JP2002302540A - Method for producing aromatic polyester - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method capable of readily producing an aromatic polyester having high flow-starting temperature from acetoxybenzoic acids, diacetoxyaromatic diols and benzenedicarboxylic acids. SOLUTION: This method for producing the aromatic polyester comprises copolymerizing acetoxybenzoic acids represented by formula (I) with diacetoxyaromatic diols represented by formula (II) and benzenedicarboxylic acids represented by formula (III) in the presence of imidazoles represented by formula (IV). In the imidazoles represented by formula (IV), it is preferable that X<4> is an alkyl group and further, X<5> , X<6> and X<7> are each hydrogen atom. The imidazoles in an amount of >=0.001 pt. wt. are usually used based on 100 pts. wt. Total amount of the acetoxybenzoylacids represented by formula (I), the diacetoxyaromatic diols represented by formula (II) and the benzenedicarboxylic acids represented by formula (III) used. After copolymerization is carried out, the resultant copolymer is usually subjected to solid phase polymerization.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] The present invention relates to a method for producing an aromatic polyester.

[0002]

2. Description of the Related Art Aromatic polyesters are useful as thermoplastic resins having excellent heat resistance. As a method for producing such an aromatic polyester, a method is known in which acetoxybenzoic acids, diacetoxyaromatic diols and benzenedicarboxylic acids are copolymerized without a catalyst. The copolymer obtained by the copolymerization is made into a powder, and the degree of polymerization is increased by solid phase polymerization in which the powder is heated, whereby the target aromatic polyester can be obtained.

However, the aromatic polyester obtained by the conventional production method does not always have a high flow start temperature. In order to obtain an aromatic polyester having a high flow start temperature, it is conceivable to increase the heating temperature in the solid phase polymerization, but this has a problem that the powders are likely to adhere to each other. If the powders adhere to each other, it is difficult to handle after the solid-phase polymerization.

[0004]

SUMMARY OF THE INVENTION Accordingly, the present inventors
As a result of intensive studies to develop a method for easily producing an aromatic polyester having a high flow start temperature from acetoxybenzoic acids, diacetoxy aromatic diols, and benzenedicarboxylic acids, copolymerization in the presence of imidazoles was carried out. The product is led to a walking group polyester having a high flow onset temperature by solid state polymerization at a relatively low temperature,
In addition, they have found that powders do not easily adhere to each other in solid-state polymerization, and have reached the present invention.

[0005]

That is, the present invention provides a compound of the formula (I) [In the formula, X ¹ represents an alkyl group, a phenyl group or a halogen atom, and x represents an integer of 0 to 2. Acetoxybenzoic acid represented by the formula (II): [Wherein, X ² represents an alkyl group, a phenyl group, or a halogen atom, y represents an integer of 0 to 2, and n represents 1 or 2
Is shown. Diacetoxy aromatic diols represented by formula (III): [In the formula, X ³ represents an alkyl group, a phenyl group, or a halogen atom, and z represents an integer of 0 to 2. A benzenedicarboxylic acid of the formula (IV) [Wherein X ^{4 to} X ⁷ each independently represent a hydrogen atom, an alkyl group, a hydroxymethyl group, a cyanoalkyl group, a carboxyl group, an aminoalkyl group, a phenyl group, a benzyl group, or a formyl group. And a method for producing an aromatic polyester, wherein the copolymerization is carried out in the presence of imidazoles.

[0006]

BEST MODE FOR CARRYING OUT THE INVENTION In the acetoxybenzoic acids of the formula (I), the alkyl group in X ¹ is
For example, a methyl group, an ethyl group, a propyl group, a butyl group, an alkyl group having about 1 to 5 carbon atoms such as a pentyl group,
Examples of the halogen atom include a chlorine atom and a bromine atom. x is an integer of 0 to 2;
When X is 2, X ¹ may be the same as each other;
It may be different. x is preferably 0.

The acetoxybenzoic acids (I) include, for example, 4-acetoxybenzoic acid, 4-acetoxy-
2-methylbenzoic acid, 4-acetoxy-3-methylbenzoic acid, 4-acetoxy-2-phenylbenzoic acid, 4-acetoxy-3-phenylbenzoic acid, 4-acetoxy-2
-Chlorobenzoic acid, 4-acetoxy-3-chlorobenzoic acid, 4-acetoxy-2-methyl-3-phenylbenzoic acid, 4-acetoxy-3-methyl-2-phenylbenzoic acid, 4-acetoxy-3-chloro -2-methylbenzoic acid, 4-acetoxy-2-chloro-3-methylbenzoic acid, 4-acetoxy-3-chloro-2-phenylbenzoic acid, 4-acetoxy-2-chloro-3-phenylbenzoic acid and the like Examples include paraacetoxybenzoic acids in which an acetyl group and a carboxyl group are introduced into the benzene ring at the para position with respect to each other. Such acetoxybenzoic acids are used alone or in combination of two or more.

In the diacetoxy aromatic diol represented by the formula (II), the alkyl group for X ² is:
For example, a methyl group, an ethyl group, a propyl group, a butyl group, an alkyl group having about 1 to 5 carbon atoms such as a pentyl group,
Examples of the halogen atom include a chlorine atom and a bromine atom. y is an integer of 0 to 2;
When X is ² , X ² may be the same as each other;
It may be different. y is preferably 0. n
Is 1 or 2, but when n is 2, the substituent X ¹ may be introduced into one of the two benzene rings and X ² may not be introduced into the other benzene ring, or the substituent X ¹ may be introduced into both. ² may be introduced. n is preferably 1.

Such diacetoxy aromatic diols (I
As I), for example, formula (21) [Wherein, X ² and y each have the same meaning as described above. A diacetoxyhydroquinone represented by the formula (2)
2) [Wherein, X ² and y each have the same meaning as described above. Diacetoxyresorcinols represented by the formula (23): [Wherein, X ² and y each have the same meaning as described above. Diacetoxybiphenyls and the like.

The diacetoxyhydroquinones (21) include, for example, 1,4-diacetoxymethylbenzene,
1,4-diacetoxy-2-methylbenzene, 1,4-
Diacetoxy-2-chlorobenzene, 1,4-diacetoxy-2-methyl-3-phenylbenzene, 1,4-diacetoxy-3-methyl-2-phenylbenzene, 1,
4-diacetoxy-2-chloro-3-methylbenzene,
Examples thereof include 1,4-diacetoxy-3-chloro-2-methylbenzene, 1,4-diacetoxy-2-chloro-3-phenylbenzene, and 1,4-diacetoxy-3-chloro-2-phenylbenzene.

The diacetoxyresorcinols (22) include, for example, 1,3-diacetoxybenzene, 1,3
-Diacetoxy-2-methylbenzene, 1,3-diacetoxy-2-phenylbenzene, 1,3-diacetoxy-2-chlorobenzene, 1,3-diacetoxy-2-methyl-4-phenylbenzene, 1,3-diacetoxy-
2,4-dimethylbenzene, 1,3-diacetoxy-2
-Chloro-4-methylbenzene, 1,3-diacetoxy-4-chloro-2-methylbenzene, 1,3-diacetoxy-2-chloro-4-phenylbenzene, 1,3-diacetoxy-4-chloro-2- Phenylbenzene and the like.

The diacetoxybiphenyls (23) include, for example, 4,4′-diacetoxybiphenyl,
4'-diacetoxy-2-methylbiphenyl, 4,4 '
-Diacetoxy-5-chlorobiphenyl, 4,4'-diacetoxy-3-phenylbiphenyl, 4,4'-diacetoxy-2-methyl-5'-biphenyl and the like.

Such diacetoxy aromatic diols (I
I) can be used alone. Two or more diacetoxyhydroquinones (21) may be used in combination, or two or more diacetoxyresorcinols (22) may be used in combination.
A combination of two or more diacetoxybiphenyls (23) may be used, or a combination of diacetoxyhydroquinones (21) and diacetoxyresorcinols (22) may be used. May be used,
Diacetoxyhydroquinones (21), diacetoxyresorcinols (22) and diacetoxybiphenyls (23) may be used in combination.

In the benzenedicarboxylic acids represented by the formula (III), examples of the alkyl group for X ³ include an alkyl group having about 1 to 5 carbon atoms such as a methyl group, an ethyl group, a propyl group, a butyl group and a pentyl group. However, examples of the halogen atom include a chlorine atom and a bromine atom. z is an integer of 0 to 2;
In the formula, X ³ may be the same as or different from each other. z is preferably 0.

The benzenedicarboxylic acids (III) include, for example, terephthalic acid, isophthalic acid, 2-methylterephthalic acid, 2-phenylterephthalic acid, 2-chloroterephthalic acid, 2-methyl-3-phenylterephthalic acid, Such as methyl-3-phenylterephthalic acid, 2-chloro-3-methylterephthalic acid, 3-chloro-2-methylterephthalic acid, 2-chloro-3-phenylterephthalic acid, 3-chloro-2-phenylterephthalic acid, etc. Terephthalic acids in which two carbonyl groups are introduced into the benzene ring at the para position to each other. These benzenedicarboxylic acids (III) are used alone or in combination of two or more.

The amounts of the acetoxybenzoic acids (I), acetoxyaromatic diols (II) and benzenedicarboxylic acids (III) to be used are appropriately selected depending on the intended aromatic polyester, for example, acetoxybenzoic acids (I), The acetoxybenzoic acids (I) are at least 20% in mole fraction based on the total amount of the acetoxyaromatic diols (II) and the benzenedicarboxylic acids (III).
0% or less, 10% of acetoxy aromatic diols (II)
Not less than 40% and not more than 1% of benzenedicarboxylic acids (III)
It is about 0% or more and about 40% or less.

The acetoxybenzoic acids (I) have the formula (I-
1) [Wherein, X ¹ and x each have the same meaning as described above. Wherein the benzoic acid is reacted with acetic anhydride. Diacetoxy aromatic diols (II)
Is the formula (II-1) [Wherein, X ² , y and n each have the same meaning as described above. And acetic anhydride. Diacetoxyhydroquinones (21) are represented by the formula (21-1) [Wherein, X ² and y each have the same meaning as described above. And acetic anhydride. Diacetoxyresorcinols (22) are represented by the formula (22-1) [Wherein, X ² and y each have the same meaning as described above. The resorcinols shown in the above formula are reacted with acetic anhydride. Diacetoxybiphenyls (2
3) is obtained by using equation (23-1). [Wherein, X ² and y each have the same meaning as described above. The biphenyls represented by the formula are reacted with acetic anhydride.

The benzoic acids (I-1) and the aromatic diols (II-1) may be individually reacted with complex anhydrides, or may be reacted with acetic anhydride in a state where these are mixed. For example, acetoxybenzoic acids (I) and diacetoxy aromatic diols (II) can be simultaneously produced by a method of mixing benzoic acids (I-1), aromatic diols (II-1) and acetic anhydride. .

The amount of acetic anhydride used depends on the amount of benzoic acid (I-
It is usually at least 1 mol times, preferably at least 1.1 mol times, usually at most 1.5 mol times, preferably at most 1.5 mol times, the sum of the hydroxyl groups of 1) and the aromatic diols (II-1). .2 mol times or less.

The reaction is usually carried out without solvent, and the reaction temperature is usually at least 100 ° C., preferably at least 130 ° C., usually at most 200 ° C., preferably at most 160 ° C. At the time of the reaction, benzenedicarboxylic acids (III) may be present in the reaction system. Since benzenedicarboxylic acids (III) do not substantially react with acetic anhydride, the reaction mixture after the reaction contains the used benzenedicarboxylic acids (III).

The reaction is carried out with pyridine, triethylamine,
It is preferable to carry out the reaction in the presence of a tertiary amine such as N, N-dimethylaniline or 4-aminodimethylpyridine, since the amount of by-products of the coloring component is small. When tertiary amines are used, the amounts used are benzoic acids (I-1), aromatic diols (II-1), benzenedicarboxylic acids (II
Usually 0.0% based on the total amount of I) and acetic anhydride used
It is at least 001 times by mass, preferably at least 0.0003 times by mass, usually at most 0.001 times by mass, and preferably at most 0.001 times by mass.
005 mass times or less.

The reaction mixture after the reaction contains acetoxybenzoic acid (I) and acetoxy aromatic diol (II)
When benzenedicarboxylic acids (III) are used, the benzenedicarboxylic acids (II)
I) is included.

In the production method of the present invention, such acetoxybenzoic acids (I), acetoxy aromatic diols (II) and benzenedicarboxylic acids (III) are reacted in the presence of imidazoles (IV).

In the imidazole represented by the formula (IV), examples of the alkyl group represented by X ^{4 to} X ⁷ include an alkyl group having about 1 to 4 carbon atoms such as a methyl group, an ethyl group, a propyl group and a butyl group. Examples of the cyanoalkyl group include a substituent in which a cyano group is introduced into an alkyl group having about 1 to 4 carbon atoms such as a cyanoethyl group. Examples of the aminoalkyl group include a substituent having 1 carbon atom such as an aminoethyl group. Substituents in which an amino group is introduced into about 4 to about 4 alkyl groups, respectively.

The imidazoles in which X ⁴ is an alkyl group are preferable in that the flow start temperature of the obtained aromatic polyester can be further increased. More preferably, X ⁴ is an alkyl group, and X ⁵ , X ⁶ and X ⁷ is a hydrogen atom.

Examples of the imidazoles (IV) include, for example, imidazole, 1-methylimidazole, 1-ethylimidazole, 2-ethylimidazole, 2-phenylimidazole, 2,4-dimethylimidazole,
Phenyl-4-methyl-5-hydroxymethylimidazole, 1-cyanoethyl-2-phenylimidazole,
Examples thereof include 4,5-imidazole dicarboxylic acid, 1-aminoethyl-2-methylimidazole, 2-phenylimidazole, 1-benzyl-2-phenylimidazole, and 4-formylimidazole.

The amount of the imidazole (IV) used is usually 0.001 part by mass per 100 parts by mass of the total amount of the acetoxybenzoic acid (I), the acetoxy aromatic diol (II) and the benzenedicarboxylic acid (III). that's all,
It is preferably at least 0.002 parts by mass, more preferably at least 0.02 parts by mass, usually at most 1 part by mass, preferably at most 0.5 part by mass.

For copolymerization, for example, acetoxybenzoic acids (I), acetoxyaromatic diols (II), benzenedicarboxylic acids (III) and imidazoles (I
V) may be mixed. When acetoxybenzoic acids (I) and acetoxyaromatic diols (II) are produced by a method of reacting benzoic acids (I-1) and aromatic diols (II-1) with acetic anhydride, The acid (I) and the acetoxy aromatic diol (II) can be used without being taken out of the reaction mixture after the reaction. For example, if the imidazole (IV) and the benzenedicarboxylic acid (III) are added to the reaction mixture, Good. The copolymerization temperature is usually at least 200 ° C., preferably at least 250 ° C., usually at most 400 ° C., preferably at most 320 ° C.

Acetic acid is generated by the copolymerization, and it is preferable to conduct the copolymerization while introducing the acetic acid out of the system. The end point of the copolymerization can be easily known from the end of the generation of acetic acid. Copolymerization is completed in a relatively short time.

After copolymerization, the obtained copolymer is usually further subjected to solid phase polymerization. In order to carry out solid-phase polymerization, for example, after the obtained copolymer is solidified by cooling, it may be heated in a solid state. In order to be cooled and solidified into powder, for example, it may be pulverized after being cooled and solidified. The particle size of the powder is, for example, about 0.1 mm or more and 3 mm or less.
The heating in the solid state is performed at a temperature lower than the melting point of the copolymer, and is usually 150 ° C or higher, preferably 200 ° C or higher, usually 400 ° C or lower, preferably 330 ° C or lower.
What is necessary is just to heat to the temperature range below ° C. By heating, the copolymer is further polymerized in a solid state, that is, in a powder state, and its degree of polymerization is increased, leading to a target aromatic polyester.

