TWI650323B - Method for producing high-purity 1,3-dialkylcyclobutane-1,2,3,4-tetracarboxylic acid-1,2:3,4-dianhydride - Google Patents

Abstract

The present invention provides a high-purity 1,3-dialkyl-1,2,3,4-cyclobutanetetracarboxylic acid-1,2:3,4-dianhydride which is a raw material of polytheneimine or the like. An efficient manufacturing method.

The method is characterized in that 1,3-dialkylcyclobutane-1,2,3,4-tetracarboxylic acid-1,2:3,4-dianhydride and 1,2-di are in an organic solvent. a mixture of alkylcyclobutane-1,2,3,4-tetracarboxylic acid-1,2:3,4-dianhydride is heated, cooled, and filtered to obtain a solid high-purity 1,3- Dialkyl-1,2,3,4-cyclobutanetetracarboxylic acid-1,2:3,4-dianhydride, 1,3-dialkylcyclobutane-1,2,3,4- A method for producing tetracarboxylic acid-1,2:3,4-dianhydride.

Description

Method for producing high-purity 1,3-dialkylcyclobutane-1,2,3,4-tetracarboxylic acid-1,2:3,4-dianhydride

The present invention relates to a high-purity 1,3-dialkylcyclobutane-1,2,3,4-tetracarboxylic acid-1,2 which can be used as a raw material monomer for polyimine or the like which is used as an optical material. : A method for producing 3,4-dianhydride.

Generally, polyimine resins are widely used as electronic materials for liquid crystal display elements, semiconductor protective materials, and insulating materials because of their high mechanical strength, heat resistance, insulating properties, and solvent resistance. Further, it has recently been expected to be used for light-transmitting signal materials such as materials for optical waveguides.

In recent years, with the development of this field, there are correspondingly higher characteristics requirements for the materials used. That is, it is expected to have not only excellent heat resistance and solvent resistance but also many properties corresponding to the use.

However, all aromatic polyimine resins which use aromatic tetracarboxylic dianhydride and aromatic diamine as raw materials exhibit a strong amber coloration, and thus have problems in applications requiring high transparency. It is also known to form a polyimine precursor by polycondensation reaction of an alicyclic tetracarboxylic dianhydride with an aromatic diamine. Then, the polyimine resin obtained by imidating the precursor with ruthenium has a small coloration and high transparency (refer to Patent Documents 1 and 2).

The alkylcyclobutyric acid dianhydride which is one of the alicyclic tetracarboxylic dianhydrides which are used as a raw material of the polyimine which has a small transparency and the high transparency is as shown in the following process. 1,3-Dimethylcyclobutane-1,2,3,4-tetracarboxylic acid-1,2:3,4-dianhydride obtained by photodimerization of citraconic anhydride (MMA for short) Mixture of (1,3-DMCBDA) with 1,2-dimethylcyclobutane-1,2,3,4-tetracarboxylic acid-1,2:3,4-dianhydride (1,2-DMCBDA) .

In addition, when 1,3-DMCBDA and 1,2-DMCBDA are compared, the former 1,3-DMCBDA having a high symmetry structure can produce a polyimine having a higher molecular weight than the latter 1,2-DMCBDA, so that it is suitable. More sexual.

However, in Patent Document 3, a mixture of 1,3-DMCBDA and 1,2-DMCBDA is described, but 1,3-DMCBDA having high applicability and high purity is not described.

Prior technical literature Patent literature

Patent Document 1: Special Fair 2-24294

Patent Document 2: JP-A-58-208322

Patent Document 3: Japanese Patent Publication No. 4-106127

Patent Document 4: International Patent Application Publication No. WO2010/092989

It is an object of the present invention to provide a 1,3-dialkylcyclobutane-1,2,3,4-tetracarboxylic acid-1,2 obtained by photodimerization reaction of a maleic anhydride compound or the like. 3,4-dianhydride (hereinafter also referred to as 1,3-DACBDA) and 1,2-dialkylcyclobutane-1,2,3,4-tetracarboxylic acid-1,2:3,4-di A mixture of an anhydride (hereinafter also referred to as 1,2-DACBDA), which is a method of obtaining the former 1,3-DACBDA with high purity and high efficiency.

