JPH0541624B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a method for producing aromatic dicarboxylic acid chlorides. More specifically, a trichloromethyl-substituted phenyl ether is produced by photochlorinating a methyl-substituted phenyl ether, and then a carboxylic acid is produced by reacting the trichloromethyl group with a carboxyl group. This invention relates to a method for producing chloride.

[Industrial Application Fields] Aromatic dicarboxylic acid chlorides are mainly used as polymer raw materials. Examples of derived polymers include polyester, polyamide, polyimide, etc., but it is especially used as a raw material for polymers with excellent properties such as strength and heat resistance, such as arylate, wholly aromatic polyamide, and wholly aromatic polyimide. Particularly when a plurality of carboxylic acid components are used in a copolymer, this method simultaneously produces all the necessary aromatic dicarboxylic acid chlorides.

[Prior Art] Many proposals have been made regarding methods for producing trichloromethyl-substituted aromatic hydrocarbons by photochlorination reactions of aromatic hydrocarbons, particularly methods for producing hexachloroxylenes. When chlorinating using free chlorine under UV irradiation, the following two side reactions occur. One is the generation of resinous substances, and the other is the generation of nuclear substituted chlorides. These side reaction products not only reduce the yield, but also
This makes industrial production difficult, such as stopping the reaction due to coloring of the reaction solution and reducing product purity. Ureas (Japanese Unexamined Patent Publication No. 129525/1982), phosphoramides (Japanese Unexamined Patent Publication No. 8221/1982), and lactams (Unexamined Japanese Patent Application No. 98225/1982) are used as photochlorination stabilizers to suppress the generation of resinous substances. JP-A-58-135826), carbamate ester derivatives (JP-A-58-135826), etc. have been proposed. It has also been shown that iron chloride (Japanese Unexamined Patent Publication No. 77022/1983) is effective in suppressing the generation of nuclear-substituted chlorides.

As methods for producing aromatic dicarboxylic acid chlorides, two methods are generally used industrially. One is a method in which an aromatic dicarboxylic acid is reacted with a bistrichloromethyl-substituted aromatic compound, and the other is a method in which an aromatic dicarboxylic acid is reacted with phosphorus pentachloride, phosphorus trichloride, thionyl chloride, or phosgene. This method involves reacting with a chlorinating agent such as In particular, if an aromatic dicarboxylic acid and a bistrichloromethyl-substituted aromatic compound having substituents at the same position are used, this method is economically and technically very effective. A method for producing terephthalic acid chloride and isophthalic acid chloride from terephthalic acid and hexachloroparaxylene, and from isophthalic acid and hexachloromethacylene is described in JP-A-51-
This method has been proposed in Publication No. 105027 and Japanese Patent Application Laid-open No. 53-53636. Furthermore, as a method for producing an equimolar mixture of terephthalic acid chloride and isophthalic acid chloride, JP-A-53-121733 proposes reacting terephthalic acid and hexachloromethaxylene or isophthalic acid and hexachloroparaxylene. . Since this method uses raw materials that differ only in the position of the substituent, it is possible to adopt exactly the same reaction conditions as when using an aromatic dicarboxylic acid and a bistrichloromethyl-substituted aromatic compound that have substituents in the same position. I can do it.

[Object of the Invention] In the photochlorination of aromatic side chain methyl groups, the present inventor discovered that aromatic side chain methyl groups having certain oxygen-containing substituents are extremely easily photochlorinated under certain conditions. I discovered that. Free chlorine generates chlorradical when exposed to ultraviolet rays. Chlorradical modifies the aromatic side chain methyl group, replacing the hydrogen atom with a chlorine atom and converting it into a chloromethyl-substituted aromatic compound. It is extremely interesting that a compound such as a phenoxy group that has an oxygen atom and the oxygen atom is adjacent to a conjugated system easily undergoes such a photochlorination reaction. Furthermore, in producing aromatic dicarboxylic acid chloride, the present inventor uses an aromatic dicarboxylic acid and a bistrichloromethyl-substituted aromatic compound, which have completely different structures, as raw materials to easily and easily produce aromatic dicarboxylic acid chloride, which has completely different structures. The present invention was arrived at as a result of extensive research into a method for simultaneously obtaining both in good yield and at the same time. In particular, even with aromatic compounds such as phenoxy groups, which have electronic substituent effects different from those of carboxyl groups and trichloromethyl groups, the reaction occurs easily and in good yields, and decomposition and elimination of phenoxy groups hardly occur. This is what I found.

