JPS58145726A - Production of poly(dialkoxyphenylene) - Google Patents

Abstract

PURPOSE:To produce the titled polymer excellent in heat resistance and processability, by polymerizing a dialkoxybenzene under a reduced pressure in an inert solvent in the presence of a Lewis acid and an oxidizing agent. CONSTITUTION:A poly(dialkoxyphenylene) is produced by polymerizing a dialkoxybenzene of the formula (wherein R is a 1-5C alkyl), e.g., p-dimethoxybenzene, under a reduced pressure in an inert solvent (e.g., nitrobenzene) in the presence of a Lewis acid (e.g., anhydrous aluminum chloride) and an oxidizing agent (e.g., cupric chloride). This polymer does not contain halogens (e.g., chlorine) originated in a catalyst, and provides a material excellent in heat resistance and processability.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for producing poly(dialkoxyphenylene).

Polyphenylene polymers, which have linear phenylene groups in their main chains, have excellent heat resistance and have long been expected to be used as metal substitute materials for aerospace applications or as engineering plastics. It is extremely unsatisfactory as a material for molding due to its heat resistance and insolubility.Although it has a good heat resistance of 550℃, it is infusible and insoluble, and has poor processability, making it difficult to use it to take advantage of its polymer properties. not present.

The present inventors searched for a new polyphenylene material with excellent heat resistance, and found that a polyphenylene material with excellent heat resistance and processability
(dialkoxyphenylene) was successfully produced.

Polymerization of dialkoxybenzene is possible using known methods for producing polyphenylene, but the yield is low, and moreover, halogen atoms due to the catalyst are introduced into the aromatic nucleus of the main chain, or during the reaction and treatment steps. The resulting polymer has poor heat resistance due to factors such as the alkoxy group being changed to a hydroxyl group due to elimination of the alkyl group, and it is impossible to obtain a product that can be used as a polymeric material for molding. As a result of intensive research to improve these drawbacks, the present inventors discovered the polymerization method of the present invention, making it possible to provide a new and useful polymeric material.

Conventionally, in the synthesis of polyphenylene using benzene as a raw material, it is known that increasing the reaction temperature increases the introduction of halogen atoms derived from the catalyst into aromatic nuclei.
When the present inventors synthesize poly(dialkoxyphenylene) from dialkoxybenzene, in order to prevent the introduction of halogen atoms, it is necessary not only to suppress the reaction temperature from increasing, but also to suppress the hydrogen chloride generated from the reaction yarn. It has been found that it is necessary to remove hydrogen bromide and other gaseous by-products by, for example, reducing the internal pressure of the system.

The reaction under reduced pressure can also prevent the elimination of alkyl groups from alkoxy groups, and as a result, the poly(dialkoxyphenylene) obtained by the method of the present invention has higher heat resistance than the polymer obtained according to the known polyphenylene synthesis method. It was found that the performance was significantly improved.

The polymerization reaction of the present invention is considered to be an oxidative coupling reaction via a cation radical intermediate, as in the case of benzene, and is carried out using dialkoxybenzene in an inert solvent in the coexistence of a Lewis acid and an oxidizing agent. .

or those used for coordination polymerization are suitable,
Anhydrous aluminum chloride, anhydrous ferric chloride, anhydrous titanium chloride (■), anhydrous stannic chloride, anhydrous molybdenum chloride, anhydrous tungsten chloride, anhydrous antimony (V) chloride, boron fluoride, boron fluoride Nieteller 1, etc. are used, but anhydrous aluminum chloride and anhydrous ferric chloride are particularly preferred. Other halides corresponding to these can also be used.

Since the production reaction of the polymer compound of the present invention proceeds in an oxidative manner, it is necessary to coexist an oxidizing agent in addition to the Lewis acid. Oxidizing agents include high-valent transition metal compounds, such as chlorides such as cupric chloride (anhydrous and hydrated), ferric chloride, tin chloride, molybdenum chloride, tungsten chloride, or other corresponding halogens. monster,
Oxides such as manganese dioxide, lead dioxide, and tin oxide,
Oxoacid salts such as permanganate, organic oxidizing agents such as chloranil, benzoquinone, and naphthoquinone, organic peracids such as peracetic acid, perbenzoic acid, and methachloroperbenzoic acid, or hydrogen peroxide are used, but among these, anhydrous Alternatively, hydrated cupric chloride, anhydrous ferric chloride, etc. are suitable. Among these oxidizing agents, when the solubility in the reaction solvent is low and the oxidizing agent does not exhibit sufficient effect, such as cupric chloride, it is effective to use oxygen in the air or use a co-catalyst. It is.

