JP2000186080A - Production of high-purity hydroquinone bis(anhydrotrimellitate) - Google Patents

Abstract

PROBLEM TO BE SOLVED: To produce the subject high-purity compound by converting a reactional crude substance prepared by transesterification of a lower alkanoic acid ester of hydroquinone with trimellitic anhydride to form into a slurrylike form with a specific solvent and then purifying the resultant substance with a specified solvent. SOLUTION: A reactional crude substance of hydroquinone bis(anhydrotrimellitate) obtained by the transesterification of a lower alkanoic acid ester of hydroquinone represented by the formula (R1 and R2 are each a 1-3C alkyl) (e.g. an acetic acid ester, a propionic acid ester or a butyric acid ester of hydroquinone) with trimellitic anhydride is converted into a slurrylike form by using one or more kinds of lactonic solvents (e.g. γ-butyrolactone or α-methylene-γ-butyrolactone) and the resultant substance is then purified by using a mixed solvent composed of one or more kinds of the above solvents and a 6-20C aromatic or a 6-20C aliphatic hydrocarbon (e.g. xylene, toluene, benzene, cyclohexane or hexane) to thereby afford the high-purity objective compound.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a method for producing high-purity hydroquinone bis (anhydrotrimellitate).

[0002]

2. Description of the Related Art General formula (2) The hydroquinone bis (anhydrotrimellitate) (hereinafter referred to as “TMHQ”) is useful as a polyimide raw material. When TMHQ is supplied as a polyimide raw material, in order to obtain a high molecular weight polyimide, TM
It is required that the purity of HQ is 98% by weight or more, and when a polyimide film is formed, no gel-like foreign matter derived from TMHQ occurs and the surface of the film is smooth. Here, the gel-like foreign matter is a particulate foreign matter having a size of 1 to 100 μm in diameter, which is observed with an optical microscope at a magnification of 100 times, and when the foreign matter is present in the polyimide film, the mechanical properties of the polyimide film Strength, electrical characteristics, etc. are impaired.

On the other hand, the following method is known as a method for producing TMHQ. (1) A method of reacting trimellitic anhydride chloride with phenols (or diols) in a solvent such as benzene or toluene (JP-B-43-5911). (2) A method by heating trimellitic anhydride and diols to 200 ° C. or higher (Japanese Patent Publication No. 45-29974)
issue). (3) A method of transesterifying a lower alkanoic acid ester of a phenol with trimellitic anhydride in the presence of an inorganic compound catalyst (JP-A-7-41472).

However, in these production methods, high-purity TMHQ having a purity of 98% by weight or more cannot be obtained.
Further, in the method shown in (1), it is necessary to use trimellitic anhydride chloride which is expensive and has a problem in terms of safety and hygiene, and there are many industrial problems.

As a method for producing high-purity TMHQ, Japanese Patent Application Laid-Open No. 10-36364 discloses a method for preparing TMHQ from a lower alkanoic acid ester of hydroquinone and trimellitic anhydride.
The HQ reaction crude is obtained, and then the reaction crude is directly taken out of the reaction vessel, and the crude is purified by using a mixed solvent of a hydrophobic solvent and a solvent such as ketone, ether and ester. Purity of TMHQ is obtained. In this method, it is necessary to directly remove the solid TMHQ crude from the reaction vessel, and there is a problem that workability is poor.

Further, depending on the method of producing TMHQ, H
Although it is a high-purity TMHQ in PLC, it contains foreign matter that cannot be detected by analysis such as HPLC, and gel-like foreign matter occurs in the film when the polyimide film is formed, and the mechanical strength decreases when used for polyimide film In some cases, such problems as TMHQ occur, and higher purification is required.

[0007]

DISCLOSURE OF THE INVENTION The present invention is to produce a high-purity TMHQ useful as a polyimide raw material, in which no gel-like foreign matter derived from TMHQ is formed in the film when the polyimide film is formed, efficiently and with good workability. The aim is to provide a method.

[0008]

Means for Solving the Problems The inventors of the present invention have conducted intensive studies to achieve the object, and as a result, the TMHQ reaction crude product is slurried using a specific solvent and then purified using a specific solvent. It has been found that the intended purpose is achieved by the series of steps described above, and the present invention has been completed based on such knowledge. In the present invention, the slurry refers to a state in which TMHQ and / or a crude TMHQ reaction precipitate in a solvent in a solid state having a diameter of 10 μm to 5 mm having fluidity and are suspended or dispersed.

