KR20160108336A - Method for producing cyclobutane tetracarboxylic acid derivative - Google Patents

Abstract

(식 중, R 은 탄소수 1 ∼ 20 의 알킬기를 나타낸다.)A process for efficiently producing a 1,2,3,4-cyclobutane tetracarboxylic acid-1,2: 3,4-2 anhydride derivative useful as a raw material for polyimide and the like. A 1,2,4,4-cyclobutanetetracarboxylic acid-1,2-dicarboxylic acid represented by the formula (2) by subjecting a maleic anhydride compound represented by the following formula (1) to a photo-dimerization reaction in a carbonate diester solvent : Preparation of 3,4-2 anhydride derivatives.
[Chemical Formula 1]

(In the formula, R represents an alkyl group having 1 to 20 carbon atoms.)

Description

TECHNICAL FIELD [0001] The present invention relates to a process for producing a cyclobutane tetracarboxylic acid derivative,

The present invention relates to a process for producing an alicyclic tetracarboxylic acid dianhydride which can be a raw material monomer such as polyamic acid or polyimide for an optical material.

In general, polyimide resins are widely used as electronic materials such as protective materials and insulating materials in liquid crystal display elements and semiconductors due to their high mechanical strength, heat resistance, insulating properties, solvent resistance and the like. Further, in recent years, the use of such materials as optical communication materials for optical waveguides is also expected.

In recent years, developments in this field have been noticeable and, correspondingly, increasingly sophisticated characteristics are required for the materials used. That is, it is expected not only to have excellent heat resistance and solvent resistance, but also to have a number of performances depending on the application.

However, in particular, in all-aromatic polyimide resins, since they exhibit a deep amber color and are colored, they have a problem in applications requiring high transparency.

On the other hand, as one method of realizing transparency, when a polyimide precursor is formed by a polycondensation reaction of an alicyclic tetracarboxylic acid dianhydride and an aromatic diamine, and the polyimide is imidized by imidizing the precursor, And polyimide having high transparency can be obtained (see Patent Documents 1 and 2).

Conventionally, in the synthesis of alkylcyclocubic acid dianhydrides, as shown by the following scheme, by optical dimerization reaction of citraconic anhydride (abbreviated as MMA), 1,3-dimethylcyclobutane-1,2 , 3,4-tetracarboxylic acid-1,2: 3,4-2 anhydride (abbreviated as 1,3-DM-CBDA) and 1,2-dimethylcyclobutane-1,2,3,4-tetra A mixture of carboxylic acid-1,2: 3,4-2 anhydride (abbreviated as 1,2-DM-CBDA) is obtained (see Patent Document 3).

[Chemical Formula 1]

On the other hand, when 1,3-DMCBDA and 1,2-DMCBDA are compared to each other, 1,3-DMCBDA having an electron with a high symmetry structure can produce polyimide having a higher molecular weight than the latter 1,2-DMCBDA And is known to have a higher usability.

However, Patent Document 3 discloses that a mixture of 1,3-DMCBDA and 1,2-DMCBDA is obtained. However, 1,3-DMCBDA, which is an isomer having high availability, is selectively and highly produced There is no description about thing.

Japanese Patent Publication No. 2-24294 Japanese Patent Application Laid-Open No. 58-208322 Japanese Unexamined Patent Publication No. 4-106127

An object of the present invention is to provide a process for producing a 1,3-dialkyl-substituted maleic anhydride, which is an isomer having a structure with high symmetry at high light reaction efficiency and high yield by subjecting a maleic anhydride compound represented by the following formula (1) 1,2,3,4-cyclobutane tetracarboxylic acid-1,2: 3,4-2 anhydride (hereinafter, also referred to as 1,3-DACBDA) derivatives.

DISCLOSURE OF THE INVENTION The inventors of the present invention have conducted intensive studies in order to solve the above problems. As a result, it has been found that when a specific solvent is used, the selectivity of the 1,3-DACBDA derivative, which is an isomer having a highly symmetrical structure, I found out I could.

The present invention is based on this new knowledge, and has the following points.

