JPH05383B2 - - Google Patents

Description

[Detailed description of the invention]

INDUSTRIAL APPLICATION FIELD OF THE INVENTION The present invention relates to a novel method for producing high-purity 4,4'-dihydroxydiphenylsulfone monometallic salts in high yields from crude 4,4'-dihydroxydiphenylsulfone products. Conventional technology 4,4'-dihydroxydiphenyl sulfone (hereinafter referred to as 4,4' body) has excellent heat resistance, oxidation resistance, light stability, etc., so it has recently been used in polyester resins, epoxy resins, and polycarbonates. It has come to be widely used in the field of polymer chemical industry, such as resins and polyethersulfone resins. In this case, synthesis is performed using 4,4'-form as a raw material containing impurities such as 2,4'-dihydroxydiphenylsulfone (hereinafter referred to as 2,4'-form) and trihydroxytriphenyldisulfone (hereinafter referred to as "tri-form"). The resulting polymer product tends to have a lower molecular weight and lower mechanical properties, and this tendency becomes more pronounced as the amount of impurities such as 2,4' and tri-isomers increases. Therefore, 2,
There is a demand for the supply of highly pure 4,4'-isomers from which impurities such as 4'-isomers and tri-isomers have been removed as much as possible. In addition, the 4,4′ body is a coupler raw material for color photography,
It is also useful as a color developer for heat-sensitive recording paper, and in this case as well, high purity is desirable. Industrially, the 4,4'-isomer is mainly produced by a dehydration reaction between phenol and a sulfonating agent such as sulfuric acid, and the reaction product contains impurities such as the 2,4'-isomer,
Contains sulfones such as tri-isomers and other sulfonic acids, etc., and the purity of the 4,4'-isomer in the 4,4'-isomer crude product after removing sulfonic acids, etc. is usually 70~70~
It is about 80% by weight. In addition, a method has been developed to suppress the by-product of 2,4'-isomer and obtain highly pure 4,4'-isomer. For example, a method of obtaining highly pure 4,4' isomer by precipitating the 4,4' isomer produced by a dehydration reaction and isomerizing the by-product 2,4' isomer into 4,4' isomer.
No. 55-8972) has been proposed. In this case, the purity of the 4,4' product in the crude 4,4' product obtained by removing sulfonic acids and the like from the reaction product is usually about 90 to 95% by weight. However, the purity of the 4,4' form for the various uses mentioned above. Due to recent demands for higher quality resins, a content of about 97% by weight or more has come to be desired. Therefore, it is necessary to further purify those produced by the former method, and it is desirable to further refine those produced by the latter method. As a method for purifying the 4,4'-isomer, for example, o-dichlorobenzene-phenol (Japanese Patent Publication No. 51-36264),
o-dichlorobenzene-acetic acid (Special Publication No. 57-48152
Treatment methods using various mixed organic solvents such as o-dichlorobenzene-ethyl acetate (Japanese Patent Publication No. 57-48153), and o-dichlorobenzene-alcohol (Japanese Patent Publication No. 58-2234) have been proposed. ing. However, since all of these methods use organic solvents, they are inconvenient to handle, pose a health hazard, and pollute the environment. In addition, conventional purification methods that do not use organic solvents include dissolving the 4,4' crude product in an alkaline aqueous solution such as sodium hydroxide, treating it with activated carbon, and then adding an acid such as sulfuric acid in an amount greater than the neutralizing amount. In addition, a method of precipitating the 4,4' isomer has been used. This method is
The 4,4' form is poorly soluble in water, but it takes advantage of the property that it easily dissolves in aqueous solutions of basic substances in the form of mono- or di-metal salts. however,
Although this method can remove sulfonic acids, it cannot remove most of the 2,4'- and tri-sulfones, and as shown in the comparative example below, the purity of the purified product is insufficient to meet the above requirements. cannot be answered at all. Problems to be Solved by the Invention The purpose of the present invention is to solve the problem without using an organic solvent.