The aromatic polyester thus obtained is
Acetoxybenzoic acids represented by the formula (I);
A diacetoxy aromatic diol represented by the formula (III) and a benzenedicarboxylic acid represented by the formula (III) are copolymerized in the presence of the imidazole represented by the formula (IV), and the compound represented by the formula (I- 2) [Wherein, X ¹ and x each have the same meaning as described above. A structural unit represented by formula (II-2): [Wherein, X ² , y and n each have the same meaning as described above. And a structural unit represented by the formula (III-3): [Wherein, X ³ and z each have the same meaning as described above. ] It comprises the structural unit shown by these. Here, the formula (I−
The structural unit represented by 2) is acetoxybenzoic acid (I)
The structural unit represented by the formula (II-2) is a structural unit derived from an acetoxy aromatic diol (II), and the structural unit represented by the formula (III-2) is benzenedicarboxylic acid It is a structural unit derived from acids (III).

[0032]

According to the production method of the present invention, acetoxybenzoic acids (I) and acetoxy aromatic diols (II)
An aromatic polyester having a high flow start temperature can be easily obtained from benzenedicarboxylic acids (III).

[0033]

EXAMPLES The present invention will be described in more detail with reference to the following Examples, which should not be construed as limiting the present invention.

Example 1 663 g (4.8 mol) of parahydroxybenzoic acid, 226.5 g (2.04 mol) of hydroquinone, 169.8 g (1.56 mol) of resorcinol and terephthalic acid 5
98.6 g (3.6 mol), 1408.8 g of acetic anhydride
(13.8 mol) and 1.533 g of pyridine were charged into a polymerization tank, and the mixture was stirred for 15 minutes, and then heated at a heating rate of 1 ° C./1 minute with stirring. When the temperature reached 145 ° C., the same temperature was maintained for 1 hour to obtain a mixture of paraacetoxybenzoic acid, diacetoxyhydroquinone, diacetoxyresorcinol and terephthalic acid.

After adding 1.497 g of 1-methylimidazole to the obtained mixture at the same temperature, the mixture was heated to 310 ° C. at a rate of 1 ° C./min. FIG. 1 shows the total amount of acetic acid produced (in terms of the mole fraction based on the amount of parahydroxybenzoic acid, hydroquinone and resorcinol) from 40 minutes, 70 minutes, and 100 minutes after the start of the temperature increase. Was. After the temperature was raised to 310 ° C., it was immediately cooled to room temperature to obtain a solid. The obtained solid was pulverized at room temperature using a coarse pulverizer.
The mixture was kept warm for an hour to obtain an aromatic polyester (powder).
Using a flow tester (“CFT-500 type”, manufactured by Shimadzu Corporation), the aromatic polyester obtained above was heated at 4 ° C. /
The temperature at which the melt viscosity at the time of extrusion from a nozzle having an inner diameter of 1 mm and a length of 10 mm at a pressure of 9.81 MPa at a pressure of 9.81 MPa was 4,800 Pa · s while heating at a heating rate of 1 minute was defined as the flow start temperature. The results are shown in Table 1.

Comparative Example 1 Example 1 except that 1-methylimidazole was not added.
In the same manner as described above, the temperature was started. FIG. 1 shows the total outflow amount of acetic acid (in terms of the mole fraction based on the amounts of parahydroxybenzoic acid, hydroquinone, and resorcinol) from 40 minutes, 70 minutes, and 100 minutes after the start of the temperature increase. Was. After the temperature was raised to 310 ° C., the mixture was immediately cooled to room temperature to obtain a solid, an aromatic polyester (powder) was obtained, and evaluated in the same manner as in Example 1. First result
It is shown in the table.

Example 2 The amount of parahydroxybenzoic acid used was 994.5 g (7.
2 mol) and the amount of hydroquinone used is 66.1 g.
(0.6 mol) and the amount of resorcinol used is 19
The same operation as in Example 1 was performed except that 8.2 g (1.8 mol), the amount of terephthalic acid used was 398.7 g (2.4 mol), and the amount of 1-methylimidazole was 0.075 g. Thus, a solid was obtained, and an aromatic polyester (powder) was obtained, and evaluated in the same manner as in Example 1. First result
It is shown in the table.

