JPH0426640A - Separation and purification of biphenyl-4,4'-diol - Google Patents

Abstract

PURPOSE:To obtain the title high-purity compound in a short time, by extracting crude biphenyl-4,4'-diol with an organic solvent, dripping the solution into hot water and recovering the title compound as powder dispersed into water while simultaneously distilling away the solvent. CONSTITUTION:Crude biphenyl-4,4'-diol is extracted with an organic solvent (preferably alcohols or ketones which can be distilled or subjected to azeotropic distillation with water especially at <=100 deg.C), the extracted solution is dripped into hot water, biphenyl-4,4'-diol is recovered as powder dispersed into water while simultaneously distilling away the solvent to separate and purify biphenyl-4,4'-diol. In this method, preferably the extracted solution of crude biphenyl-4,4'-diol is treated with active carbon. By this method, a high-purity product having reduced content of impurities and excellent hue can be industrially and advantageously obtained by simple operations and in a short time.

Description

Detailed Description of the Invention [Industrial Field of Application] The present invention provides biphenyl-4,4-diol (hereinafter BP
(abbreviated as DO)).

BPDO has attracted attention in recent years as a monomer for engineering plastics, especially liquid crystal polymers, and
It is also a useful compound as an antioxidant for polymeric materials.

[Conventional technology]

Several methods have been proposed so far for producing BPDO. For example, ■method of brominating and hydrolyzing biphenyls, ■method of sulfonating biphenyls and melting them with alkali, and ■tetra-tert-butyl obtained by oxidative coupling of 2.6-di-tert-butylphenols. A method of dealkylating diphenols under an acid catalyst, and (2) a method of dehalogenating dimerization of P-chlorophenols are known.

In the crude BPDO obtained from these various production methods,
All contain inorganic impurities such as alkali metal compounds, alkaline earth metal compounds, transition metal compounds, aluminum compounds, or sulfur oxides. Specifically, Na
, Ca, Cu.

These impurities include /'triogenides, oxides, or sulfates of Fe, Ni, Cr, A1, etc. Since the contamination of these impurities adversely affects not only the appearance but also the polymerizability of the polymer, it is necessary to remove them. For information on how to remove these impurities, see B.
Since PDO is a high melting point and high boiling point substance and is difficult to purify by distillation, several purification methods using recrystallization have been proposed.

For example, in Japanese Patent Application Laid-Open No. 59-98027, crude BPD
After dissolving O in an aliphatic lower alcohol, ketones, or cyclic ether, aromatic hydrocarbons are added to this solution, and the resulting solution is distilled to remove most of the alcohol, ketones, or cyclic ether. A method for precipitating BPDO and separating it is disclosed. However, with this method, impurities such as alkali metal compounds, alkaline earth metal compounds, transition metal compounds, aluminum compounds, and sulfur oxides in BPDO cannot be removed because water is not present, and the purity of BPDO cannot be removed. The problem was that it did not improve.

Moreover, in JP-A-1-226841, crude BPDO
is dissolved in a mixed solvent of water and one or more organic solvents selected from aliphatic lower ketones and alcohols, treated with activated carbon, a part of the solvent is distilled off, and the resulting solution is cooled to perform crystallization. A method is disclosed for carrying out the method and separating the resulting crystals. However, this method has problems in that the recovery rate of BPDO is low, and in addition, the crystallization operation requires cooling and takes a long time, and cannot be said to be an industrially advantageous method.

[Problem to be solved by the invention]

The purpose of the present invention is to improve the separation and recovery method of BPDO as a powder, which has conventionally been complicated and economically problematic in terms of separation and purification processes, and which can achieve high purity and color in a short time using simple operations. BPDO that allows you to obtain excellent BPDO
The goal is to develop industrial processes for

[Means to solve the problem]

The present inventors have conducted various studies to solve the above-mentioned problems, and as a result, they have arrived at the present invention.

That is, the method for purifying BPDO of the present invention involves extracting crude BPDO obtained in the manufacturing process into an organic solvent, dropping the extracted solution into hot water, and simultaneously distilling off the solvent to obtain BPDO.
A method for separating and purifying BPDO, which is characterized by recovering BPDO as a powder dispersed in water.

The details will be explained below.

[Effect]

The method for separating and purifying BPDO according to the present invention involves extracting crude BPDO obtained in the manufacturing process into an organic solvent, dropping the extracted solution into hot water, and simultaneously distilling off the solvent to form a powder in which BPDO is dispersed in water. This is achieved by taking it up as

The content of inorganic impurities in crude BPDO varies depending on the manufacturing method, but in general, in the hydrolysis method of brominated biphenyl,
In the alkali melting method of sulfonate, halides and oxides such as Na, Cu, Fe, etc.
In the oxidative coupling method of phenols, halides, oxides, and sulfates such as AI, Cu, and Na are included.

Since crude BPDO is often obtained in the form of an alkaline aqueous solution, acid is added to make it acidic, and the aqueous layer is extracted into an organic solvent.

The organic solvent for extracting BPDO in the present invention refers to BPD
It refers to a good solvent that dissolves O, and alcohols or ketones that can be distilled or azeotropically distilled with water at 100° C. or lower are preferred. Examples include methanol, ethanol, 1-propanol, 2-probanol, 1-butanol, 2-butanol, t-butanol, amyl alcohol, cyclohexanol, acetone, methyl ethyl ketone, diethyl ketone, methyl isobutyl ketone, and cyclohexanone. Among these solvents, methyl ethyl ketone and methyl isobutyl ketone are particularly preferred solvents because they have high solubility for BPDO.

It is sufficient that the amount of these solvents used is at least the amount that dissolves BPDO, and although it varies depending on the type of solvent, the concentration of the BPDO solution is usually about 1 to 50% by weight.

If the crude BPDO extract contains insoluble matter, it can be filtered, and if it is significantly colored, it can be treated with activated carbon, if necessary. The amount of activated carbon used is preferably about 0.01 to 50% by weight based on BPDO. The temperature of the activated carbon treatment is preferably above room temperature and below the boiling point of the solvent.

As a method of activated carbon treatment, activated carbon may be added to the crude BPDO extract and brought into contact with it, or activated carbon may be packed in an adsorption tower and the crude BPDO extract may be passed through and brought into contact with the activated carbon, and the method is not limited. Of course, if the crude BPDO extract has little colored content, the next operation may be carried out without performing the activated carbon treatment.

The amount of hot water is determined by the concentration of the BPDO slurry after the completion of desolvation, and is selected to be an amount that can be handled as a slurry and is economically advantageous.

The temperature of the hot water is higher than either the boiling point of the solvent of the crude BPDO extract or the azeotropic temperature with water, and is usually 40 to 1
It is about 00℃. During desolvation, the inside of the desolvation tank contains BPDO.
It is desirable to perform sufficient stirring so that it is uniformly dispersed in the water.

As a method of adding the crude BPDO extract to the hot water, a method of dropping the crude BPDO extract onto the heated water surface or a method of spouting the crude BPDO extract onto the heated water surface from a nozzle with a small diameter is selected. In addition, if the rate of addition of the crude BPDo extract into the hot water is faster than the rate of distillation of the organic solvent, impurities may be introduced due to solidification of the BPDO, so the organic solvent must be instantly distilled out of the system. Therefore, it is desirable that the addition rate be lower than the distillation rate of the organic solvent.

The method of the present invention is usually carried out under normal pressure. can also be carried out under reduced pressure.

When the crude BPDO extract is dropped into the above-mentioned hot water and simultaneously the solvent is removed by the above-described operation, BPDO precipitates in a short time and becomes a fine powder uniformly dispersed in the water. Therefore, the precipitated BPDO powder can be easily separated and recovered from the slurry liquid in a short time by a conventional method. for example,
It can be separated and recovered by centrifugation, suction filtration, spray drying, etc.

By these methods, BPDO can be quantitatively separated and recovered as a fine powder from the reaction solution obtained from the manufacturing process.

The recovery rate of purified BPDO thus obtained is very high and almost quantitative. In addition, the purified BPDO obtained is crude B
Alkali metal compounds, alkaline earth metal compounds, transition metal compounds, aluminum compounds contained in PDO,
It is highly pure, containing almost no inorganic impurities such as sulfur oxide, and is a white crystal with a good hue.

〔Effect of the invention〕

As is clear from the above explanation, according to the method of the present invention,
BPDO with reduced inorganic impurities, high purity, and excellent color can be produced in an industrially advantageous manner in a short time by simple operations.

〔Example〕

EXAMPLES The present invention will be explained below with reference to Examples, but the present invention is not limited to these Examples.

Example 1 Crude BPDO (Fe150ppm
Methyl ethyl ketone 2001d was added to a reaction solution containing 14 g of (containing 300 ppm of Cu, 1500 ppm of Na, 300 ppm of Na) in the form of a slurry for extraction.

Next, the above extract was poured into 600 d of hot water heated to 90°C for 0.6. Methyl ethyl ketone was continuously distilled off while dropping at a dropwise rate of 11/hr.

During distillation, BPDO immediately precipitated into fine powder and was uniformly dispersed in water.

After dropping the crude BPDO extract, the obtained water slurry of BPDO was filtered, and the powder was washed with 2 g of water and dried to obtain 13.5 g of white purified BPD. Recovery rate is 9
6.4%, and when purified BPDO was analyzed, the purity was 99.9%, Fe3ppm, Cu5ppm,
Example 2 Crude BPDO (Fe200 ppm) obtained by alkaline hydrolysis reaction of 4.4-dibromobiphenyl
+, Cu 350 ppm, Na 2000
200 d of methyl ethyl ketone was added to the reaction solution containing 14 g (containing ppm) in the form of a slurry, and extracted with powdered activated carbon 1
, 4 g was added thereto, and the mixture was heated under reflux for 30 minutes. After heating to reflux, the mixture was cooled to room temperature and filtered to remove activated carbon and insoluble matter in the crude BPDO.

Next, the above extract was added to 600-degree hot water heated to 90°C. Methyl ethyl ketone was continuously distilled off while dropping at a dropping rate of /hr.

During distillation, BPDO immediately precipitates and becomes a fine powder] 1 Evenly dispersed in water.

After dropping the crude BPDO extract, the obtained BPDO water slurry was treated in the same manner as in Example 1 to obtain white purified BP.
4 g of D01B was obtained. The recovery rate was 95.7%, and when purified BPDO was analyzed, the purity was 99.9%.
6ppm, Cu4ppm.

N a was 8 ppm.

Example 3 Crude BPDO (Fe 150 ppm,
Contains 300ppm Cu and 1500ppm Na) 14g
1-butanol 300- was added to the reaction solution containing in the form of a slurry for extraction.

Next, the above extract was added dropwise to 600 ml of hot water heated to 100° C. at a dropping rate of 0.6 ρ/hr, while methyl ethyl ketone was continuously distilled off. During distillation, B
PDO immediately precipitated into fine powder and was uniformly dispersed in the water.

After dropping the crude BPDO extract, the obtained BPDO water slurry was treated in the same manner as in Example 1 to obtain white purified BP.
13.4 g of D0 was obtained. The recovery rate was 95.7%, and when purified BPDO was analyzed, the purity was 99.9%.
e3ppm, Cu7ppm.

Na10ppI11.

Example 4 Yellow crude BPDO obtained by alkali melting of biphenyl-4,4-disulfonic acid sodium salt (
Contains 2500ppm Na, 53000ppn+)1
Methyl ethyl ketone 200i was added to a reaction solution containing 0 g in a slurry state for extraction.

Next, the above extract was added dropwise to 600 ml of hot water heated to 90°C at a dropwise rate of 0.40/hr, while methyl ethyl ketone was continuously distilled off.

During distillation, BPDO immediately precipitated into fine powder and was uniformly dispersed in water.

After dropping the crude BPDO extract, the obtained BPDO water slurry was treated in the same manner as in Example 1 to obtain white purified BP.
9.6 g of DO was obtained. The recovery rate was 96.0%, and when purified BPDO was analyzed, the purity was 99.8%, N8
6 ppm, S 3 ppHl.

Example 5 Crude BPDO (A
To a reaction solution containing 10 g (containing 320 ppm) in a slurry state, 200 g of methyl ethyl ketone was added and extracted.

Next, methyl ethyl ketone was continuously distilled off while the above extract was added dropwise to 600 liters of hot water heated to 90° C. at a dropping rate of 0.4 Ω/hr.

During distillation, BPDO immediately precipitated into fine powder and was uniformly dispersed in water.

After dropping the crude BPDO extract, the obtained BPDO water slurry was treated in the same manner as in Example 1 to obtain white purified BP.
9.5 g of DO was obtained. The recovery rate was 95.0%, and the purity was 99.8% when purified BPDO was analyzed.
It was ppm.

Comparative Example 4. Crude BPDO (Fe200ppm
, CCu250pp, Na1500ppm)1
The reaction solution containing 4 g in the form of a slurry was filtered by suction filtration.

Next, the filtered wet crystals were washed with 2 g of water and dried to obtain 13.4 g of pale yellow BPD.

The recovery rate was 95.7%, and when BPDO was analyzed, it was found to be FFe 35 pp, Cu 52 ppH, and NNa 30 pp.

Claims (3)

[Claims] (1) In the method of purifying biphenyl-4,4'-diol and separating and recovering it as a powder, the crude biphenyl-4,4'-diol obtained in the manufacturing process is extracted into an organic solvent, and the extraction solution is Biphenyl-4,4, which is characterized by dropping biphenyl-4,4'-diol into hot water and recovering biphenyl-4,4'-diol as a powder dispersed in water while simultaneously distilling off the solvent.
A method for separating and purifying '-diol. (2) Separation according to claim 1 using alcohols or ketones that can be distilled at 100°C or below or azeotropically distilled with water as the organic solvent for extracting the crude biphenyl-4,4'-diol. Purification method. (3) The separation and purification method according to claim 1, wherein the extracted solution of crude biphenyl-4,4'-diol is treated with activated carbon.