In addition, it is useful as a purification intermediate for obtaining the 4,4'-isomer with a high purification yield (yield relative to the 4,4'-isomer before purification) and high purity, and can sufficiently meet the above-mentioned needs. , 4' monometallic salts. Means for Solving the Problems As a result of intensive research to achieve the above object, the present inventor has found that when a crude 4,4' product is dissolved in an aqueous solution of a basic substance and then salted out, the percentage is usually about 90%. We discovered the unique fact that a 4,4' monometallic salt can be precipitated with a high yield of 98% by weight or higher, and by further treating it with an acid, a purity of 85% or higher is usually obtained. It has been found that the 4,4' isomer can be obtained with a high purification yield and a high purity of about 99% by weight or more. The fact that the 4,4'-isomer can be salted out as a highly pure monometallic salt under specific conditions is based on the common knowledge that 4,4'-isomer mono- and dimetallic salts are easily soluble in water. This is completely unexpected for those skilled in the art. The present invention was completed based on this new knowledge. That is, the present invention is characterized in that the 4,4' crude product is dissolved in an aqueous solution of a basic substance and then salted out to precipitate and separate the 4,4' monometallic salt.
This invention relates to a method for producing a 4' monometallic salt. As used herein, monometallic salts refer to monoalkali metal salts, mono1/2 alkaline earth metal salts, and the like. The method of the present invention can be applied to various 4,4' synthesis reaction products, 4,4' crude products of any purity, including products from which sulfonic acids have been removed, and commercially available 4,4' products. It can also be applied to In the present invention, the crude 4,4' product is first dissolved in an aqueous solution of a basic substance, usually under stirring.
As the basic substance, hydroxides and carbonates of alkali metals such as sodium and potassium, alkaline earth metals such as calcium and magnesium, etc. can be preferably used. Particularly preferred are sodium hydroxide, sodium carbonate, and the like. The amount of the basic substance to be used is approximately 1 equivalent or more and approximately 2 equivalents per mole of sulfones such as 4,4', 2,4', and tri-isomers, in addition to the neutralizing amount of strong acids such as sulfonic acids. The following is appropriate. If it is less than this range,
This is not preferable since free 4,4' is mixed in during salting out of a monometallic salt of 4,4', which tends to deteriorate the crystal shape and reduce the impurity removal effect. Further, if the amount exceeds this range and the salting-out agent is added as is, a large amount of 4,4' dimetal salts that are not salted out tend to be produced, resulting in a decrease in yield, which is not preferable. However, the use of the basic substance in an amount exceeding 2 equivalents per mole of sulfones such as 4,4' sulfones does not pose any problem and is an advantageous embodiment of the present invention. That is, by using an excess of more than 2 equivalents of a basic substance to create a dissolved state in which a large amount of 4,4' dimetal salt that is not salted out is produced,
If necessary, activated carbon treatment etc. can be suitably carried out, and then an acid is added to convert the dimetal salt into a monometallic salt, at the same time a salting-out agent is generated, and if necessary, a salting-out agent is further added to convert the dimetallic salt into a monometallic salt. Salt can be salted out. In the above-mentioned dissolution treatment of the 4,4′ crude product,
The processing liquid exhibits a solution or suspension state depending on the amount of basic substance and water used. In a suspended state, the liquid phase generally consists of a 4,4' monometallic salt and a small amount of 4,4' monometallic salt.
The 4' dimetal salt is dissolved, and the solid phase is mainly composed of the 4,4' monometal salt that becomes supersaturated and precipitates after dissolution, and the subsequent salting out removes the 4,4' dimetal salt from the liquid phase. It is thought that the 4′ monometallic salt further precipitates and the crystals grow. The amount of water used during dissolution treatment can be selected from a wide range, but it is usually 1.8 to
Approximately 8.0 parts by weight is appropriate. If the amount of water is less than this range, a suspension state with a large amount of solid phase will occur, resulting in poor fluidity and stirring will tend to become difficult, and if the amount of water is more than this range, the purification yield will tend to decrease. I don't like it because it is. A particularly preferable amount of water is 1.3 to 3.0 for the 4,4′ crude product.
It is about twice the weight. Further, the temperature during the dissolution treatment is not particularly limited, but it is advantageous to set it to about 40° C. to the boiling point in that the production rate of the 4,4′ monometallic salt can be increased. Next, the solution or suspension obtained by treating the crude 4,4' product as described above is salted out, usually with stirring, to precipitate the monometallic salt of the 4,4' product. This typically results in a purity of 98
The 4,4' monometallic salt with a high purity of about % by weight or more is usually precipitated in a high yield of 87% or more based on the 4,4' monometal salt in the crude raw material. This fact is
This was discovered for the first time by the present inventor. Salting out is carried out by adding a salting out agent, adding an excess of the basic substance and adding an acid such as hydrochloric acid or sulfuric acid to generate a salting out agent, or using a combination of these methods. It will be done. As the salting-out agent, chlorides and sulfates of alkali metals such as sodium and potassium, alkaline earth metals such as calcium and magnesium, etc. can be preferably used. Further, the amount of the salting-out agent to be used can be selected from a wide range, and it is usually appropriate to set the amount to be at least 2% by weight and at most the saturation concentration. If the amount is less than this range, the salting-out effect will be low and the yield will decrease, which is not preferable. Also,
If the concentration exceeds the saturation concentration, crystals of the salting-out agent will precipitate, which is not preferable. The preferred usage amount of the salting-out agent is usually 4
The amount is approximately 15% by weight. The temperature when adding the salting-out agent is not particularly limited, but it is advantageous to set it to about 40°C to the boiling point in order to improve the crystal form of the 4,4' monometallic salt and improve the yield and purity. It is. After adding salting out agent, at that temperature
It may be aged for about 0.2 to 12 hours. Next, the precipitated 4,4' monometallic salt is separated by filtration and, if necessary, washed appropriately to obtain a highly purified 4,4' monometallic salt. The 4,4' monometallic salt produced by the present invention is extremely useful as a purification intermediate for obtaining highly purified 4,4' monometallic salts, and is usually acid-treated to form free 4,4' monometallic salts. ' Get a body. Acid treatment can be carried out according to a conventional method, and the 4,4' monometal salt is dissolved in water or an alkaline aqueous solution, treated with activated carbon if necessary, and then an acid such as sulfuric acid or hydrochloric acid is added. and pH 3~
6, and the precipitated 4,4' isomer is separated by filtration, etc., and the result is almost quantitative. In this way, the 4,4'-isomer can be purified with high purification yield and high purity. Further, the highly purified 4,4' monometallic salt obtained by the present invention can be used as it is as an industrial raw material depending on the application. Effects of the Invention By using the highly purified 4,4' monometallic salt obtained by the method of the present invention as a 4,4' monometallic intermediate, the following particularly remarkable effects can be achieved. (1) Easy to handle because no organic solvent is used.
There are no occupational hygiene or environmental problems. (2) Usually, the 4,4′ isomer can be obtained with a high purification yield of 85% or more and a high purity of 99% by weight or more.
This can fully meet the demands of the industry. (3) Compared to conventional methods, a large amount of purification can be efficiently carried out using a small amount of liquid. Additionally, the equipment can be made compact and workability is good. EXAMPLES Hereinafter, the present invention will be explained in more detail with reference to reference examples, examples, and comparative examples. Reference Example 1 A 4,4' crude product was produced by the method described in Japanese Patent Publication No. 55-8972. That is, a mixture of 290 g of phenol, 146 g of 98% by weight sulfuric acid, and 150 g of o-dichlorobenzene (ODCB) was heated with stirring. The reaction solution boiled around 150°C, and reaction product water began to distill out along with ODCB. The distillate is condensed, the ODCB phase is continuously returned to the reaction system, and from the point when the liquid volume of the aqueous phase reaches 52 ml, the reaction temperature is maintained at 175 to 185°C, and the produced water and The ODCB containing a small amount of phenol was recovered by distillation over a period of 4 hours until the reaction product was dried to dryness. The analysis results of the dried reaction product obtained here by high performance liquid chromatography showed that 84.6% by weight of the 4,4′ isomer;
2.0% by weight of 2,4'-isomer, 4.5% by weight of tri-isomer, and 8.9% by weight of other sulfonic acids. Example 1 100 g of the reaction dry product, which is the crude 4,4' product obtained in Reference Example 1, was mixed with 155 g of water and 18.1 g of sodium hydroxide (the amount necessary for neutralizing the sulfonic acid content and the 4,4' product). , 1.2 times the equivalent of the total amount of 2,4'- and tri-sulfones), and the temperature was raised to 95° C. with stirring. The liquid was not completely dissolved and remained in a suspended state. Next, 10 g of common salt was added, and the mixture was kept at the same temperature for 30 minutes to age and then cooled. After keeping warm at 50℃ for 1 hour,
The precipitate was collected and washed with 50 ml of 5% brine to obtain 84.0 g of 4,4' monosodium salt (purification yield 91.3%).
I got it. The obtained 4,4' monosodium salt was treated with hydrochloric acid and analyzed by high performance liquid chromatography. The results are shown in Table 1. The 4,4′ monosodium salt obtained above was dissolved in water.
The solution was dissolved in 900 ml, and 78% by weight sulfuric acid was added at a temperature of 90 to 95°C to neutralize the pH to 4.0 to precipitate the 4,4' isomer.
After cooling to 40°C, it was taken and dried to obtain 76.6 g of a purified 4,4' product. The purification yield was 90.4% (based on the 4,4' isomer in the raw material). The analysis results by high performance liquid chromatography were as shown in Table 1. Example 2 Example 1 except that 15 g of anhydrous sodium sulfate was used in place of 10 g of common salt as a salting-out agent in Example 1.
Salting out in the same manner as 4,4′ monosodium salt
83.2g (purification yield: 90.4%) was obtained, which was further treated with sulfuric acid in the same manner to obtain 75.9g of a 4,4' purified product. The purification yield was 89.5%, and the results of analysis by high performance liquid chromatography were as shown in Table 1. Example 3 Reaction dried product as 4,4' crude product obtained in Reference Example 1
100g corresponds to the sum of 280g of water and 31.6g of sodium hydroxide (an amount equivalent to 2.1 times the amount required for neutralizing the sulfonic acid component and the total amount of sulfones such as 4,4' bodies). ), and the temperature was raised to 95°C while stirring.
The liquid was completely dissolved. Next, after gradually adding 24.1 g of 78 wt% sulfuric acid,
After cooling and keeping at 50°C for 1 hour, the precipitated crystals were collected and washed with 5% by weight sodium sulfate water.
81.0 g (purification yield: 88.0%) of 4' monosodium salt was obtained. As a result of analysis of the obtained 4,4' monosodium salt by high performance liquid chromatography, the composition ratio was as shown in Table 1. The 4,4' monosodium salt obtained above was
When treated with sulfuric acid in the same manner as in Example 1, 73.9 g of a purified 4,4' product was obtained. The purification yield is 87.3%,
The analysis results by high performance liquid chromatography are
It was as shown in Table 1. Example 4 The composition of a commercially available crude product of 4,4' body was analyzed by high performance liquid chromatography, and it was found that 4,4' body,
2,4' and tri-isomers each account for 82.6% by weight. 14.0
weight%. It was 3.4% by weight. 100g of this crude product was mixed with 160g of water and 33.2g of sodium hydroxide (based on the total amount of sulfones such as 4,4'-sulfones).
2.1 times equivalent) and the temperature was raised to 97°C while stirring. The liquid was not completely dissolved and remained in a suspended state. Next, after gradually adding 25.1 g of 78 wt% sulfuric acid,
After cooling and keeping at 50°C for 1 hour, the precipitated crystals were collected and washed with 5% by weight sodium sulfate water.
80.4 g (purification yield: 87.4%) of 4' monosodium salt was obtained. As a result of analysis of the obtained 4,4' monosodium salt by high performance liquid chromatography, its composition ratio was as shown in Table 1. The 4,4' monosodium salt obtained above was
When treated in the same manner as in Example 1, 71.5 g of a purified 4,4' product was obtained. The purification yield is 85.8% by weight,
The results of analysis by high performance liquid chromatography are shown in Table 1.

[Table] Comparative Example 1 100 g of the 4,4′ crude product obtained in Reference Example 1, 31.6 g of sodium hydroxide, and 280 g of water were dissolved at elevated temperature with stirring.
After adding 48.0 g of 78% by weight sulfuric acid at 95°C to adjust the pH to 4, the mixture was cooled, kept at 50°C for 1 hour, and dried separately to obtain 89.9 g of 4,4' compound. The yield is 99.3%,
Analysis results by high-performance liquid chromatography showed 93.4% by weight of 4,4′ form, 1.7% by weight of 2,4′ form, and 1.7% by weight of tri form.
It was 4.9% by weight.

Claims (1)

[Claims] A crude product of 4,4'-dihydroxydiphenylsulfone is dissolved in an aqueous solution of a basic substance and then salted out to precipitate and separate a monometallic salt of 4,4'-dihydroxydiphenylsulfone. A method for producing 4,4'-dihydroxydiphenylsulfone monometallic salt, characterized in that: