JP2022001559A - Aromatic ketone compound and method for producing the same - Google Patents

Abstract

To provide a high purity aromatic ketone compound which is useful as a raw material of a heat resistant resin and a method for producing the same.SOLUTION: A method for producing an aromatic ketone compound represented by the following formula (A) comprises reacting terephthalic acid chloride and chlorobenzene in the presence of a Friedel-Crafts catalyst at 90°C or less.SELECTED DRAWING: None

Description

The present invention relates to an aromatic ketone compound and a method for producing the same.

Dihalogenated aromatic ketone compounds having a rigid structure are known to be useful as raw materials for highly heat-resistant resins. For example, 4,4'-difluorobenzophenone is used as a raw material for polyetheretherketone (PEEK). Widely used.

It has been reported that an aromatic ketone compound represented by the following formula (A), which is one of such dihalogenated aromatic ketone compounds, can be used as a raw material for aromatic polyetherketone, which is a kind of highly heat-resistant resin. (For example, Non-Patent Document 1).

The aromatic ketone compound (A) can be produced, for example, by a Friedel-Crafts reaction between a terephthalic acid chloride and chlorobenzene (Non-Patent Document 1).

Further, in Patent Document 1, 2.0 mol to 2.3 mol of parachlorbenzotrichloride is reacted per 1 mol of terephthalic acid, and then the reaction product is reacted with 20 to 100 mol of chlorbenzene. A mixture having a molar ratio of 4'-dichlorobenzophenone to 4,4'-dichloroterephthalofenone in the range of 1.8: 1 to 2.2: 1 was synthesized, and after the reaction was completed, the mixture was added to the chlorbenzene solution phase. Disclosed is a production method characterized by separating 4,4'-dichlorobenzophenone and 4,4'-dichloroterephthalophenone in a solid phase.

In Patent Document 2, p-halogenobenzyl halide represented by the general formula (B) and benzene are reacted in the presence of a Friedel-Crafts catalyst to obtain an aromatic dihalide represented by the general formula (C). Next, a method for producing dihalogenoftalofenone represented by the general formula (D), which comprises oxidizing the aromatic dihalide thus obtained with molecular oxygen in the presence of an oxidation catalyst, is disclosed. ing.

^{(X 1} and X ² in the equation are halogen atoms, respectively)

^{(X 1} in the formula has the same meaning as above)

^{(X 1} in the formula has the same meaning as above)

In Patent Document 3, a dehalogenated hydrogen condensation reaction is carried out when an aromatic compound and a trihalogenomethyl-substituted aromatic compound are subjected to a dehalogenation hydrogen condensation reaction, and then the condensation reaction product is hydrolyzed to produce an aromatic ketone. A method for producing an aromatic ketone, which comprises using a crystalline aluminosilicate as a catalyst, is disclosed.

Japanese Unexamined Patent Publication No. 3-161459. Japanese Unexamined Patent Publication No. 3-47145 Japanese Unexamined Patent Publication No. 4-1154

Polymer, Volume 29, Issue 2, 358-369 (1988)

High purity is required for the raw material of the highly heat-resistant resin, and if structural isomers are contained as impurities, it leads to deterioration of the thermal characteristics of the target resin. Therefore, a high-purity aromatic ketone compound (A) and a method for producing the same. Is required.

Although the method described in Non-Patent Document 1 is a method for obtaining an aromatic ketone compound (A), there is room for improvement in terms of suppressing the structural isomers produced. In addition, no information is given regarding the purity or impurity information of the obtained aromatic ketone compound.

Further, the method described in Patent Document 1 requires separation of 4,4'-dichlorobenzophenone and 4,4'-dichloroterephthalofenone to be produced, and there is room for improvement in production efficiency. rice field. Further, the purity of 4,4'-dichloroterephthalofenone has been required to be further improved.

Further, the method described in Patent Document 2 requires a Friedel-Crafts reaction and a multi-step reaction of oxidation with molecular oxygen, and there is room for improvement in the efficiency of repeated steps.

Further, although the method described in Patent Document 3 is a method for obtaining the aromatic ketone compound (A), there is room for improvement in the yield of the product and the selectivity of the structural isomer.