1. A process for producing a 1,2,3,4-cyclobutanetetracarboxylic acid represented by the formula (2), which comprises subjecting a maleic anhydride represented by the following formula (1) to a photo-dimerization reaction in a carbonate diester solvent -1,2: Process for producing 3,4-2 anhydride derivative.

(2)

(In the formula, R represents an alkyl group having 1 to 20 carbon atoms.)

2. The method according to the above 1, wherein R is an alkyl group having 1 to 4 carbon atoms.

3. The production method according to the above 1 or 2, wherein the carbonic acid diester is a diester of alkyl having 1 to 4 carbon atoms in carbonic acid.

4. The production process according to any one of the above-mentioned 1 to 3, wherein the carbonic acid diester is dimethyl carbonate or diethyl carbonate.

Wherein the solvent is at least one selected from the group consisting of methyl formate, ethyl formate, methyl acetate, ethyl acetate, n-propyl acetate, i-propyl acetate, methyl propionate, ethyl propionate, n- propyl propionate, The production process according to the above 4, wherein the solvent contains a solvent other than carbonic acid diester which is ethylene glycol diacetate.

6. The production method according to any one of 1 to 5 above, wherein the total amount of the solvent used in the reaction is 3 to 300 times the amount of the maleic anhydride compound.

7. The production method according to any one of 1 to 5 above, wherein the amount of the total solvent used in the reaction is 3 to 10 mass times the amount of the maleic anhydride compound.

8. The production method according to any one of the above-mentioned 1 to 7, wherein a sensitizer is used.

9. The production method according to the above 8, wherein the sensitizer is benzophenone, benzaldehyde, benzophenone substituted with electron-withdrawing group, acetophenone substituted with electron-withdrawing group, benzaldehyde substituted with electron-withdrawing group, or anthraquinone.

10. The production method according to the above 9, wherein the electron-attractive group is at least one selected from the group consisting of a fluoro group, a chloro group, a bromo group, an iodo group, a nitro group, a cyano group and a trifluoromethyl group.

11. The production method according to the above 9 or 10, wherein the number of electron-attracting groups is 1 to 5.

12. The production method according to any one of 8 to 11 above, wherein the amount of the sensitizer used is 0.1 to 20 mol% based on the maleic anhydride compound.

13. The production method according to any one of 1 to 12 above, wherein the reaction temperature is 0 to 20 占 폚.

According to the production process of the present invention, in the production of the 1,2,3,4-cyclobutane tetracarboxylic acid-1,2: 3,4-2 anhydride derivative by the photo-dimerization reaction of the maleic anhydride compound, The selectivity of 1,3-dialkylcyclobutane-1,2,3,4-tetracarboxylic acid-1,2: 3,4-2 anhydride can be improved.

Hereinafter, the present invention will be described in more detail.

The 1,2,3,4-cyclobutane tetracarboxylic acid-1,2: 3,4-2 anhydride derivative represented by the formula (2) by the photo-dimerization reaction of the maleic anhydride compound represented by the formula (1) The production method is shown by the following reaction scheme.

(3)

In the formulas, R represents an alkyl group having 1 to 20 carbon atoms, more preferably 1 to 12 carbon atoms, and particularly preferably 1 to 6 carbon atoms.

As the alkyl group having 1 to 20 carbon atoms, a linear or branched saturated alkyl group or a linear or branched unsaturated alkyl group may be used.

Specific examples thereof include a methyl group, an ethyl group, a n-propyl group, an i-propyl group, an i-butyl group, an i- n-butyl, 3-methyl-n-butyl, 1,1-dimethyl-n- Butyl, 1-ethyl-n-butyl, 1,1,2-trimethyl-n-propyl, n-heptyl, n-octyl, n-nonyl, Alkyl group, 1-methylvinyl, 2-allyl, 1-ethylvinyl, 2-methylallyl, 2-butenyl, Butenyl, 2-hexenyl, 4-methyl-3-pentenyl, 4-methyl-4-pentenyl, , Propargyl, 3-butynyl, 3-methyl-2-propynyl, 9-decynyl and the like.

In addition, n represents normal, i represents iso, s represents secondary, and t represents tertiary.