Also, depending on the combination of these reaction components, it may be effective to have 0 to 1 mole of water in the system as water of crystallization contained in the Lewis acid, oxidizing agent or co-catalyst, or as an additive relative to the Lewis acids mentioned above. There are cases where

In the production method of the present invention, cobalt acetate (11), cobalt benzoate (n), cobalt oxalate) (II)
Cobalt (■) salts of carboxylic acids such as
T) The use of cobalt(II) complex compounds such as acetylacetonate, or similar compounds such as manganese (■), chromium ([1), etc., as cocatalysts can lead to the formation of poly(dialkoxyphenylenes) for the purpose of the present invention. It is possible to dramatically increase the yield of However, this cocatalyst tends to cause the elimination of alkyl groups from alkoxy groups, although in small amounts, and therefore, especially when a polymer having no free phenolic hydroxyl groups is required, the method of the present invention can be used. It is necessary to alkylate the resulting polymer.

The production method of the present invention can be applied to any of the dialkoxybenzenes having an alkoxy group having 1 to 5 carbon atoms represented by the general formula (I), and the corresponding polymer can be produced under similar polymerization conditions. I can do it.

As the inert solvent used in the method of the present invention, any organic solvent that is inert to the aryl cation used in the normal free-sol tarafluor reaction can be used, but in particular, nitroalkanes such as nitromethane and nitroethane, nitrobenzene or qO-dichlorobenzene and the like are preferred.

The Lewis acid, oxidizing agent, co-catalyst and solvent described above can be used in various combinations without any limitations, but particularly suitable combinations include anhydrous aluminum chloride and cupric chloride using nitrobenzene as a solvent. , and systems of cobalt-based cocatalysts, and systems of ferric chloride in nitroalkanes such as nitromethane or diI-loethane as solvents.

The amount of solvent used in the method of the present invention may be any amount that can dissolve the raw material dialkoxybenzene, but it is preferably an amount that also dissolves the Lewis acid used.
Usually, 1 to 20 parts per 5 parts by weight of dialkoxybenzene (hereinafter simply referred to as parts) is used.

The amount of Lewis acid to be used is determined depending on the solubility or activity in the solvent, but usually 1 to 5 mol is used per 1 mol of dialkoxybenzene. For example, when using aluminum chloride, 1 mole gives a good yield, but when using titanium chloride or ferric chloride, 2 moles give a good yield.
It is desirable to use ~2.5 mol.

The oxidizing agent needs to be used in an amount of at least 2 equivalents per 1 mol of dialkoxybenzene, and in the case of ferric chloride and cupric chloride, 2 mol is required, but cupric chloride has a low solubility in the solvent. Since it is small, it is recommended to increase the amount appropriately. Also,
In order to complete the reaction in a shorter time, it is also effective to use an increased amount of ferric chloride, which is easily soluble in the solvent. This increase rate is determined mainly for operational reasons or economic reasons, but it is generally increased to 5 equivalents.

The co-catalyst used in the present invention sufficiently exhibits its effect at 1/200 to 1/10 mole per mole of dialkoxybenzene. For example, by using 1/20 mole of cocatalyst per mole of dialkoxybenzene, the polymer yield can be increased from 20 to 30% to 50 to 60%.

The pressure conditions for removing hydrogen halide generated in the method of the present invention are 1 to 100 mmHg. As the pressure approaches normal pressure, substitution of halogen on aromatic rings and elimination of alkyl groups from alkoxy groups become more likely to occur.
There is no particular difference in the effect even if it is less than w II g, and 10 to 40 dragon Hg is usually appropriate for operation.

