KR890000792B1 - Process for the preparation of aromatic polyester monomer - Google Patents

Abstract

Aromatic polyester monomer of formula (III) is prepd. by reacting 1 mole of (I) with 4 moles of (II). In the formula, X=H, Cl, Br, Ph or C1-4 alkyl. Thus, put p-acetoxybenzoic acid (ABA) 180.15g and hydroquinone diacetate (HD) 582.54g into flask, heat to near 195 deg.C under N atm. and slowly elevate temp. to 265 deg.C with distilling of acetic acid, crystg. in MeOH, washing with MeOH, IN NaHCO3 and water, recrystg. in dioxane to give APB(yield 91.36%, mp 102.3-103.6 deg.C).

Description

Method for producing monomer of aromatic polyester

The present invention relates to a method for producing a monomer capable of imparting excellent properties in the production of an aromatic polyester having a liquid crystal forming ability upon melting.

All aromatic polyesters have the ability to form liquid crystals and have high elasticity, high strength, low elongation, and many studies have been conducted to develop them. However, most aromatic polyesters have a high melting point and high melting point, and thus, are radioactive. The disadvantage is that the sex is very poor.

In order to solve this problem, a method of preparing a copolymer using three or four monomers is mainly used for research, but at this time, due to the difference in the amount of addition or reactivity between monomers, which is inevitably generated, It may be in the form of a copolymer or random copolymer, and the physical properties of the polymer, in particular, the melting point and the melt viscosity change drastically depending on the reaction.

In particular, as a method for producing a wholly aromatic polyester composed of a hydroquinone diol, a para-hydroxy benzoic acid derivative, and isophthalic acid, an ecidolith method (such as USP 367595) and a phenolic method (Japanese Patent Laid-Open No. 56-90829) are known so far. Way.

However, as known in the ash polysis method, when hydroquinone diacetate (HD) para-acetoxybenzoic acid (ABA) isophthalic acid (IPA) is simultaneously introduced into a polymerization tube and polymerized, The highly blocky part, especially the block of acetoxybenzoic acid (ABA), is present in the molecular chain, resulting in high melting point and high melt viscosity, resulting in poor operability, in particular radioactivity, and impractical polymer.

Therefore, a method for producing a polymer by reacting para-hydroxy benzoic acid, diphenyl isophthalate and hydroquinone is known as a panolisis method designed to improve the above drawbacks. Although some improvement has been made by this method, substantial problems have not been solved due to fundamental differences in reactivity between monomers. Thus, the present inventors have long researched to solve the above-mentioned drawbacks, and reacted with IPA to include radicals having the structural formulas (II), (III) and (IV) below, but the structure is regular and the radioactivity is very good. In addition, the present invention was completed by preparing a monomer of Structural Formula (I), which is capable of producing a polymer having much better physical properties than the polymer produced by a known method.

Structural regularity in the present invention means that the radicals of structural formulas (II), (III) and (IV) are regularly arranged irrespective of the orientation of X and Y which are benzene nucleus substituents in the polymer.

Wherein X and Y are each H, Cl, Br phenyl or alkyl having 1-4 carbon atoms, n means the number of substituents, and is an integer of 1-4.

As a manufacturing method of the aromatic polyester containing the radical of structural formula (II), (III), and (IV), a well-known method is compared with the method of this invention as follows.

1) Ashdolis method

Wherein X is H, Cl, Br phenyl or alkyl of 1-4 carbon atoms, a, b, d, l, m. z is an integer greater than or equal to zero.

2) Phenolicis Method

Wherein X is H, Cl, Br phenyl or alkyl of 1-4 carbon atoms, a ', b', d ', l', m '... z 'is an integer greater than or equal to zero.

3) the method of the present invention

Wherein X is H, Cl, Br phenyl or alkyl of 1-4 carbon atoms, and a ", b" and l "are integers of 1 or more.

As shown in the schemes 1), 2) and 3), in the method of asholisis and panolisis, various repeating units are irregularly distributed to produce a copolymer having a random or block form. Adopting the method in the invention

의 구조가반복되는 구조 규칙적인 중합체가 생성된다.

A structured regular polymer is produced in which the structure of is repeated.

The present invention will be described in more detail as follows.