[Structure of the Invention] The present invention comprises (A) the following general formula [] [However, in the formula, n represents 0 or 1, and when it is 0, it represents a bond. Furthermore, the two bonds in each benzene ring are not located at ortho positions to each other in the benzene ring. ] The methyl-substituted phenyl ethers represented by are photochlorinated to form the following general formula [] [However, in the formula, the definitions of n and the position of the bond in each benzene ring are the same as in the above general formula []. ] A reaction mixture containing a chloromethyl-substituted phenyl ether represented by the formula [ ] is reacted with a chloromethyl-substituted phenyl ether of the general formula [ ] [However, in the formula, the definitions of n and the position of the bond in each benzene ring are the same as in the above general formula []. ] This is a method for producing a carboxylic acid chloride consisting of phenyl ether carboxylic acid chloride represented by the following and terephthalic acid chloride and/or isophthalic acid chloride.

The present invention will be explained in more detail below.

The method of the present invention is carried out by introducing chlorine gas into the methyl-substituted phenyl ether represented by the above general formula [] in a liquid state, ie, a molten state or a solution state, under irradiation with ultraviolet-containing light. The solvent used is a chlorinated hydrocarbon that is inert to the photochlorination reaction.
For example, chlorinated paraffins such as chloroform, carbon tetrachloride, dichloroethane, trichloroethane, and tetrachloroethane, and chlorinated aromatic compounds such as chlorobenzene are preferred. The concentration of methyl-substituted phenyl ether is preferably 5% or more by weight.

The ultraviolet-containing light may be light with a wavelength that activates chlorine, such as sunlight, discharge lamps, and incandescent lamps. In particular, indium lamps, low-pressure mercury lamps, high-pressure mercury furnaces, and ultra-high-pressure mercury furnaces are suitable for industrial use. It's advantageous.

The reaction temperature is preferably 50°C or higher and lower than the boiling point of the solvent. At temperatures below 50℃, the reaction rate is very slow.
Additionally, since the amount of dissolved chlorine increases, bumping may occur once the reaction starts. Even if the temperature is below the boiling point of the solvent, if the temperature is above 150°C, side reactions will increase and the yield will drop significantly.

The reaction time is 10 minutes to 100 hours, usually about 1 to 8 hours. At the same time as the reaction starts, the raw materials begin to decrease, but monochloro derivatives are produced first.
Next, dichlor derivatives and trichlor derivatives are sequentially produced and disappear, and the desired perchlor derivative, that is, trichloromethyl-substituted phenyl ethers, is finally produced. The reaction proceeds until hydrogen chloride, which is generated when the substituted hydrogen combines with chlorine, stops being generated.

Use of the photochlorination stabilizers and nuclear chlorination inhibitors described above to suppress side reactions often brings about favorable results.

The chlorine gas used can be liquefied chlorine gas filled in a cylinder or chlorine generated at an electrolytic factory and directly introduced into the reactor, but chlorine gas that is normally used industrially can also be used. . The amount of chlorine gas to be introduced should be equivalent or more, but if it exceeds twice the equivalent amount, it will not only be economically disadvantageous, but also side reactions will increase, resulting in a decrease in yield and the desired chloromethyl substitution. 1.05 times the equivalent amount or
A range of 1.5 times is preferred.

The chloromethyl-substituted phenyl ether obtained by the method of the present invention is then reacted with terephthalic acid and/or isophthalic acid in the presence of a Friedel-Crafts catalyst as described below. In addition, the chlorinated hydrocarbon used as a solvent in the photochlorination reaction can be distilled off, or it can be used as a solvent in the disproportionation reaction without being distilled off. be. Such solvents include
Examples include chlorinated hydrocarbons that are inert to the photochlorination reaction and the disproportionation reaction, such as carbon tetrachloride,
Chlorinated paraffins such as dichloroethane, trichloroethane, and tetrachloroethane and chlorinated aromatic compounds such as chlorobenzene are preferred. The total amount of chloromethyl-substituted phenyl ether, terephthalic acid, and isophthalic acid relative to the solvent is 20%.
The above is preferable.

As the Friedel-Crafts catalyst, chlorides of aluminum, antimony, iron, titanium, tin, and zinc are used, and ferric chloride is particularly preferably used. The amount of catalyst is 0.005% to 5% by weight, preferably 0.1% to 2.50%, based on the total amount of chloromethyl-substituted phenyl ether, terephthalic acid, and isophthalic acid.

The ratio of trichloromethyl-substituted phenyl ether to terephthalic acid and/or isophthalic acid must be set so that the number of chloromethyl groups and the number of carboxyl groups are approximately equal, and the ratio is 1:0.95 to 1:1.05. If so, it is sufficient.

The reaction temperature is 100 to 250°C. At temperatures lower than 100°C, the reaction rate is too slow due to the low solubility of terephthalic acid and isophthalic acid, making it industrially impractical. If the temperature is higher than 250°C, desorption of chlorine and generation of tar-like substances occur, resulting in a decrease in yield.
The preferred reaction temperature is 150°C to 230°C.

