved, and the amount of catalyst used can be reduced. Therefore, even in the method of the present invention in which the catalyst is stirred into the polyphenylene oxide, it is possible to significantly reduce the occurrence of crosslinking, decomposition, deterioration, and coloring due to heating during molding due to the residual catalyst. To achieve oxidative coupling of the phenolic monomer, the catalyst, amine and monomer may be mixed in the presence of an alkali using a suitable organic solvent, and oxygen or an oxygen-containing gas introduced. Suitable polymerization solvents are lower alkanols having 1 to 6 carbon atoms (e.g. methanol, ethanol) and aromatic organic solvents (e.g. benzene, toluene, chlorobenzene, xylene or styrene).
It is a mixture of The relative proportions of phenolic monomer and solvent can vary widely. Generally, a weight percentage of 40:60 to 5:95 is preferred, and 30:70.
to 10:90 is more preferable. The oxidative coupling of phenolic monomers promoted by manganese()-based catalysts is achieved by the presence of a strong alkali metal base, such as an alkali metal hydroxide, an alkali metal alkoxide, or a mixture thereof. carried out in a reactive reaction medium. As basic reaction medium, alkali metal bases such as sodium hydroxide, potassium hydroxide,
Lithium hydroxide, sodium methoxide and the like are preferred. Currently, it is considered preferable to use anhydrous sodium hydroxide in order to provide a strong basic reaction environment essential for the polymerization reaction, but for convenience,
An aqueous solution such as a 48% aqueous sodium hydroxide solution can be used. The amount of alkali metal base essential to promote oxidative coupling of phenols is generally such that the phenol:alkali metal base molar ratio is from about 1:1 to 100:1, preferably about
40:1 to 5:1 and more preferably about 20:1 to
The ratio is approximately 10:1. It is generally said that the optimum reaction conditions for forming polyphenylene oxide from 2,6-xylenol are for the molar ratio of 2,6-xylenol to alkali metal hydroxide to be in the range of about 14:1 to 18:1. . In general, the molar ratio of the catalyst consisting of manganese salt and orthohydroxyazo compound to the phenolic monomer is such that the polymerization reaction rate to polyphenylene oxide is as high as desired (minimum, maximum or optimum). can be varied extremely widely. Since it is preferable to minimize the amount of manganese contained in polyphenylene oxide, the catalyst consisting of manganese() salt and orthohydroxyazo compound is used in the smallest possible amount compared to the amount of phenolic monomer. It is preferable. Although it generally varies depending on the type of orthohydroxyazo compound and the type of amine used in combination with the manganese() salt, the molar ratio of the manganese()-based catalyst to the phenolic monomer is used at approximately 1/100 or less. . It is preferably used in a range of about 1/500 to about 1/4000. When oxidatively polymerizing a phenolic monomer by the method of the present invention, the reaction is carried out in the presence of an amine selected from primary and secondary amines. This is because the presence of the amine makes the obtained polymer even lighter in color and can improve the yield. Useful amines include mono- and dialkylamines containing 1 to 10 carbon atoms, such as n-butylamine, iso-butylamine, n-hexylamine, di-n-butylamine, di-iso
-Butylamine, di-n-hexylamine, etc. Other alkanolamines and polyamines such as monoethanolamine and diethanolamine, piperidine, morpholine, 1-3-
Examples include dipiperidylpropane. The amount of amine used in the practice of this invention can vary widely, but can generally be added in a proportion of 0.05 to 2 mole percent relative to the phenols. Oxygen gas or air is used as oxygen. When air is used, the reaction rate is low, but it is still usable. The reaction temperature for preparing polyphenylene oxide in the presence of a manganese complex catalyst can vary widely. Generally, it is appropriate for the polymerization temperature to be in the range of about 0 to about 60°C, preferably in the range of about 10 to about 50°C, and more preferably in the range of about 20 to 40°C.
It is ℃. In general, the self-condensation reaction of phenols is exothermic in nature, and Mn() chelates are susceptible to a decrease in activity due to heat. The reaction temperature can also be maintained within the optimum range by adjusting the addition. The method of the invention can also be carried out at atmospheric pressure or above. For example, a pressure of 1 to 100 Kg/cm ² is used. In this case, the upper latitude of the reaction temperature range becomes large. In carrying out the present invention, the polyphenylene oxide-containing reaction mixture produced by oxidative polymerization of the phenolic monomer as described above is used as is or after separating the aqueous phase, the reaction mixture is used as a non-solvent for the polyphenylene oxide. to stop the reaction and precipitate polyphenylene oxide. The nonsolvent is a well-known one, and lower alkanols having 1 to 8 carbon atoms such as methanol and ethanol are used. A preferred nonsolvent is methanol. The non-solvent may be added directly to the polyphenylene oxide-containing reaction mixture, or the polyphenylene oxide-containing reaction mixture may be added to the non-solvent. Additionally, the precipitation of polyphenylene oxide and catalyst from polyphenylene oxide-containing reaction mixtures is generally between 15 and 60%.
It may be carried out at a temperature of ℃. The precipitated polyphenylene oxide resin is separated using a conventional solid-liquid separator such as a centrifuge or a vacuum filtration machine, dried, and used as a molding composition or the like. When carrying out the method of the present invention, it is preferable that the polyphenylene oxide resin composition precipitated by contact with a non-solvent is separated by a solid-liquid separator and then slurried again with the non-solvent to complete the precipitation. . In the present invention, the manganese component can also be in the form of a stable inorganic manganese salt when precipitated with stirring in the polyphenylene oxide. This step preferably includes adding sulfides, disulfides, carbonates, bicarbonates, sulfates, borates, phosphates, oxalates, citrates to the reaction mixture before precipitating the polyphenylene oxide from the reaction solution. It is sufficient to add an anionic precipitating agent such as. Next, the method of the present invention will be explained with reference to Examples.
These are illustrative and do not limit the scope of the method of the invention. Example 1 0.00033 mol of manganese chloride, 1-(1'-hydroxy-naphthyl-2'-azo)-4-sulfo-6-
Dissolve 0.00067 mol of nitro-β-naphthol sodium salt (Eriochrome Black T, manufactured by Tokyo Chemical Industry Co., Ltd.) in 140 g of methanol, and add a solution of 1 mol of 2,6-dimethylphenol dissolved in 350 g of xylene. and di-n-butylamine 0.009 mol,
After adding 0.062 mol of sodium hydroxide, 500 mol of oxygen
It was introduced at a flow rate of ml/min and polymerized with stirring at 30°C. After 5 hours, half of the polymerization reaction solution obtained was added to methanol to precipitate the polymer. The precipitated polymer was filtered, reslurried with methanol, and then dried. The intrinsic viscosity of the polymer was 0.49 in chloroform at 25°C. The manganese content is
It was 125ppm. This amount is 83% of the theoretical amount of 150ppm
It is. For comparison, 3.8 g (0.036 mol) of 35% hydrochloric acid aqueous solution was added to the remaining half of the polymerization reaction solution obtained by the above method, the reaction solution was added to methanol to precipitate the polymer, and the slurry was re-slurried in the same manner as above. It was then dried. The intrinsic viscosity of the polymer is 0.48;
Manganese content was less than 0.5 ppm. The polymer powder obtained above was press-molded at 290°C to obtain a sheet with a thickness of 1 mm. Comparing the coloring states of the polymer directly precipitated without acid treatment and the acid-treated polymer, both were pale yellow with no discernible difference. The intrinsic viscosity of the press sheet and its rate of change are shown in the table below, and no influence was found due to mixing manganese into the resin without acid treatment.

[Table] Next, based on the polymer powder obtained above, a composition with the following composition was prepared using a Brabender plastograph.
The mixture was prepared by kneading at 250°C for 10 minutes. Part by weight Poly(2,6-dimethyl-1,4-phenylene oxide) 50 Rubber-modified impact-resistant styrene resin (S-Brite 500AS manufactured by Nippon Polymethylene Co., Ltd.) 45 Styrene-butadiene copolymer (Asahi Kasei Corporation) The notched isot impact strength, tensile strength, elongation, and heat distortion temperature of the Solprene 1204) 5 composition are as shown in the table below, and no influence was found due to the addition of manganese.

[Table] Example 2 2-(2'-
The procedure of Example 1 was carried out using 0.001 mol of α-naphthol Na salt (Eriochrome Blue Black B, manufactured by Tokyo Kasei Kogyo Co., Ltd.) of hydroxy-4'-sulfonaphthyl-1'-azo) and 0.0005 mol of manganese chloride. Polymerization was carried out repeatedly. After 4 hours, methanol was added to half of the reaction solution obtained to precipitate the polymer. The precipitated polymer was filtered and reslurried with methanol. The resulting polymer had an intrinsic viscosity of 0.53 and a manganese content of less than 185 ppm. This is a theoretical quantity
This corresponds to 82% of 225ppm. For comparison, 0.036 mol of acetic acid was added to the remaining half of the polymerization reaction solution obtained by the above method, and methanol was added to precipitate the polymer. After filtering the precipitated polymer, reslurry it with methanol in the same manner as above,
A polymer with an intrinsic viscosity of 0.52 was obtained. The manganese content in the polymer was less than 0.5 ppm. A 1 mm thick press sheet was prepared in the same manner as in Example 1, and changes in coloring state and intrinsic viscosity were examined. Pale yellow sheets were obtained for both the directly deposited product and the acid-treated product, and no difference was observed in the coloring and intrinsic viscosity of the sheets.

[Table] Next, a composition having the same composition as shown in Example 1 was prepared. The physical properties of the composition are shown in the table below, and no influence was observed due to the fact that manganese was mixed into the resin.

[Table] Comparative Example 1 A reaction was carried out in the same manner as in Example 1 using 0.00067 mol of benzoin oxime instead of the orthohydroxyazo compound. The intrinsic viscosity of the polymer after 5 hours was as low as 0.15, and a polymer that could be put to practical use could not be obtained. The procedure of the example was repeated by increasing the amount of manganese chloride used to 0.0005 mol and the amount of benzoin oxime to 0.001 mol, and the same treatment as in Example 1 was carried out without acid treatment. The intrinsic viscosity of the obtained polymer was 0.51. Next, press sheets were created in the same manner as in Examples 1 and 2. The sheet was colored brown, and its coloring was inferior to that of the directly deposited products obtained in Examples 1 and 2. The intrinsic viscosity of the press sheet was 0.61, containing 1.2% insoluble matter, and the rate of change in intrinsic viscosity was 120%.

Claims (1)

[Claims] 1 Manganese () salt and 1-(2'-hydroxy-
5′-sulfophenylazo)-β-naphthol, 1
-(1'-hydroxy-naphthyl-2'-azo)-4
-Sulfo-6-nitro-β-naphthol, 2-
(2'-Hydroxy-4'-sulfonactyl-1'-azo)-α-naphthol, a phenolic compound in the presence of a catalyst and an amine and at least one orthohydroxyazo compound selected from these alkali metal salts. Contacting monomers with oxygen in a basic reaction catalyst to form polyphenylene oxide,
A method for producing polyphenylene oxide, which comprises then contacting the polyphenylene oxide-containing reaction mixture with a non-solvent without adding an acid to precipitate the polyphenylene oxide. 2. The manufacturing method according to claim 1, wherein the phenolic monomer is 2,6-xylenol. 3. The production method according to claim 1, wherein the amine is a primary or secondary amine.