JPH0322376B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to the production of P,P'-biphenol. More specifically, 3,5,3',5'-tetra-t-
This invention relates to a method for producing P,P'-biphenol by removing butyl from butyl-4,4'-biphenol.

P,P'-biphenol is used as an oxidation stabilizer for resins, as a dye intermediate, and as a raw material for synthetic resins such as polycarbonate, polyepoxide, polyester, and polysulfone, and is attracting attention from various quarters because it has particularly excellent heat resistance. There is. P,P'-biphenol as the above raw material is required to be highly pure in order to fully utilize the physical properties of the polymer, but due to the properties of P,P'-biphenol it is used as a polymerization raw material. It is very difficult to obtain refined products with high purity suitable for.

Conventionally, it has been known that aluminum alkoxide catalysts are effective as a method for debutylating 3,5,3',5'-tetra-t-butylbiphenol to obtain P,P'-biphenol. This catalyst is very problematic in its separation from the P,P'-biphenol formed.

Furthermore, a method of dealkylating without a solvent and without a catalyst is known (Japanese Patent Application Laid-Open No. 55-92332, UCC), but this method requires a high temperature of 250 to 500°C and is not practical.

Furthermore, since P,P'-biphenol is a substance with a high melting point and a high boiling point, it is virtually impossible to purify it by distillation. In addition, since P,P'-biphenol is relatively difficult to dissolve in solvents, a large amount of solvent or special operations are required for recrystallization, which is not economical.
It is desired to separate highly pure P,P'-biphenol directly from the reaction mixture.

The present inventor has completed the present invention as a result of intensive research in consideration of the above circumstances.

That is, in the present invention, phenol or phenol substituted with 1 to 3 lower alkyl groups or lower alkoxy groups is used as a solvent for 3,5,3',5'-tetra-t-butyl-4,4'-biphenol, 120-150 in the presence of sulfuric acid or sulfonic acid as catalyst
Debutylated and subsequently melting point of the solvent at a temperature of ~80 °C
Specific examples of the phenol obtained by substituting P,P'-biphenol crystals with the above-mentioned 1 to 3 lower alkyl groups or lower alkoxy groups at a temperature of °C include o-, m- or p-cresol; 2-, 3-
or 4-ethylphenol; 2-, 3- or 4-
t-butylphenol; 2,3-, 2,4-,
2,5-, 2,6-, 3,4- or 3,5-dimethylphenol; 2,3-2,4-, 2,5-,
2,6-, 3,4- or 3,5-di-t-butylphenol; anisole or o-, m- or p-
Methoxyphenol; 2-, 3- or 4-ethoxyphenol, and the like. Among these, phenol and cresol are particularly preferred as solvents in the method of the present invention. Further, examples of the sulfonic acid of the catalyst include alkyl or aryl sulfonic acids such as methylsulfonic acid, ethylsulfonic acid, phenylsulfonic acid, and toluenesulfonic acid, but preferably a sulfuric acid catalyst is used.

Although there are no strict limitations on the reaction conditions, it is generally appropriate to carry out the reaction within the following ranges. Reaction temperature: 120-250℃, preferably 180-200℃
°C, amount of solvent used (weight): the same amount to about 10 times that of the raw material, preferably 1.5 to 2.0 times, amount of catalyst (weight): 0.01 to 20%, preferably 0.1 to 5.0% based on the raw material,
Reaction time: 1 to several hours, however, these conditions are only a guideline, and it is desirable to adjust them as necessary.

Through the reaction, the t-butyl group of the raw material tetra-t-butylbiphenol is eliminated to obtain biphenol, and the eliminated t-butyl group is recovered as isobutene. At this time, a portion of the phenol or substituted phenols used as a solvent is alkylated (transalkylation) with t-butyl groups from the raw materials, and depending on the reaction conditions, the proportion of t-butyl groups may vary. However, by increasing the reaction time, the proportion of transalkylation decreases and the proportion of isobutene recovered increases.

When the reaction solution is cooled after the completion of the reaction, crystals of P,P'-biphenol, which is the target product, are precipitated, but at this time, the temperature of the reaction solution is preferably kept above the melting point of the solvent
By keeping the temperature below 80°C and collecting the product by filtration, the target product of high purity can be easily obtained. In this case, 80℃
Although it is possible to obtain crystals of P,P'-biphenol even at temperatures above, the solubility of the target substance increases, resulting in a lower recovery rate and poor efficiency. Also,
On the other hand, if the temperature is too low, there are disadvantages such as the phenol or substituted phenols in the solvent coagulate and separation becomes impossible, or transalkylated phenols or substituted phenols precipitate, resulting in a decrease in purity. Suitable temperatures cannot be uniformly defined because the freezing point (melting point) and solubility of the target substance vary depending on the type of solvent, but as an example, 50 to 80°C for phenol solvents and 50 to 80°C for cresol solvents. In this case, a temperature of about 40 to 80°C is appropriate. It should be noted that it is better to precipitate P,P'-biphenol from the reaction solution slowly over a relatively long period of time rather than rapidly, and to avoid contamination with impurities, the precipitation should be within the above range. It is desirable to precipitate by keeping the temperature at a constant temperature, and then filter it while maintaining that temperature.

The recovery rate of P,P'-t-biphenol varies slightly depending on the type and amount of solvent and the temperature of filtration, but is between 55 and 84%. Although the precipitated and separated crystals of P,P'-biphenol are of sufficiently high purity, they may be slightly colored in some cases, so if necessary, they may be treated with an aromatic hydrocarbon such as toluene or benzene. By washing thoroughly, the pale pink color is removed and almost pure white P,P'-biphenol can be obtained. The purity of this product is determined by gas chromatography and is over 99%.

In addition, the raw material 3,5,3',5'-tetra-t-butyl-3,5,3',5'-tetra-t-butyl-
By adding 4,4'-biphenol and performing the same operation as above, the debutylation reaction can be repeated. In this case, the filtrate of hot filtration is a saturated solution of P,P'-biphenol, so
Added 3,5,3',5'-tetra-t-butyl-
Almost quantitatively P for 4,4'-biphenol,
P'biphenol is obtained.

Next, the present invention will be explained in more detail by showing examples.

[Example 1] 3,5,3',5'-tetra-t-butyl-4,
4′-biphenol 2.8g (7.04mmol), phenol
12.84g and 2 drops of sulfuric acid were placed in a 50ml flask and reacted at 150°C for 5 hours while stirring with a magnetic stirrer. After the reaction was completed, the reaction mixture was cooled to 70°C, and crystals were precipitated at this temperature for 2 hours. After crystals were precipitated, they were filtered while hot at 70°C to obtain a crude product of P,P'-biphenol. By washing this material with toluene, 0.83g of P,P'-biphenol was obtained.
(4.46 mmol, yield 63%) was obtained. The color was white, and the purity was 99% or more as a result of gas chromatography analysis.

[Example 2] 3,5,3',5'-tetra-t-butyl-4,
4'-biphenol 2.27g (5.54mmol), p-t-
Put 9.22g of butylphenol and 2 drops of sulfuric acid into a 50ml flask and stir with a magnetic stirrer.
The reaction was carried out at 200°C for 3 hours. After the reaction was completed, the reaction mixture was cooled to 70°C and maintained at this temperature for 2 hours to precipitate crystals. After this, 0.743 g (3.99 mmol, yield 72
%) was obtained. The purity was 99% or more as a result of gas chromatography analysis.

[Example 3] 3,5,3',5'-tetra-t-butyl-4,
80.45 g (0.196 mmol) of 4'-biphenol, 160.44 g of phenol, and 0.1 ml of sulfuric acid were placed in a 300 ml two-necked flask, and reacted at 180° C. for 5 hours while blowing nitrogen. After the reaction was completed, the reaction solution was cooled to 60°C and
Crystals were precipitated over time and filtered while hot to obtain P,P'-biphenol. This product was washed with toluene and dried directly in the air, and 28.63 g of P,P'-biphenol was obtained.
(0.154 mol, yield 78.5%) was obtained. The purity was determined to be 99% or more by gas chromatography analysis.

[Example 4] In the filtrate of hot filtration in Example 3, 3,5,
50.60 g (0.123 mol) of 3',5'-tetra-t-butyl-4,4'-biphenol was added and reacted in a 300 ml two-necked flask at 200°C for 2 hours while blowing nitrogen. The reaction mixture was cooled to 60°C, crystals were precipitated for 2 hours, filtered hot at 60°C, the separated crystals were washed with toluene and dried to give P,P'-biphenol.
22.87g (0.123mol, yield 99.9%) was obtained. The purity was 99% or higher as determined by gas chromatography analysis.

[Example 5] 3,5,3',5'-tetra-t-butyl-4,
2.062 g (5.02 mmol) of 4'-biphenol, 10.042 g of o-cresol, and 1 drop of sulfuric acid were placed in a 50 ml flask and reacted at 170° C. for 3 hours while stirring with a magnetic stirrer. After the reaction was completed, the reaction mixture was cooled to 50°C, crystals were precipitated for 2 hours, and filtered while hot at 50°C. After washing the crystals with toluene and drying them, 0.830 g of P,P'-biphenol was obtained.
(4.46mmol88.8%) was obtained. The purity was 99% or higher as determined by gas chromatography analysis.

[Example 6] 3,5,3',5'-tetra-t-butyl-4,
Put 10.04 g (25.33 mmol) of 4′-biphenol, 50.02 g of anisole, and 0.5 g of sulfuric acid into a 100 ml flask.
The mixture was reacted at 170°C for 6 hours while stirring with a magnetic stirrer. After the reaction was completed, the reaction mixture was cooled to 50°C, and the same procedure as in Example 5 was carried out to obtain 4.32 g (23.2 mmol 91.6%) of P,P'-biphenol. The purity was 99% or more by gas chromatography analysis.

[Example 7] 3,5,3',5'-tetra-t-butyl-4,
100ml of 4′-biphenol 10.1647g (24.8mmol), p-methoxyphenol 49.9811g, sulfuric acid 0.1ml
The mixture was placed in a flask and reacted at 150°C for 1 hour while stirring with a magnetic stirrer. 80 minutes after the reaction
℃ and allowed to precipitate crystals at this temperature for 2 hours,
The mixture was filtered while hot to obtain P,P'-biphenol. This material was washed with toluene, dried in vacuum, and P,P'-
2.91 g (15.6 mmol yield 63.0%) of biphenol was obtained. [Example 8] 3,5,3',5'-tetra-t-butyl-4,
4′-biphenol 14.048g (34.2mmol), 1,3
- 48.364 g of dimethoxybenzene, 1.0 ml of sulfuric acid in 100 g
The mixture was placed in a ml flask and reacted at 170°C for 2 hours while stirring with a magnetic stirrer. After the reaction
Cool to 50°C and perform the same operation as in Example 5 to prepare P, P'-
5.16 g (27.7 mmol, yield 81.0%) of biphenol was obtained.

[Example 9] 3,5,3',5'-tetra-t-butyl-4,
50 ml of 4′-biphenol 2.25 g (5.49 mmol), phenol 8.20 g, p-toluenesulfonic acid 0.21 g
The mixture was placed in a flask and reacted at 160°C for 3 hours while stirring with a magnetic stirrer. After the reaction was completed, the reaction mixture was cooled to 60°C and maintained at this temperature for 2 hours to precipitate crystals. Thereafter, it was filtered while hot at 60°C, and the separated crystals were washed with toluene to obtain 0.87 g (4.67 mmol, yield 85%) of white P,P'-biphenol. The purity was 99% or higher as determined by gas chromatography analysis.

[Example 10] 3,5,3',5'-tetra-t-butyl-4,
4'-biphenol 2.22g (5.41mmol) phenol
7.03g, 3 drops of methanesulfonic acid, phenol 7.03
Using g, white P,
P'-biphenol 0.85g (4.54mmol yield 84%)
I got it. Purity is 99% as a result of gas chromatography analysis
% or more.

Claims (1)

[Claims] 1 3,5,3',5'-tetra-t-butyl-4,
4′-biphenol is debutylated at a temperature of 120 to 250°C in the presence of sulfuric acid or sulfonic acid as a catalyst using phenol or phenol substituted with 1 to 3 lower alkyl groups or lower alkoxy groups as a solvent to obtain P. , P'-biphenol is produced, and then filtered at a temperature between the melting point of the solvent and 80°C to produce P,
A method for producing P,P'-biphenol, which comprises separating P'-biphenol.