The reaction time is 10 minutes to 100 hours, usually about 1 to 8 hours. The reaction between a trichloromethyl group and a carboxyl group generates two molecules of chlorocarbonyl group and one molecule of chlorine hydrogen. Therefore, the reaction must continue until the evolution of hydrogen chloride has ceased.

After the reaction is completed as described above, the target product is recovered and produced by removing the solvent, distilling, and crystallizing as necessary. The phenyl ether carboxylic acid chloride and the terephthalic acid chloride and/or the isophthalic acid chloride can be recovered as a mixture, or the terephthalic acid chloride and/or the isophthalic acid chloride can be first separated and then the phenyl ether carboxylic acid chloride can be recovered. can. Hydrocarbons containing paraffins such as hexane and heptane, and chlorinated hydrocarbons such as carbon tetrachloride or chlorobenzene are used for crystallization and purification of phenyl ether carboxylic acids.

[Effects of the Invention] According to the method of the present invention, phenyl ether carboxylic acid is produced using chloromethyl-substituted phenyl ethers obtained by photochlorinating metal-substituted phenyl ethers having a substituent such as a phenoxy group as a raw material. An equimolar mixture of chloride and terephthalic acid chloride and/or isophthalic acid chloride can be easily obtained with good yield.

The present invention will be described in detail below with reference to Examples.

[Example] 100 g (0.504 mol) of 3,4'-dimethyl diphenyl ether, 1,
Add 250ml of 1,2,2-tetrachloroethane,
Equipped with a cooler, stirrer, chlorine injection tube, thermometer, high-pressure mercury furnace (UM-102 model manufactured by Ushio Inc.), and lamp cooler, the internal temperature was raised to 70℃ in an oil bath and irradiated with light. Then I blew chlorine into it. The chlorine gas blowing rate was 300 ml/min, and the reaction time was 4 hours and 30 minutes. After the reaction was completed, nitrogen gas was introduced at 100 ml/min for 10 minutes to purge unreacted chlorine gas and dissolved by-produced chlorine hydrogen. Transfer the reaction mixture to a 500ml eggplant flask and add 85g of terephthalic acid thereto.
(0.506 mol) and 2.5 g (0.015 mol) of anhydrous iron chloride were added, and the temperature was raised in an oil bath while stirring with a magnetic stirrer. The reaction was completed by refluxing the solvent for 4 hours. 50-60℃/15 after reaction completion
Distill the solvent at ~20 mmHg and further heat at 105-115℃/1
Terephthalic acid chloride 95g (0.468
mole) was obtained. Add 150% carbon tetrachloride to this distillation residue.
Add ml, heat, separate insoluble matter, cool, and 3.
4'-Diphenyl ether carboxylic acid chloride
115 g (0.390 mol) was obtained. The yield was 77%.
Furthermore, this was distilled at 185-190℃/0.5mmHg and 109
I got g. The yield was 73%.

Claims (1)

[Claims] 1 (A) The following general formula [] [However, in the formula, n represents 0 or 1, and when it is 0, it represents a bond. Furthermore, the two bonds in each benzene ring are not located at ortho positions to each other in the benzene ring. ] The methyl-substituted phenyl ethers represented by are photochlorinated to form the following general formula [] [However, the definitions of n in the formula and the position of the bond in each benzene ring are the same as in the above general formula []. ] Obtain a reaction mixture containing a chloromethyl-substituted phenyl ether represented by (B) Then, terephthalic acid and/or isophthalic acid is added to the reaction mixture, and in the presence of a Friedel-Crafts catalyst, a reaction mixture containing a chloromethyl-substituted phenyl ether is obtained. The following general formula [] is characterized by a homogenization reaction with a chloromethyl-substituted phenyl ether of [However, the definitions of n in the formula and the position of the bond in each benzene ring are the same as in the above general formula []. ] A method for producing a carboxylic acid chloride consisting of phenyl ether carboxylic acid chloride represented by the following and terephthalic acid chloride and/or isophthalic acid chloride. 2. The production method according to item 1, wherein the chlorination and homogenization reactions are carried out in the same solvent. 3. The method for producing chloromethyl-substituted phenyl ethers according to item 1, wherein the chlorination is carried out at a temperature in the range of 50°C or higher and 150°C or lower. 4. The method for producing a carboxylic acid chloride according to item 1, wherein the carboxylic acid and the chloromethyl-substituted phenyl ether are brought into contact at a temperature in the range of 100°C to 250°C. 5. The production method according to item 1, wherein the homogenization reaction is carried out in the presence of an iron catalyst.