JPS636091B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to a method for producing polyphenylene oxide. More specifically, the present invention relates to oxidative polymerization of nuclear-substituted phenols using a manganese compound, a basic compound, and an alkanolamine as catalysts. Polyphenylene oxide itself or especially its polymer alloy with polystyrene has excellent thermal properties, mechanical properties, electrical properties, hot water resistance, etc., and in recent years has been widely used as a molding material. Conventionally, in the method of producing polyphenylene oxide by oxidative polymerization of phenols, many catalyst systems have been proposed that combine copper compounds, manganese compounds, or cobalt compounds with ligands selected from various amines and bases. has been done. Among them, the catalyst system that combines a manganese compound and a base such as sodium hydroxide, as shown in Japanese Patent Publication No. 45-30354, is unique in that it does not use amines, has a high polymerization rate, and has a high polymerization rate. This is a useful system with features such as low cost because it does not require recovery.
However, this catalyst is not a self-controlling catalyst system, and as the polymerization time elapses, the rate of increase in the intrinsic viscosity of the polyphenylene oxide produced increases, making it practically impossible to control the molecular weight. Phenylene oxide has the disadvantage that it is of poor quality and tends to gel when heated and melted. As a method for improving this drawback, a method has been proposed in which a small amount of secondary amine is used in combination (Japanese Patent Application Laid-open No. 79993/1983). However, although this method allows the intrinsic viscosity to be leveled over time, the above-mentioned quality problems are not solved. Under such circumstances, the present inventors have established a method for producing polyphenylene oxide that does not have the above-mentioned disadvantages and is based on an economically advantageous catalyst consisting of a combination of a manganese compound and a base. As a result of intensive studies, it was discovered that when a small amount of monoethanolamine or diethanolamine, which had not been previously proposed, was used in combination with a base, polyphenylene oxide of significantly better quality could be obtained, leading to the completion of the present invention. Ivy. That is, the present invention provides a basic compound, a manganese compound, an organic solvent, and a monomer selected from the group consisting of hydroxides, alkoxides, or phenoxides of group 1A metals of the periodic table, and hydroxides or oxides of group 2A metals. The present invention provides a method for producing polyphenylene oxide, which comprises oxidatively polymerizing nuclear-substituted phenols with an oxygen-containing gas in the presence of ethanolamine and/or diethanolamine. The nuclear substituted phenols used in the present invention have the general formula (However, R ₁ , R ₂ , R ₃ , R ₄ , and R ₅ are each hydrogen, halogen, hydrocarbon group, cyano group, hydrocarbonoxy group, or substituted hydrocarbonoxy group, and their At least one is hydrogen and at least one is other than hydrogen), specific examples are 2-methylphenol, 3-methylphenol, 2-ethylphenol, 4-methylbenzyl Phenol, 2,6-dimethylphenol, 2
-Methyl-6-ethylphenol, 3-methyl-
6-t-butylphenol, 2,6-diallylphenol, 2,6-diphenylphenol, 2.
Examples include 6-dichlorophenol, 2,6-dibromophenol, 2,6-dimethoxyphenol, 4-cyanophenol, 2,3,6-trimethylphenol, 2,4-dimethyl-3-chlorophenol, and the like. A preferred substituted phenol is 2.
6-dimethylphenol, 3-methyl-6-t-
These include butylphenol, 2,3,6-trimethylphenol, and the like. These can be used alone or in combination. Manganese compounds used in the present invention include manganese halides such as manganese chloride and manganese bromide, inorganic acids such as manganese nitrate, manganese sulfate, manganese carbonate, manganese formate, manganese acetate, manganese oxalate, and manganese naphthenate; There are manganese salts of acids, manganates such as sodium manganate, permanganates such as potassium permanganate and calcium permanganate, manganese hydroxide, and manganese oxide. These can be suitably used in either anhydrous or hydrated form. Basic compounds listed in Periodic Table 1A include lithium hydroxide, sodium hydroxide, potassium hydroxide, etc.
Hydroxides of group metals, hydroxides of group 2A metals of the periodic table such as calcium hydroxide, magnesium hydroxide, and their oxides, sodium methoxide, potassium methoxide, sodium ethoxide, sodium-n-propoxide , sodium-iso-
Examples include alkoxides of group 1A metals in the periodic table such as propoxide and potassium t-butoxide, and phenoxides of group 1A metals in the periodic table such as sodium phenoxide and potassium phenoxide. Among these, sodium hydroxide and potassium hydroxide are particularly preferred. These basic compounds are supplied to the reaction system as they are or in a state dissolved in a polar solvent such as alcohol. The organic solvent used in the present invention is not particularly limited as long as it is inert to nuclear substituted phenols and liquid at the reaction temperature, but suitable examples include benzene, toluene, Aromatic hydrocarbons such as xylene, chain and cyclic aliphatic hydrocarbons such as heptane and cyclohexane, halogenated hydrocarbons such as chlorobenzene, dichlorobenzene and dichloromethane, dioxane,
Ethers such as diethyl ether, ketones such as cyclohexanone and acetophenone, esters such as ethyl acetate and propiolactone, nitriles such as acetonitrile and benzonitrile, methanol, ethanol, n-propanol, isopropanol, n-butanol, sec -Alcohols such as butanol, nitrobenzene, sulfolane, etc. can be mentioned. These may be used alone or as a mixture. Preferred organic solvents are mixed solvents of aromatic hydrocarbons and alcohols, particularly preferably toluene/methanol, toluene/ethanol, toluene/n-propanol, toluene/isopropanol, xylene/methanol, xylene/ethanol, and xylene/n-propanol. -propanol and a mixed solvent of xylene/isopropanol. The object of the present invention, which is to obtain polyphenylene oxide of good quality, can only be achieved by using monoethanolamine and/or diethanolamine in addition to the above-mentioned manganese compound and basic compound. Oxygen or air is used as the oxygen-containing gas. In carrying out the method of the present invention, the manganese compound is 0.05 to 10 mol% based on the nuclear-substituted phenol used.
It is preferably used in a proportion of 0.1 to 5 mol%.
The proportion of the basic compound used is usually 1 to 500 times, preferably 5 to 50 times, the amount of the manganese compound. Monoethanolamine and/or diethanolamine 0.1 for manganese compounds
It is used at a ratio of ~50 moles, preferably 0.5 to 10 moles. If the proportion of monoethanolamine and/or diethanolamine used is less than 0.1 times by mole, the effect of producing polyphenylene oxide of substantially good quality cannot be obtained, so it is not preferable, and if it is more than 50 times by mole, a high polymerization rate cannot be obtained. This is not preferable because it reduces the effect of The oxygen-containing gas is introduced into the reaction system by blowing into the liquid, or by a method of gas-liquid contact using strong stirring, liquid circulation, or the like. The reaction temperature is not particularly limited as long as it is within the range that keeps the reaction system in a liquid state, but in order to avoid side reactions, it is usually
The temperature is selected to be 150°C or lower, preferably 10 to 100°C. The reaction pressure is preferably selected from normal pressure or increased pressure. After the reaction is complete, the polyphenylene oxide can be precipitated by contacting the resulting reaction mixture with a non-solvent for the produced polyphenylene oxide, and then separated by solid-liquid separation means such as filtration or centrifugation. The solid polyphenylene oxide product can be obtained through isolation, drying treatment, etc. According to the method of the present invention as detailed above, it is possible to supply a polyphenylene oxide resin with excellent electrical properties, mechanical properties, and thermal properties that can be used as a molding material for a variety of applications in an extremely economical manner. Its industrial value is enormous. The method of the present invention will be explained in more detail with reference to Examples below, but the scope of the method of the present invention is not limited by these Examples. In addition, in the examples, the gel fraction, which indicates the ease with which polyphenylene oxide gels by heating and melting, is 10