Examples of the maleic anhydride compound represented by the formula (1) include anhydrides such as citraconic anhydride, 2-ethyl maleic anhydride, 2-isopropyl maleic anhydride, 2-n-butyl maleic anhydride, 2-n-hexyl maleic anhydride, 2-n-hexyl maleic anhydride, 2-n-hexyl maleic anhydride, 2- maleic anhydride, 2- (2-allyl) maleic anhydride, 2-n-octyl maleic anhydride, 2- Maleic anhydride, 2- (2-hexenyl) maleic anhydride, 2- (2-methylhexyl) maleic anhydride, 2- Maleic anhydride, 2- (3-butenyl) maleic anhydride, 2- (3-dodecenyl) maleic anhydride, 2- 3-methyl-2-propynyl) maleic anhydride, and 2- (9-decynyl) maleic anhydride.

Among these, from the viewpoint that the photoreaction proceeds efficiently, it is preferable to use an acid anhydride such as citraconic anhydride, 2-ethylmaleic anhydride, 2-isopropylmaleic anhydride, 2-n-butylmaleic anhydride, 2-n-hexyl maleic anhydride, 2-n-octyl maleic anhydride, 2-n-nonyl maleic anhydride, 2-n-hexyl maleic anhydride, 2-n-butyl maleic anhydride, 2-n-butyl maleic anhydride, 2-n-butyl maleic anhydride, 2-n-butyl maleic anhydride, t-butyl maleic anhydride, 2-n-pentyl maleic anhydride, or 2-n-hexyl maleic anhydride.

The reaction solvent plays an important role in the photoreaction, and the reaction solvent is a carbonic acid diester. The carbonic acid diester is preferably an alkyl diester in which the carbon number of carbonic acid is preferably 1 to 4, more preferably 1 to 3, and particularly preferably 1 or 2. Specifically, dimethyl carbonate or diethyl carbonate is preferable, and dimethyl carbonate is particularly preferable.

In the present invention, a carbonic acid diester and a minor solvent other than carbonic acid diester may be used in combination. Examples of the solvent include methyl formate, ethyl formate, n-propyl formate, i-propyl formate, n-butyl formate, i-butyl formate, methyl acetate, ethyl acetate, n- Butyl propionate, i-butyl propionate, ethylene glycol diformate, ethylene glycol diacetate, ethylene glycol dipropionate, ethyleneglycol dipropionate, ethyleneglycol dipropionate And the like.

Of these, more preferred solvents are methyl formate, ethyl formate, methyl acetate, ethyl acetate, n-propyl acetate, i-propyl acetate, methyl propionate, ethyl propionate, n- propyl propionate, Mate, ethylene glycol diacetate and the like, and the most preferable solvent is ethyl acetate.

An excellent feature of the method for producing a DACBDA derivative using a carbonic acid diester as a solvent is that the solubility of the resulting CBDA compound is low and precipitates as crystals even though the solubility of the maleic anhydride compound as a raw material is high, It is possible to suppress side reactions such as reverse reaction or oligomer formation from the maleic anhydride compound.

The amount of the solvent to be used is 3 to 300 mass times, more preferably 3 to 250 mass times, relative to the maleic anhydride compound.

The amount of the reaction solvent to be used is preferably small when the reaction is intended to be accelerated or when the amount of the product is to be increased. For example, when the concentration of the maleic anhydride compound is increased, the reaction is accelerated, The quantity increases. Therefore, when the reaction is intended to be accelerated or when the amount of the product is to be increased, the amount of the solvent to be used is preferably 3 to 10 mass times the amount of the maleic anhydride compound.

In the present light reaction, the wavelength of the light is 200 to 400 nm, more preferably 250 to 350 nm, and particularly preferably 280 to 330 nm. As the light source, a low pressure mercury lamp, a medium pressure mercury lamp, a high pressure mercury lamp, an ultra high pressure mercury lamp, a xenon lamp, an electrodeless lamp, a light emitting diode and the like are preferable in terms of giving a CBDA derivative compound specifically. Among them, high-pressure mercury lamps, ultra-high-pressure mercury lamps, or light-emitting diodes are preferable.

Further, by changing the light source cooling pipe from quartz glass to Pyrex (registered trademark) glass as a photochemical reaction device, adhesion of colored polymer to the light source cooling pipe and impurities are reduced, and the yield of the CBDA derivative compound can be improved desirable.

The reaction temperature is preferably -20 to 80 占 폚, more preferably -20 to 80 占 폚, from the viewpoints of the byproducts of the polymerisation at a high temperature and the lowering of the solubility of the maleic anhydride compound at a low temperature, 10 to 50 ° C. Particularly, in the temperature range of 0 to 20 占 폚, generation of by-products is largely suppressed, and CBDA derivative compounds are obtained with high selectivity and yield.

The reaction time varies depending on the amount of the maleic anhydride compound, the kind of the light source, the amount of irradiation, etc., but is carried out for a period of time until the unreacted maleic anhydride compound reaches 0 to 40%, preferably 0 to 10% can do.

Specifically, the reaction time is determined by using a high-pressure mercury lamp or a light-emitting diode as a light source, using dimethyl carbonate or ethyl acetate as a reaction solvent, and using 4,4'-difluorobenzophenone or 4,4'- Dichlorobenzophenone is used for 1 to 200 hours, preferably 1 to 100 hours, and more preferably 1 to 60 hours under the condition of the reaction temperature range of 0 to 20 ° C.

The conversion can be obtained by analyzing the reaction solution by gas chromatography or the like.

When the conversion time of the maleic anhydride compound becomes high and the precipitation amount of the CBDA derivative compound increases, the resulting CBDA derivative compound starts to adhere to the outer wall (reaction liquid side) of the light source cooling tube, And the light efficiency (yield per unit electric power x hour) is lowered. Therefore, in order to increase the conversion rate of the maleic anhydride compound, it is not preferable to add a long period of time in one batch, accompanied with a decrease in production efficiency in practical use.

In addition, although the reaction can be carried out batchwise or flow-through, the batch-type is preferably used.

The pressure at the time of the reaction may be either normal pressure or pressurized pressure. Preferably, it is normal pressure.

The production method of the present invention may also be carried out by adding a sensitizer. Examples of the sensitizer include benzophenone, benzaldehyde, anthraquinone, benzophenone substituted with an electron-withdrawing group, acetophenone substituted with an electron-withdrawing group, and benzaldehyde substituted with an electron-withdrawing group.

Examples of the electron-withdrawing group include at least one member selected from the group consisting of a fluoro group, a chloro group, a bromo group, an iodo group, a nitro group, a cyano group, and a trifluoromethyl group, , A bromo group, a cyano group, and a trifluoromethyl group are preferable. Particularly preferred electron-attracting groups are a fluoro group or a chloro group.

The number of electron-withdrawing groups is 1 to 10, preferably 1 to 5, and preferably 1 to 3 in view of the effects of the present invention.

The substitution position of the electron-withdrawing group may be an ortho, meta, or para position with respect to the carbonyl group, but is preferably an ortho or para position.

When the number of electron-withdrawing groups is two or more, the electron-withdrawing groups may be the same or different from each other. In addition, the case where two electron-attracting groups substituted at the ortho position become one to form a carbonyl group (anthraquinone).

Specific examples of benzophenone substituted with benzophenone and electron-attracting group include benzophenone, 2-fluorobenzophenone, 3-fluorobenzophenone, 4-fluorobenzophenone, 2-chlorobenzophenone, 3- 2-nitrobenzophenone, 2-nitrobenzophenone, 4-nitrobenzophenone, 2-cyanobenzophenone, 4-cyanobenzophenone, 4'-dichlorobenzophenone, 4,4'-difluorobenzophenone, 4,4'-dichlorobenzophenone, 4,4'-dibromobenzophenone, 3,3'-bis (trifluoromethyl) Benzophenone, 3,4'-dinitrobenzophenone, 3,3'-dinitrobenzophenone, 4,4'-dinitrobenzophenone, 2-chloro-5-nitrobenzophenone, 1,3-bis Benzene, 1,3-dibenzoyl-4,6-dinitrobenzene, anthraquinone, and the like can be used. have.

Of these, 4,4'-difluorobenzophenone, 4,4'-dichlorobenzophenone and the like are preferable.

Specific examples of acetophenone substituted with acetophenone and electron-withdrawing group include acetophenone, 2'-fluoroacetophenone, 3'-fluoroacetophenone, 4'-fluoroacetophenone, 2'-chloroacetophenone , 3'-chloroacetophenone, 4'-chloroacetophenone, 2'-cyanoacetophenone, 3'-cyanoacetophenone, 4'-cyanoacetophenone, 2'-nitroacetophenone, 3'-nitro 2 ', 4'-dichloroacetophenone, 3'4'-difluoroacetophenone, 3'4'-difluoroacetophenone, 2'4'-dichloroacetophenone, Dichloroacetophenone, 4'-chloro-3'-nitroacetophenone, 4'-bromo-3'-nitroacetophenone, and 4'-fluoro-3'-nitroacetophenone.

Among these, 4'-fluoroacetophenone, 4'-chloroacetophenone, 2 ', 4'-difluoroacetophenone, 3', 4'-difluoroacetophenone, 2 ', 4'- Acetophenone, or 3 ', 4'-dichloroacetophenone are preferable.

Examples of the benzaldehyde and the benzaldehyde substituted by the electron-withdrawing group include benzaldehyde, 2-fluorobenzaldehyde, 3-fluorobenzaldehyde, 4-fluorobenzaldehyde, 2- chlorobenzaldehyde, 3- 4-nitrobenzaldehyde, 4-nitrobenzaldehyde, 4-nitrobenzaldehyde, 4-nitrobenzaldehyde, 2-cyanobenzaldehyde, 4-cyanobenzaldehyde, Dichlorobenzaldehyde, 3,4-dichlorobenzaldehyde, 2-chloro-5-nitrobenzaldehyde, 4-chloro-2-nitrobenzaldehyde, 3,4-dichlorobenzaldehyde, 3,4-dichlorobenzaldehyde, , 4-chloro-3-nitrobenzaldehyde, 5-chloro-2-nitrobenzaldehyde, 2-fluoro-5-nitrobenzaldehyde, Nitro There may be mentioned's aldehyde and the like.

Among them, 4-fluorobenzaldehyde, 4-chlorobenzaldehyde, 2,4-difluorobenzaldehyde, 3,4-difluorobenzaldehyde, 2,4-dichlorobenzaldehyde, Dichlorobenzaldehyde and the like are preferable.

The amount of the sensitizer to be used is not particularly limited, but is preferably from 0.1 to 20 mol%, more preferably from 0.1 to 5 mol%, based on the maleic anhydride compound, as long as the photoreaction rate accelerates.

The benzophenone derivative, the acetophenone derivative or the benzaldehyde derivative may be used alone or in combination of at least one of the benzophenone derivatives and the benzaldehyde derivatives described above. However, from the viewpoint of ease of treatment after the reaction, desirable.

The objective compound is obtained by filtering the precipitate in the reaction solution after the photoreaction, washing the filtrate in an organic solvent, and drying under reduced pressure.

The amount of the organic solvent used for washing the filtrate should be such an amount as to allow the precipitate remaining in the reaction vessel to be transferred to the filter. If the amount of the organic solvent is large, the desired product is converted into the filtrate. Therefore, the amount of the organic solvent used for washing the filtrate is preferably from 0.5 to 10 times by weight, and more preferably from 1 to 2 times by weight, based on the maleic anhydride compound used in the reaction.

The organic solvent used for cleaning the filtrate is not particularly limited, but the use of a solvent having a high solubility of the product is not preferable because the objective compound is converted into the filtrate and the recovery rate is lowered. Therefore, examples of the organic solvent used for washing the filtrate include organic solvents such as methyl formate, ethyl formate, n-propyl formate, i-propyl formate, n-butyl formate, i- Butyl acetate, i-propyl acetate, n-butyl acetate, i-butyl acetate, methyl propionate, ethyl propionate, n-propyl propionate, i-propyl propionate, n-butyl propionate, such as i-butyl, ethylene glycol diformate, ethylene glycol diacetate, ethylene glycol dipropionate, dimethyl carbonate, diethyl carbonate, etc., or a solvent that does not react with the product and does not react with the product such as toluene, , Heptane, acetonitrile, acetone, chloroform, acetic anhydride, mixed solvents thereof and the like. Among these, ethyl acetate, dimethyl carbonate, acetic anhydride and the like are preferable, and ethyl acetate or dimethyl carbonate is more preferable.

Example

Hereinafter, the present invention will be specifically described by way of examples, but the present invention is not limited thereto.

The analytical methods used in the examples are as follows.

<GC analysis conditions>

Apparatus: GC-2010 Plus (manufactured by SHIMADZU),

Column: DB-1 (manufactured by GEI Science Co., Ltd.) 0.25 mm 占 30 m, film thickness 0.25 占 퐉,

Carrier gas: He, detector: FID, sample injection amount: 1 um, inlet temperature: 160 占 폚, detector temperature: 220 占 폚, column temperature: 70 占 폚 (20 min) - 40 占 min -1 220 占 폚 Ratio: 1: 50, internal standard substance: butyl lactate.

< ¹ H NMR analysis conditions>

Apparatus: Fourier transform type superconducting nuclear magnetic resonance apparatus (FT-NMR) INOVA-400 (manufactured by Varian) 400 MHz,

Solvent: DMSO-d6, internal standard: tetramethylsilane (TMS).

<Melting Point Analysis Conditions>

Apparatus: DSC1 (manufactured by METTLER TOLEDO Co., Ltd.),

Temperature: 35 ℃ - 5 ℃ / min - 400 ℃, Fan: Au (sealed).

Comparative Example 1

[Chemical Formula 4]

(270 mmol) of citric acid anhydride (CA) and 200 g of methyl acetic anhydride (CA) were placed in a 30 mL Pyrex (registered trademark) glass test tube in a nitrogen atmosphere, wt.), and the mixture was stirred with a magnetic stirrer to dissolve. Thereafter, while stirring at 5 - 10 캜, a 100 W high pressure mercury lamp was irradiated for 4 hours. After the irradiation, the reaction solution was quantitatively analyzed by gas chromatography. As a result, the residual ratio of citraconic anhydride (CA) was 29.9%. Further, 2 g of the reaction solution in the reactor was collected, and the solvent was distilled off at 70-80 Torr with this distributor. The obtained crude product was analyzed by ¹ H NMR analysis to find that a mixture containing 1,3-DM-CBDA and 1,2-DM-CBDA (1,3-DM-CBDA: 1,2-DM-CBDA = 42.6: 57.4).

^{1 H NMR (DMSO-d6,} δ ppm) (1,3-DM-CBDA): 1.38 (s, 6H), 3.89 (s, 2H).

^{1 H NMR (DMSO-d6,} δ ppm) (1,2-DM-CBDA): 1.37 (s, 6H), 3.72 (s, 2H).

Example 1

[Chemical Formula 5]

(0.89 mmol) of citraconic anhydride (CA) and 20 g (222 mmol, dimethyl carbonate) of citric acid anhydride (CA) were placed in a 30 mL Pyrex (registered trademark) wt.), and the mixture was stirred with a magnetic stirrer to dissolve. Thereafter, while stirring at 15 - 20 캜, a 100 W high pressure mercury lamp was irradiated for 4 hours. After the irradiation, the reaction solution was quantitatively analyzed by gas chromatography. As a result, the residual ratio of citraconic anhydride (CA) was 26.2%. Further, 2 g of the reaction solution in the reactor was collected, and the solvent was distilled off at 70-80 Torr with this distributor. The obtained crude product was analyzed by ¹ H NMR analysis to find that a mixture containing 1,3-DM-CBDA and 1,2-DM-CBDA (1,3-DM-CBDA: 1,2-DM-CBDA = 48.3: 51.7).

