KR101169859B1 - Preparation of Polyphenyleneoxide - Google Patents

Abstract

The present invention relates to a method for producing polyphenylene oxide having excellent workability by oxidatively polymerizing 2,6-dialkylphenol at a temperature of 10 ° C. to 50 ° C. using a heterogeneous vanadium compound as a metal catalyst and using oxygen molecules. Most important as said 2, 6- dialkyl phenol is 2, 6- dimethyl phenol. The vanadium compound includes vanadium (V) and its oxides and mixtures and alloys thereof. The oxide includes vanadium trioxide (V ₂ O ₃ ), vanadium tetraoxide (V ₂ O ₄ ), and vanadium pentoxide (V ₂ O ₅ ). The patent also includes the formation of a complex between an amine compound and vanadium and an amine compound and vanadium oxide used as a cocatalyst. The said metal catalyst is used 0.1-5 mol% with respect to 2, 6- dialkyl phenol at the time of superposition | polymerization. Thereby, this invention can manufacture polyphenylene oxide excellent in workability efficiently and cheaply.

Description

Method for producing polyphenylene oxide {Preparation of Polyphenyleneoxide}

In the present invention, phenol having an alkyl substituent at both ortho positions, that is, 2,6-dialkylphenol, is oxidatively polymerized using an inhomogeneous vanadium compound as a catalyst at a temperature of 10 ° C. to 50 ° C. and an oxygen molecule. It relates to a method for producing a polyphenylene oxide.

Polymers obtained by oxidative polymerization of 2,6-dialkylphenols are often called polyphenylene oxides (PPO). This polymer PPO is a plastic for the thermoplastic industry, especially in the electronics industry. The reason is that this polymer material is a high functional material with excellent mechanical properties, excellent electrical properties, thermal durability, water resistance and dimensional stability.

In order to oxidatively polymerize 2,6-dialkylphenol using oxygen (O ₂ ), a catalyst capable of initiating a polymerization reaction is essential. If there is no catalyst, the reaction does not proceed, or even a little slower.

Polymeric poly (2,6-dimethyl-1,4-phenylene oxide) (PDMP, in which an ether bond is linked to the para position of a phenyl group by oxidative polymerization of 2,6-dialkylphenol or 2,6-dimethylphenol (DMP) ), Get a PPO soon. The molecular weight of PPO is often 5,000 to 30,000, but industrially 10,000 to 20,000 is preferred. This is because PPO in the molecular weight range has the best workability.

In the preparation of PPO, homogeneous copper salts and manganese compounds have been used together with various amine compounds. U.S. Pat.Nos. 3,306,874 (1967) and 3,306,875 (1967) have 2,6-dimethylphenol and copper chloride (CuCl) salts as catalysts and pyridine as cocatalysts to form a complex, which is a low DMP molecule A method for preparing a polymer PPO by oxidative coupling is presented. US Pat. No. 4,028,341 (1977) uses a copper bromide (CuBr) salt and a diamine base and US Pat. No. 4,092,294 (1978) describes a method for preparing PPO from DMP using a copper bromide salt and a butylamine base. Japanese Patent Nos. 30,335 (1970) and US Pat. No. 4,059,553 (1977) disclose methods for producing PPO from DMP using amine compounds such as manganese chloride (MnCl ₂ ) salts and benzoinoximes.

U.S. Patent 4,083,828 (1978) uses manganese chloride salts and divalent amines, and Japanese Patent 44,625 (1982) describes a process for preparing PPO from DMP using manganese chloride salts and ethanolamine. In US Patent 3,573,057 (1971), manganese chloride salts, amines and caustic soda were used together. In US Patent 4,054,559 (1977), manganese chelate compounds were used, and in US Patent 4,418, 224 (1983), manganese hydroxide or manganese carbonate was used. A method for preparing PPO from DMP is presented.

In the literature so far, in preparing poly (2,6-dimethyl-1,4-phenylene oxide) (PDMP), that is, polyphenylene oxide (PPO) from 2,6-dimethylphenol (DMP), The homogeneous (solvent soluble) copper chloride salt was mainly used as the first catalyst (main catalyst), and the solvent soluble amine base was used as the second catalyst (subcatalyst). Here, metal salts such as copper chloride are involved in increasing the molecular weight of the prepared PPO, and the amine base blocks the reaction of the ortho portion of the DMP to linearize the PPO chain. The homogeneous metal salt (main catalyst) and the amine compound (subcatalyst) are dissolved in the solvent constituting the reaction solution to form an amine complex to participate in the polymerization reaction. Therefore, after the reaction, these two compounds, especially salt compounds, are difficult to recover and difficult to reuse. This contributes to an increase in PPO manufacturing costs. In addition, one of the disadvantages of this process is that metal salt catalysts such as copper chloride are very sensitive to water, and thus the activity as a catalyst can be lost by water discharged as a reaction residue during the polymerization process.

Accordingly, an object of the present invention is to provide a novel polyphenylene oxide production method characterized by preventing the above-mentioned problems, namely, lowering of catalytic activity by water and facilitating catalyst recovery to lower PPO production cost. do.