In order to solve the above problems, the present inventors have intensively studied and found that the solubility of 1,3-DACBDA and 1,2-DACBDA with respect to a heated organic solvent, particularly a specific organic solvent, is very different, and the solubility ratio of the former is relatively large. In the latter case, it is extremely small, and therefore, by separating the two by the difference in solubility, high-purity 1,3-DACBDA can be obtained with high efficiency, and the present invention has been completed.

The present invention is an invention having the following gist.

A method for producing 1,3-DACBDA, which comprises heating a mixture of 1,3-DACBDA and 1,2-DACBDA in an organic solvent, cooling, and filtering to obtain a solid high-purity 1 , 3-Dialkyl-1,2,3,4-cyclobutanetetracarboxylic acid-1,2:3,4-dianhydride.

2. The production method according to the above 1, wherein the organic solvent is an organic carboxylic acid ester or anhydride having a boiling point of 50 to 200 ° C or a carbonate.

3. The production method according to the above 1, wherein the organic solvent is acetic anhydride.

4. The production method according to any one of the above 1 to 3, wherein the organic solvent is used in an amount of 2 to 20 parts by mass based on 1 part by mass of the mixture of 1,3-DACBDA and 1,2-DACBDA.

5. The production method according to any one of the above 1 to 4, wherein the mixture is heated in an organic solvent at a temperature of from 10 ° C to the boiling point of the organic solvent.

6. The production method according to any one of the above 1 to 5, wherein the heating is followed by cooling to -10 to 50 °C.

7. The production method according to any one of the above 1 to 6, wherein a mass ratio of 1,3-DACBDA to 1,2-DACBDA in the mixture is 50:50 to 99.5:0.5.

8. The production method according to any one of the above 1 to 7, wherein the mixture of the 1,3-DACBDA and 1,2-DACBDA is obtained by photodimerization reaction of maleic anhydride.

9. The production method according to any one of 1 to 8, wherein the alkyl group of the 1,3-DACBDA and the 1,2-DACBDA is a methyl group.

By the production method of the present invention, high purity 1,3-dialkylcyclobutane-1,2,3,4-tetracarboxylic acid-1,2:3,4- can be easily obtained with high efficiency and high recovery. Dihydride (1,3-DACBDA).

The mixture of 1,3-DACBDA and 1,2-DACBDA used as a raw material in the production method of the present invention is typically obtained by photodimerization of a maleic anhydride compound represented by the formula (1) by the following reaction scheme. .

In the above formula, R represents an alkyl group having 1 to 20 carbon atoms, preferably 1 to 12 carbon atoms, more preferably 1 to 6 carbon atoms. Particularly preferred is methyl.

The alkyl group having 1 to 20 carbon atoms may be a linear or branched saturated alkyl group or a linear or branched unsaturated alkyl group. Specifically, for example, methyl, ethyl, n-propyl, i-propyl, n-butyl, i-butyl, s- Butyl, t-butyl, n-pentyl, 1-methyl-n-butyl, 2-methyl-n-butyl, 3-methyl-n-butyl, 1,1-dimethyl -n-propyl, n-hexyl, 1-methyl-n-pentyl, 2-methyl-n-pentyl, 1,1-dimethyl-n-butyl, 1-ethyl-n- Butyl, 1,1,2-trimethyl-n-propyl, n-heptyl, n-octyl, n-fluorenyl, n-fluorenyl, n-dodecyl, n-icosane Base, 1-methylvinyl, 2-allyl, 1-ethylvinyl, 2-methylallyl, 2-butenyl, 2-methyl-2-butenyl, 3-methyl 2-butenyl, 3-methyl-3-butenyl, 2-hexenyl, 4-methyl-3-pentenyl, 4-methyl-4-butenyl, 2,3 - dimethyl-2-butenyl, 1-ethyl-2-pentenyl, 3-dodecenyl, propargyl, 3-butynyl, 3-methyl-2-propynyl, 9-decynyl and the like.