That is, the present invention provides a compound represented by the general formula (1) [Wherein, R ¹ and R ² are the same or different and each have 1 to 1 carbon atoms.
3 represents an alkyl group. In the production of hydroquinone bis (anhydrotrimellitate) by transesterification of a lower alkanoic acid ester of hydroquinone represented by the following formula and trimellitic anhydride, hydroquinone bis (anhydrotrimellitate) obtained by the transesterification reaction The reaction crude is made into a slurry using a solvent belonging to the group (A), and then purified using a mixed solvent consisting of the groups (A) and (B). Group (A): One or more lactone solvents. Group (B): One or more aromatic or aliphatic hydrocarbons having 6 to 20 carbon atoms.

At the same time, the present invention provides a method for producing a hydroquinone bis (anhydrotrimellitate) by transesterification of a lower alkanoic acid ester of hydroquinone represented by the general formula (1) with trimellitic anhydride. A hydroquinone bis (anhydrotrimellitate) reaction crude product obtained by the reaction is converted into a slurry using a solvent belonging to Group (A), and then purified using a solvent belonging to Group (A). A method for producing high-purity hydroquinone bis (anhydrotrimellitate) is also provided.

Further, the present invention relates to a hydroquinone bis (anhydrotrimellitate) having a purity of 98% by weight or more, a polyimide film formed on a smooth surface and a gel-like film in the film. Also provided is a high-purity hydroquinone bis (anhydrotrimellitate) which does not generate foreign matter.

[0012]

BEST MODE FOR CARRYING OUT THE INVENTION The lower alkanoic acid ester of hydroquinone represented by the general formula (1) according to the present invention includes:
Examples thereof include acetate, propionate and butyrate of hydroquinone, and particularly preferably acetate.

[0013] The lower alkanoic acid esters of hydroquinone can be prepared using conventional esterification techniques. Specific methods include, in the absence of a catalyst, a method of using an excess of an alkanoic anhydride to form an alkanoic acid ester,
A method of reacting hydroquinone with an alkanoic acid or an alkanoic anhydride in the presence of a conventionally known esterification catalyst (see Organic Chemistry I, pp. 181 to 189, written by Sumio Umezawa, Maruzen Co., 1959, etc.), and the like. Is exemplified.

In the transesterification reaction between the lower alkanoic acid ester of hydroquinone and trimellitic anhydride (hereinafter referred to as "TMA") according to the present invention, the amount of TMA charged to 1 mole of the lower alkanoic acid ester of hydroquinone is 1 0.8 to 5.0 mol, more preferably 2.0 to 4.0 mol. If the charged amount of TMA is less than 1.8 mol, hydroquinone monoacetyl mono (anhydrotrimellitate) is liable to be generated in the reaction crude, which is very difficult to remove from hydroquinone bis (anhydrotrimellitate). It is not preferable because it becomes difficult.
On the other hand, if it exceeds 5.0 moles, the purity of the reaction crude will be low, and the following purification steps will not provide the desired purity, or if it is obtained, it will be necessary to increase the number of purifications. Is not preferred.

The transesterification can be carried out without a catalyst or in the presence of a catalyst. Suitable catalysts include acid catalysts such as sulfuric acid and p-toluenesulfonic acid, zeolites, and the like.
Silica-alumina catalysts such as bentonite and kaolin,
Examples thereof include alkali metal salt-based catalysts such as sodium acetate and sodium hydroxide, tertiary amines, and triphenylphosphine. Depending on the use of TMHQ, the presence or absence of the catalyst and the type thereof can be appropriately selected. . For example, TM
When HQ is used as a polyimide raw material for electronic components, tertiary amines, sulfuric acid, etc., which are non-catalytic or in the form of a catalyst in a liquid form, are preferred.

The amount of the catalyst to be added is appropriately selected depending on the type of the catalyst and the conditions of the transesterification reaction.
0 to 10% by weight based on the total amount of A is exemplified, and more preferably 0 to 5% by weight is recommended.

The transesterification is carried out under stirring,
The reaction temperature is usually 150 to 300 ° C., especially 22
It is carried out by successively distilling the lower alkanoic acid generated during the transesterification reaction out of the reaction system at normal pressure or under reduced pressure.

In order to promote the transesterification more advantageously, it is effective to use an entrainer such as xylene, toluene, or anisole during the reaction, or to pass a gas inert to the reaction, such as nitrogen gas or carbon dioxide gas. .

Regarding the reaction pressure, the reaction can be more effectively advanced by gradually reducing the pressure to 500 to 20 mmHg in the latter half of the transesterification reaction.

The amount of lower alkanoic acid distilled in the transesterification reaction is, for example, 65% by weight or more of the theoretical amount, and preferably 90% by weight or more. The reaction time varies depending on the reaction conditions, but is usually 0.5 to 20 hours.