Example 3 The same procedure as in Example 2 was carried out except that the amount of 1-methylimidazole used was changed to 0.301 g, to obtain a solid, and to obtain an aromatic polyester (powder). It evaluated similarly. The results are shown in Table 1.

Example 4 A solid was obtained in the same manner as in Example 2 except that the amount of 1-methylimidazole used was changed to 0.753 g, to obtain an aromatic polyester (powder). It evaluated similarly. The results are shown in Table 1.

Example 5 A solid was obtained in the same manner as in Example 2 except that the amount of 1-methylimidazole used was changed to 1.506 g, to obtain an aromatic polyester (powder). It evaluated similarly. The results are shown in Table 1.

Comparative Example 2 The procedure of Example 2 was repeated, except that 1-methylimidazole was not used, to obtain a solid substance, to obtain an aromatic polyester (powder), which was evaluated in the same manner as in Example 1. The results are shown in Table 1.

[0042]

[Table 1]

FIG. 2 shows the relationship between the amount of 1-methylimidazole (NMI) added and the flow start temperature for each of the aromatic polyesters obtained in Examples 1 to 5 and Comparative Examples 1 and 2.

Example 6 663 g (4.8 mol) of parahydroxybenzoic acid, 125.5 g (1.14 mol) of hydroquinone, 154.2 g (0.83 mol) of 4,4'-dihydroxybiphenyl,
Resorcinol 179.7 g (1.63 mol), terephthalic acid 598.1 g (3.6 mol), acetic anhydride 134
7.6 g (13.2 mol) and pyridine 1.533 g
Was charged into a polymerization tank, and the mixture was stirred for 15 minutes, and then heated while stirring. When the temperature reached 145 ° C., the temperature was maintained for 1 hour to obtain a mixture of paraacetoxybenzoic acid, diacetoxyhydroquinone, 4,4′-diacetoxybiphenyl and terephthalic acid.

After 1.563 g of 1-methylimidazole was added to the obtained mixture at the same temperature, the temperature was raised to 310 ° C. at a rate of 1 ° C./min. The total amount of acetic acid produced (40 minutes, 70 minutes, and 100 minutes after the start of heating) (molar fraction based on the total amount of parahydroxybenzoic acid, hydroquinone, 4,4'-dihydroxybiphenyl and resorcinol used) ) Is shown in FIG. 310 ° C
And then immediately cooled to room temperature to obtain a solid.

The obtained solid was pulverized at room temperature using a coarse pulverizer, and then kept at 230 ° C. for 10 hours under a nitrogen atmosphere to obtain an aromatic polyester (powder). Table 2 shows the results of measuring the flow start temperature of this aromatic polyester in the same manner as in Example 1.

Comparative Example 3 Example 6 except that 1-methylimidazole was not added.
In the same manner as described above, the temperature was started. The total effluent amount of acetic acid (parahydroxybenzoic acid, hydroquinone, 4,4 minutes, 40 minutes, 70 minutes, and 100 minutes after the start of the temperature increase)
It is shown as a mole fraction based on the total amount of 4'-dihydroxybiphenyl and resorcinol used. ) Is shown in FIG. After the temperature was raised to 310 ° C., the mixture was immediately cooled to room temperature to obtain a solid, and an aromatic polyester (powder) was obtained.
Evaluation was performed in the same manner as in Example 1. The results are shown in Table 2.

[0048]

[Table 2]

[Brief description of the drawings]

FIG. 1 shows the relationship between the temperature (° C.) in the system and the total amount of acetic acid produced (molar fraction based on the total amount of parahydroxybenzoic acid, hydroquinone and resorcinol) in Example 1 and Comparative Example 1 during heating. The horizontal axis shows the temperature in the system (° C.), and the vertical axis shows the total production amount (%).

