JP2015042720A - Aromatic polyester - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a novel aromatic polyester having a reactive functional group within the molecule, and a method for producing the same.SOLUTION: The aromatic polyester is a polymer obtained by condensation-polymerizing gallic acid. The aromatic polyester can be produced by condensation-polymerizing gallic acid under the presence of an acid such as phosphoric acid. In the production method, the gallic acid may be condensation-polymerized under the presence of an acid as well as carboxylic acid anhydride. The reaction temperature is, for example, -10°C to 100°C. The use amount of the acid is, for example, 0.1 to 5 mole per 1 mole of gallic acid. The use amount of the carboxylic acid anhydride is, for example, 0.5 to 10 mole per 1 mole of gallic acid.

Description

  The present invention relates to a novel aromatic polyester using gallic acid as a raw material and a method for producing the same. This aromatic polyester can be used as a functional polymer or a raw material thereof.

  A parahydroxybenzoic acid polyester is known as a polymer having extremely high heat resistance. This polyester has a rigid molecular chain and is excellent not only in heat resistance but also in strength and chemical resistance. In addition, aromatic polyesters based on parahydroxybenzoic acid and ester-bonded with various dicarboxylic acids, dihydroxy compounds, hydroxycarboxylic acids and the like are used as liquid crystalline polymers (Patent Document 1).

JP 2004-256656 A

  The objective of this invention is providing the novel aromatic polyester which has a reactive functional group in a molecule | numerator, and its manufacturing method.

  As a result of intensive studies to achieve the above object, the present inventors have found that when gallic acid is polymerized in the presence of an acid, a novel aromatic polyester having a hydroxyl group in the aromatic ring can be obtained. completed.

  That is, the present invention provides an aromatic polyester obtained by polycondensation of gallic acid.

  The present invention also provides a method for producing an aromatic polyester, characterized in that an aromatic polyester is obtained by polycondensation of gallic acid in the presence of an acid. In this production method, gallic acid may be polycondensed with an acid in the presence of a carboxylic acid anhydride.

  According to the present invention, a novel aromatic polyester is provided. This aromatic polyester is excellent in heat resistance and strength. Moreover, since it has a hydroxyl group which is a reactive functional group in the molecule, a new function according to the purpose and application can be imparted by modification or the like. Therefore, the aromatic polyester of the present invention can be used as a functional polymer or a raw material thereof.

It is a figure which shows the infrared absorption spectrum of a gallic acid hydrate. 1 is an infrared absorption spectrum of the polymer obtained in Example 1. FIG. It is a figure which shows the DSC measurement result (1st run, 2nd run) of a gallic acid hydrate. FIG. 3 is a diagram showing DSC measurement results (1st run, 2nd run, 3rd run) of the polymer obtained in Example 1. It is a figure which shows the TG-DTA measurement result of a gallic acid hydrate. FIG. 3 is a view showing a TG-DTA measurement result of the polymer obtained in Example 1. It is a figure (comparison figure) which shows the TG-DTA measurement result of the gallic acid hydrate (dashed line) and the polymer (solid line) obtained in Example 1.

  The aromatic polyester of the present invention is a polymer obtained by polycondensation of gallic acid represented by the following formula (1), and has a repeating structural unit represented by the following formula (2) and / or (3). .

  The aromatic polyester of the present invention can be produced by polycondensation of gallic acid in the presence of an acid.

  Examples of the acid include inorganic acids such as phosphoric acid, boric acid, hydrochloric acid, hydrobromic acid, hydrofluoric acid, and sulfuric acid; carboxylic acids such as trifluoroacetic acid, methanesulfonic acid, ethanesulfonic acid, and trifluoromethanesulfone. Examples thereof include sulfonic acids such as acid, benzenesulfonic acid, p-toluenesulfonic acid, and naphthalenesulfonic acid. Among these, inorganic acids are preferable and phosphoric acid is particularly preferable from the viewpoint of reaction rate and suppression of side reactions.

  The amount of the acid used can be appropriately selected in consideration of the reaction rate, production cost, and side reaction suppression, and is usually 0.1 to 5 mol, preferably 0.1 mol to 1 mol of gallic acid used as a raw material. Is 0.2-3 mol, more preferably 0.5-2 mol.

  In the above production method, gallic acid may be polycondensed with an acid in the presence of a carboxylic acid anhydride. The reaction rate can be improved by using a carboxylic acid anhydride.

  Examples of the carboxylic acid anhydride include C2-C10 fluorine-containing aliphatic carboxylic acid anhydrides such as trifluoroacetic anhydride (TFAA); C2-C10 aliphatics such as acetic anhydride and propionic anhydride. Examples thereof include carboxylic acid anhydrides. Among these, a fluorine atom-containing aliphatic carboxylic acid anhydride having 2 to 10 carbon atoms such as trifluoroacetic anhydride (TFAA) is preferable from the viewpoint of reaction rate.

  The amount of the carboxylic acid anhydride to be used can be appropriately selected in consideration of reaction rate, production cost, and side reaction suppression. Mol, preferably 1 to 8 mol, more preferably 2 to 6 mol.

  The polymerization reaction is performed in the presence or absence of a solvent. The solvent may be any solvent inert to the reaction, for example, water; aromatic hydrocarbons such as benzene, toluene and xylene; aliphatic hydrocarbons such as pentane, hexane, heptane, octane and decane; cyclopentane, And alicyclic hydrocarbons such as cyclohexane; and mixed solvents thereof.

  The reaction temperature (polymerization temperature) is, for example, -10 ° C to 100 ° C, preferably 0 to 50 ° C. The reaction time is, for example, 0.5 hour to 48 hours, preferably 1 hour to 24 hours, more preferably 3 hours to 24 hours.

  After the reaction, the aromatic polyester of the present invention may be isolated by using a conventional separation and purification means.

  The aromatic polyester thus obtained is excellent in heat resistance and mechanical strength because the repeating unit has an aromatic ring. Moreover, since it has a hydroxyl group which is a reactive functional group in the molecule, various modifications and derivatizations are possible, and new functions according to the purpose and application can be imparted by the modification. Therefore, the aromatic polyester of the present invention can be used as a functional polymer or a raw material thereof.

  Hereinafter, the present invention will be described in more detail based on examples, but the present invention is not limited to these examples.

Example 1
In a nitrogen atmosphere, 1 g of gallic acid hydrate (Tokyo Chemical Industry Co., Ltd.), 0.68 g of 85% by weight aqueous phosphoric acid solution (Kanto Chemical Co., Ltd.), trifluoroacetic anhydride (Wako Pure Chemical Industries, Ltd.) ) 4.94g was charged. Stirring was continued at room temperature for 7 hours while introducing nitrogen. Next, 10 mL of cold water was added into the flask. Insoluble matter was recovered by centrifugation and dried at 80 ° C. under vacuum for 6 hours to obtain 0.047 g of a product.

[FT-IR]
The product and raw material were each pulverized and mixed with potassium bromide, and the infrared absorption spectrum was measured with a Fourier transform infrared spectrophotometer (manufactured by Agilent Technologies, model: FTS3100). The infrared absorption spectrum of the raw material (gallic acid hydrate) is shown in FIG. The infrared absorption spectrum of the product is shown in FIG. Since the carbonyl absorption peak of carboxylic acid at 1703 cm ⁻¹ seen in the raw material monomer is shifted to 1721 cm ⁻¹ in the product, it can be seen that an ester bond is formed in the product.

[DSC]
The product and the raw material (gallic acid hydrate) were subjected to thermal analysis using a differential scanning calorimeter. DSC measurement conditions are shown below.
<Measurement conditions>
Measuring device: differential scanning calorimeter (trade name “DSC-Q2000”, manufactured by T.A. Instruments)
Atmosphere: Nitrogen Temperature range: 30 ° C. to 200 ° C. Up to 2nd run (gallic acid hydrate) / 30 ° C. to 300 ° C. Up to 3rd run (product) Temperature rising rate: 10 ° C./min during temperature rising, −20 during cooling ° C / min
FIG. 3 shows DSC measurement results (1st run, 2nd run) of gallic acid hydrate, and FIG. 4 shows DSC measurement results (1st run, 2nd run, 3rd run) of the product obtained in Example 1.
As for gallic acid hydrate, only desorption of crystal water is observed in 1 st run, and no change such as melting is observed. Since heat balance is not measured with 2nd run, it is considered that decomposition and state change have not occurred in the range of 30 to 200 ° C.
On the other hand, the product has a component that volatilizes (or decomposes) at around 90 ° C and around 220 ° C. The product was observed to have inflection points of 2nd run and 3rd run in the vicinity of 220 to 240 ° C., presumably Tg. This shows that the product is a polymer.

[TG-DTA]
The product and the raw material (gallic acid hydrate) were subjected to thermal analysis using a differential thermothermal gravimetric simultaneous measurement apparatus. The measurement conditions for TG-DTA are shown below.
<Measurement conditions>
Measuring device: Differential thermothermal weight simultaneous measuring device (trade name “TG-DTA 6200”, manufactured by SII Nanotechnology)
Atmosphere: Nitrogen Sample container: Aluminum Temperature range: 30 ° C to 570 ° C
Temperature increase rate: 20 ° C / min
FIG. 5 shows the TG-DTA measurement result of gallic acid hydrate, FIG. 6 shows the TG-DTA measurement result of the product obtained in Example 1, and FIG. 7 shows the gallic acid hydrate and Example 1. The figure (comparison figure) which shows the TG-DTA measurement result of the obtained product is shown. In FIG. 7, the broken line is gallic acid hydrate data, and the solid line is the product data obtained in Example 1.
The above results show that the product has a higher decomposition temperature than the raw material (gallic acid hydrate). Gallic acid hydrate undergoes desorption of water of crystallization at 100 ° C., causes thermal decomposition at 250 ° C., and greatly reduces the weight. Moreover, although the weight decreases even at 330 ° C., it is considered that it is not a simple thermal decomposition because it is seen with an exothermic peak.
On the other hand, the weight of the product gradually decreased from 30 to 200 ° C., which seems to be caused by volatilization of moisture or solvent. In addition, it is estimated that the slight decrease in weight at 200 ° C. is due to volatilization of volatile components. Moreover, a weight reduction similar to that of gallic acid is observed at 330 ° C. In addition, the sample after a heating was discolored black.

[Solubility]
In order to examine the solubility of the product, about 0.2 mg of a sample was dispersed in 1 mL of a solvent in a glass sample bottle, and the solubility was confirmed. As a result, the product was insoluble in tetrahydrofuran, chloroform, water, dimethyl sulfoxide and N, N-dimethylformamide.

Claims (3)

  An aromatic polyester obtained by polycondensation of gallic acid.   A process for producing an aromatic polyester, characterized in that an aromatic polyester is obtained by polycondensation of gallic acid in the presence of an acid.   The method for producing an aromatic polyester according to claim 2, wherein gallic acid is polycondensed with an acid in the presence of a carboxylic anhydride.

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