The TMHQ reaction crude product produced by the transesterification reaction is continuously converted into a slurry by adding a solvent belonging to the group (A) into the reaction system and stirring. On this occasion,
Preferably the temperature is above 200 ° C., more preferably 24
The solvent of the group (A) is added to the TMHQ reaction crude at 0 to 220 ° C., and the slurry is formed by stirring for 0.1 to 5 hours, preferably 0.2 to 1 hour while cooling slowly.

The solvent according to the group (A) is a lactone-based solvent, and one kind or a mixture of two or more kinds is used as appropriate.

Specific lactone solvents include γ-butyrolactone, α-methylene-γ-butyrolactone and the like. Among them, γ-butyrolactone is a preferred solvent used for slurrying.

The amount of the solvent belonging to the group (A) at the time of slurrying is 50 to 100 parts by weight of the crude product of TMHQ reaction.
To 300 parts by weight. If the amount of the solvent used is less than 50 parts, the slurry becomes very high in concentration and it is very difficult to extract the slurry. If the amount exceeds 300 parts by weight, the yield of the TMHQ crude material decreases, which is not preferable as an industrial method.

The slurried TMHQ is subsequently purified by any of the following methods (1) to (3) to obtain high-purity TMHQ.

(1) A method of filtering and drying the slurry to obtain high-purity TMHQ. (2) A solvent of group (B) is added to the slurry to form a mixed solvent consisting of group (A) and group (B). TMHQ is purified using this mixed solvent, followed by filtration and drying. A method for obtaining high purity TMHQ. (3) A method of filtering the slurry, adding a mixed solvent consisting of groups (A) and (B) to purify TMHQ, and subsequently filtering and drying to obtain high-purity TMHQ.

[0027] Among the above three purification methods, when a higher purity TMHQ is desired, the method (3) is used.
In consideration of the isolation yield, the method (1) or (2) is preferable.

As the solvent according to the group (B), those having 6 to 6 carbon atoms are used.
20 aromatic or aliphatic hydrocarbons, specifically, aromatic hydrocarbons such as benzene, toluene, xylene, and ethylbenzene; and aliphatic chain or aliphatic cyclic hydrocarbons such as hexane, octane, and cyclohexane. Xylene, toluene, benzene, cyclohexane and hexane are particularly preferred. These solvents belonging to the group (B) may be used alone or in combination of two or more.

Hereinafter, the three methods will be specifically described.

(1) The slurry is filtered and dried to obtain a high purity
This is a method for obtaining TMHQ by removing the solvent of group (A) from the slurry, and is generally performed by filtration or centrifugation.

After cooling the slurry to about 40 ° C., high purity TMHQ is obtained by filtration or centrifugation, and subsequently under normal pressure or reduced pressure (preferably 5 to 300 mmHg).
High-purity TMHQ is obtained by drying at room temperature to 200 ° C. for about 0.1 to 20 hours.

It is recommended to use 100 to 300 parts by weight of the solvent of the group (A) per 100 parts by weight of the crude TMHQ reaction product.

If necessary, the TMHQ filtered crystal may be
Alternatively, the TMHQ from which the solvent has been removed may be purified again using the solvent of the group (A).

(2) The solvent of group (B) is added to the slurry and mixed.
A method of obtaining a high-purity TMHQ by purifying as a mixed solvent This is a method of adding a solvent of the group (B) to the slurry to prepare and purify a mixed solvent composed of the groups (A) and (B) in the system. .

In this case, it is more preferable to use 100 to 300 parts by weight of the solvent of the group (A) per 100 parts by weight of the crude TMHQ reaction product as the amount of the solvent of the group (A) to be slurried.

After adding the solvent of group (B) to the slurry at a temperature of 30 to 150 ° C.,
Preferably, the mixture is heated and stirred at 30 to 160 ° C. for 0.1 to 10 hours to dissolve or suspend. Next, the system is gradually cooled to 40 ° C. or lower, and the precipitate is filtered out according to the method (1) to obtain a TMHQ filtered crystal. High purity TMHQ obtained
The filtered crystals are dried according to the method (1).

In addition, when the solvent of the group (B) is added to the slurry, the amount of the solvent of the group (B) may be a solvent belonging to the group (A) and a solvent belonging to the group (B) when the mixed solvent is obtained. (Solvent of group A / solvent of group B) is 0.5 / 9.5.
The amount of the solvent is from 9.5 / 0.5 to 9.5 / 0.5, and preferably, the mixed solvent is from 5/5 to 9.5 / 0.5.

(3) After the slurry is filtered off, group (A) and
Purification with a mixed solvent of group (B) to obtain high-purity TMHQ
This is a method of removing the solvent of group (A) from the slurry to obtain a TMHQ filtered crystal, and then purifying the crystal using a mixed solvent consisting of group (A) and group (B). In particular, the method (1) or (2) is effective when the purity of TMHQ is insufficient.

In this case, it is more preferable to use 80 to 250 parts by weight of the solvent of the group (A) per 100 parts by weight of the crude TMHQ reaction product as the amount of the solvent of the group (A) to be slurried.

According to the method (1), the slurry is filtered or centrifuged to obtain TMHQ filtered crystals. The separated crystals are further purified using a mixed solvent consisting of the groups (A) and (B).

The solvent belonging to the group (A) at the time of slurrying is preferably the same as the solvent which is a component of the mixed solvent used for purification.

When the purification is carried out using a mixed solvent consisting of groups (A) and (B), the solvent belonging to group (A) and (B)
The mixing weight ratio of the solvents belonging to the group (solvent of group A / solvent of group B) is usually 0.5 / 9.5 to 9.5 / 0.5, preferably 0.5 / 9.5. It is appropriately selected within the range of ５ to ／. When the ratio of the solvent belonging to Group B is high, it is difficult to obtain a predetermined high-purity product, and when the ratio is extremely low, the yield of the purified product is reduced.

The amount of the mixed solvent used is preferably T
The amount is 50 to 1000 parts by weight, preferably 200 to 400 parts by weight, based on 100 parts by weight of the MHQ filtered crystal. If the amount of the solvent used is less than 50 parts by weight, it is difficult to obtain high-purity TMHQ, and if it exceeds 1000 parts by weight, the yield decreases, which is not preferable as an industrial method.

In the purification, (A) was added to the TMHQ filtered crystal.
After adding the mixed solvent consisting of the group (B) and the group (B), 100
The mixture is heated and stirred at about -200 ° C, preferably about 100-160 ° C, and dissolved or suspended. Next, the slurry obtained by gradually cooling the system to 40 ° C. or lower is separated by filtration according to the method (1). The obtained crystals are desirably washed with the above-mentioned mixed solvent. Next, the solvent remaining in the TMHQ crystal is removed by drying to obtain high-purity TMHQ. The operation is desirably performed in an atmosphere of an inert gas such as nitrogen gas for safety.

In the purification method using a mixed solvent of (2) or (3), a preferred combination of a mixed solvent comprising a solvent belonging to the group (A) and a solvent belonging to the group (B) is * γ-butyrolactone (A) : Xylene (B), * γ-butyrolactone (A): hexane (B).

For the purpose of further purifying the high-purity TMHQ before drying obtained by the purification method of (1) to (3), the filtered TMHQ or the TMHQ after removing the solvent is further subjected to (A) The purification may be repeated using a mixed solvent consisting of the group (B) and the group (B).

The high-purity TMHQ thus obtained can be used as a raw material for a heat-resistant resin such as polyimide, a curing agent for an epoxy resin or a urethane resin, an intermediate raw material for a chemical product, a resin modifier, and the like.

[0048]

The present invention will be described below in detail with reference to examples. In addition, the purity of the product in each example was measured by high performance liquid chromatography.

Preparation of Polyimide Film TMHQ (1 mol) and 4,4'-diaminodiphenyl ether (1 mol) were amide-bonded in N, N-dimethylacetamide (the amount of a solvent to give a substrate concentration of 10% by weight) at room temperature for 10 hours. The reaction is carried out to obtain a polyamic acid. The N, N-dimethylacetamide solution of this polyamic acid was cast on a glass plate, and was heated from room temperature to 300 mm under a reduced pressure of 5 mmHg.
C. and gradually heated to 300.degree. C., and when heated to 300.degree. C., heated for 5 to 20 minutes to prepare a polyimide film having a thickness of about 20 .mu.m.

Observation of Polyimide Film The presence or absence of protrusions and gel-like foreign matters on the surface of the imide film is observed using an optical microscope of 100 times.

Production Example 1 Hydroquinone 11 was placed in a 1 L four-necked flask equipped with a stirrer, a thermometer, a decanter equipped with a cooling tube, and a nitrogen gas inlet.
0.1 g (1.0 mol) and 306.3 g of acetic anhydride
(3.0 mol) at 130 ° C. in a nitrogen atmosphere.
Allowed to react for hours. After completion of the reaction, excess acetic anhydride and generated acetic acid were distilled off under reduced pressure to obtain 192.2 g (yield: 99%) of hydroquinone diacetate having a purity of 99.9%.

Example 1 In the same apparatus as in Production Example 1, 58.3 g (0.3 mol) of hydroquinone diacetate obtained in Production Example 1 and TMA18
In a nitrogen atmosphere, 4.4 g (0.96 mol) was charged.
The temperature was raised to 60 ° C. The reaction was carried out at the same temperature for 0.5 hour, and further, the pressure was gradually reduced to 80 mmHg, and the reaction was carried out for 0.5 hour.
The pressure was returned to normal pressure with nitrogen to obtain a crude reaction product. This reaction crude is
After cooling to 25 ° C., 516.8 g of γ-butyrolactone
(2.5 weight times the theoretical reaction crude) was added dropwise over 0.5 hour with stirring. At the end of the drop, the temperature dropped to 85 ° C. It was further cooled to 40 ° C. to obtain a TMHQ slurry.

The TMHQ slurry was filtered to obtain a separated crystal. The separated crystals were dried at 140 ° C. for 10 hours under a reduced pressure of 5 mmHg to give a TMHQ purity of 98.7%.
62 g of TMHQ having an A content of 1.0% and hydroquinone monoacetyl mono (anhydrotrimellitate) (hereinafter referred to as "TMHQ mono-form") 0.3% was obtained. The yield (vs. the theoretical reaction crude) was 30%.

10 g of the obtained TMHQ was mixed with 90 g of N,
When dissolved in N-dimethylformamide (hereinafter referred to as "DMF"), no turbidity was observed in the obtained solution.

Further, 4.64 g of this TMHQ (TMHQ
1.0 mol), 2.0 g (1.0 mol) of 4,4'-diaminodiphenyl ether and 59.8 g of N, N-dimethylacetamide were placed in a 100 ml three-necked flask equipped with a stirrer and a nitrogen gas inlet. The mixture was charged in an atmosphere and stirred at room temperature for 10 hours to obtain a viscous polyamic acid solution having a solid content of 10% by weight. The polyamic acid solution was cast on a glass plate, gradually heated from room temperature to 300 ° C. under a reduced pressure of 5 mmHg, and heated at 300 ° C. for 10 minutes to obtain a polyimide film having a thickness of 20 μm. Peel this polyimide film from the glass plate,
When observed with an optical microscope of 100 times, no gel-like foreign matter was observed and the film surface was smooth.

Example 2 After the TMHQ reaction crude was synthesized in the same manner as in Example 1,
At 5 ° C., 252.2 g of γ-butyrolactone (1.22 times the weight of the theoretical reaction crude) was added dropwise with stirring over 0.5 hours. At the end of the drop, the temperature dropped to 125 ° C. It was further cooled to 40 ° C. to obtain a TMHQ slurry.

The TMHQ slurry was filtered to obtain 116.3.
g of filtered crystals were obtained. A part of the crystal separated by filtration is 5 mmHg.
After drying at 140 ° C. for 10 hours under reduced pressure of
MHQ purity 96.2%, TMA content 3.0%, TMH
The Q mono body was 0.8%. The solid content in the filtered crystal was 80% by weight, and the remaining 20% by weight was a solvent.

Next, 100 g (solid content: 80 g) of the obtained filtered crystals, 48 g of γ-butyrolactone and xylene 1
Under a nitrogen gas atmosphere, 92 g of the mixture was charged in the same apparatus and stirred at the reflux temperature of the mixed solvent (142 ° C.) for 2 hours. Then 4
After cooling to 0 ° C., the mixture was filtered, and the obtained separated crystals were washed with a mixed solvent of 6 g of γ-butyrolactone and 24 g of xylene. Further, the filtered crystal was subjected to 120 ° C. under a reduced pressure of 5 mmHg.
, Dried at a temperature of 10 hours, TMHQ purity 99.1%, T
TMH with MA content 0.8%, TMHQ mono body 0.1%
71.1 g of Q was obtained. Purification yield (vs. theoretical crude) is 4
It was 0%.

The obtained TMHQ was used as a DMF solution in the same manner as in Example 1 to prepare a polyimide film.
No turbidity was observed in the DMF solution, no gel-like foreign matter was observed in the polyimide film, and the film surface was smooth.

Example 3 A TMHQ reaction crude product was synthesized in the same manner as in Example 1,
At 5 ° C., 413.4 g of γ-butyrolactone (2 times the weight of the theoretical reaction crude) was added dropwise with stirring over 0.5 hours.
At the end of the addition, the temperature was 95 ° C. It was further cooled to 40 ° C. to obtain a TMHQ slurry.

The TMHQ slurry was filtered and 103.4
g of filtered crystals were obtained. A part of the crystal separated by filtration is 5 mmHg.
After drying at 140 ° C. for 10 hours under reduced pressure of
MHQ purity 97.4%, TMA content 2.2%, TMH
The Q mono body was 0.4%, and the solid content was 80%.

Next, 90 g (solid content: 72 g) of the obtained separated crystals, 108 g of γ-butyrolactone and xylene 1
08 g was charged into a similar apparatus under a nitrogen gas atmosphere, and the mixture was stirred at the reflux temperature of the mixed solvent (145 ° C.) for 2 hours. Then 4
After cooling to 0 ° C., the mixture was filtered, and the obtained separated crystals were washed with a mixed solvent of 15 g of γ-butyrolactone and 15 g of xylene. Further, the separated crystals were filtered under reduced pressure of 5 mmHg for 120 minutes.
Dried at a temperature of 10 ° C. for 10 hours, TMHQ purity 99.8%,
66.1 g of TMHQ having a TMA content of 0.2% was obtained. Purification yield (vs. theoretical crude) was 32%.

The obtained TMHQ was used as a DMF solution in the same manner as in Example 1 to prepare a polyimide film.
No turbidity was observed in the DMF solution, no gel-like foreign matter was observed in the polyimide film, and the film surface was smooth.

Example 4 After the TMHQ reaction crude was synthesized in the same manner as in Example 1,
At 5 ° C., 252.2 g of γ-butyrolactone (1.22 times the weight of the theoretical reaction crude) was added dropwise with stirring over 0.5 hours. At the end of the dropwise addition, the temperature was 127 ° C. Then 1
After 28.0 g of xylene was added dropwise at 25 ° C. with stirring for 5 minutes, the mixture was cooled to 40 ° C. to obtain a TMHQ slurry. The TMHQ slurry was filtered to obtain 126.6 g of crystals separated by filtration. A part of the separated crystals was filtered under reduced pressure of 5 mmHg to 14
After drying at 0 ° C. for 10 hours, TMHQ purity 9
3.5%, TMA content 5.5%, TMHQ monobody
0% and the solids content was 80%.

Then, 100 g (solid content: 80 g) of the obtained filtered crystals, 48 g of γ-butyrolactone and xylene 19
2 g of the mixture was charged into a similar apparatus under a nitrogen gas atmosphere, and the mixture was stirred at the reflux temperature of the mixed solvent (142 ° C.) for 2 hours. Then 40
After cooling to 0 ° C., the mixture was filtered, and the obtained separated crystals were washed with a mixed solvent of 6 g of γ-butyrolactone and 24 g of xylene. Further, the filtered crystal was subjected to 120 ° C. under a reduced pressure of 5 mmHg.
, Dried at a temperature of 10 hours, TMHQ purity 98.6%, T
TMH with MA content 1.2% and TMHQ mono body 0.2%
90.9 g of Q was obtained. Purification yield (vs. theoretical crude) is 4
4%.

The obtained TMHQ was used as a DMF solution in the same manner as in Example 1 to prepare a polyimide film.
No turbidity was observed in the DMF solution, no gel-like foreign matter was observed in the polyimide film, and the film surface was smooth.

Example 5 Hydroquinone 3 was placed in a 1 L four-necked flask equipped with a stirrer, a thermometer, a decanter equipped with a cooling tube, and a nitrogen gas inlet.
3.0 g (0.3 mol), acetic anhydride 91.9 g (0.9
Mol) and 2.5 g of lauryldimethylamine (0.01
Mol), and reacted at 130 ° C. for 0.5 hour in a nitrogen atmosphere. A portion was taken out and analyzed. As a result, the purity of hydroquinone diacetate was 99.9%.

Next, 184.4 g (0.96 mol) of TMA was charged and heated to 220 ° C. under a nitrogen atmosphere.
The reaction was carried out at the same temperature for 0.5 hour, and the temperature was further raised to 225 ° C
The pressure was gradually reduced to 80 mmHg, and the reaction was performed for 0.5 hour.
The pressure was returned to normal pressure with nitrogen to obtain a crude reaction product. 252.2 g of γ-butyrolactone (1.22 times the weight of the theoretical reaction crude) was added dropwise to the reaction crude at 225 ° C. over 0.5 hour with stirring. At the end of the dropwise addition, the temperature was 129 ° C. Further 40
It cooled to ° C and obtained TMHQ slurry.

The TMHQ slurry was filtered, and 114.
0 g of crystals separated by filtration were obtained. A part of the filtered crystal is 5 mmH
g at a temperature of 140 ° C. for 10 hours under a reduced pressure to give TMHQ purity of 96.7%, TMA content of 2.8%, TM
The HQ mono body was 0.5%, and the solid content was 80%.

Next, 100 g (solid content: 80 g) of the obtained separated crystals, 48 g of γ-butyrolactone and xylene 19
2 g of the mixture was charged into a similar apparatus under a nitrogen gas atmosphere, and the mixture was stirred at the reflux temperature of the mixed solvent (142 ° C.) for 2 hours. Then 40
After cooling to 0 ° C., the mixture was filtered, and the obtained separated crystals were washed with a mixed solvent of 6 g of γ-butyrolactone and 24 g of xylene. Further, the filtered crystal was subjected to 120 ° C. under a reduced pressure of 5 mmHg.
, Dried at a temperature of 10 hours, TMHQ purity 99.6%, T
TMH with MA content 0.3% and TMHQ mono body 0.1%
68.9 g of Q were obtained. Purification yield (vs. theoretical reaction crude) is 3
8%.

The obtained TMHQ was used as a DMF solution in the same manner as in Example 1 to prepare a polyimide film.
No turbidity was observed in the DMF solution, no gel-like foreign matter was observed in the polyimide film, and the film surface was smooth.

Example 6 Hydroquinone 4 was placed in a 1-L four-necked flask equipped with a stirrer, a thermometer, a decanter equipped with a cooling tube, and a nitrogen gas inlet.
4.0 g (0.4 mol), 122.5 g of acetic anhydride (1.
2 mol) and 3.4 g of lauryldimethylamine (0.0
2 mol), and reacted at 130 ° C. for 0.5 hour under a nitrogen atmosphere. A portion was taken out and analyzed. As a result, the purity of hydroquinone diacetate was 99.9%.

Next, 153.7 g (0.8 mol) of TMA
And heated to 260 ° C. in a nitrogen atmosphere. The reaction was carried out at the same temperature for 0.5 hour, and further, the pressure was gradually reduced to 80 mmHg, and the reaction was carried out for 0.5 hour. The pressure was returned to normal pressure with nitrogen to obtain a crude reaction product. After cooling the reaction crude to 240 ° C., γ
223.6 g of butyrolactone (1.2% of the theoretical reaction crude)
(2 weight times) was added dropwise over 0.5 hour with stirring. At the end of the addition, the temperature was 136 ° C. It was further cooled to 40 ° C. to obtain a TMHQ slurry.

The TMHQ slurry was filtered and 145.2
g of filtered crystals were obtained. A part of the crystal separated by filtration is 5 mmHg.
After drying at 140 ° C. for 10 hours under reduced pressure of
MHQ purity 97.1%, TMA content 1.4%, TMH
The Q mono body was 1.5%, and the solid content was 77%.

Next, 120 g (solid content: 92.4 g) of the obtained separated crystals, 55.4 g of γ-butyrolactone and 221.8 g of xylene were charged into a similar apparatus under a nitrogen gas atmosphere, and the reflux temperature of the mixed solvent (142 ° C.) ) For 2 hours. Next, the mixture was cooled to 40 ° C., and then filtered. The obtained separated crystals were washed with a mixed solvent of 7 g of γ-butyrolactone and 28 g of xylene. Further, the filtered crystals were dried at a temperature of 120 ° C. for 10 hours under a reduced pressure of 5 mmHg.
9.0%, TMA content 0.1%, TMHQ mono-form
81.8 g of 9% TMHQ was obtained. The purification yield (vs. the theoretical reaction crude) was 54%.

The obtained TMHQ was converted into a DMF solution in the same manner as in Example 1 to prepare a polyimide film. D
No turbidity was observed in the MF solution, no gel-like foreign matter was observed in the polyimide film, and the film surface was smooth.

Comparative Example 1 97.1 g (0.5 mol) of hydroquinone diacetate obtained in Production Example 1 and TMA30 were placed in the same apparatus as in Production Example 1.
7.4 g (1.6 mol) was charged and the temperature was raised to 260 ° C. The reaction was carried out at the same temperature for 0.5 hour, and further, the pressure was gradually reduced to 80 mmHg, and the reaction was carried out for 0.5 hour. After completion of the reaction, the reaction crude was taken out at 240 ° C. into a stainless steel container. At the time of extraction, gas and off-flavor were generated from the reaction crude. After the reaction crude was solidified by cooling, it was pulverized with a small pulverizer and passed through an 8-mesh (Tyler) sieve to obtain a powdery reaction crude.
This crude powdery product had a TMHQ purity of 65.1%, a TMA content of 33.2%, a TMHQ mono-form of 1.7% and a yield of 95.2.
%Met.

Next, 200 g of the powdery reaction crude product, 300 g of cyclohexanone and 300 g of xylene were charged into a similar apparatus under a nitrogen gas atmosphere, and stirred at the reflux temperature of the mixed solvent (142 ° C.) for 2 hours. Next, the mixture was cooled and filtered to 40 ° C., and the obtained separated crystals were washed with a mixed solvent of 40 g of cyclohexanone and 40 g of xylene, and dried at 120 ° C. under a reduced pressure of 5 mmHg for 10 hours, and the TMHQ purity was 98.3.
%, 80% of TMHQ having a TMA content of 1.2% and a TMHQ mono-form of 0.5% were obtained at a purification yield of 40% (vs. reaction crude).

The obtained TMHQ was used as a DMF solution in the same manner as in Example 1 to prepare a polyimide film.
Turbidity was observed in the DMF solution, and 1
Many gel-like foreign substances of about 0 to 20 μm were observed, and many fine projections were observed on the film surface.

[0080]

According to the method for producing TMHQ according to the present invention, a high purity of 98% by weight or more suitable for a raw material for a polyimide film can be obtained under industrially advantageous conditions with good efficiency and good workability. Purified hydroquinone bis (anhydrotrimellitate) can be obtained.

Claims (10)

[Claims] 1. General formula (1) [Wherein, R ¹ and R ² are the same or different and each have 1 to 1 carbon atoms.
3 represents an alkyl group. In the production of hydroquinone bis (anhydrotrimellitate) by transesterification of a lower alkanoic acid ester of hydroquinone represented by the following formula and trimellitic anhydride, hydroquinone bis (anhydrotrimellitate) obtained by the transesterification reaction A high-purity hydroquinone bis (anthrene) is characterized in that the reaction crude is made into a slurry using a solvent belonging to the group (A) and then purified using a mixed solvent consisting of the groups (A) and (B). Hydrotrimellitate). Group (A): One or more lactone solvents. Group (B): One or more aromatic or aliphatic hydrocarbons having 6 to 20 carbon atoms. 2. A slurry obtained by adding a solvent belonging to the group (A) to a hydroquinone bis (anhydrotrimellitate) reaction crude product having a temperature of 200 ° C. or higher. 3. The method for producing high-purity hydroquinone bis (anhydrotrimellitate) according to item 1. 3. A transesterification reaction between a lower alkanoic acid ester of hydroquinone represented by the general formula (1) and trimellitic anhydride to produce hydroquinone bis (anhydrotrimellitate). High purity, characterized in that a hydroquinone bis (anhydrotrimellitate) reaction crude product is made into a slurry using a solvent belonging to the group (A) and then purified using a solvent belonging to the group (A). A method for producing hydroquinone bis (anhydrotrimellitate). 4. The slurry is prepared by adding a solvent belonging to the group (A) to a hydroquinone bis (anhydrotrimellitate) reaction crude product having a temperature of 200 ° C. or higher. 3. The method for producing high-purity hydroquinone bis (anhydrotrimellitate) according to 1. 5. The slurry according to claim 1, wherein the amount of the solvent belonging to the group (A) is 50 to 300 parts by weight based on 100 parts by weight of the hydroquinone bis (anhydrotrimellitate) reaction crude product. The method for producing high-purity hydroquinone bis (anhydrotrimellitate) according to any one of claims 1 to 4. 6. The method for producing high-purity hydroquinone bis (anhydrotrimellitate) according to claim 1, wherein the solvent in group (A) is γ-butyrolactone. 7. The high-purity hydroquinone bis () according to claim 1 or 2, wherein the solvent in the group (B) is one or more selected from the group consisting of xylene, toluene, benzene, cyclohexane and hexane. Anhydrotrimellitate). 8. The weight ratio of the mixed solvent comprising the groups (A) and (B) is 0.5 / 9.5 to 9.5 / 0.5 ((A)
The method for producing high-purity hydroquinone bis (anhydrotrimellitate) according to claim 1 or 2, which is a group / (B) group. 9. The method according to claim 1, wherein the purity of the hydroquinone bis (anhydrotrimellitate) is 98% by weight or more, and the surface of the film when the polyimide film is formed is smooth and no gel-like foreign matter is generated in the film. The method for producing high-purity hydroquinone bis (anhydrotrimellitate) according to any one of claims 1 to 8. 10. A high-purity hydroquinone bis (anhydrotrimellitate) having a purity of 98% by weight or more, and a polyimide film formed with a smooth surface and no gel-like foreign matter in the film. Purity hydroquinone bis (anhydrotrimellitate).