In order to solve the above problems, the present invention uses a heterogeneous (solvent-insoluble) metal catalyst in synthesizing polyphenylene oxide from 2,6-dialkylphenol. As the means for solving the problem.

The present invention, which has the above-mentioned means for solving the above problems, uses a non-homogeneous (solvent-insoluble) metal catalyst instead of a homogeneous (solvent-insoluble) catalyst in the synthesis of PPO using oxygen. Since it still remains in the solid state, there is no fear of deterioration of the catalytic activity by water during the reaction, and it is advantageous that the recovery of the catalyst after the reaction is easy, reliable and simple to reduce the manufacturing cost.

The present invention for solving the above problems provides a method for producing a polyphenylene oxide polymer by oxidative polymerization of 2,6-dialkylphenol by oxygen gas or oxygen in the air in the presence of a metal catalyst.

In the present invention, the basic compound 2,6-dialkylphenol is represented by the following formula (1).

R ₁ and R ₂ are hydrocarbons having 1 to 4 carbon atoms. Such compounds include the following. They are 2,6-dimethylphenol, 2,6-diethylphenol, 2,6-dipropylphenol, 2-methyl-6-ethylphenol, 2-methyl-6-propylphenol, 2-methyl-6-isopropyl Phenol, 2-methyl-6-butylphenol, 2-ethyl-6-propylphenol, 2-ethyl-6-isopropylphenol, 2-ethyl-6-butylphenol and 2,6-dibutylphenol. The most important compound among these 2,6-dialkylphenols is 2,6-dimethylphenol.

Some other phenols may be used in part in the present polymer system. If used intentionally, they may be used together with 2,6-dialkylphenols to form side-by-side binary copolymers or terpolymers that can be used to control crystallinity. This includes 2-methylphenol (orthocresol), 3-methylphenol (methcresol), 4-methylphenol (paracresol), 2-ethylphenol, 3-ethylphenol, and 2-propylphenol.

Metal catalysts used in the present invention include vanadium, oxides thereof, and mixtures and alloys thereof as metal powders. The oxide includes vanadium trioxide (V ₂ O ₃ ), vanadium tetraoxide (V ₂ O ₄ ), and vanadium pentoxide (V ₂ O ₅ ). In addition, the amine compound and the vanadium and the amine compound and the vanadium oxide complexes are included in the protection scope of the present invention.

The metal catalyst is selected according to the molecular weight and crystallinity of the desired PPO and the reaction yield. These are used at least 0.1 mol%, largely 5 mol%, based on the 2,6-dialkyl phenol at the time of polymerization, with 0.2 to 2.5 mol% being more preferred.

In the present invention, in addition to the metal catalyst, an amine compound may be used as a cocatalyst (subcatalyst). These include dimethylamine, diethylamine, dipropylamine, dibutylamine, dimethylbutylamine, dibutylethylenediamine, diethylenetriamine, trimethylamine, triethylamine, tripropylamine, triisopropylamine, tetramethylethylene Diamine, pyridine, pyrrole, dimethylpiperazine, morpholine, picoline, quinoline, diethanolamine, diisopropanolamine, dimethylisopropanolamine, triethanolamine, triisopropanolamine, methylimidazole and the like. These may be used alone or in combination of two or more. These are used 2-25 mol% with respect to the low molecular weight 2, 6- dialkyl phenol. Of these amine compounds, important compounds are dibutylethylenediamine and tetramethylethylenediamine, and the most important compound is tetramethylethylenediamine.

In the polymerization process according to the present invention, the solvent constituting the reaction solution is added 1 to 20 times the amount of the low molecular weight 2,6-dialkylphenol. The solvent should be such that the low molecular weight 2,6-dialkylphenol must be oxidized, while not easily oxidized to oxygen. The solvent includes a nonpolar solvent of the resulting PPO and a polar solvent of a low molecular weight 2,6-dialkylphenol. Nonpolar solvents include benzene, toluene, xylene (dimethylbenzene), ethylbenzene, diethylbenzene, chloroform, carbon tetrachloride, trichloroethylene, tetrachloroethylene, chlorobenzene, dichlorobenzene, trichlorobenzene, nitrobenzene, etc. Used alone or two or more together. Or they are used with polar solvents. Polar solvents include acetone, methanol, ethanol, propanol, 2-propanol, butanol, benzyl alcohol, cyclohexanol, methyl ethyl ketone, diethyl ether, tetrahydrofuran and the like.

The oxidation polymerization process of 2,6-dialkylphenol in the present invention proceeds as follows. The polymerization is initiated by injecting oxygen gas into the reactor or exposing the reactor to air. When the solvent is toluene, oxygen gas may be diluted with nitrogen gas because of its explosiveness. The oxidative polymerization is carried out in the temperature range of 10 ° C to 50 ° C under atmospheric pressure. Preferred temperature is 20 ° C-40 ° C. The polymerization reaction is usually carried out under atmospheric pressure but can also be carried out under pressurized conditions.

