KR20150112649A - Novel method for preparing fluorinated pyromellitic dianhydride - Google Patents

Abstract

The present invention relates to a method for preparing fluorinated pyromellitic dianhydrides represented by the chemical formula 1. The method includes the steps of: (1) preparing the compound of the chemical formula 2 by bromiation of the pyromellitic dianhydrides; (2) initiating the reaction between the compound of the chemical formula 2 and 1-bromo-3,5-bis (trifluoromethyl) benzene with a catalyst to prepare a compound of the chemical formula 4; and (3) sublimating the compound of the chemical formula 4 under reduced pressure to prepare a compound of the chemical formula 1. The present invention can omit the complex intermediate generation process required preparing fluorinated pyromellitic dianhydrides, thereby simplifying the process and ensuring high productivity. The fluorinated pyromellitic dianhydrides prepared by the preparing method of the present invention can be used to prepare polyimides having a low dielectric constant and high heat resistance.

Description

FIELD OF THE INVENTION The present invention relates to novel fluorinated pyromellitic dianhydrides,

The present invention relates to a novel process for the preparation of fluorinated pyromellitic dianhydrides.

In general, polyimide (PI) resin refers to a high heat resistant resin prepared by solution polymerization of an aromatic dianhydride and an aromatic dianhydride or an aromatic diisocyanate to prepare a polyamic acid derivative, followed by ring-closing dehydration at a high temperature and imidization.

The polyimide resin is an insoluble and infusible ultra high heat resistant resin which is used in electric, electronic, automobile and aerospace industries due to its high glass transition temperature, excellent heat resistance, heat resistance, radiation resistance, low temperature characteristics, Films, resins, molded parts, adhesives, and insulators. Especially, as an electronic industrial material, it has excellent insulating properties and thermal and chemical stability, and its use as an interlayer insulating film of semiconductor chips is expanding. Particularly, in the field of the film industry, it has been proposed to use pyromellitic acid dianhydride (hereinafter referred to as PMDA), para-phenylenediamine (hereinafter referred to as PPD) and a flexible ether structure Component polyimide film (SKC) having a proper polyimide rigidity controlled through a combination of 4,4'-diaminodiphenyl ether (4,4-oxydianiline, hereinafter referred to as 4,4-ODA) KOLON PI IF grade, and Apical NPI Grade) are widely used as insulating materials for electronic materials such as mobile phones due to excellent heat resistance, low thermal expansion, excellent heat resistance and sliding characteristics.

However, in recent years, there has been an increasing need for improvement of polyimide, development of new composition, and development of new processing technology due to an increase in demand for super insulation and functionality. In particular, in order to be used in an electronic device having a highly integrated multilayer structure, a lower dielectric constant, a higher glass transition temperature and a lower thermal expansion property are required, and development of a polyimide satisfying this requirement is required.

Recent studies on this point have shown that the use of aromatic dianhydride monomers or aromatic amine monomers containing a fluorine substituent having a low van der Waals radius and a high binding energy between electronegativity and heteroatoms Lt; RTI ID = 0.0 > dielectric constant. ≪ / RTI >

Polyimide prepared using 4,4 '- (hexafluoroisopropylidene) bis (phthalic acid) (hereinafter referred to as 6FDA), which is a typical fluorinated monomer, has a low dielectric constant and colorless and transparent characteristics, 6FDA containing hexafluoroisopropylidene, which is a fluorinated flexible aliphatic bond in the main chain of polyimide, is used as a material for high-tech electronic parts such as photosensitive polyimide (Patent Publication No. 2013-0008386) and low dielectric substrate. It has been pointed out that the polyimide prepared by using the polyimide has a problem in that it is deteriorated in high heat resistance characteristic inherent to the polyimide and can not be used as a high-performance electronic material.

On the other hand, Korean Patent Laid-Open Publication No. 2002-63073 and Korean Patent Publication No. 2004-38334 disclose 3,6-di (3 ', 5'-dihydroxyphenyl) dihydroxy compounds each containing a fluorine-containing phenyl substituent at the para position of pyromellitic dianhydride, (3,6 ', 5'-bis (trifluoromethyl) benzene) pyromellitic dianhydride (12FPMDA) and 1- (3'- Discloses pyromellitic dianhydride (6FPPMDA), which is an aromatic fluorine-containing monomer in the rigid structure of pyromellitic dianhydride, Has the same excellent heat resistance characteristics and is excellent in electrical characteristics with low dielectric constant, but has a drawback in that the synthesis process for producing the same is very complicated.

Such conventional reactions are complicated in each stage, and in particular, tetracarboxylic compounds prepared by the oxidation reaction of tetramethyl group are a major cause of lowering the yield of 12FPMDA or 6FPPMDA due to the difficult purification process, It was judged that there was difficulty in securing economical efficiency.

Therefore, the oxidation reaction of the methyl substituent can be omitted and the process can be simplified. Accordingly, it is required to develop a novel method for producing 12FPMDA or 6FPPMDA, which has high economical efficiency.

It is an object of the present invention to provide a novel process for preparing fluorinated pyromellitic dianhydride (PMDA) used in the production of polyimides.

In order to achieve the above object,

(1) brominating pyromellitic dianhydride to produce a compound of formula (2);

(2) sequentially reacting the compound of formula (3) with magnesium and trimethylborate and then hydrolyzing to prepare a compound of formula (4);

(3) reacting a compound represented by the following formula (2) and a compound represented by the following formula (4) under a catalyst to prepare a compound represented by the following formula (5); And

(4) Submerging the compound of the following formula (5) under reduced pressure to prepare a compound of the formula

Wherein the fluorinated pyromellitic acid dianhydride is represented by the following formula (1): < EMI ID =

In the above formulas,

이고, R₃ 및 R₄는 각각 독립적으로 불소 치환된 C_{1 - 4}알킬이고, 이때 R₁ 및 R₂는 동시에 수소가 아니며;R ₁ and R ₂ are each independently hydrogen or

And, R ₃ and R ₄ each independently represent a fluorine-substituted C _{1 - 4} alkyl and, wherein R ₁ and R ₂ are not simultaneously hydrogen;

A ₁ and A ₂ are each independently hydrogen or bromine.

The production method of the present invention is a production method in which a complicated production process of an intermediate required for producing fluorinated pyromellitic dianhydride is omitted so that the process is simple and high productivity can be exhibited. Pyromellitic dianhydride can be usefully used in the production of polyimides having low dielectric constant and high heat resistance.

The process for preparing the fluorinated pyromellitic dianhydride of the present invention comprises the steps of: (1) brominating pyromellitic dianhydride to prepare a compound of formula (2); (2) sequentially reacting the compound of formula (3) with magnesium and trimethylborate and then hydrolyzing to prepare a compound of formula (4); (3) reacting a compound represented by the following formula (2) and a compound represented by the following formula (4) under a catalyst to prepare a compound represented by the following formula (5); And (4) depressurizing the compound of formula (5) to prepare a compound of formula (1).

[Chemical Formula 1]

(2)

(3)

[Chemical Formula 4]

[Chemical Formula 5]

In the above formulas,

이고, R₃ 및 R₄는 각각 독립적으로 불소 치환된 C_{1 - 4}알킬이고, 이때 R₁ 및 R₂는 동시에 수소가 아니며;R ₁ and R ₂ are each independently hydrogen or

And, R ₃ and R ₄ each independently represent a fluorine-substituted C _{1 - 4} alkyl and, wherein R ₁ and R ₂ are not simultaneously hydrogen;

A ₁ and A ₂ are each independently hydrogen or bromine.

The fluorine-substituted C _{1 - 4} alkyl is 1 to 3 fluorine-substituted C _{1 -} can be a ₄ alkyl, and preferably C _{1 - 4} alkyl are one to three fluorine at the terminal carbon is substituted be of number and, more preferably C _{1 -} may be one of the 1 to 3 fluorine at the terminal carbons of the _4-alkyl substituted.

일 수 있고, R₂는 수소일 수 있다. Further, in the above-mentioned formula (I), wherein R ₁ is

And R < ₂ > may be hydrogen.

인 화합물(3,6-디(3',5'-비스(트리플루오로메틸)벤젠)피로멜리틱디안하이드라이드(12FPMDA))일 수 있다.
In Formula 1, R ₁ and R ₂ are both

(3,6-di (3 ', 5'-bis (trifluoromethyl) benzene) pyromellitic dianhydride (12FPMDA).

(1) brominating pyromellitic dianhydride to prepare a compound of formula (2)

[Reaction Scheme 1]

In the above Reaction Scheme 1, A ₁ and A ₂ are each independently hydrogen or bromine.

The step of preparing the compound of the above formula (1) and the compound of the formula (2) can be represented by the above reaction formula (1).

The step (1) includes a step of dissolving the pyromellitic dianhydride in an aqueous base solution and adding bromine to the mixture.

In step (1), an aqueous base solution is added to pyromellitic dianhydride, and the mixture is completely dissolved by stirring. Then, bromine (Br ₂ ) is slowly added thereto. After completion of the bromine addition, , Followed by work-up with acid addition.

The bromine may be used in an amount of 80 to 300 molar equivalents, preferably 100 to 250 molar equivalents based on 100 molar equivalents of the pyromellitic dianhydride.

이고, R₂가 수소인 화합물인 경우, 상기 브로민을 상기 피로멜리트산 이무수물 100 몰 당량에 대하여 80 내지 150 몰 당량 사용할 수 있고, 바람직하게는 100 내지 120 몰 당량 사용할 수 있으며, 상기 R₁ 및 R₂가 모두

인 화합물인 경우, 상기 브로민을 상기 피로멜리트산 이무수물 100 몰 당량에 대하여 200 내지 300 몰 당량, 바람직하게는 220 내지 250 몰 당량의 양으로 사용할 수 있다. At this time, the final compound to be produced through if said step (1) to (4), wherein R ₁

And R ₂ is hydrogen, the bromine may be used in an amount of 80 to 150 molar equivalents, preferably 100 to 120 molar equivalents, based on 100 molar equivalents of the pyromellitic dianhydride, and R ₁ And R < ₂ >

The bromine may be used in an amount of 200 to 300 molar equivalents, preferably 220 to 250 molar equivalents based on 100 molar equivalents of the pyromellitic dianhydride.

The aqueous base solution may be an aqueous solution of a base such as sodium hydroxide, potassium hydroxide, barium hydroxide or calcium hydroxide.

The bromine may be added for 30 minutes to 3 hours, preferably 45 minutes to 1 hour and 30 minutes. When addition of bromine to the pyromellitic dianhydride is completed by addition of bromine, the reaction mixture is diluted with 30 To 80 ° C, preferably 40 to 60 ° C, for 30 minutes to 3 hours, preferably 45 minutes to 1 hour and 30 minutes.

After the addition reaction is carried out, a small amount of the aqueous base solution may be added to remove unreacted bromine, and then the reaction may be terminated by adding an inorganic acid.

The inorganic acid may be hydrochloric acid, nitric acid, phosphoric acid or sulfuric acid.

When the reaction is completed, the reaction product can be extracted using a solvent to prepare the compound of Formula 2.

The solvent for the extraction may be a solvent such as dichloromethane, methyl ethyl ketone, or ethyl acetate. The solvent is added and stirred for 2 to 5 hours, preferably 2 to 4 hours to obtain an organic layer in which the reactants are dissolved have.

When the extraction solvent is added to the reaction product, the reaction product can be separated into an organic layer and an aqueous solution layer. The resulting mixture of the organic layer and the aqueous solution is transferred to a separating funnel, the lower organic layer is separated, and a small amount of magnesium sulfate (MgSO ₄ ) to remove residual water and then filtrate to obtain a compound of formula (2). The compound of formula (2) may be further purified by recrystallization with a solvent such as the above-mentioned extraction solvent to obtain a pure compound of formula (2).

(2) sequentially reacting the compound of formula (3) with magnesium and trimethylborate and then hydrolyzing to prepare a compound of formula (4);

[Reaction Scheme 2]

R < ₃ > and R < ₄ > are the same as defined in the above formula (1).

The step of sequentially reacting the compound of the above formula (2), the compound of the formula (3) with magnesium and trimethylborate and then hydrolyzing the compound to prepare the compound of the formula (4)

Specifically, the compound of formula (3) is reacted with magnesium turnings and a low temperature of 0 to 5 ° C in a solvent such as tetrahydrofuran to produce compound (I), and trimethyl Compound (IV) can be prepared by hydrolyzing compound (II) by adding borate to compound (II) and then adding an acid aqueous solution to compound (II).

The acid aqueous solution may be, for example, an aqueous solution of hydrochloric acid, nitric acid, phosphoric acid or sulfuric acid.

(3) reacting the compound of formula (2) with the compound of formula (4) in the presence of a catalyst to produce a compound of formula

[Reaction Scheme 3]

In Formula 3, A ₁ and A ₂ are each independently hydrogen or bromine, and R ₁ to R ₄ are the same as defined in Formula 1.

The step of preparing the compound of the above formula (3) and the compound of the formula (5) can be represented by the above reaction formula (3).

The step (3) comprises dissolving the compound of formula (2) and the compound of formula (4) in a solvent to prepare a mixed solution, and then adding a catalyst to the mixed solution to react.

In step (3), the compound of formula (2) and the compound of formula (4) are dissolved in a solvent and completely dissolved to prepare a mixed solution, followed by addition of an inorganic base and a catalyst, followed by uniform stirring.

The solvent may be a solvent such as toluene or benzene, and the inorganic base may be sodium carbonate, calcium carbonate, or the like.

The catalyst can be a metal catalyst such as palladium or platinum and is preferably a palladium catalyst such as tetrakistriphenylphosphine palladium [((C ₆ H ₅ ) ₃ P) ₄ Pd] have.

The reaction for preparing the compound of Chemical Formula 5 may be performed by adding a catalyst to the mixed solution and then heating the mixed solution to a boiling point for 24 hours to 72 hours, preferably 36 hours to 60 hours have.

After completion of the reaction, the organic layer is separated using a separatory funnel, and the reaction solution comprising the organic layer is distilled under reduced pressure to obtain a compound of the general formula (5) as a solid residue.

When the organic layer is separated, a small amount of magnesium sulfate or the like may be added to remove residual moisture. The solid residue may be further purified by recrystallization from a solvent to obtain a pure compound of formula have.

The solvent for recrystallization may be a solvent such as ethyl acetate, dichloromethane or acetone.

(4) Submerging the compound of formula (5) under reduced pressure to prepare a compound of formula

[Reaction Scheme 4]

In the above Reaction Scheme 4, R ₁ and R ₂ are as defined in Formula 1.

Step (4) and deprotecting the compound of formula (5) to prepare the compound of formula (1) according to the present invention may be represented by the reaction formula (4).

In the present specification, the term "reduced pressure sublimation" refers to vaporization under reduced pressure without being subjected to a molten state to be collected in a crystalline phase.

The compound of formula 5 may be preferentially dried and the drying may be performed at a temperature of 200 to 300 ° C, preferably 220 to 280 ° C, and a pressure of 10 in Hg to 100 in Hg, preferably 20 in Hg to 40 in Hg Lt; RTI ID = 0.0 > 6-18 < / RTI > hours.

When the compound of formula (5) is sublimed under reduced pressure at a temperature of 200 to 350 ° C, preferably 280 to 320 ° C, and a pressure of 10 in Hg to 100 in Hg, preferably 20 in Hg to 40 in Hg, To obtain the compound of the formula (1).

Example

Hereinafter, the present invention will be described in more detail with reference to the following examples. However, the following examples are intended to illustrate the present invention, but the scope of the present invention is not limited thereto.

Example  1: 3,6-di (3 ', 5'- Bis (trifluoromethyl) benzene ) Pyromellitic dianhydride ( 12FPMDA)  Produce

Step (1): 3,6- Dibromo -1,2,4,5- Benzene tetracarboxylic acid (DBB4C)  Produce

A 1000 ml 4-neck round bottom flask equipped with a stirrer, an addition funnel, a condenser and a nitrogen inlet was thoroughly dried, and then 100 g (0.458 mol) of pyromellictic dianhydride (Mitsubishi Gas Chemical Co., Ltd.) ) And 222.22 g (NaOH, 1.83 mol) of 33 wt% sodium hydroxide aqueous solution were added and stirred to completely dissolve the pyromellitic dianhydride. To this reaction solution, 91.57 g (1.14 mol) of bromine was slowly added over 1 hour using an addition funnel. At this time, bromine was reacted in a state in which the whole of the reactor was covered with aluminum foil in order to prevent side reaction by light, and the light from the outside was cut off. After the addition was completed, the reaction mixture was further reacted at 50 DEG C for 1 hour, and a small amount of 5N aqueous sodium hydroxide solution was added to the flask to remove unreacted bromine. Thereafter, 650 g of a 10% HCl aqueous solution was added to terminate the reaction, and then dichloromethane was added thereto, followed by stirring for 3 hours to obtain an organic layer and an aqueous solution in which the reactant dissolved. The resulting mixture of the organic layer and the aqueous solution was transferred to a separating funnel and the lower organic layer was separated. A small amount of magnesium sulfate was added to the separated organic layer to remove residual water, which was then filtered and purified by recrystallization from a dichloromethane solvent to obtain pure white crystals. This was dried in a 60 DEG C vacuum oven for 6 hours to obtain the target compound, 3,6-dibromo-1,2,4,5-benzenetetracarboxylic acid (DBB4C) (yield: 90%).

The FT-IR analysis of the obtained compounds were able to identify a large peak in the alkyl CH in aromatic C = C stretching peak, 2934cm ^-1 of the C-Br bond of the peak at 1174cm ^-1, 1413cm ^-1, The It was found that the bromination reaction proceeded successfully.

Step (2): 3 ', 5'- Bis (trifluoromethyl) benzeneboronic acid (6 FBB )

A 500 ml three-neck round bottom flask with a rod magnet, an addition funnel, a condenser and a nitrogen inlet was dried, and then 9.30 g of magnesium turnings (manufactured by Aldrich) and distilled and purified tetrahydrofuran (manufactured by Fisher) , 220 ml were added. At this time, the temperature of the reactants was maintained at 0 to 5 ° C using ice. 44.0 ml of 3 ', 5'-bis (trifluoromethyl) bromobenzene (product of Aldrich) was gradually added over 1 hour by using an addition funnel while keeping the temperature of the reactant constant. After completion of the addition, the reaction solution was allowed to slowly reach room temperature, and the reaction product was further reacted at room temperature for 16 hours to obtain a dark brown viscous solution. This viscous solution was cooled and maintained at -70 ° C using dry ice and acetone, and 28.97 ml of trimethylborate (manufactured by Aldrich) was added dropwise to the viscous solution using an addition funnel.

After the addition was completed, the reaction mixture was allowed to reach room temperature and further reacted at room temperature for 12 hours to obtain a brown viscous solution. This viscous solution was mixed with 63.3 ml of an aqueous hydrochloric acid solution (37 wt%) in 144.5 ml of distilled water while maintaining the temperature below 0 ° C using ice, and the mixture was further reacted for 24 hours to obtain a water- Red organic compounds were obtained. After completion of the reaction, the organic layer was separated using a mixed liquid fractionation funnel and dried under reduced pressure. The solid residue obtained after drying was purified by recrystallization using distilled water as a solvent. The obtained white crystals were collected, washed with petroleum ether, and dried at normal temperature / pressure for 24 hours or more to obtain the target compound, 3 ', 5'-bis (Trifluoromethyl) benzeneboronic acid (6FBB) (19.44 g, yield: 85%).

Elemental analysis was performed on the obtained compound by using an element analyzer (CE Instrument EA110 analyzer), the melting point was measured using a melting point meter (Fisher 1A9100), and the structure was analyzed through FTIR .

Elemental analysis showed that the compound was composed of 37.60% carbon, 2.01% hydrogen and 12.67% oxygen. Considering the error in the equipment, it is considered that the same amount of money is composed of carbon, 37.25% of carbon, 1.95% of hydrogen and 12.41% of oxygen. Melting point 218.6 to 220.0 ℃ exhibited a range, FT-IR analysis, 1339, 1324, 1289, 1170, and a CF bond peak at 1125 cm ^-1, an aromatic C = C stretching peak at 1614 and 1410 cm ^-1, A broad peak of OH was observed at 3400 cm ^-1 .

Step (3): Synthesis of 3,6-di (3 ', 5'- Bis (trifluoromethyl) benzene ) -1,2,4,5-benzenetetracarboxylic acid (12 FB4C)  Produce

16 g (0.038 mol) of the DBB4C prepared in the above step (1) and 6FBB 20.01 (0.038 mol) prepared in the step (2) in a 1,000 ml three-necked round bottom flask equipped with a stirrer, an addition funnel, a condenser and a nitrogen inlet, g (0.0776 mol) and toluene (270 ml) were stirred and the DBB4C and 6FBB were completely dissolved. Then, 135 ml of 2 N sodium carbonate (manufactured by Aldrich) and 0.6422 g of tetrakistriphenylphosphine palladium Lt; / RTI > This homogeneous mixed solution was heated to boiling point (98 DEG C) and reacted for 48 hours. At this time, the reaction mixture gradually changed from orange to sour red. After completion of the reaction, the organic layer was separated through a separatory funnel, and a small amount of magnesium sulfate was added thereto to remove residual moisture, followed by stirring for 1 hour and then filtration. The reaction solution was distilled under reduced pressure to obtain a solid residue. The residue was dissolved in 500 ml of ethyl acetate and purified by recrystallization to obtain 3,6-di (3 ', 5'-bis (trifluoromethyl) benzene) -1 , 2,4,5-benzenetetracarboxylic acid (12FB4C) (72% yield). In the FT-IR analysis of the obtained target compound 1368, 1284 and a CF bond in the 1186 cm ^-1 peak, 1612, and aromatic C = C stretching at 1418 cm ^-1 peak, the large alkyl CH at 2934 cm ^-1 I could confirm the peak.

Step (4): Synthesis of 3,6-di (3 ', 5'- Bis (trifluoromethyl) benzene ) Pyromellitic dianhydride ( 12FPMDA)  Produce

The purified 12FB4C prepared in the above step (2) was dried at 250 DEG C under reduced pressure (30 in Hg) for 12 hours and then reduced at 30 DEG C under reduced pressure at 290 DEG C to obtain pure 3,6-di (3 ', 5'-bis (trifluoromethyl) benzene) pyromellitic dianhydride (10 g, yield: 70%).

FT-IR analysis was performed on the objective compound obtained. According to FT-IR analysis of 1368, 1284 and 1186cm ^-1 peak in the CF bond, and aromatic 1612 C = C stretching peak at 1418cm ^-1, and determine the C = O bond peaks of the anhydride groups in the 1850 cm ^-1 I could.

Example  2 : 3,6-di (3 ', 5'- Bis (trifluoromethyl) benzene ) Pyromellitic dianhydride ( 12FPMDA)  Produce

Step (1): 3,6- Dibromo -1,2,4,5- Benzene tetracarboxylic acid (DBB4C)  Produce

Except that 102.78 g (1.00 mol) of sodium bromide (NaBr) and 71.53 g (1.008 mol) of chlorine gas (Cl ₂ ) were added instead of bromine in the step (1) 6-dibromo-1,2,4,5-benzenetetracarboxylic acid (DBB4C) was prepared (yield: 80%).

In steps (2) to (4)

Then, 3,6-di (3 ', 5'-bis (trifluoromethyl) benzene) pyromellitic dianhydride (12FPMDA) was obtained in the same manner as in steps (2) (Yield: 85%).

Example  3: 3,6-di (3 ', 5'- Bis (trifluoromethyl) benzene ) Pyromellitic dianhydride ( 12FPMDA)  Produce

22.73 g (0.0776 mol) of 3 ', 5'-bis (trifluoromethyl) bromobenzene was used instead of 3', 5'-bis (trifluoromethyl) benzeneboronic acid in the step (3) (Yield: 50%) of 3,6-di (3 ', 5'-bis (trifluoromethyl) benzene) -1,2,4,5-benzenetetracarboxylic acid (12FB4C) (3 ', 5'-bis (trifluoromethyl) benzene) pyromellitic dianhydride was obtained in the same manner as in steps (1), (3) and (4) (12FPMDA) (yield: 85%).

Comparative Example  1: 3,6-di (3 ', 5'- Bis (trifluoromethyl) benzene ) Pyromellitic dianhydride ( 12FPMDA)  Produce

Step (1): 3 ', 6- Dibromo -1,2,4,5- Tetramethylbenzene (2B4MB)  Produce

A 150 ml four-necked round bottom flask equipped with a stirrer, an addition funnel, a condenser and a nitrogen inlet was thoroughly dried and then charged with 8.0 g of 1,2,4,5-tetramethylbenzene (manufactured by Aldrich) and 0.124 g And 23.84 ml of dichloromethane were added and completely dissolved by stirring. 22.86 ml of bromine was added to the reaction solution over 2 hours using an addition funnel. At this time, the bromine was reacted in a state in which the whole of the reactor was covered with aluminum foil in order to prevent the side reaction by light, and the light from the outside was cut off. After the addition was completed, the reaction mixture was further reacted at 50 DEG C for 1 hour, and a small amount of 5N aqueous sodium hydroxide solution was added to the flask to remove unreacted bromine. The resulting mixture of the organic layer and the aqueous solution was transferred to a separating funnel and the lower organic layer was separated. A small amount of magnesium sulfate was added to the separated organic layer to remove residual water, followed by filtration. The dichloromethane was purified by recrystallization using a solvent to obtain pure white crystals. This was dried in a 60 DEG C vacuum oven for 6 hours to obtain the objective compound, 3 ', 6-dibromo-1,2,4,5-tetramethylbenzene (16.53 g, yield: 95%).

The obtained compound was analyzed using FT-IR. FT-IR analysis confirmed a binding peak of C-Br at 1174 cm ^-1 , an aromatic C═C stretching peak at 1413 cm ^-1 , and a broad peak of alkyl CH at 2934 cm ^-1 .

Step (2): 3 ', 5'- Bis (trifluoromethyl) benzeneboronic acid (6 FBB )

A 500 ml three-neck round bottom flask with a rod magnet, an addition funnel, a condenser and a nitrogen inlet was dried, and then 9.30 g of magnesium turnings (manufactured by Aldrich) and distilled and purified tetrahydrofuran (manufactured by Fisher) , 220 ml were added. At this time, the temperature of the reactants was maintained at 0 to 5 ° C using ice. 44.0 ml of 3 ', 5'-bis (trifluoromethyl) bromobenzene (product of Aldrich) was gradually added over 1 hour by using an addition funnel while keeping the temperature of the reactant constant. After completion of the addition, the reaction solution was allowed to slowly reach room temperature, and the reaction product was further reacted at room temperature for 16 hours to obtain a dark brown viscous solution. This viscous solution was cooled and maintained at -70 ° C using dry ice and acetone, and 28.97 ml of trimethylborate (manufactured by Aldrich) was added dropwise to the viscous solution using an addition funnel.

After the addition was completed, the reaction mixture was allowed to reach room temperature and further reacted at room temperature for 12 hours to obtain a brown viscous solution. This viscous solution was mixed with 63.3 ml of an aqueous hydrochloric acid solution (37 wt%) in 144.5 ml of distilled water while maintaining the temperature below 0 ° C using ice, and the solution was further reacted for 24 hours, A dark red organic compound was obtained. After completion of the reaction, the organic layer was separated using a mixed liquid fractionation funnel and dried under reduced pressure. The solid residue obtained after drying was purified by recrystallization using distilled water as a solvent. The obtained white crystals were collected, washed with petroleum ether, and dried at normal temperature / pressure for 24 hours or more to obtain the target compound, 3 ', 5'-bis (Trifluoromethyl) benzeneboronic acid (6FBB) (19.44 g, yield: 85%).

Elemental analysis was performed on the obtained compound by using an element analyzer (CE Instrument EA110 analyzer), the melting point was measured using a melting point meter (Fisher 1A9100), and the structure was analyzed through FTIR .

Elemental analysis showed that the compound was composed of 37.60% carbon, 2.01% hydrogen and 12.67% oxygen. Considering the error in the equipment, it is considered that the same amount of money is composed of carbon, 37.25% of carbon, 1.95% of hydrogen and 12.41% of oxygen. Melting point 218.6 to 220.0 ℃ exhibited a range, FT-IR analysis, 1339, 1324, 1289, 1170, and a CF bond peak at 1125 cm ^-1, an aromatic C = C stretching peak at 1614 and 1410 cm ^-1, A broad peak of OH was observed at 3400 cm ^-1 .

Step (3): Synthesis of 3,6-di (3 ', 5'- Bis (trifluoromethyl) benzene ) -1,2,4,5- Of tetramethylbenzene (12F4MB)  Produce

270 ml of 3 ', 6-dibromo-1,2,4,5-tetramethylbenzene (2B4MB) was added to a 1000 ml three-necked round bottom flask equipped with a stirrer, bar magnet, addition funnel, condenser and nitrogen inlet, Of toluene were added and stirred to dissolve completely. 135 ml of 2N sodium carbonate and 0.6422 g of tetrakis (triphenylphosphine) palladium (Aldrich) were added and stirred uniformly. A solution of 43 g of the 3 ', 5'-bistrifluoromethylbenzeneboronic acid prepared in the above step (2) in 67.5336 ml of ethanol was added to the homogeneous mixed solution, and the mixed reaction product reached the boiling point (98 ° C) Lt; / RTI > for 3 days. At this time, the reaction mixture gradually changed from orange to sour red. After completion of the reaction, the organic layer was separated through a separatory funnel, and a small amount of magnesium sulfate was added thereto to remove residual water, followed by stirring for 1 hour and then filtration. The reaction solution was distilled under reduced pressure to obtain a solid residue. The residue was dissolved in 500 ml of ethyl acetate and purified by recrystallization to obtain 3,6-di (3 ', 5'-bis (trifluoromethyl) benzene) -1, 2,4,5-tetramethylbenzene (12F4MB) was obtained (22.96 g, 70% yield).

The obtained target compound was analyzed by FT-IR. Melting point 246.7 to ℃ exhibited a range of 246.9 ℃ in the FT-IR analysis at 1368, 1284, and 1186cm ^-1 CF bond peaks, 1612, and 1418cm ^-1 in the aromatic C = C stretching peak, alkyl from 2934cm ^-1 CH A wide peak of < RTI ID = 0.0 >

Step (4): Synthesis of 3,6-di (3 ', 5'- Bis (trifluoromethyl) benzene ) -1,2,4,5-benzenetetracarboxylic acid (12 FB4C)  Produce

(3 ', 5'-bis (trifluoromethyl) benzene) -1, 3'-bis (trifluoromethyl) benzene prepared in the above step (3) was placed in a 1,000 ml 3-neck round bottom flask equipped with a stirrer, an addition funnel, 22.96 g of 2,4,5-tetramethylbenzene (12F4MB) was mixed with 479.5 ml of pyridine and stirred to completely dissolve, and 63.93 ml of distilled water was further added. The reaction mixture was heated and boiled (95 DEG C). 30.73 g of potassium permanganate was added to the reaction solution over a period of 4 hours using an addition funnel, and the reaction solution was further reacted for 1 hour when the color of the reaction solution changed from purple to black. After completion of the reaction, the permanganate in the aqueous solution was removed by filtration, and the reaction aqueous solution was distilled under reduced pressure to obtain a solid residue. The resulting solid residue was boiled (95 [deg.] C) with 25.57 g of sodium hydroxide and 400 ml of distilled water in a 1,000 ml three-necked round bottom flask equipped with a stirrer, an addition funnel and a condenser. 30.73 g of potassium permanganate was added to the reaction solution over a period of 5 hours using an addition funnel, 31 ml of ethanol was added to remove unreacted potassium permanganate, and the precipitate was filtered to obtain a transparent basic aqueous solution. The aqueous solution was acidified by adding a small amount of hydrochloric acid to obtain leached white crystals. After filtration, the crystals were washed with distilled water and filtered to obtain 3,6-di (3 ', 5'-bis (trifluoromethyl) ) Benzene) -1,2,4,5-benzenetetracarboxylic acid (12FB4C) (13.18 g, yield: 70%).

The objective compound obtained was analyzed using FT-IR. In the FT-IR analysis 1368, 1284, and a CF bond in the peak 1186cm ^-1, 1612, and the carboxyl group at the aromatic C = C stretching peak at 1728cm ^-1 1418cm ^-1 C = O bond of the peak, and The broad peak of OH at 3400 cm ^{- 1} peak was confirmed and it was confirmed that the title compound was generated.

Step (5): Synthesis of 3,6-di (3 ', 5'- Bis (trifluoromethyl) benzene ) Pyromellitic dianhydride (12 FPMDA )

The 3,6-di (3 ', 5'-bis (trifluoromethyl) benzene) -1,2,4,5-benzenetetracarboxylic acid prepared in the step (4) in Hg) for 12 hours and then sublimed under reduced pressure (30 in Hg) at 290 ° C to obtain the pure title compound, 3,6-di (3 ', 5'-bis (trifluoromethyl) benzene) pyromellitic acid (10 g, yield: 80%).

The objective compound obtained was analyzed using FT-IR. In the FT-IR analysis 1368, 1284, and a CF bond peaks, 1612, and aromatic C = C stretching peak, and C = O bond of the anhydride peak at 1850 cm ^-1 of the group at 1418cm ^-1 in 1186cm ^-1 I could confirm. It was confirmed that the title compound was produced.

Claims (8)

(1) brominating pyromellitic dianhydride to produce a compound of formula (2);
(2) sequentially reacting the compound of formula (3) with magnesium and trimethylborate and then hydrolyzing to prepare a compound of formula (4);
(3) reacting a compound represented by the following formula (2) and a compound represented by the following formula (4) under a catalyst to prepare a compound represented by the following formula (5); And
(4) Submerging the compound of the following formula (5) under reduced pressure to prepare a compound of the formula
Wherein the fluorinated pyromellitic dianhydride is represented by the following formula (1): < EMI ID =
[Chemical Formula 1]

(2)

(3)

[Chemical Formula 4]

[Chemical Formula 5]

In the above formulas,
R ₁ and R ₂ are each independently hydrogen or

And, R ₃ and R ₄ each independently represent a fluorine-substituted C _{1 - 4} alkyl and, wherein R ₁ and R ₂ are not simultaneously hydrogen;
A ₁ and A ₂ are each independently hydrogen or bromine.
The method according to claim 1,
Wherein the step (1) of producing the compound of the formula (2) comprises the step of dissolving the pyromellitic dianhydride in an aqueous base solution and adding bromine to the mixture to react the fluorinated pyromellitic dianhydride.
The method according to claim 1,
The step (3) of preparing the compound of formula (5) comprises dissolving the compound of formula (2) and the compound of formula (4) in a solvent to prepare a mixed solution, ≪ / RTI > wherein the fluorinated pyromellitic acid dianhydride is a fluorinated pyromellitic dianhydride.
The method of claim 3,
Wherein the reaction is carried out by adding the catalyst to the mixed solution and reacting the mixed solution for 24 to 72 hours while heating the mixed solution to a boiling point.
The method according to claim 1,
Wherein the catalyst is tetrakistriphenylphosphine palladium. ≪ RTI ID = 0.0 > 8. < / RTI >
The method according to claim 1,
Wherein in the step (4), the depressurization sublimation is carried out at a temperature of 200 to 350 DEG C and a pressure of 10 in Hg to 100 in Hg.
The method according to claim 1,
Wherein R < _{1 &}

≪ / RTI > and R < ₂ > is hydrogen.
The method according to claim 1,
Wherein R ₁ and R ₂ is

Wherein the fluorinated pyromellitic acid dianhydride is a fluorinated pyromellitic dianhydride.