Further, n represents positive, i represents difference, s represents a pair, and t represents a tertiary.

A maleic anhydride compound represented by the formula (1), for example, citraconic anhydride, 2-ethylmaleic anhydride, 2-isopropylmaleic anhydride, 2-n-butylmaleic anhydride, 2-t-butyl Kamaine anhydride, 2-n-pentyl maleic anhydride, 2-n-hexyl maleic anhydride, 2-n-heptyl maleic anhydride, 2-n-octyl maleic anhydride, 2-n-fluorenyl Maleic anhydride, 2-n-mercapto maleic anhydride, 2-n-dodecyl maleic anhydride, 2-n-eicosyl maleic anhydride, 2-(1-methylvinyl) Malay Anhydride, 2-(2-allyl)maleic anhydride, 2-(1-ethylvinyl)maleic anhydride, 2-(2-methylallyl)maleic anhydride, 2-(2-butyl Alkenyl) maleic anhydride, 2-(2-hexenyl)maleic anhydride, 2-(1-ethyl-2-pentenyl)maleic anhydride, 2-(3-dodecenyl)malan Anhydride, 2-propargylmaleic anhydride, 2-(3-butynyl)maleic anhydride, 2-(3-methyl-2-propynyl)maleic anhydride, 2-(9-fluorenyl) Maleic anhydride, etc.

1,3- photodimerization reaction of maleic anhydride compound The production conditions of the mixture of DACBDA and 1,2-DACBDA are as follows.

The solvent used in the photodimerization reaction may be methyl formate, ethyl formate, n-propyl formate, i-propyl formate, n-butyl formate, i-butyl formate, methyl acetate, ethyl acetate, N-propyl acetate, i-propyl acetate, n-butyl acetate, i-butyl acetate, methyl propionate, ethyl propionate, n-propyl propionate, i-propyl propionate, ethylene Alcoholic acid ester, ethylene glycol diacetate, ethylene glycol dipropionate, dimethyl carbonate, diethyl carbonate, and the like.

The amount of the solvent to be used is preferably from 3 to 300 parts by mass, more preferably from 3 to 100 parts by mass, per mole of the maleic anhydride compound.

Further, in order to accelerate the reaction and increase the yield of the product, the amount of the reaction solvent used is preferably small. For example, when the concentration of the maleic anhydride compound is increased, the reaction is accelerated, and the yield of the resultant product is increased. Therefore, in order to accelerate the reaction and increase the yield of the product, the amount of the solvent used is preferably from 3 to 10 parts by mass relative to the maleic anhydride compound.

The wavelength of light in the photodimerization reaction is preferably 200 to 400 nm, more preferably 250 to 350 nm, and particularly preferably 280 to 330 nm. The light source uses 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.

In particular, a light-emitting diode having a wavelength of 275 to 500 nm can be modified to obtain a 1,3-DACBDA. Further, by changing the quartz glass in the quartz tube of the light source to Pyrex glass, it is possible to reduce the adhesion of the colored polymer and the impurities to the light source cooling tube, and obtain the 1,3-DACBDA with an improved selectivity.

When the reaction temperature is high, the polymer is produced as a by-product, and at a low temperature, the solubility of the maleic anhydride compound is lowered to reduce the production efficiency, so that it is preferably carried out at -20 to 80 °C. More preferably, it is -10 to 50 ° C, and particularly preferably 0 to 20 ° C can inhibit the formation of by-products such as 1,2-DACBDA, and obtain 1,3-DACBDA at a high selectivity and yield.