The present invention employs the following means in order to solve such a problem.

That is, the present invention is as follows.
[1] A method for producing an aromatic ketone compound (A) represented by the following formula (A), in which terephthalic acid chloride and chlorobenzene are reacted at 90 ° C. or lower in the presence of a Friedel-Crafts catalyst.

[2] A method for producing an aromatic ketone compound (A), which comprises obtaining an aromatic ketone compound by the method of [1] and then recrystallizing it with an amide solvent.
[3] An aromatic ketone compound (A) represented by the following formula (A) in which the content of structural isomers is less than 1% by weight.

[4] In thermogravimetric analysis (TG), the weight loss rate was more than 99% when heated from 50 ° C. to 450 ° C. at a heating rate of 20 ° C./min in a non-oxidizing atmosphere and held at 450 ° C. for 20 minutes. The aromatic ketone compound (A) according to a certain [3].

According to the present invention, it is possible to provide a high-purity aromatic ketone compound (A) useful as a raw material for a heat-resistant resin and a method for producing the same.

Hereinafter, embodiments of the present invention will be described.

(1) Aromatic ketone compound (A)
The aromatic ketone compound in the present invention is a compound represented by the above formula (A) in which the content of structural isomers calculated from the peak area by gas chromatography is less than 1% by weight. From the viewpoint of being used as a raw material for a heat-resistant resin, the higher the purity is, the more preferable it is, preferably more than 99%, and more preferably 99.5% or more.

(2) Terephthalic acid chloride The terephthalic acid chloride used in the present invention preferably has a high purity, more preferably 90% or more, and more preferably 95%, from the viewpoint of improving the yield of the target product. The above is more preferably 98% or more.

(3) Chlorobenzene In the present invention, chlorobenzene acts as a solvent and a substrate. The chlorobenzene used in the present invention preferably has a high purity, preferably 90% or more, more preferably 95% or more, and further preferably 95% or more, from the viewpoint of improving the yield and purity of the target product. Is over 98%.

(4) Friedel-Crafts catalyst The Friedel-Crafts catalyst used in the present invention is a compound that acts as a catalyst for the Friedel-Crafts reaction. Specific examples include Lewis acid compounds such as aluminum chloride, gallium chloride, iron (III) chloride, titanium chloride (IV) and boron trifluoride, and protonic acid compounds such as sulfuric acid, phosphoric acid and hydrogen fluoride. .. Of these, aluminum chloride is preferably used.

(5) Method for Producing Aromatic Ketone Compound (A) In the present invention, terephthalic acid chloride and chlorobenzene are reacted at 90 ° C. or lower in the presence of a Friedel-Crafts catalyst to produce an aromatic ketone compound (A). Hereinafter, preferred embodiments of the aromatic ketone compound (A) in the present invention will be described in detail.

The amount of the Friedel-Crafts catalyst used in the present invention is preferably 1.5 mol or more, more preferably 2 mol or more, still more preferably 2.5 mol or more, relative to 1 mol of terephthalic acid chloride. The upper limit of the amount of the Friedel-Crafts catalyst used is preferably 10 mol or less, more preferably 8 mol or less, still more preferably 6 mol or less, relative to 1 mol of terephthalic acid chloride. In such a preferable range, the aromatic ketone compound (A) tends to be obtained in a high yield.

The amount of chlorobenzene used in the present invention can be exemplified by 0.2 liters or more and 10 liters or less per mol of terephthalic acid chloride, preferably 0.5 liters or more and 5 liters or less, and more preferably 1 liter or more and 2 liters or less. In such a range, the aromatic ketone compound (A) can be efficiently produced.

In the method for producing the aromatic ketone compound (A) of the present invention, the purity of the aromatic ketone compound (A) and the third component that does not inhibit the reaction other than the terephthalic acid chloride, chlorobenzene and Friedel-Crafts catalyst do not occur. It is also possible to add a third component, a third component that has the effect of accelerating the reaction.

In the method for producing the aromatic ketone compound (A) of the present invention, the order and method of charging the terephthalic acid chloride, chlorobenzene, and Friedel-Crafts catalyst into the reactor are not particularly limited, but since it is an exothermic reaction, it is cooled. It is preferable to mix them in the same state.