FIG. 2 shows the aromatic polyesters obtained in Examples 1 to 5 and Comparative Examples 1 and 2 as 1-methylimidazole (NM
It is a figure which shows the relationship between the addition amount (g) of I) and a flow start temperature, and a horizontal axis | shaft shows the addition amount (g) of NMI, and a vertical axis | shaft shows a flow start temperature (degreeC), respectively.

FIG. 3 shows the system temperature (° C.) and the total amount of acetic acid (parahydroxybenzoic acid, hydroquinone, resorcinol and 4,4′-) in Example 6 and Comparative Example 3 during heating.
FIG. 4 is a graph showing the relationship between the total amount of dihydroxybiphenyl used and the molar fraction), and the horizontal axis represents the temperature in the system (° C.).
Is shown on the vertical axis, and the total production amount (%) is shown.

 ────────────────────────────────────────────────── ─── Continued on the front page (72) Inventor Hiroshi Harada 3-1-198 Kasuganaka, Konohana-ku, Osaka Sumitomo Chemical Co., Ltd. F-term (reference) 4J029 AA06 AB01 AB04 AC02 AE01 BB04A BB04B BB05A BB09A BB09B BB10A BB10B CB05A CB05B CB06A CB06B CG05X CG08X EB04A EB04B EB05A EB05B EE05 JC263 KE08 KE12 KF09

Claims (11)

[Claims] (1) Formula (I) [In the formula, X ¹ represents an alkyl group, a phenyl group or a halogen atom, and x represents an integer of 0 to 2. Acetoxybenzoic acid represented by the formula (II): [Wherein, X ² represents an alkyl group, a phenyl group, or a halogen atom, y represents an integer of 0 to 2, and n represents 1 or 2
Is shown. Diacetoxy aromatic diols represented by formula (III): [In the formula, X ³ represents an alkyl group, a phenyl group, or a halogen atom, and z represents an integer of 0 to 2. A benzenedicarboxylic acid of the formula (IV) [Wherein, X ^{4 to} X ⁷ each independently represent a hydrogen atom, an alkyl group, a hydroxymethyl group, a cyanoalkyl group, a carboxyl group, an aminoalkyl group, a phenyl group, a benzyl group, or a formyl group. ] A method for producing an aromatic polyester, comprising copolymerizing in the presence of an imidazole represented by the formula: 2. The method according to claim 1, wherein n in the formula (II) is 1. 3. The acetoxybenzoic acid represented by the formula (I) is a compound represented by the formula (I-1): [Wherein, X ¹ and x each have the same meaning as described above. The diacetoxy aromatic diol represented by the formula (II) is obtained by reacting a benzoic acid represented by the formula (II-1) with acetic anhydride. [Wherein, X ² , y and n each have the same meaning as described above. The production method according to claim 1, which is obtained by reacting an aromatic diol represented by the formula (1) with acetic anhydride. 4. The method according to claim 1, wherein X ⁴ in the formula (IV) is an alkyl group. 5. The method according to claim 4, wherein X ⁵ , X ⁶ and X ⁷ in the formula (IV) are hydrogen atoms. 6. An imidazole represented by the formula (IV) is used in an acetoxybenzoic acid represented by the formula (I), a diacetoxy aromatic diol represented by the formula (II) and a formula (III): The production method according to claim 1, wherein the total amount of the benzenedicarboxylic acids is 0.001 part by mass or more per 100 parts by mass. 7. The production method according to claim 1, wherein the copolymerization is followed by a solid phase polymerization. 8. An acetoxybenzoic acid represented by the formula (I), a diacetoxy aromatic diol represented by the formula (II) and a benzenedicarboxylic acid represented by the formula (III) are represented by the formula (IV). An aromatic polyester obtained by copolymerization in the presence of imidazoles. 9. The aromatic polyester according to claim 8, wherein X ⁴ in the formula (IV) is an alkyl group. 10. The aromatic polyester according to claim 9, wherein X ⁵ , X ⁶ and X ⁷ in the formula (IV) are hydrogen atoms. 11. The aromatic polyester according to claim 8, which is copolymerized and then solid-phase polymerized.