The percentage of insoluble matter when a sheet made by pressing under the conditions of 5 g/100 ^ml of chloroform is dissolved in chloroform at a rate of 5 g/100 ml, that is, gel fraction (%) = weight of dry insoluble matter. /Indicates press sheet weight x 100. Moreover, [η] represents the intrinsic viscosity measured at 25°C in chloroform. Example 1 Thermometer, reflux condenser, oxygen blowing pipe,
and 1 mol of 2,6-dimethylphenol, 0.015 mol of monoethanolamine and 447 mol of xylene in two four-necked separable flasks equipped with a stirrer.
ml to make a homogeneous solution. Here, add a solution of 0.006 mol of manganese chloride dissolved in 86 ml of methanol and 0.06 mol of sodium hydroxide in methanol.
A solution dissolved in 212 ml was added, and while stirring vigorously, oxygen was blown at a rate of 300 ml/min at 30° C. for 3 hours for polymerization. Hydrochloric acid was then added to the reaction mixture.
Solid polyphenylene oxide was precipitated by adding 738 ml of methanol containing 0.09 mol, and the resulting slurry was heated at 60° C. for 2 hours with stirring. After the heat treatment was completed, the solid polyphenylene oxide was taken out, washed with hot methanol, and then dried to obtain a product polyphenylene oxide in the form of a beige powder.
The yield was 96.2%, and [η] was 0.61 dl/g. The gel fraction of this polyphenylene oxide was measured and found to be 0%. In addition, a mixture consisting of 50 parts by weight of this polyphenylene oxide, 45 parts by weight of High Impact Polystyrene S-Brite 500A manufactured by Nippon Polystyrene, and 5.3 parts by weight of SBR Solprene-1204 was prepared using a full-flight type uniaxial with L/D = 15/1 and a diameter of 20 mm. The notched Izot impact strength of the molded product, which was press-molded at 260℃/100Kg/cm ² /10 minutes for the molten blend obtained by granulation using an extruder, was as high as 25Kg・cm/cm. The value was shown. Comparative Example 1 Polyphenylene oxide produced in exactly the same manner as in Example 1 except that monoethanolamine was not added had [η] of 1.2 dl/g and a gel fraction of 7.2%. In addition, the notched Izo impact strength of the press-formed product made in the same manner as in Example 1 was 14.2.
It was low at Kg・cm/cm. Incidentally, the relationship between [η] of polyphenylene oxide during polymerization and polymerization time in Example 1 and Comparative Example 1 is shown in FIG. This shows that monoethanolamine has a remarkable effect on molecular weight control. Examples 2 to 4, Comparative Examples 2 to 5 1 mole of 2,6-dimethylphenol to 2,6-
0.96 mol of dimethylphenol and 3-methyl-6-
Production and evaluation of polyphenylene oxide in the same manner as in Example 1 except that monoethanolamine and sodium hydroxide were changed to a mixture consisting of 0.04 mole of t-butylphenol and the amine and basic compound shown in Table 1. I went there. These results are shown in Table 1.

[Table] *Represents the notched isot impact strength measured in the same manner as in Example 1.

[Brief explanation of the drawing]

FIG. 1 is a diagram showing the relationship between [η] of polyphenylene oxide during polymerization and polymerization time in Example 1 and Comparative Example 1. In the figure, 1 indicates Example 1, and 2 indicates Comparative Example 1.

Claims (1)

[Scope of Claims] 1. Basic compounds, manganese compounds, and organic solvents selected from the group consisting of hydroxides, alkoxides, or phenoxides of Group 1A metals of the Periodic Table and hydroxides or oxides of Group 2A metals. and a method for producing polyphenylene oxide, which comprises oxidatively polymerizing nuclear-substituted phenols with an oxygen-containing gas in the presence of monoethanolamine and/or diethanolamine. 2. The method for producing polyphenylene oxide according to claim 1, wherein the basic compound is sodium hydroxide or potassium hydroxide. 3. The organic solvent is a mixed solvent of alcohols selected from the group consisting of methanol, ethanol, propyl alcohol and butyl alcohol and aromatic hydrocarbons selected from the group consisting of benzene, toluene, xylene and ethylbenzene. A method for producing polyphenylene oxide according to claim 2.