The reaction temperature in the method for producing the aromatic ketone compound (A) of the present invention is 90 ° C. or lower, preferably 80 ° C. or lower, and more preferably 75 ° C. or lower. Further, as the lower limit thereof, 0 ° C. or higher can be exemplified, 20 ° C. or higher is more preferable, and 40 ° C. or higher is further preferable. In such a preferable temperature range, it is possible to achieve both higher structural isomer selectivity and shorter reaction time. Further, the reaction may be either a one-stage reaction performed at a constant temperature or a type of reaction in which the temperature is continuously changed.

The reaction time cannot be unconditionally defined because it depends on the reaction temperature, the substrate concentration, and the type of Friedel-Crafts catalyst, but it is preferably 0.5 hours or more, more preferably 1 hour or more. By setting the time to this preferable time or longer, the unreacted raw material component can be reduced, and the yield of the aromatic ketone compound (A) tends to increase. On the other hand, although there is no particular upper limit to the reaction time, the reaction proceeds sufficiently even within 40 hours, and preferably 20 hours or less, more preferably 15 hours or less can be adopted.

The method for carrying out the reaction is not particularly limited, but it is preferable to carry out the reaction under stirring conditions in order to proceed the reaction efficiently. Further, the atmosphere in the production is preferably a non-oxidizing atmosphere, preferably an inert gas atmosphere such as nitrogen, helium, and argon, and a nitrogen atmosphere is preferable from the viewpoint of economy and ease of handling.

(6) Purification Operation In the production of the aromatic ketone compound (A) of the present invention, it is also possible to separate and recover the aromatic ketone compound (A) from the reaction product obtained by the above-mentioned reaction.

The method for separating and recovering the aromatic ketone compound (A) from the reaction product is not particularly limited, and known methods such as washing with water or an organic solvent, filtration, and recrystallization can be adopted. Specifically, after washing with water to remove the inorganic component, the organic component excluding the aromatic ketone compound (A) is removed by using an organic solvent having a low solubility in the aromatic ketone compound (A). An example is a method for obtaining the aromatic ketone compound (A). Further, a method of obtaining an aromatic ketone compound (A) having a higher purity by performing recrystallization can also be adopted.

Here, the amide solvent is preferable as the solvent for performing recrystallization, and specific examples thereof include N-methylpyrrolidone (NMP), dimethylformamide (DMF), dimethylacetamide (DMA), diethylformamide, tetramethylurea, and the like. Hexamethylphosphoramide, 1,3-dimethyl-2-imidazolidinone and the like can be mentioned.

(7) Aromatic ketone compound (A) obtained by the production method of the present invention.
As described above, the aromatic ketone compound (A) having a low content of structural isomers and a low metal residue can be obtained by performing the reaction at 90 ° C. or lower and then performing appropriate purification. Specifically, the content of the structural isomer obtained from the ratio of the peak area by gas chromatography is less than 1% by weight, preferably 0.5% by weight or less, and more preferably 0.1% by weight or less. Is.

The content of structural isomers is calculated from the following formula.
Content of structural isomer (%) = Peak area of structural isomer of aromatic ketone compound (A) / (Peak area of aromatic ketone compound (A) + Peak of structural isomer of aromatic ketone compound (A) Area) x 100

Further, in the production method of the present invention, an aromatic ketone compound (A) having a small amount of residue when kept at a high temperature can be obtained, and in thermogravimetric analysis (TG), the temperature is from 50 ° C to 450 ° C in a non-oxidizing atmosphere. An aromatic ketone compound (A) having a weight loss rate of more than 99% when heated at a heating rate of 20 ° C./min and held at 450 ° C. for 20 minutes is obtained, preferably 99.5% or more. More preferably, it is 99.9% or more.

(8) Use of Aromatic Ketone Compound (A) The aromatic ketone compound (A) thus obtained has few impurities such as metals and structural isomers, and is a highly heat-resistant resin such as aromatic polyetherketone. Can be preferably used as a raw material for.

Hereinafter, the present invention will be specifically described with reference to examples. These examples are exemplary and not limiting.