The reaction time varies depending on the amount of the maleic anhydride compound to be added, the type of the light source, and the amount of the irradiation, and the unreacted maleic anhydride compound can be used in an amount of from 0 to 40%, preferably from 0 to 10%. Further, the conversion ratio is easily measured by analyzing the reaction liquid by gas chromatography or the like.

When the reaction time is long, the conversion rate of the maleic anhydride compound is increased, and the precipitation amount of 1,3-DACBDA is increased, so that the generated 1,3-DACBDA starts to adhere to the outer wall of the light source cooling tube (the reaction liquid side). The simultaneous decomposition reaction causes the crystal to be colored and the light efficiency to be lowered (yield per unit of electricity x time). Therefore, in order to increase the conversion rate of the maleic anhydride compound, it is unfavorable to practically reduce the productivity when the batch is consumed for a long period of time. The reaction can be carried out batchwise or in a flow-through manner, or it can be carried out under normal pressure or pressure.

After the photodimerization reaction, the precipitate in the reaction mixture is filtered, and the filtrate is washed with an organic solvent and dried under reduced pressure to obtain a mixture of 1,3-DACBDA and 1,2-DACBDA.

The amount of the organic solvent used for washing the filtrate may be such that the precipitate remaining in the reaction tank can be transferred to the filter. However, when the amount of the organic solvent is too large, the target substance is easily transferred to the filtrate to lower the recovery rate. Therefore, the amount of the organic solvent used for washing the filtrate is preferably 0.5 to 10 parts by weight, more preferably 1 to 2 parts by weight, based on the maleic anhydride compound used in the reaction.

The solvent for washing the filtrate is not particularly limited, but when a solvent having a higher solubility with respect to the target 1,3-DACBDA is used, the target is easily transferred to the filtrate to lower the recovery. Therefore, the organic solvent used for washing the filtrate, such as methyl formate, ethyl formate, n-propyl formate, i-propyl formate, n-butyl formate, formic acid i-, used in the photodimerization reaction. Butyl ester, methyl acetate, ethyl acetate, n-propyl acetate, i-propyl acetate, n-butyl acetate, i-butyl acetate, methyl propionate, ethyl propionate, n-propyl propionate Ester, i-propyl propionate, ethylene glycol dicarboxylate, ethylene glycol diacetate, ethylene glycol dipropionate, dimethyl carbonate, diethyl carbonate or a solvent which does not dissolve the product For example, toluene, xylene, heptane, acetonitrile, acetone, chloroform, acetic anhydride, or the like, or a mixed solvent thereof. Among them, ethyl acetate and dimethyl carbonate are preferred, and ethyl acetate, dimethyl carbonate and acetic anhydride are more preferred.

Further, the photodimerization reaction of the maleic anhydride compound can be carried out in the presence of a sensitizer. The sensitizer is preferably benzophenone, hydrazine roll, acetophenone, benzaldehyde or the like. In particular, benzophenone substituted by an electron-derived group, acetophenone substituted by an electron-donating group or benzaldehyde substituted by an electron-derived group can produce 1,3-DACBDA and 1 with high photoreaction efficiency. A mixture of 2-DACBDA is preferred.

The sensitizing amount to be used is preferably from 0.1 to 20 mol%, more preferably from 0.1 to 5 mol%, based on the maleic anhydride compound.

In the present invention, as described above, a reaction mixture liquid containing a mixture of 1,3-DACBDA and 1,2-DACBDA is obtained. 1,3-DACBDA and 1,2-DACBDA are present as solids in the reaction mixture, so filtration The reaction mixture solution can be used as a raw material for obtaining high-purity 1,3-DACBDA of the present invention by isolating 1,3-DACBDA from 1,2-DACBDA.

Further, the organic solvent contained in the reaction mixture containing a mixture of 1,3-DACBDA and 1,2-DACBDA can be used as a second organic solvent for producing high-purity 1,3-DACBDA. A reaction mixture containing a mixture of 1,3-DACBDA and 1,2-DACBDA is used as a raw material. Further, after the reaction mixture liquid is separated from the mixture of 1,3-DACBDA and 1,2-DACBDA, it is preferably washed, so that high-purity 1,3-DACBDA is easily obtained.