In the method of the present invention, increasing the reaction temperature includes:
This is not advantageous because it causes substitution of halogen to aromatic ring and elimination of alkyl group. On the other hand, carrying out the reaction at too low a temperature is not advantageous because it reduces the solubility of dialkoxybenzene in the solvent and also slows down the reaction rate. Therefore, the reaction is -3
Although it is possible to carry out the process at a temperature between 0'C and 100C, it is preferable to carry out the process at a temperature of 0 to 4.0''C1, especially around room temperature.

The reaction time varies depending on the type of dialkoxybenzene, but generally the time required until the generation of hydrogen halide gas is no longer observed and the reaction is considered complete is 30 minutes.
The duration ranges from minutes to 2 hours.

The present invention will be explained below with reference to Examples.

Example 1 13.4 g of ground anhydrous aluminum chloride and 13.5 g of anhydrous cupric chloride were vigorously stirred in nitrobenzene at 100 mA, and 13.8 g of paradimethoxybenzene was dissolved under a reduced pressure of 20 mm T (g). Add 0 ml! of nitrobenzene and react for 30 minutes at room temperature. Add the reaction solution to 6N m#10 (1 m#) (stir). Separate insoluble matter by filtration, add a large amount of hexane, dilute hydrochloric acid, 0.0 ml!
After repeated washing with a 2N aqueous sodium hydroxide solution and water, and finally with distilled water, it was dried in a drying bed at 100° C. for 8 hours to obtain 4.6 g of a brown polymer.

Table 1 shows elemental analysis, thermogravimetric analysis (TGA), and intrinsic viscosity when dissolved in concentrated sulfuric acid. No chlorine atoms originating from the catalyst were observed by elemental analysis.

Example 2 The reaction and treatment were carried out in the same manner as in Example 1, except that 17.1 g of hydrated cupric chloride was used instead of 1 s.5 g of anhydrous cupric chloride, and 2.9 g of a brown polymer was obtained. . Elemental analysis, thermogravimetric analysis, and intrinsic viscosity when dissolved in concentrated sulfuric acid are shown in Table 1. As a result of elemental analysis, no chlorine atoms derived from the catalyst were observed.

Example 3 13.4 g of crushed aluminum chloride, 13 g of cupric chloride
．． 5 g of cobalt acetate tetrahydrate and 1.25 g of cobalt acetate tetrahydrate were mixed in nitrobenzene 1 (l Omβ) with vigorous stirring;
While blowing dry air from the capillary, maintain a reduced pressure of 25 to 35 mmHg, and add 50 ml of nitrobenzene in which 13.8 g of P-dimethoxybenzene has been dissolved.
7! Add. After reacting for 30 minutes at room temperature, the reaction solution was added with 100 mj of 6N hydrochloric acid! and stir.

Insoluble matter was collected by filtration and washed with a large amount of hexane, 2N hydrochloric acid, 0.2N aqueous sodium hydroxide solution and water,
Drying in a drying bed at 100° C. for 8 hours under reduced pressure yields 6.7 g of light brown polymer. Figure 1 shows the infrared absorption spectrum of the obtained polymer. A slight amount of hydroxyl group is observed. The elemental analysis values of the polymer are C,
69.48%, H.

5.96%, and the calculated value assuming that the repeating unit is CθH,02 (C; 70.57%, H,5,
92%) was observed. When TGA was measured in air to investigate thermal properties, the degree of 5% weight loss was 320°C, and the temperature of 50% weight loss was 500°C.
No major difference from that obtained in Example 1 was observed.

Example 4 In place of 1.25 g of cobalt acetate tetrahydrate in Example 3, 1.28 g of cobalt acetylacetonate was used. The reaction was carried out in the same manner as in Example 3, and post-treatment was performed to obtain light brown polymer 7. Obtain .1g.

Table 1 shows the elemental analysis results, TGA analysis results, and limiting viscosity [η] in concentrated sulfuric acid. It almost matches that of Example 3.