Comparative Examples 2 to 28 and Example 2

A series of operations were carried out in the same manner as in Comparative Example 1, except that each solvent was added to the citraconic anhydride (CA) in an amount of 200 wt times. In the same manner as in Comparative Example 1, the residual ratio of the citraconic anhydride (CA) And the production ratio of 1,3-DM-CBDA and 1,2-DM-CBDA (1,3-DM-CBDA: 1,2-DM-CBDA) were calculated.

The solvent, temperature, by-product amount and results are shown in the following table. The residual ratio of citraconic anhydride and the ratio of 1,3-DM-CBDA to 1,2-DM-CBDA in the obtained reaction solution were calculated, and the results were compared with those obtained in Comparative Example 1 and Example 1 Are shown in the table. The reaction rate in the table was calculated from the number of moles of citraconic acid used and the residual ratio of citraconic acid at the time of reaction for 4 hours.

Example 3

[Chemical Formula 6]

35.0 g (312 mmol) of citraconic anhydride (CA) and 152 g (1682 mmol, dimethylcitrate (CA)) were added to a 300 ml Pyrex (registered trademark) glass five- 4.33 wt. Times), and the mixture was stirred with a magnetic stirrer to dissolve. Thereafter, while stirring at 10 - 15 캜, a 100 W high pressure mercury lamp was irradiated for 48 hours. It was confirmed by gas chromatography analysis that the residual ratio of the raw material was 23.7%. Then, the precipitated white crystals were taken out by filtration at 10-15 캜, and the crystals were washed twice with 43.8 g (497 mmol, 1.25 wt times with respect to citraconic anhydride (CA)) of ethyl acetate. This was dried under reduced pressure to obtain 8.1 g (yield: 23.1%) of white crystals. This crystal was identified by ¹ H NMR analysis as a mixture containing 1,3-DM-CBDA and 1,2-DM-CBDA (1,3-DM-CBDA: 1,2-DM-CBDA = 90.3: 9.7 ). The resulting crystals, filtrate and washing liquid were quantitatively analyzed by ¹ H NMR analysis and gas chromatography, respectively, and the mass balance with respect to the amount of injection was 88.9%.

Example 4

(7)

(CA) (0.10 g, 0.89 mmol) and benzophenone (BP) (0.020 g, 0.11 mmol, in the presence of citraconic anhydride (CA)) were placed in a 30 ml Pyrex (registered trademark) 20 mass%), and 20 g of dimethyl carbonate (222 mmol, 200 mass times of citraconic anhydride (CA)) were charged and dissolved by stirring with a magnetic stirrer. Thereafter, while stirring at 10 - 15 캜, a 100 W high-pressure mercury lamp was irradiated for 4 hours. After the irradiation, the reaction solution was quantitatively analyzed by gas chromatography. As a result, the residual ratio of citraconic anhydride (CA) was 3.9%. Further, 2 g of the reaction solution in the reactor was collected, and the solvent was distilled off at 70-80 Torr with this distributor. The obtained crude product was analyzed by ¹ H NMR analysis to find that a mixture containing 1,3-DM-CBDA and 1,2-DM-CBDA (1,3-DM-CBDA: 1,2-DM-CBDA = 48.3: 51.7 ).

Example 5

A series of operations were carried out in the same manner as in Example 4, except that 4,4'-dichlorobenzophenone (DClBP) was added as a sensitizer. In the same manner as in Comparative Example 1, the residual ratio of citraconic anhydride (CA) And the production ratio of 1,3-DM-CBDA and 1,2-DM-CBDA (1,3-DM-CBDA: 1,2-DM-CBDA) were calculated.

The solvent, temperature, sensitizer, by-product and results are shown in the following table. The residual ratio of citraconic anhydride and the ratio of 1,3-DM-CBDA to 1,2-DM-CBDA in the obtained reaction liquid were calculated, and are shown in the table together with the results obtained in Example 4. The reaction rate in the table was calculated from the number of moles of citraconic acid used and the residual ratio of citraconic acid at the time of reaction for 4 hours.

Reference Example 1

[Chemical Formula 8]

A mixture (1,3-DM-CBDA: 1,2-DM-CBDA) containing 1,3-DM-CBDA and 1,2-DM-CBDA obtained in the same manner as in Example 3 was placed in a 200- 1,2-DM-CBDA = 85: 15) and 92 g of acetic anhydride, and suspended at 25 DEG C under stirring with a magnetic stirrer. Thereafter, the mixture was heated under reflux (130 캜) for 4 hours. Thereafter, the inner temperature was cooled to 25 DEG C or lower and stirred at 25 DEG C or lower for 1 hour. Thereafter, the precipitated white crystals were filtered, and the crystals were washed twice with 18 g of ethyl acetate, and the resulting white crystals were dried under reduced pressure to obtain 14.4 g (yield 92%) of high purity 1,3-DM-CBDA . This determination was made by ¹ H NMR analysis that the ratio of 1,3-DM-CBDA and 1,2-DM-CBDA was 1,3-DM-CBDA: 1,2-DM-CBDA = 99.5: 0.5 Respectively.

^{1 H NMR (DMSO-d6,} δ ppm) (1,3-DM-CBDA): 1.38 (s, 6H), 3.89 (s, 2H).

^{1 H NMR (DMSO-d6,} δ ppm) (1,2-DM-CBDA): 1.37 (s, 6H), 3.72 (s, 2H).

mp. (1,3-DM-CBDA): 316 - 317 [deg.] C

Industrial availability

The cyclobutane tetracarboxylic acid derivative obtained in the present invention is useful as a raw material for polyamic acid, polyimide and the like. The polyimide and the like are used for electronic materials such as protective materials and insulating materials in liquid crystal display devices and semiconductors Which is widely used in the industry.

Further, the entire contents of the specification, claims, and abstract of Japanese Patent Application No. 2014-007186 filed on January 17, 2014 are incorporated herein by reference and the disclosure of the specification of the present invention is hereby incorporated herein by reference.

Claims (13)

A process for producing a 1,2,3,4-cyclobutane tetracarboxylic acid-1 represented by the formula (2), which comprises subjecting a maleic anhydride compound represented by the following formula (1) to a photo-dimerization reaction in a carbonate diester solvent , 2: A process for producing a 3,4-2-anhydride derivative.
[Chemical Formula 1]

(In the formula, R represents an alkyl group having 1 to 20 carbon atoms.) The method according to claim 1,
And R is an alkyl group having 1 to 4 carbon atoms. 3. The method according to claim 1 or 2,
Wherein the carbonic acid diester is an alkyl diester of carbonic acid having 1 to 4 carbon atoms. 4. The method according to any one of claims 1 to 3,
Wherein the carbonic acid diester is dimethyl carbonate or diethyl carbonate. 5. The method of claim 4,
Wherein the solvent is selected from the group consisting of methyl formate, ethyl formate, methyl acetate, ethyl acetate, n-propyl acetate, i-propyl acetate, methyl propionate, ethyl propionate, n-propyl propionate, And a minor solvent other than carbonic acid diester which is diacetate. 6. The method according to any one of claims 1 to 5,
Wherein the total amount of the solvent used in the reaction is 3 to 300 times the amount of the maleic anhydride compound. 6. The method according to any one of claims 1 to 5,
Wherein the amount of the total solvent used in the reaction is 3 to 10 mass times the amount of the maleic anhydride compound. 8. The method according to any one of claims 1 to 7,
Further comprising a sensitizer. 9. The method of claim 8,
Wherein the sensitizer is benzophenone, benzaldehyde, benzophenone substituted with electron-withdrawing group, acetophenone substituted with electron-withdrawing group, benzaldehyde substituted with electron-withdrawing group, or anthraquinone. 10. The method of claim 9,
Wherein the electron-attractive group is at least one selected from the group consisting of a fluoro group, a chloro group, a bromo group, an iodo group, a nitro group, a cyano group, and a trifluoromethyl group. 11. The method according to claim 9 or 10,
Wherein the number of electron-withdrawing groups is 1 to 5; The method according to any one of claims 8 to 11,
Wherein the amount of the sensitizer used is 0.1 to 20 mol% based on the maleic anhydride compound. 13. The method according to any one of claims 1 to 12,
Wherein the reaction temperature is 0 to 20 占 폚.