In the present invention, the mixture of 1,3-DACBDA and 1,2-DACBDA is heated in an organic solvent, and after cooling, the high-purity 1,3-dialkyl-1 is filtered as a solid by filtration. In the case of 2,3,4-cyclo-butanetetracarboxylic acid-1,2:3,4-dianhydride, high purity 1,3-DACBDA can be obtained with high recovery.

When the organic solvent used at this time is heated, most of the organic solvent does not react with 1,3-DACBDA and 1,2-DACBDA, and the solubility with respect to 1,3-DACBDA is small, and relative to 1 2-DACBDA has a high solvent content and can be used.

The organic solvent is preferably a boiling point of 30 to 200 ° C, more preferably 50 to 180 ° C. As the organic solvent, hexane, heptane, acetonitrile, acetone, chloroform, toluene or the like can also be used. The organic solvent is particularly preferably an ester or anhydride of an organic carboxylic acid, or a carbonate.

The ester of an organic carboxylic acid is preferably of the formula: R ¹ COOR ² (wherein R ¹ is hydrogen, or a carbon number is preferably from 1 to 4, more preferably an alkyl group of 1 or 2, and R ² is a carbon number of 1~ 4. A fatty acid alkyl ester represented by 4, more preferably an alkyl group of 1 to 3).

The ester of an organic carboxylic acid is preferably, for example, ethyl formate, n-propyl formate, i-propyl formate, n-butyl formate, i-butyl formate, methyl acetate, ethyl acetate, n-propyl acetate , i-propyl acetate, n-butyl acetate, i-butyl acetate, methyl propionate, ethyl propionate, n-propyl propionate, i-propyl propionate, n-butyl propionate, I-butyl propionate. Further, ethylene glycol dicarboxylate, ethylene glycol diacetate, ethylene glycol dipropionate or the like can be used.

Further, the anhydride of the organic carboxylic acid is preferably a compound represented by the formula: (R ¹ CO) ² O (wherein R ¹ together with preferred embodiments are synonymous with the above). A specific example thereof is preferably propionic anhydride, butyric anhydride, trifluoroacetic anhydride, or acetic anhydride. Among them, the viewpoint of obtaining 1,3-DACBDA at a higher recovery rate is preferably acetic anhydride.

Further, the carbonate is preferably a dialkyl carbonate having an alkyl group having 1 to 3 carbon atoms, more preferably 1 or 2. Specific examples thereof are preferably, for example, dimethyl carbonate, diethyl carbonate or a mixture thereof.

Further, a mixture of 1,3-DACBDA and 1,2-DACBDA may be partially hydrolyzed at the time of removal or storage, but when a carboxylic anhydride is used, a partially hydrolyzed substance may be anhydrideized under heating and stirring, and the stability is high. The purity of 1,3-DACBDA is preferred.

Moreover, most of the solvent contains a lot of water, and is partially hydrolyzed during the purification, so the water in the solvent needs to be adjusted, but the anhydride of the organic carboxylic acid can close the hydrolyzate, so that it is not necessary to adjust the water in the solvent to obtain high purity. 1,3-DACBDA is preferred.

The amount of the organic solvent is preferably 2 to 20 parts by mass based on 1 part by mass of the mixture of 1,3-DACBDA and 1,2-DACBDA. The viewpoint of efficiency and volumetric efficiency is preferably 3.5 to 6 parts by mass.

The temperature at which the organic solvent is heated is generally from 10 ° C to the boiling point of the organic solvent to be used, but the viewpoint of efficiently dissolving 1,2-DACBDA is preferably from 50 ° C to the boiling point of the organic solvent to be used. The temperature. The heating time is preferably from 30 minutes to 10 hours, but if it is too short, the purity may be lowered, so it is preferably from 1 to 6 hours.

After the above heating, it is preferably cooled to -10 to 50 ° C, more preferably -10 to 20 ° C, and the crystal of 1,3-DACBDA is precipitated as a solid. The liquid containing the solid of 1,3-DACBDA was filtered, and the crystal of 1,3-DACBDA was collected by filtration and separated from 1,2-DACBDA dissolved in the liquid to obtain high-purity 1,3-DACBDA.

Further, the ratio of the mixture of 1,3-DACBDA and 1,2-DACBDA used above is not particularly limited, but when the ratio of 1,2-DACBDA is large, the purity may be lowered. Therefore, in the mixture used in the present invention, the mass of 1,3-DACBDA and 1,2-DACBDA is preferably 50:50 to 99.5:0.5, more preferably 70:30 to 99.5 to 0.5.

Example

The invention will be more specifically illustrated by the following examples, but the invention is not limited thereto. Further, the analysis method used in the examples is as follows.

<GC analysis conditions>

Device: GC-2010 Plus (SHIMADZU company)

Pipe column: DB-1 (Giesye) diameter 0.25mm × length 30m, film thickness 0.25μm

Carrier: He

Verifier: FID

Sample injection amount: 1μm

Injection inlet temperature: 160 ° C

Verifier temperature: 220 ° C

Column temperature: 70 ° C (20 min) -40 ° C / min - 220 ° C (15 min)

Distribution ratio: 1:50

Internal standard substance: butyl lactate

< ¹ H-NMR analysis conditions>

Device: Fourier variable-type superconducting nuclear magnetic resonance device (FT-NMR) INOVA-400 (Varian) 400MHz

Solvent: DMSO-d6

Internal reference material: tetramethyl decane (TMS)

<melting point analysis conditions>

Device: DSC1 (Mittra)

Temperature: 35 ° C - 5 ° C / min - 400 ° C

Vessel: Au (closed)

Reference Example 1: Synthesis of 1,3-DM-CBDA and 1,2-DM-CBDA

35.0 g (312 mmol) of citraconic anhydride (CA) and 152 g of ethyl acetate (1720 mmol, 4.33 parts by weight based on citraconic anhydride (CA)) were placed in a 300 mL Pyrex (registered trademark) glass 5-neck flask under nitrogen. After stirring with a magnetic stirrer to dissolve, a 100 W high pressure mercury lamp was irradiated for 48 hours while stirring at 5 to 10 °C. The reaction liquid was analyzed by gas chromatography, and it was confirmed that the residual ratio of the raw material was 16.4%, and the precipitated white crystals were filtered at 5 to 10 ° C, and then 43.8 g (497 mmol) of ethyl acetate was compared with citraconic anhydride (CA). The crystal was washed twice with 1.25 parts by weight, and dried under reduced pressure to give 5.8 g (yield: 16.6%) of white crystals.

The crystal was analyzed by ¹ H-NMR to confirm that it contained a mixture of 1,3-DM-CBDA and 1,2-DM-CBDA (1,3-DM-CBDA: 1,2-DM-CBDA=92.2: 7.8 ).

Further, each of the obtained crystals, the filtrate and the washing liquid were quantitatively analyzed by ¹ H-NMR analysis and gas chromatography, and the mass balance with respect to the added amount was 93.1%.

Example 1: Production of high purity 1,3-DM-CBDA (acetic anhydride)

A mixture containing 1,3-DM-CBDA and 1,2-DM-CBDA obtained by the same method as the reference example under a nitrogen stream (1,3-DM-CBDA: 1,2-DM-CBDA=85:15) 18.3 g and 92 g of acetic anhydride were placed in a 200 mL four-necked flask, stirred under a magnetic stirrer at 25 ° C, and heated under reflux for 4 hours (130 ° C). Thereafter, the internal temperature was cooled to 20 ° C and stirred at 20 ° C for 1 hour.

Next, the precipitated white crystals were filtered, and the crystals were washed twice with ethyl acetate (18 g), and then dried under reduced pressure to yield white crystals (14.4 g (yield: 92.6%). The crystal was analyzed by ¹ H-NMR, and it was confirmed that the ratio of 1,3-DM-CBDA to 1,2-DM-CBDA was 1,3-DM-CBDA: 1,2-DM-CBDA=99.5:0.5 The composition.

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 ° C

Example 2: Production of high purity 1,3-DM-CBDA (acetic anhydride)

A mixture containing 1,3-DM-CBDA and 1,2-DM-CBDA obtained by the same method as Reference Example 1 under a nitrogen stream (1,3-DM-CBDA: 1,2-DM-CBDA=70:30) 5 g and 25 g of acetic anhydride were placed in a 100 mL four-necked flask, and the mixture was stirred at 25 ° C with a magnetic stirrer, and then heated to reflux for 4 hours (130 ° C). Thereafter, the internal temperature was cooled to 20 ° C and stirred at 20 ° C for 1 hour.

Next, the precipitated white crystals were filtered, and the crystals were washed twice with 5 g of ethyl acetate, and then dried under reduced pressure to yield white crystals (yield: 94.3%). The crystal was analyzed by ¹ H-NMR to confirm that the ratio of 1,3-DM-CBDA to 1,2-DM-CBDA was 1,3-DM-CBDA: 1,2-DM-CBDA=99.5: 0.5.

Example 3: Production of high purity 1,3-DM-CBDA (acetonitrile)

A mixture containing 1,3-DM-CBDA and 1,2-DM-CBDA obtained by the same method as Reference Example 1 under a nitrogen stream (1,3-DM-CBDA: 1,2-DM-CBDA=89:11) 70 g and 420 g of acetonitrile were placed in a 500 mL four-necked flask, stirred with a magnetic stirrer, suspended at 17 ° C, and stirred at 32 ° C for 1 hour. Thereafter, the internal temperature was cooled to 10 ° C and stirred at 10 ° C for 1 hour.

Next, the precipitated white crystals were filtered, and the crystals were washed twice with 70 g of acetonitrile, and then dried under reduced pressure to yield 52.56 g (yield: 84.3%). The crystal was analyzed by ¹ H-NMR to confirm that the ratio of 1,3-DM-CBDA to 1,2-DM-CBDA was 1,3-DM-CBDA: 1,2-DM-CBDA=99.5: 0.5.

Example 4: Production of high purity 1,3-DM-CBDA (ethyl acetate)

A mixture containing 1,3-DM-CBDA and 1,2-DM-CBDA obtained by the same method as Reference Example 1 under a nitrogen stream (1,3-DM-CBDA: 1,2-DM-CBDA=89:11) 80 g and 800 g of ethyl acetate were placed in a 500 mL four-necked flask, and the mixture was suspended at 17 ° C with stirring with a magnetic stirrer, and then stirred at 50 ° C for 1 hour. Thereafter, the internal temperature was cooled to 17 ° C, and further stirred at 20 ° C for 1 hour.

Next, the precipitated white crystals were filtered, and the crystals were washed twice with ethyl acetate (160 g), and the obtained white crystals were dried under reduced pressure to give a ratio of 1,3-DM-CBDA to 1,2-DM-CBDA. 3-DM-CBDA: 1,2-DM-CBDA=99.0:1 crystal. Further, the ratio of the crystallized 1,3-DM-CBDA to 1,2-DM-CBDA was confirmed by ¹ H-NMR analysis. Thereafter, the total amount of the obtained crystals and 800 g of ethyl acetate were placed in a 500 mL four-necked flask under a nitrogen stream, and the mixture was suspended at 17 ° C with stirring with a magnetic stirrer, and further stirred at 50 ° C for 1 hour.

Next, the internal temperature was cooled to 20 ° C or lower, and stirred at 20 ° C for 1 hour. Then, the precipitated white crystals were filtered, and the crystals were washed twice with ethyl acetate (160 g), and dried under reduced pressure to yield white crystals (53.32 g) (yield: 74.9%). The crystal was analyzed by ¹ H-NMR to confirm that the ratio of 1,3-DM-CBDA to 1,2-DM-CBDA was 1,3-DM-CBDA: 1,2-DM-CBDA=99.3:0.7.

Industrial use possibility

The high-purity 1,3-dimethyl-1,2,3,4-cyclobutanetetracarboxylic acid-1,2:3,4-dianhydride obtained by the present invention is suitably used as a polyimine or the like. A compound for a raw material, such as a polyimine, is widely used as a resin composition of an electronic material such as a liquid crystal display element, a semiconductor protective material, or an insulating material.

In addition, the entire contents of the specification, the scope of the application, the drawings and the abstract description of the Japanese Patent Application No. 2014-007189, filed on Jan. 17, 2014, are hereby incorporated by reference.

Claims (9)

Method for producing 1,3-dialkylcyclobutane-1,2,3,4-tetracarboxylic acid-1,2:3,4-dianhydride characterized by 1,3- in an organic solvent Dialkylcyclobutane-1,2,3,4-tetracarboxylic acid-1,2:3,4-dianhydride and 1,2-dialkylcyclobutane-1,2,3,4-tetra Heating a mixture of carboxylic acid-1,2:3,4-dianhydride, cooling, and filtering to obtain a solid high-purity 1,3-dialkyl-1,2,3,4-cyclobutane Tetracarboxylic acid-1,2:3,4-dianhydride wherein the aforementioned organic solvent is relative to 1,3-dialkylcyclobutane-1,2,3,4-tetracarboxylic acid-1,2: The solubility of 3,4-dianhydride is relatively small, and it is relative to the solvent of 1,2-dialkylcyclobutane-1,2,3,4-tetracarboxylic acid-1,2:3,4-dianhydride. Larger. The production method of claim 1, wherein the organic solvent is an ester or anhydride of an organic carboxylic acid having a boiling point of 50 to 200 ° C, or a carbonate. The production method of claim 1, wherein the organic solvent is acetic anhydride. The production method according to any one of claims 1 to 3, wherein the organic solvent is relative to 1,3-dialkylcyclobutane-1,2,3,4-tetracarboxylic acid-1,2:3,4 A mixture of dianhydride and 1,2-dialkylcyclobutane-1,2,3,4-tetracarboxylic acid-1,2:3,4-dianhydride is used in an amount of 2 to 20 parts by mass. The production method according to any one of claims 1 to 3, wherein the mixture is heated in an organic solvent at a temperature of from 10 ° C to the boiling point of the organic solvent. The production method according to any one of claims 1 to 3, wherein the heating is followed by cooling to -10 to 50 °C. The manufacturing method of any one of claims 1 to 3, wherein the aforementioned mixing 1,3-Dialkylcyclobutane-1,2,3,4-tetracarboxylic acid-1,2:3,4-dianhydride and 1,2-dialkylcyclobutane-1, The mass ratio of 2,3,4-tetracarboxylic acid-1,2:3,4-dianhydride is 50:50 to 99.5:0.5. The production method according to any one of claims 1 to 3, wherein the 1,3-dialkylcyclobutane-1,2,3,4-tetracarboxylic acid-1,2:3,4:dianhydride is A mixture of 1,2-dialkylcyclobutane-1,2,3,4-tetracarboxylic acid-1,2:3,4-dianhydride is obtained by photodimerization of maleic anhydride. The production method according to any one of claims 1 to 3, wherein 1,3-dialkylcyclobutane-1,2,3,4-tetracarboxylic acid-1,2:3,4-dianhydride and 1 The alkyl group of 2-dialkylcyclobutane-1,2,3,4-tetracarboxylic acid-1,2:3,4-dianhydride is a methyl group.