The polymerization reaction can be run batchwise or continuously. Termination of the polymerization reaction, polymer separation and purification follow conventional methods. For example, the termination of the polymerization reaction can be effected by shutting off the oxygen supply or adding acid. In this case, the acid reacts with a hydroxyl group at the end of the polymer chain to change into an inactive group, thereby blocking the end of the chain to prevent further chain growth, and eliminating the tendency of the phenol at the end of the polymer to oxidize to quinone. Imparts oxidative stability to. Such acids include acetic acid, acetic anhydride, acetic chloride, maleic acid, maleic anhydride, maleic chloride, benzoic acid, benzoic anhydride, benzoic chloride and the like. At the end of the reaction, the reactants are immediately poured into the non-solvent of the resulting polymeric PPO (in this case a highly polar compound, eg methanol) to obtain a precipitate which is then washed again with a non-solvent, filtered and dried to give a polymeric PPO.

Hereinafter, the present invention will be described in more detail with reference to the following examples. However, this is only presented to aid the understanding of the present invention, the present invention is not limited thereto.

(Example 1)

2,6-dimethylphenol (DMP) used in the experiment was used as ACROS Co., Ltd. product (purity 99%) without purification. Many other metal powders and oxygen gases were purchased from the market. A three-necked reactor (1000 mL) with a stirrer in the center hole and an oxygen gas inlet and outlet in each of the two outer holes was immersed in a water bath set at 30 ° C, and then 10 g of toluene, 90 g of 2-propanol, 2 g (0.0164 mol) of low molecular weight DMP and 29.38 g (0.253 mol) of tetramethylethylenediamine (TMEDA) were added thereto and stirred for 5 minutes. Thereafter, 0.18 g (0.0036 mol) of vanadium (V) powder was added thereto, followed by vigorous stirring while introducing oxygen gas in an amount of 100 mL per minute, and the reaction was continued for 1 hour. After that, 10 g of toluene, 90 g of 2-propanol, and 20 g of DMP (0.164 mol) were slowly added to the reactor, followed by reaction under vigorous stirring for 2 hours. After the reaction, the reaction solution is filtered through a glass fiber filter, and the precipitated solution is poured into a container containing 1000 mL of methanol and stirred. The precipitate was collected and dried in a vacuum dryer (60 ° C.) for 6 hours, weighed to obtain a reaction yield. The solid was further dissolved in toluene to give four lean solutions (0.125%, 0.25%, 0.5%, 1%). To obtain the specific viscosity at 25 ° C with the Uberod viscosities, and from it the intrinsic viscosity, [

] To obtain the MHS equation, [

] = kMv ^a where a = 0.68, k = 0.0285 mL / g, the molecular weight (Mv) of the resulting polymer PPO was calculated.

(Examples 2-5)

The same reaction procedure as in Example 1 is used but only the metal powder used as a catalyst is different from each other. That is, in Example 1, vanadium was used as the metal powder, and in Examples 2 to 4, vanadium trioxide (V ₂ O ₃ ), vanadium tetraoxide (V ₂ O ₄ ), and vanadium pentoxide (V ₂ O), respectively. ₅ ) was used as the metal powder.

(Comparative Example 1)

Instead of the metal catalyst in the embodiment, 0.2 g (0.002 mol) of copper chloride (CuCl), which is an existing salt catalyst, and 7.6 g (0.02 mol) of pyridine, a subcatalyst, were polymerized.

Table 1 shows the experimental results of the Examples and Comparative Examples.

[Table 1]

In Table 1, the use of the metal catalyst in the present invention was able to obtain a higher molecular weight than when using the existing copper chloride / pyridine under the same conditions. In addition, the metal powder can be removed with a glass fiber filter, so the catalyst recovery is extremely easy, and the recovered catalyst can be reused. The molecular weight of the polymer obtained by this production method is in the range of 15,000 to 20,000, which is considered to be industrially excellent PPO.

Claims (7)

A method for producing polyphenylene oxide by oxidatively polymerizing 2,6-dialkylphenol, wherein at least one of vanadium, vanadium oxide, a mixture of vanadium and vanadium oxide, and an alloy of vanadium and vanadium oxide is used as a metal polymerization catalyst. Method for producing a polyphenylene oxide, characterized in that. delete The method of claim 1, wherein the 2,6-dialkylphenol is 2,6-dimethylphenol. The method for producing polyphenylene oxide according to claim 1, wherein a tetramethylethylenediamine amine compound is used as an auxiliary catalyst. 2. The polyfunctional according to claim 1, wherein at least one of vanadium, vanadium oxide, a mixture of vanadium and vanadium oxide, and an alloy of vanadium and vanadium oxide forms a complex with an amine compound is used as a polymerization catalyst. Method for producing phenylene oxide. The method for producing a polyphenylene oxide according to claim 1, wherein the metal of the metal polymerization catalyst is used in an amount of 0.1 to 5 mol% based on 2,6-dialkylphenol used. The method for producing polyphenylene oxide according to claim 4, wherein the amine compound is used in an amount of 2 to 25 mol% based on 2,6-dialkylphenol used.