JPS6159619B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an improved method for producing aromatic oxycarboxylic acid aryl esters.

It has been well known that aromatic oxycarboxylic acid aryl esters are useful compounds as raw materials for polyesters. The method for industrially producing this aryl ester is as follows:
For example, a method has been proposed in which p-oxybenzoic acid and phenol are esterified using sulfuric acid or an aromatic sulfonic acid such as p-toluenesulfonic acid as a catalyst. If you use this method,
It is true that the esterification reaction proceeds even at relatively low temperatures such as 200°C, and the desired esterification reaction product can be obtained. However, with this method, the yield of the reaction product is low, and when trying to obtain a polyester with a high degree of polymerization using this reaction product as a raw material,
The disadvantage was that it required a long polymerization time.

The present inventors have repeatedly conducted research on methods for obtaining aromatic oxycarboxylic acid aryl esters in good yield, and as a result, they have arrived at the present invention.

That is, in the present invention, when an aromatic oxycarboxylic acid and an aromatic oxy compound are esterified to produce an aromatic oxycarboxylic acid aryl ester, the esterification reaction is carried out using a catalytic amount of an aliphatic sulfonic acid and/or an aliphatic oxycarboxylic acid. This is a method for producing an aromatic oxycarboxylic acid aryl ester, characterized in that it is carried out in the presence of a group sulfonic acid.

Examples of aromatic oxycarboxylic acids used in the present invention include p-oxybenzoic acid, m-
oxybenzoic acid, 6-oxy-2-naphthoic acid,
7-oxy-2-naphthoic acid, 4'-oxydiphenyl-4-carboxylic acid, etc., and those whose aromatic group is substituted with a halogen atom, lower alkyl group, or alkoxy group, such as 3-chloro-
4-oxybenzoic acid, 3-methoxybenzoic acid,
4-chloro-3-oxybenzoic acid, 7-chloro-
6-oxy-2-naphthoic acid, 3-methyl-4-
Examples include oxybenzoic acid.

In addition, examples of the aromatic oxy compounds mentioned above include those having a nucleus substituted with a halogen atom or an alkyl group, such as phenol, cresol, p-ethylphenol, p-chlorophenol, m-chlorophenol, β-naphthol, hydroquinone, resorcinol, etc. , or unsubstituted aromatic monooxy compounds or aromatic dioxy compounds. Among these, particularly preferred are aromatic monooxy compounds.

The esterification reaction in the present invention is carried out at a molar ratio of hydroxyl groups of the aromatic oxy compound to carboxyl groups of the aromatic oxycarboxylic acid at least 1 times, preferably 1.2 times to 4 times, by mole.
This esterification reaction is carried out at a temperature in the range of 100°C to 250°C, more preferably in the range of 120 to 220°C, even more preferably in the range of 150 to 200°C, while removing water produced as a result of the reaction. It is preferable to do so. For example, water can be removed by 1) azeotroping with the aromatic oxy compound used in the esterification reaction; 2)
3) Allowing an organic solvent that is azeotropic with water, such as benzene, toluene, xylene, ethylbenzene, pseudocumene, etc., to coexist in the esterification reaction system to azeotrope water; 3) Evaporating only water from the reaction system, etc.
Water can be removed from this type of esterification reaction system by conventionally known methods.

In the present invention, an aliphatic sulfonic acid and/or an aliphatic sulfonic acid is used as a catalyst in the esterification reaction. Examples of the aliphatic sulfonic acids include methanesulfonic acid, ethanesulfonic acid,
Examples include propanesulfonic acid, butanesulfonic acid, hexanesulfonic acid, octanesulfonic acid, ethanedisulfonic acid, and butanedisulfonic acid. Furthermore, examples of aliphatic sulfonic acids include cyclohexane sulfonic acid and cycloheptane sulfonic acid. Among these, lower aliphatic sulfonic acids having 6 or less carbon atoms are preferred.

The amount of such a catalyst used is 0.005 to 10 mol%, preferably 0.005 to 10 mol%, based on the aromatic oxycarboxylic acid, based on the sulfonic acid group contained in the sulfonic acid.
The amount ranges from 0.01 to 1.0 mol%.

If the amount used is too small, the catalytic effect will not be sufficient, and if it is too large, the amount of sulfonic acid residues contained in the aromatic oxycarboxylic acid aryl ester, which is the reaction product, will increase, and this will not be used as a raw material. The resulting aromatic oxycarboxylic acid polyester has disadvantages such as poor thermal stability.

The esterification reaction in the present invention is usually carried out for 2 to 12 hours, and the progress of the reaction can be determined by the amount of water distilled out as a result of the reaction. This esterification reaction is normally carried out until the distillation of water produced as a result of the esterification reaction is substantially completed.

The aromatic oxycarboxylic acid aryl ester obtained by such an esterification reaction can be used as it is as a polyester raw material, but the reaction mixture usually contains unreacted aromatic oxycarboxylic acid, aromatic oxy compound, catalyst, etc. For example, the reaction product mixture is (1) brought into contact with water to remove water-soluble unreacted substances and catalyst, (2) benzene, toluene, xylene, ethylbenzene, butoid cumene, pentane, hexane,
It is preferable to purify by washing or recrystallizing with a hydrocarbon solvent such as heptane, cyclohexane, decalin, etc.

The aryl ester of aromatic oxycarboxylic acid obtained in this way contains, in addition to unreacted aromatic oxycarboxylic acid and aromatic oxy compound, a sulfonic acid derived from the aliphatic or aliphatic sulfonic acid used as the esterification reaction catalyst. It often contains a small proportion of groups.

Even with the above purification method, the amount of unreacted aromatic oxycarboxylic acid and aromatic oxy compound in the aromatic oxycarboxylic acid aryl ester is about 1 mol% or less, respectively, based on the total aromatic oxycarboxylic acid component, and The sulfonic acid group derived from the aliphatic or alicyclic sulfonic acid used as a catalyst may be contained in an amount of 0.001 to 1.0 mol%, particularly 0.001 to 0.1 mol%, based on the total aromatic oxycarboxylic acid component. . In this case, if such aromatic oxycarboxylic acid aryl ester is used as it is in the production of aromatic oxycarboxylic acid polyester without further purification or other measures, the rate of polycondensation of the polyester will be slow, and therefore the rate will be high. It becomes difficult to obtain the polymer in a short time. However, when a small proportion of a specific basic metal and/or its compound is added to carry out the polycondensation reaction in the production of polyester using the aromatic oxycarboxylic acid aryl ester, for example, the melt viscosity increases to 70,000 poise. In particular, high polymers exceeding 100,000 poise can be easily obtained. Therefore, it is preferable to add a basic metal or a compound thereof to the aromatic oxycarboxylic acid aryl ester obtained by the present invention. Examples of the basic metals include Li, Na, K, Rb, Cs, Ca, Mg,
Examples include alkali metals and alkaline earth metals such as Sr, Ba, etc., and examples of the compounds include sodium hydride, sodium oxide, potassium oxide, magnesium oxide, sodium carbonate, potassium bicarbonate, sodium formate, rubidium acetate,
Cesium acetate, calcium propionate, strontium butyrate, sodium hydroxide, potassium hydroxide, calcium hydroxide, sodium methylate,
Sodium ethylate, potassium phenolate,
Hydride, oxide, carbonate, bicarbonate, carboxylate, hydroxide such as lithium acetylacetone, magnesium acetylacetone, calcium acetylacetone, sodium chloride, sodium bromide, potassium bromide, sodium iodide, calcium chloride, etc. , alcoholates, phenolates, chelate compounds, halogen compounds, and the like.

The amount of the basic metal and/or its compound added is preferably based on the amount of sulfonic acid groups present.
The range is from 1/1 equivalent to 5/1 equivalent.

The effect of adding such a basic metal and/or its compound to the aromatic oxycarboxylic acid aryl ester obtained by the present invention or during the polycondensation reaction using the aryl ester is as follows.
For example, the effect is greater than that when a basic metal or its compound is added to an aromatic oxycarboxylic acid aryl ester obtained by a conventionally known esterification reaction, or when added during a polycondensation reaction using the aryl ester. It's noticeably large. This is one of the advantages of the method of the present invention.

When the aromatic oxycarboxylic acid aryl ester obtained by the present invention is used, for example, in the production of aromatic oxycarboxylic acid polyester with a high degree of polymerization, it can exhibit the excellent effects described above.

The aromatic oxycarboxylic acid polyester is an aromatic oxycarboxylic acid aryl ester.
or by condensation polymerization of one or more aromatic oxycarboxylic acid aryl esters, one or more aromatic dicarboxylic acid aryl esters, and one or more aromatic dioxy compounds, such as those mentioned above. homopolyester or copolyester. In addition, as the aromatic dicarboxylic acid that becomes the copolymerization component of the copolyester,
Terephthalic acid, isophthalic acid, naphthalene-2,
Examples include 6-dicarboxylic acid.

The polycondensation reaction is preferably carried out using a polycondensation catalyst. Specifically, such condensation polymerization catalysts include, for example, titanium tetrabutoxide,
Stannous acetate, lead oxide, antimony trioxide, bismuth pentoxide, cerium acetate, lanthanum oxide, zinc carbonate, manganese benzoate, lithium acetate, sodium metal, potassium acetate, magnesium acetate, calcium oxide, strontium stearate, propionic acid Examples include metals such as titanium such as barium, tin, lead, antimony, bismuth, cerium, lanthanum, zinc, manganese, lithium, sodium, potassium, magnesium, calcium, strontium, barium, and compounds containing these metals. The amount of condensation catalyst used is based on the total acid components that make up the polyester.
It is used in a range of 0.005 to 0.5 mol%.

In addition, the condensation polymerization reaction is carried out at 200-400℃, preferably
The temperature range is 250 to 350°C, more preferably 280 to 320°C, and the reaction pressure is preferably normal pressure until the reaction rate reaches 50%, but after 50%, the reaction pressure is reduced to 100 to 0.01 mmHg under reduced pressure. It is preferable to do it at the same time.

According to the present invention, the desired aromatic oxycarboxylic acid aryl ester can be obtained in good yield through an esterification reaction between an aromatic oxycarboxylic acid and an aromatic oxy compound, and this aryl ester has a small proportion of basicity. By using a metal and/or a compound thereof in combination, a polyester with a high degree of polymerization can be easily produced even by a conventional polycondensation reaction.

The present invention will be described below with reference to Examples. Note that "parts" in the examples mean "parts by weight."

In addition, analysis of sulfonic acid groups contained in aromatic oxycarboxylic acid aryl esters is as follows: 1)
Calculation based on the measurement of sulfur atoms using fluorescent X-ray analysis, or 2) oxidation method, in which the sample is treated with an oxidation method, and the sulfur content is determined by iodometric titration using a Dorman micrometer. In the Examples, Method 2 was used. Furthermore, the content of unreacted aromatic oxycarboxylic acid in the aryl ester was determined by trimethylsilylation according to a conventional method and quantitatively using a gas chromatograph.

Example 1 Add 0.2 parts of methanesulfonic acid to a mixture of 276 parts of p-oxybenzoic acid and 372 parts of phenol, and heat the mixture to 170 to 200°C in the presence of xylene to azeotropically convert the water produced as a result of the reaction. While distilling it 5
Allowed time to react. The obtained reaction product was poured into about 2000 parts of water, and the precipitated crystals were dried separately.
380 parts of phenyl p-oxybenzoate were obtained. This phenyl ester contained 0.1 mol% of unreacted p-oxybenzoic acid and 0.01 mol% of sulfonic acid groups calculated from the results of sulfur analysis. Furthermore, this phenyl ester contained an oligomer, and the average degree of polymerization of this oligomer was estimated to be about 1.1 from the results of NMR analysis.

The phenyl p-oxybenzoate thus obtained was used as a raw material for polyester as shown below, and its usefulness was confirmed.

That is, the above p-oxybenzoic acid phenyl 115
114 parts of diphenyl isophthalate, 42 parts of hydroquinone, 0.089 parts of stannous acetate, and 0.010 parts of sodium acetate were added to this part, and the reaction was carried out at normal pressure at a temperature of 280 to 290°C for 4 hours, and 65% of the theoretical amount of phenol was distilled out. At that point, gradually shift to decompression and at the same time 310
The temperature was raised to ℃ and reacted for 30 minutes under 20 mmHg. The obtained polymer was dissolved in a mixed solvent of phenol and tetrachloroethane (mixing ratio by weight: phenol:tetrachloroethane = 4:6) at 100°C, and the relative viscosity (ηr) was determined at 35°C using an Ostwald viscometer. ), and the intrinsic viscosity (IV) IV=ln ηr/C (where C is 0.5 g/dl in concentration) was found to be 1.12 from the following formula.

This polymer is ground into 12 to 24 meshes and further
Solid phase polymerization was carried out at 250°C for 10 hours under reduced pressure of 0.01 mmHg.
The resulting high polymer was melted at 350°C using a Koka type flow tester with a capillary diameter and length of 1.0 mm and 5.0 mm, respectively, and the melt viscosity was determined, and the shear rate was 100 sec ^- It showed a viscosity of 100,000 poise under ¹ .

Comparative Example 1 0.7 parts of p-toluenesulfonic acid was added to a mixture of 276 parts of p-oxybenzoic acid and 1000 parts of phenol, and the mixture was heated to 180 to 182°C in the coexistence of xylene to azeotrope the water produced as a result of the reaction. The reaction was continued for 5 hours while distilling the mixture. Then the reaction temperature was increased to 30
It took several minutes to raise the temperature to 205℃, and during this time, phenol was added.
630 copies were distilled. The reaction mixture obtained here is
The mixture was mixed with 100 parts of petroleum benzine, and after cooling to room temperature, the precipitate was separated, and the crystals were then washed with 200 parts of petroleum benzine and further dried at 150°C to obtain 310 parts of phenyl p-oxybenzoate. This phenyl ester contained 0.1 mol% of p-oxybenzoic acid and 0.06 mol% of sulfonic acid groups calculated from the results of sulfur analysis. In addition, this phenyl ester has an average degree of polymerization of approximately 1.1 as determined by NMR analysis.
It was hot.

Example 2 An esterification reaction was carried out in the same manner as in Example 1 except that 0.4 parts of ethanesulfonic acid was used instead of 0.2 parts of methanesulfonic acid to obtain 375 parts of phenyl p-oxybenzoate. This phenyl ester contains 0.2 mol% of unreacted p-oxybenzoic acid, and as a result of sulfur analysis, sulfonic acid groups were found.
It contained 0.03 mol%. Furthermore, this phenyl ester contained an oligomer, and the average degree of polymerization of this oligomer was estimated to be about 1.1 from the results of NMR analysis.

Using phenyl p-oxybenzoate obtained in this way, and reducing the amount of sodium acetate used,
Melt polymerization was carried out in the same manner as in Example 1, except that the amount was changed to 0.020 part, and a polymer having an intrinsic viscosity of 1.10 was obtained.
This polymer was further subjected to solid phase polymerization at 250°C in the same manner as in Example 1, resulting in a high polymer having a viscosity of 80,000 poise at 350°C and a shear rate of 100 sec ^-1 .

Example 3 An esterification reaction was carried out for 7 hours in the same manner as in Example 1 except that 0.4 part of cyclohexane sulfonic acid was used instead of 0.2 part of methanesulfonic acid.
365 parts of oxybenzoic acid were obtained. This phenyl ester contains 0.2 mol% of unreacted p-oxybenzoic acid, and sulfur analysis revealed that sulfonic acid groups were present.
It contained 0.03 mol%. Furthermore, this phenyl ester contained oligomers, and the average degree of polymerization was estimated to be about 1.1 from the results of NMR analysis.

Using phenyl p-oxybenzoate obtained in this way, and reducing the amount of sodium acetate used,
Melt polymerization was carried out in the same manner as in Example 1, except that the amount was changed to 0.020 part, to obtain a polymer with an intrinsic viscosity of 1.05. This polymer was further solid-phase polymerized at 250°C in the same manner as in Example 1, resulting in a polymerization rate of 65,000 at a shear rate of 100 sec ^-1 at 350°C.
It became a polymer of Poise.

Claims (1)

[Claims] 1. When producing an aromatic oxycarboxylic acid aryl ester by esterifying an aromatic oxycarboxylic acid and an aromatic oxy compound, the esterification reaction is carried out using a catalytic amount of aliphatic sulfonic acid and/or alicyclic sulfone. 1. A method for producing an aromatic oxycarboxylic acid aryl ester, the method being carried out in the presence of an acid.