[Gas Chromatography (GC)]
Equipment: Shimadzu GC-2010
Column: J & W DB-5 0.32 mm x 30 m (0.25 μm)
Carrier gas: Helium detector: Hydrogen flame ionization detector (FID)
The structural isomer content of the aromatic ketone compound (A) is a value calculated by the following formula.
Structural isomer content (%) = peak area of structural isomer of aromatic ketone compound (A) / (peak area of aromatic ketone compound (A) + peak area of structural isomer of aromatic ketone compound (A) ) × 100

[Thermogravimetric analysis (TG)]
Equipment: TGA7 manufactured by PerkinElmer
Measurement atmosphere: Nitrogen airflow temperature rise program:
(A) Holding at a program temperature of 50 ° C. for 1 minute (b) Heating from a program temperature of 50 ° C. to 450 ° C. at a heating rate of 20 ° C./min (c) Holding at a program temperature of 450 ° C. for 20 minutes Weight reduction rate: 1 at 50 ° C. The weight loss rate was calculated from the weight after holding for 20 minutes at 450 ° C. based on the weight after holding for minutes.

[Example 1]
<Synthesis process>
Aluminum chloride (26.65 g, 0.20 mol) and chlorobenzene (35 mL, 0.35 mol) were added to a 300 mL three-necked eggplant flask equipped with a dropping funnel, and the mixture was cooled in an ice bath. A solution of terephthalic acid chloride (10.15 g, 0.050 mol) in chlorobenzene (60 mL, 0.59 mol) was added to the dropping funnel, and the mixture was slowly added dropwise under a nitrogen gas stream. At this time, the total amount of chlorobenzene used is 1.9 liters per mole of terephthalic acid. After completion of the dropping, the reaction vessel was returned to room temperature under a nitrogen gas stream, stirred for 30 minutes, then heated to 65 ° C. in an oil bath and reacted for 7 hours.

The obtained reaction solution was poured into a 500 mL aqueous hydrochloric acid solution, the aqueous layer was removed, methanol (400 mL) was added to the organic layer, the mixture was stirred, and the precipitated solid was recovered by filtration. The solid was washed again with methanol, collected by filtration and dried under vacuum. As a result of analyzing the obtained product by GC, the structural isomer content was 2.3% and the yield was 90%.

By comparing with the result of Comparative Example 1, it was found that the formation of structural isomers can be suppressed by carrying out the reaction at 90 ° C. or lower.

<Recrystallization process>
75 mL of NMP was added to 10 g of the above crude product, heated to 175 ° C. to dissolve, allowed to cool to room temperature, and the precipitated solid was recovered by filtration and vacuum dried.

As a result of analyzing the obtained solid by GC, the structural isomer content was 0.1%. Further, in thermogravimetric analysis (TG), the weight loss rate was 100% when heated from 50 ° C. to 450 ° C. at a heating rate of 20 ° C./min under a nitrogen atmosphere and held at 450 ° C. for 20 minutes. It was confirmed that no non-volatile impurities were contained.

[Comparative Example 1]
<Synthesis process>
Here, an example in which the reaction was carried out in the same manner as in Example 1 is shown except that the reaction was carried out at 95 ° C. for 3 hours.

As a result of analyzing the product obtained under these conditions by GC, the structural isomer content was 3.6% and the yield was 85%.

Claims (4)

A method for producing an aromatic ketone compound (A) represented by the following formula (A), in which terephthalic acid chloride and chlorobenzene are reacted at 90 ° C. or lower in the presence of a Friedel-Crafts catalyst.

A method for producing an aromatic ketone compound (A), which comprises obtaining an aromatic ketone compound by the method of claim 1 and then recrystallizing the aromatic ketone compound with an amide solvent. The aromatic ketone compound (A) represented by the following formula (A) having a structural isomer content of less than 1% by weight.

Claimed in thermogravimetric analysis (TG) that the weight loss rate is more than 99% when heated from 50 ° C. to 450 ° C. at a heating rate of 20 ° C./min in a non-oxidizing atmosphere and held at 450 ° C. for 20 minutes. 3. The aromatic ketone compound (A) according to 3.