9- Examples 5 and 6 In Example 5, aluminum chloride 13 in Example 1
, 4 g, using 32.5 g of ferric chloride instead of 13.5 g of cupric chloride (Lewis acid and oxidizing agent), Example 6
In Example 1, the reaction was carried out in the same manner as in Example 1, using the same O-dichlorobenzene in place of nitrobenzene (solvent), resulting in 4.3 g and 3.1 g, respectively.
g of brown polymer is obtained. The elemental analysis results are: C; [i 8.74%, H, 6.05% in Example 5; C; 67.22%, H in Example 6.

It showed 6.18%, and a slight difference was observed between the calculated value and the calculated value.

The measurement results of TGA and intrinsic viscosity are shown in Table-1. All of the obtained polymers are expected to have a low degree of polymerization.

Example 7 Nitromethane 5 Qm in which 40 g of anhydrous ferric chloride was dissolved
ff was placed under a reduced pressure of 20 mHg, and 13.
Add 8 g carefully so that the internal temperature does not exceed 40°C.

After completion, the mixture was stirred at room temperature under a reduced pressure of 20 g and 11 g for 2 hours. The reaction product was added to 300 mA of methanol at room temperature, stirred for 1 hour, and insoluble matter was filtered off. The insoluble matter was thoroughly washed repeatedly with 2N hydrochloric acid and then with water, and dried at 100° C. in vacuum for 6 hours to obtain 9.2 g of a light brown polymer.

=10- The elemental analysis result of the obtained polymer is C; 7 (1,
14%, H, 5.90%, showing good agreement with the calculated values. The measurement results for i''GA were as follows: 5% weight loss in air: 320°C, 50% i!, 1 weight loss temperature: 550°C, and the intrinsic viscosity [η] was 0.17.

Examples 8 to 13 Dialkoxybenzenes, solvents, and solvents listed in Table 1, respectively.
A polymerization reaction and post-treatment were carried out in the same manner as in Examples 1 to 7 using a Lewis acid, an oxidizing agent, and a cocatalyst. The results are summarized in Table-1.

Comparative Example P - 13.8 g of dimethoxybenzene, 13.4 g of finely crushed aluminum chloride and 6.7 g of anhydrous cupric chloride are mixed in 150 ml of nitrobenzene under water cooling, followed by reaction at 35 DEG C. for 2 hours. The contents of the reactor were poured into 300 ml of methanol, and insoluble matter was collected by filtration. Insoluble matter was thoroughly washed repeatedly with 2N hydrochloric acid, water, 0.2N aqueous sodium hydroxide solution and methanol, and dried at 100° C. under vacuum for 6 hours to obtain a dark brown powdery polymer 4.
Obtain 5g. Elemental analysis result is Ci 68.26%
, H, 5.61%, which was consistent with the calculated value assuming C3H802, and it was found that it contained 5.82% of chlorine atoms.

[Explanation of Table-1] In Table-1, the column for yield and yield is shown in the upper row as yield W (unit: g).
The bottom row shows the yield (%) based on the monomer. The column for elemental analysis shows the observed values in the upper row and the calculated values in parentheses in the lower row. The left side of the same type shows the value of carbon, and the right side shows the value of hydrogen. In addition, in the comparative example, the presence of chlorine was confirmed by elemental analysis, and the value is shown in the table. All TGA was performed in an air atmosphere, the sample size was approximately 5 cm, and the heating rate was 10"7".
This shows the results measured in minutes. Among the same types, the top row is 5
The % weight tM reduction temperature is shown, and the bottom row shows the 50% weight 1 reduction temperature.

All intrinsic viscosities were measured at 37°C in concentrated sulfuric acid, and the concentration (C)
is 0.7 to 0. 1nher measured in the range of +15
This value is obtained by extrapolating the ent viscocHy curve to C=O.

[Brief explanation of the drawing]

Figure 1 shows the infrared absorption spectrum of poly(dimethoxyphenylene) obtained in Example 3 of the present invention. Patent applicant: Dainippon Ink & Chemicals Co., Ltd. 14-

Claims (1)

[Claims] Dialkoxybenzene represented by the general formula (wherein R represents an alkyl group having 1 to 5 carbon atoms) is polymerized in an inert solvent in the presence of a Lewis acid and an oxidizing agent under reduced pressure. A method for producing poly(dialkoxyphenylene) characterized by: