JPH089657B2 - Method for producing high-purity polyphenols - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for producing high-purity polyphenols with few by-products.

[Field of Industrial Application] The high-purity polyphenols obtained by the production method of the present invention are used as epoxy resins, phenol resins, plastic modifiers, and the like. In particular, it has excellent heat resistance, mechanical strength, electric drop characteristics (volume resistance, dielectric characteristics), etc., and is suitable for use in electrical and electronic parts.

[Prior Art and its Problems] When a phenol and a crotonaldehyde or a cinnamaldehyde are subjected to a condensation reaction, a polyphene containing a compound of formula (I) or formula (II), respectively. The norls are produced, and in addition, many by-products are produced depending on the type of catalyst and / or the reaction temperature.

As prior art, U.S. Pat. No. 3,357,946, Japanese Patent Laid-Open No. 61-6
No. 2519 is disclosed. In these, an acid is mentioned as a catalyst for the reaction. However, when a hydrogen halide acid such as hydrochloric acid, hydrogen chloride or hydrobromic acid is used, some of these act as halogenating agents and react with unsaturated aldehydes or phenol compounds to form halogenated phenol compounds. . Further, the sulfuric acid catalyst reacts with a phenol compound to produce a sulfonated phenol compound, and the nitric acid catalyst reacts with a phenol compound to produce a nitrated phenol compound as a byproduct, and these are mixed into polyphenols.

On the other hand, with weak acid catalysts such as oxalic acid, formic acid, and acetic acid, the reaction is slow, and a large amount of the by-product of the formula (III) is produced as a product.

R is hydrogen, a methyl group or a phenol group.

Such halogenated phenol compounds, sulfonated phenol compounds, nitrated phenol compounds and by-products such as formula (III) are extremely difficult to separate from polyphenols, and polyphenols containing these by-products are treated with epoxy resin. When used as a phenol resin or a plastic modifier, the electrical properties such as volume resistance and dielectric properties, heat resistance, and mechanical strength are significantly reduced.

[Means for Solving Problems] The present invention is characterized in that in the method for producing polyphenols by the reaction of phenols with an unsaturated aldehyde selected from crotonaldehyde and cinnamaldehyde, the method comprises the following steps: A method for producing high-purity polyphenols.

First Step The reaction is carried out at a molar ratio (a / b) of the phenols (a) and the unsaturated aldehydes (b) of 6 to 40 and 0.01 to 0.05 wt% of the phenols (a). It is carried out at 60 to 130 ° C in the presence of sulfonic acid to obtain polyphenols.

Second step Neutralize the sulfonic acid in the produced porphenols.

Third Step The generated polyphenols are washed with a mixed solvent of water and a solvent, and the aqueous layer containing the neutralized salt is separated and removed to remove the neutralized salt as a by-product.

Fourth step Unreacted phenol is distilled off at 120 ° C to 190 ° C under reduced pressure. Things.

Examples of the phenols (a) used in the present invention include phenol, cresol, xylenol, catechol, resorcin, and hydroxy, and the molar ratio (a / b) between the phenols (a) and the unsaturated aldehyde (b). Is 3-40, preferably 4-20. When a / b is less than 3, a gelled product is formed, and when a / b is more than 40, the amount of unreacted phenol with respect to polyphenols is large, and a large amount of energy is spent for recovering them, which is not preferable.

Examples of the sulfonic acid catalyst include toluene sulfonic acid, benzene sulfonic acid, xylene sulfonic acid, naphthalene sulfonic acid, phenol sulfonic acid, etc., and these catalyst concentrations are 0.01 to 4% by weight with respect to the raw material phenols.
Is preferred.

The reaction temperature in the first step is 60 to 130 ° C, preferably 80 to 110
If the temperature is lower than 60 ° C, the reaction rate will be slower, and more by-products of the formula (II) will be produced.

In the second step, the sulfonic acid in the produced polyphenols (reaction liquid) is neutralized with alkali such as caustic soda, caustic potash, calcium hydroxide, sodium carbonate, potassium carbonate and the like.

Washing with water is the most preferable method for removing the neutralized salt produced as a by-product in the third step. However, if only water is added and washed, the water dissolves in the phenol layer, the boundary between the water layer and the phenol layer becomes unclear, and liquid separation is extremely difficult. Therefore, add a solvent such as methyl ethyl ketone or methyl isobutyl ketone. Is effective.

In the fourth step, the polyphenols from which the neutralized salts have been removed are depressurized and water, solvent and unreacted phenol are removed by successive distillation at 120 to 190 ° C. to obtain high purity polyphenols. When removing unreacted phenol by distillation,
If the sulfonic acid catalyst remains or the distillation temperature exceeds 190 ° C., the polyphenols are decomposed, and many low molecular weight compounds and gelled products are formed, which is not preferable. Also, 12
Below 0 ℃, the effect of separating unreacted substances and by-products is low.

[Effects of the Invention] The high-purity polyphenols obtained by the production method of the present invention do not contain a gelled product, and contain few impurities such as by-products, metals and chlorine, and high-purity polyphenols are obtained. When used for phenolic resin, it has excellent heat resistance, mechanical strength, and electrical characteristics, and can be used for electrical and electronic parts, encapsulants, etc.

[Examples of the present invention] Hereinafter, the present invention will be described with reference to specific examples, but the present invention is not limited to these examples.

Example 1 A flask having an inner volume of 3 was charged with 940 g of phenol, 117 g of crotonaldehyde, and 0.95 g of p-toluenesulfonic acid, and reacted at 80 ° C. for 30 minutes and then at 100 ° C. for 3 hours. After the reaction was completed, 5.4 g of 4% aqueous sodium hydroxide solution was added to neutralize the catalyst, and subsequently 200 g of water and 1200 g of methylisobutylketone were added, and the mixture was stirred at 80 ° C for 5 minutes, then allowed to stand for 1 hour, then the aqueous layer was formed. The liquid was removed. Further, 200 g of water was added to the organic layer, the mixture was stirred at 80 ° C. for 5 minutes, and allowed to stand for 1 hour, and then the aqueous layer was separated and removed.

Continue to add polyphenols (reaction solution) from 120 ℃ to 180
Heat up to ℃, while the pressure inside the reaction system from 760mmHg to 5mm
Water, methyl isobutyl ketone and unreacted phenol were removed by distillation while reducing the pressure to Hg.

The obtained polyphenols were composed of 2.0% of the low molecular weight compound of the formula (III), 44.6% of 1.1.3-tris (hydroxyphenyl) butane, and 53.4% of a higher-order condensate, and had a softening point of 115 ° C. Further, the gelled substance contained in this polyphenol was 0%, Na was 6 ppm, and Cl was 3 ppm.

Example 2 In the same flask as in Example 1, 940 g phenol, 176 g cinnamaldehyde, and p-toluenesulfonic acid 4.
5 g was charged and reacted at 80 ° C. for 30 minutes and then at 100 ° C. for 3 hours. After the reaction was completed, 27.3 g of a 4% aqueous sodium hydroxide solution was added to neutralize the catalyst. Subsequently, 200 g of water and 1200 g of methyl isobutyl ketone were added, and the mixture was stirred at 80 ° C for 5 minutes, then allowed to stand for 1 hour, then the aqueous layer was separated. The liquid was removed.

Further, 200 g of water was added to the organic layer, the mixture was stirred at 80 ° C. for 5 minutes, and allowed to stand for 1 hour to separate and remove the aqueous layer.

Continue to add polyphenols (reaction solution) from 120 ℃ to 170
Heat up to ℃, while the pressure inside the reaction system from 760mmHg to 5mm
Water, methyl isobutyl ketone and unreacted phenol were removed by distillation while reducing the pressure to Hg.

The obtained polyphenols are low-molecular compounds 9.1%,
1.1.3-Tris (hydroxyphenyl) -3-phenylpropane 54.4%, high-order condensate 36.5%, softening point 12
It was 3 ° C. The gelled substance contained in this polyphenol was 0%, and Na and Cl were 8 ppm and 6 ppm, respectively.

Comparative Example 1 35% in place of the p-trienesulfonic acid catalyst of Example 1
The procedure of Example 1 was repeated except that 6.3 g of hydrochloric acid was used.

The obtained polyphenols are low-molecular compounds 4.1%,
1.1.3-tris (hydroxyphenyl) butane 37.3%,
It was composed of 58.5% of high-order condensate and had a softening point of 118 ° C. This polyphenol contains 15ppm of Na and 1430ppm of Cl.
Met.

Comparative Example 2 The same reaction as in Example 1 was carried out. After the reaction was completed, the catalyst was heated from 80 ° C. to 180 ° C. without being neutralized and removed, and the pressure in the reaction system was reduced from 760 mmHg to 5 mmHg while adding water. And unreacted phenol was removed by distillation.

The obtained polyphenols are low-molecular compounds 8.2%,
1.1.3-tris (hydroxyphenyl) butane 32.5%,
The high-order condensate was composed of 59.3% and had a softening point of 124 ° C. Also, this polyphenol has 2.5% gel, Cl20p
pm, p-toluenesulfonic acid remaining as catalyst 1980 pp
m was included.

Comparative Example 3 In Example 1, the polyphenols (reaction solution) in the fourth step were heated from 120 ° C. to 210 ° C., and the pressure in the reaction system was adjusted to 76
Water, methyl isobutyl ketone and unreacted phenol were removed by distillation while reducing the pressure from 0 mmHg to 30 mmHg.

The obtained polyphenols are low-molecular compounds 5.1%,
1.1.3-tris (hydroxyphenyl) butane 39.6%,
It was composed of 52.9% of higher-order condensates and had a softening point of 123 ° C. This polyphenol contains 2.4% gel, Na7ppm, Cl4pp
m was included.

Comparative Example 4 Phenol and crotonaldehyde were reacted in the same manner as in Example 1. After the reaction was completed, 5.4 g of a 4% aqueous sodium hydroxide solution was added to neutralize the catalyst, 200 g of water was subsequently added, the mixture was stirred at 80 ° C. for 5 minutes, and allowed to stand for 1 hour, and then the aqueous layer was separated and removed.

Continue to add polyphenols (reaction solution) from 120 ℃ to 180
Heat up to ℃, while the pressure inside the reaction system from 760mmHg to 5mm
Water and unreacted phenol were removed by distillation while reducing the pressure to Hg.

The obtained polyphenols consisted of 2.0% of the low molecular weight compound of the formula (III), 40.1% of 1.1.3-tris (hydroxyphenyl) butane and 55.4% of the higher-order condensate, and had a softening point of 117 ° C. In addition, this polyphenol contains 2.5
%, Cl10 ppm, 0.01% sodium p-trienesulfonate.

Claims (1)

[Claims] 1. A method for producing polyphenols by the reaction of a phenol with an unsaturated aldehyde selected from crotonaldehyde and cinnamaldehyde, which comprises passing through the following steps. First Step The reaction is carried out at a molar ratio (a / b) of the phenols (a) and the unsaturated aldehydes (b) of 6 to 40 and 0.01 to 0.05 wt% of the phenols (a). It is carried out at 60 to 130 ° C in the presence of sulfonic acid to obtain polyphenols. Second step The sulfonic acid in the produced polyphenols is neutralized. Third step By washing the generated polyphenols with a mixed solvent of water and a solvent, and separating and removing an aqueous layer containing a neutralized salt,
The by-product neutralized salt is removed. Fourth step Unreacted phenol is distilled off at 120 ° C to 190 ° C under reduced pressure.