JPS582235B2 - Method for producing dihydroxydiphenyl sulfone - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for producing dihydroxydiphenyl sulfone.

More specifically, a novel method for producing dihydroxydiphenyl sulfone with few impurities in a short time, in high yield, by subjecting phenol to a dehydration condensation reaction with a sulfonating agent such as concentrated sulfuric acid, oleum, or sulfuric anhydride, or phenolsulfonic acid. It provides:

Dihydroxydiphenyl sulfone has heat resistance, oxidation resistance, and light stability due to the specificity of its diphenyl sulfone bond. Therefore, in recent years, bisphenol A has been used in the field of plastics such as polyester resins, epoxy resins, and polycarbonate resins. In addition to being used as a substitute, it is also a useful compound as a raw material intermediate for crosslinking agents, leather tanning agents, dyes, etc.

Conventionally, phenol and a sulfonating agent such as concentrated sulfuric acid, oleum or sulfuric anhydride, or phenol sulfonic acid were combined in one part.
A method for producing dihydroxydiphenyl sulfone through a dehydration condensation reaction at a high temperature of 00 to 250°C is known.

In this case, the rate of reaction is generally very slow and a reaction time of 10 hours or more is required under optimal conditions to minimize side reactions.

High-temperature, long-term reactions in the presence of strong acidic substances result in frequent side reactions, resulting in impurities that color the final product and lower yields.

For this reason, various methods have been studied to prevent side reactions, suppress the production of colored substances, and improve reaction yields.

For example, in Japanese Patent Publication No. 47-20223, when phenol and sulfuric acid are reacted in a stoichiometric ratio at a temperature of 130 to 170°C, benzene is used as an azeotropic solvent to eliminate the cause of coloration. In addition to preventing the by-product of tar, resin, and other undesirable impurities, the reaction yield is improved by removing water produced during the reaction from the system by azeotropic distillation.

However, this method requires a long reaction time of several hours, and is not fully satisfactory as an industrial production method.

Furthermore, in JP-A-53-103446, when producing dihydroxydiphenyl sulfone by reacting phenol and sulfur trioxide at 20 to 160°C, 1 mole of sulfur trioxide is mixed with 10 hydrogen fluoride. It is shown that by having the amount present in a molar or more amount, a product with a low content of impurities and coloring components can be obtained.

However, since this method handles an acidic solution containing a large amount of fluorine ions at high temperatures, when it is adopted as an industrial process, there are many difficult problems such as the selection of materials for the equipment.

The present inventors conducted a dehydration condensation reaction of phenol and a sulfonating agent such as concentrated sulfuric acid, oleum, or sulfuric acid anhydride, or phenolsulfonic acid to produce dihydroxydiphenyl sulfone, and effectively promoted the reaction. As a result of intensive research into methods for suppressing side reactions, we have come to invent a very advantageous method that can be implemented industrially.

That is, the present invention uses phenol, concentrated sulfuric acid, fuming sulfuric acid,
Alternatively, when producing dihydroxydiphenyl sulfone by dehydration condensation reaction of sulfuric acid anhydride or phenolsulfonic acid, at least one selected from the group consisting of activated carbon and activated clay is present as a catalyst. The present invention relates to a method for producing dihydroxydiphenyl sulfone characterized by the following.

According to the method of the present invention, the dehydration condensation reaction proceeds extremely rapidly, and dihydroxydiphenyl sulfone with a low content of by-product impurities can be obtained in a high yield in a short period of time.

When carrying out the method of the present invention, the reaction temperature is 140-25
The temperature is 0°C, preferably 170-200°C.

If the reaction temperature is below 140°C, the dehydration condensation reaction will not substantially proceed, and even if the catalyst of the present invention is added, it will be difficult to obtain a sufficient effect.

Furthermore, at temperatures above 250° C., side reactions are activated and dihydroxyphenyl sulfone is decomposed and polymerized, leading to a decrease in yield and an increase in colored substances.

In addition, the ratio of phenol to sulfonating agent or phenol sulfonic acid is phenol/sulfonating agent = 2 to 6 (molar ratio) or phenol/phenol sulfonic acid = 1 to 3 (molar ratio).
The molar ratio) is preferred, in particular the use of phenol in stoichiometric proportions or a slight excess, i.e. phenol/sulfonating agent = 2-4 (molar ratio) or phenol/phenolsulfonic acid = 1-2 (molar ratio). ) is preferred.

The amount of the catalyst used in the method of the present invention is suitably 0.01 to 1.0% by weight based on the reactants.

In addition, since catalysts have a large effect even when added in small amounts, there is almost no economic problem in discarding them after the reaction.
If necessary, the mother liquor from which the target product has been separated can be recycled to maintain its catalytic effect.

The method of the present invention can be applied in a continuous, semi-continuous or batch manner.

Furthermore, in carrying out the present invention, organic solvents other than phenol, such as chlorobenzene, o-dichlorobenzene, trichlorobenzene, chlorotoluene, and tetrachlorobenzene, are used for the purpose of preventing caking of reaction products and separating isomers. Chlorethane,
Trichloroethane, benzene, toluene, xylene, cresol, etc. may be present, but these do not affect the present invention in any way.

EXAMPLES Next, the present invention will be specifically explained with reference to examples, but the present invention is not limited to the following examples.

Example 1 250 g of phenol, 100 g of 98% sulfuric acid, 1 g of activated carbon
The mixture is heated at 180° C. with stirring.

The produced water is azeotropically distilled out along with the phenol.

This distillate was condensed and separated into two phases, and the reaction was carried out for 2 hours while the organic phase was continuously returned to the reactor.

As a result of liquid chromatography analysis of dihydroxydiphenylsulfone in the reaction product, the amount of dihydroxydiphenylsulfone produced was 239 g, and the yield based on sulfuric acid was 95.6%.

Comparative Example 1 The same operation as in Example 1 was carried out without adding activated carbon as a catalyst to the reaction system, and dihydroxydiphenyl sulfone in the reaction product after 2 hours of reaction and after 10 hours of reaction was purified by liquid chromatography. It was analyzed.

As a result, the amount produced after 2 hours was 122 g (yield based on sulfuric acid: 4
8.8%), and the amount produced after 10 hours was 179 g (yield based on sulfuric acid: 71.6%).

Next, the present invention was repeated according to the method of Example 1 by changing the type of catalyst and the composition of the reactant, and the results are shown in Table 1.

Claims (1)

[Claims] 1. Dihydroxydiphenyl sulfone, which is characterized in that when producing dihydroxydiphenyl sulfone by reacting phenol with a sulfonating agent or phenolsulfonic acid, at least one member selected from the group consisting of activated carbon and activated clay is present in the reaction system. Method for producing enylsulfone.