When reacting with bifunctional carboxylic acid, especially IPA, the present invention is a liquid crystal forming polyester having structural regularity, which has good moldability such as radioactivity, and can produce a polymer having good physical properties of the final molded product. It relates to the preparation of the monomer of structural formula (I).

The synthesis method of APB is as follows.

Put 1 mole of ABA and 1-4 moles of HD into a flask equipped with a stirrer, nitrogen inlet, thermometer, and distillation tube, and heat up slowly to get 240-280 ° C while receiving acetic acid from around 195 ° C. Precipitate the crystals. After washing 3-5 times with methanol to remove unreacted HD and ABA, 2-4 times washing with 1-2N aqueous NaOH solution or NaHCO ₃ aqueous solution, then washing 4 times with water and recrystallized with dioxane. ) Obtains pure APB where X and Y are H.

In the case where Cl, Br phenyl or alkyl having 1 to 4 carbon atoms is substituted on the HD ring, synthesis is also performed in the same manner as described above.

When the present invention is described in more detail in comparison with the conventionally known methods, in the conventional asholithism method and the phenolicsis method, due to the difference in the reactivity between the monomers used, a block in the unit of structural formula (II) is generated. The silver tetramer alone has a melting point of 340 ° C or higher, so if these units are included in the polymer, there is no industrial value of this polymer.

Efforts to prevent the blockage of Structural Formula (II) by the phenolicsis method to solve this drawback have shown that the processability of the polymer is much improved compared to the ashidolisis. Was considered to be.

Therefore, in order to solve the above-mentioned shortcomings, the inventors synthesized APB and reacted with IPA while studying the formation nuclei of blocks formed of repeating units of formula (II). The present invention has been completed by having the repeating unit of (IV), but eliminating the possibility that the unit of the structural formula (II) can be blocked. As a result, the structural regularity of the polymer can be controlled at will, and since the unit of formula (II) is not blocked, the melting point of the polymer is lowered, and the liquid crystal region is widened in the molten state due to the increase of the structural regularity, and the liquid crystal formability and The crystallinity of the solid state has been increased to increase the strength and modulus of the polymer.

In the examples below, purified APB was subjected to TLC in a developing solvent system of chloroform: 1, 1, 1, 3, 3, 3-hexafluoro-2-propanol (1: 1) (v / v) to obtain a single material. It was confirmed that the elemental analysis, IR and NMR were performed.

피크(1660 ㎝^-1)가 없어졌으며, 구조식(Ⅰ)의 APB의 특징적인 관능기인

(1740㎝^-1)만 나타났다.IR results show that the functional group of ABA of structural formula (II)

The peak (1660 cm ^-1 ) disappeared and is a characteristic functional group of APB of structural formula (I).

(1740 cm ^-1 ) only appeared.

As a result of elemental analysis, C ₁₇ H ₁₄ O ₆ was as follows.

Theoretic value: C; 64.77%, H; 4.49%

Experimental value: C; 46.88%, H; 4.51%

And it was shown as follows by NMR (CF ₃ COOD).

a; δ 2.26 b; δ 2.36 c; δ8.20

d; δ 7.32 e; δ7.12

EXAMPLE

Into a flask equipped with a stirrer, a nitrogen inlet, a thermometer, and a distillation tube, ABA 180.15 g (1 mol) and HD 2.52.54 g (3 mol) were added and heated in the presence of nitrogen to obtain acetic acid, a reaction product, from the 195 ° C. 265 The temperature was gradually raised to 0 ° C, acetic acid was taken out, and the crystals were precipitated with methanol. Washed four times with methanol to remove excess HD and unreacted ABA, washed three times with 1N aqueous NaHCO ₃ solution, washed four times with water, and recrystallized with dioxane to obtain X in the formula (IV). Get pure APB which is

Yield: 91.36%

MP: 102.3-103.6 ℃

Claims (1)

A process for preparing a substance of formula C by reacting a compound of formula A with a compound of formula B in a molar ratio of 1: 4.

Provided that in Formulas B and C, X represents H, Cl, Br, phenyl, alkyl having 1 to 4 carbon atoms, and in Formula C, X may be present at any of 2, 3, 5, 6 positions in the benzene ring.