JP3486633B2 - Purification of 2,4'-dihydroxydiphenyl sulfone - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION The present invention relates to a crude product of 2,4'-dihydroxydiphenylsulfone having a high purity of 2,4'-.
It relates to a method for purifying dihydroxydiphenyl sulfone in high yield.

[0002]

2. Description of the Related Art 2, 4 '
-Dihydroxydiphenyl sulfone (hereinafter, also referred to as 2,4'-form) is extremely useful as a developer for thermal paper among various phenolic compounds, and has recently attracted attention. For example, in a heat-sensitive recording material containing a leuco dye as a color-developing substance and 2,4'-form as a main component as a color-developing substance, deterioration of a coloring part due to a plasticizer and deterioration due to light can be prevented, and low energy Also has the effect of developing color at a sufficient density.

The 2,4'-form is industrially produced mainly by a dehydration reaction of phenol with a sulfonating agent such as sulfuric acid, and 4,4'-dihydroxydiphenyl as an impurity in the reaction product. Sulfone (hereinafter, also referred to as 4,4 ′ form), trihydroxytriphenyldisulfone (hereinafter,
(Also referred to as a triform) and other sulfonic acids and the like.

As a method for purifying the 2,4'-form from such a reaction product, for example, there is a method using a mixture of two kinds of organic solvents as a purifying solvent (Japanese Patent Laid-Open No. 6-107623).
issue).

However, in this method, since it is necessary to mix two kinds of organic solvents in a specific ratio,
Not only is its management complicated, but solvent recovery is also troublesome. Further, since an organic solvent is used, it is inconvenient to handle, and there are problems in safety and work hygiene.

[0006] An object of the present invention is to provide a purification method capable of easily obtaining a highly pure 2,4'-isomer with an aqueous solvent which is easy to manage.

[0007]

According to the present invention, a crude product of 2,4'-dihydroxydiphenyl sulfone is dissolved or suspended in an aqueous solution of a basic alkali metal compound,
A method for purifying 2,4'-dihydroxydiphenyl sulfone, which comprises depositing and separating 2,4'-dihydroxydiphenyl sulfone or its 1/2 alkali metal salt, and then subjecting this to acid treatment if necessary. .

[0008]

BEST MODE FOR CARRYING OUT THE INVENTION The method of the present invention can be applied to the purification of various 2,4'-form synthetic reaction products and any 2,4'-form crude products such as those obtained by removing sulfonic acids from the reaction products. Although applicable, the proportion of the 2,4'-form in the total amount of the 2,4'-form, 4,4'-form and the tri-form is 65% by weight or more.
It is preferably applied to 4'body crude products.

In the present invention, a 2,4 'crude product is
First, it is dissolved or suspended in an aqueous solution of a basic alkali metal compound, usually with stirring. Examples of the basic alkali metal compound include sodium, potassium and other alkali metal hydroxides and carbonates, preferably alkali metal hydroxides, more preferably sodium hydroxide,
It is potassium hydroxide.

The amount of the basic alkali metal compound used is
Proportion of 2,4 'in the 2,4' crude product (2,4 '
Body content).

That is, the amount of the basic alkali metal compound used is preferably 2,4 'in terms of alkali metal atom.
It is the sum of 0 to 1.0 equivalent to the 2,4'-form contained in the crude body product and 1.0 equivalent to the total of the 4,4'-form and the tri-form, and more preferably, 0 to 0.5 equivalents based on the 2,4 'body contained in the 2,4' body crude product,
This is a total of 1.0 equivalent to the total of 4,4 ′ form and avian form. Here, 1.0 equivalent means 2,4 ′ body, 4,
The amount corresponds to 1.0 alkali metal atom per 1 molecule of 4'-form or tri-form.

Therefore, when an alkali metal hydroxide is used, it is preferable that the amount of the alkali metal hydroxide is 0 to 1.0 times the mole of the 4,4'-form contained in the 2,4'-form crude product and 4,4 '. It is a total of 1.0 times the mole of the total of the'-form and the tri-form, and more preferably 0-0.5 times the 2,4'-form contained in the 2,4'-form crude product. This is the sum of moles and 1.0 times the moles of the total of 4,4'-form and tri-form.

When an alkali metal carbonate is used, it is preferable that the content of the alkali metal carbonate in the 2,4 'crude product is 2 ,.
It is a total of 0 to 0.5 times mol relative to the 4'-form and 0.5 times mol to the total of the 4,4'-form and the tri-form, and more preferably the 2,4'-form crude product. 2,4 'contained in
It is a total of 0 to 0.25 times the mole of the body and 0.5 times the mole of the total of the 4,4 ′ body and the tri body.

When the amount of the basic alkali metal compound used is less than the above range, the purity of the 2,4'-form is lowered,
If the amount is more than the above range, the purification yield of the 2,4'-form is lowered, which is not preferable.

When the 2,4 'crude product contains sulfonic acids, the amount of the basic alkali metal compound necessary for neutralizing the sulfonic acids should be added to the above amount used. Good.

The crystal form to be precipitated is either a 2,4'-form 1/2 alkali metal salt or a free 2,4'-form. Within the above range, the larger the amount of the basic alkali metal compound used, the greater the tendency to form a 2,4′-form ½ alkali metal salt. In the case of a 1/2 alkali metal salt, a free 2,4'-form can be obtained by treating this with an acid.

The aqueous solution of the basic alkali metal compound is preferably an aqueous solution of the basic alkali metal compound or a solution prepared by dissolving the basic alkali metal compound in a mixed solution of a water-soluble organic solvent and water. Such an aqueous solution can be obtained by dissolving a basic alkali metal compound in water or a water-water readily soluble organic solvent mixture. Two
When the 4'-form crude product is dissolved or suspended, such an aqueous solution may be prepared in advance, or the solvent may be an aqueous solution such as water or a water-water-soluble organic solvent mixture. A liquid (aqueous solvent) may be used, and a basic alkali metal compound or an aqueous solution of a basic alkali metal compound may be added thereto during the dissolution or suspension treatment.

As the water-soluble organic solvent, methanol,
Alcohol such as ethanol and isopropyl alcohol,
Examples thereof include polyhydric alcohols such as ethylene glycol and its derivatives, ketones such as acetone and methyl ethyl ketone, and phenol. Among them, alcohol is preferable. The content of the water-soluble organic solvent in the water-water-soluble organic solvent mixture is preferably 50% by weight or less, more preferably 30% by weight or less.

The aqueous solution of the basic alkali metal compound is preferably an aqueous solution of the basic alkali metal compound or an alcoholic aqueous solution.

The amount of the aqueous liquid (aqueous solvent) used as a solvent for the dissolution or suspension treatment can be selected from a wide range, but it is 1.5 to 6 times by weight that of the 2,4 'crude product. Preferably. If the amount of aqueous liquid is less than this range, the solid phase portion will be in a suspended state and the flowability will be poor, and stirring will tend to be difficult. Is likely to decrease, which is not preferable. The more preferable amount of the aqueous liquid is 2 to 5.5 times by weight that of the crude product of 2,4 'body.

The temperature for the dissolution or suspension treatment is not particularly limited, but it is preferably 40 ° C. or higher.

In the above-mentioned dissolution or suspension treatment of the crude 2,4'-form product, the treatment liquid exhibits a dissolved or suspended state corresponding to the treatment temperature and the treatment time. For example, 90-10
When the solution is treated at 0 ° C., the solution is completely dissolved once, but after a few minutes, the 2,4 ′ form or its ½ alkali metal salt is precipitated and becomes a suspension. In such a suspension state, 4,4'-form monoalkali metal salt and a small amount of tri-form monoalkali metal salt are generally dissolved in the liquid phase portion. The solid phase portion is a portion mainly composed of a 2,4 'body or a 1/2 alkali metal salt thereof, which is precipitated after being dissolved and supersaturated, and then cooled to a 2,4' body from the liquid phase portion. Alternatively, it is considered that the 1/2 alkali metal salt thereof is further precipitated and the number of crystals is increased.

The solution or suspension obtained by treating the crude product of the 2,4 'body as described above is salted out with stirring to prepare a 1,4' body.
The precipitation of a / 2 alkali metal salt improves the purification yield. In the salting-out, a salting-out agent is added, or the above basic alkali metal compound is excessively added, and an acid such as hydrochloric acid or sulfuric acid is added thereto to form a salting-out agent, or these methods are used in combination. It is done by The salting-out agent is a chloride or sulfate of an alkali metal such as sodium or potassium, and examples thereof include sodium chloride, sodium sulfate, potassium chloride and potassium sulfate. The amount of salting-out agent used is
Although it can be selected from a wide range, the concentration is preferably 2% by weight to a saturated concentration, more preferably 4 to 15% by weight.

The temperature for adding the salting-out agent is not particularly limited, but is preferably 40 ° C. or higher.

Then, the treatment solution in the dissolved or suspended state is cooled to further precipitate the 2,4'-form or its 1/2 alkali metal salt. Preferred cooling temperature is 20-4
It is 0 ° C. The solubility (30 ° C.) of 4,4′-form monoalkali metal salt and tri-form monoalkali metal salt in water is several percent, while that of 2,4′-form or its 1/2 alkali metal salt is 0%. Since it is less than 1%, only the 2,4'-form or its 1/2 alkali metal salt is precipitated due to the difference in solubility.

Next, the precipitated 2,4 'body or its 1 /
(2) The alkali metal salt is separated by filtration or the like and appropriately washed as necessary to obtain a highly pure 2,4'-isomer or its 1/2 alkali metal salt.

In the case of the 2,4'-form 1/2 alkali metal salt, the high-purity 2,4'-form 1/2 alkali metal salt is then acid-treated to obtain a free 2,4'-form. . Acid treatment
It may be carried out according to a conventional method, such that 2,4'-isomer of 1/2 alkali metal salt is dissolved or suspended in water or an alkaline aqueous solution,
After treatment with activated carbon as necessary, acid such as sulfuric acid or hydrochloric acid is added to adjust the pH to about 3 to 6, and the precipitated 2,4'-form is separated by filtration or the like to perform almost quantitatively. Be seen.

Thus, the desired 2,4'-form can be purified with high purification yield and high purity.

[0029]

【Example】

Reference Example 1 100.0 g (1.0 mol) of 98% sulfuric acid was added dropwise under stirring to a mixture of 216.4 g (2.3 mol) of phenol and 975 g of o-dichlorobenzene (o-DCB), and then the temperature was raised. The reaction solution started to boil at around 150 ° C, and o-
Reaction product water started to distill with DCB. The distillate was condensed by a condenser and separated into two phases by a trap, and the lower o-DCB phase was continuously returned to the reaction system. About 5 hours after the temperature was raised, the temperature of the reaction system reached 180 ° C., the production of water stopped, and the amount of water in the trap became constant at 38 ml. Then, the reaction liquid was cooled to 120 ° C., and the precipitated crystals were filtered off to obtain a wet cake (A). Further, the filtrate was cooled to 25 ° C., and then the precipitated crystals were filtered out to obtain a wet cake (B). The analysis results (excluding o-DCB) of the wet cake (B) by high performance liquid chromatography showed that the 2,4′-form was 73.9% by weight,
The content of the 4,4'-form was 9.4% by weight, the content of the tri-form was 4.8% by weight, and the sulfonic acids were 11.9% by weight.

The wet cake (B) was washed with water and dried to obtain 95.3 g of a crude product of 2,4 'body. The results of analysis by high performance liquid chromatography were 84.6% by weight of 2,4'-form, 10.5% by weight of 4,4'-form and 4.9% by weight of tri-form.

Example 1 95.3 g of the crude 2,4 ′ product obtained in Reference Example 1 was mixed with 50 parts of water.
0 g and 18.0 g of 48% NaOH aqueous solution (corresponding to the total of 0.5 times the molar amount with respect to the 2,4 'form and 1.0 times with respect to the total of the 4,4' form and the tri form). .) Was added and the mixture was heated to 95 ° C. to suspend it, then cooled to 30 ° C., and the 1/2 sodium salt of the 2,4 ′ form was filtered off.

The thus obtained 2,4'-form 1/2 sodium salt was 88.7 g, and the water content was 21% by weight.
(Note that the composition was analyzed by high performance liquid chromatography after drying a small amount of the 1/2 sodium salt of the 2,4'-form obtained by filtration at 100 ° C for 4 hours.
Body 1/2 sodium salt 96.5% by weight and 4,4 '
It was 3.5% by weight of the body's monosodium salt. In addition, 0.5 g of the dried product is precisely weighed and 60 ml of ion-exchanged water is added,
As a result of titration with 1N-NaOH and then 1N-sulfuric acid, 1N
-NaOH 2.77 ml, 1N-sulfuric acid 3.70 ml
Met. Furthermore, Na content was 4.2% by elemental analysis.
Met. From these facts, 2 molecules of 2,4 'body and Na
It was confirmed that the salt consisted of one atom. Melting point is 23
It was 7 ° C. ) Then, obtained by filtration above 2,
The total amount of the 4'-form 1/2 sodium salt was added to 1000 ml of water, and the mixture was heated to 90 ° C. and suspended, and 65% sulfuric acid was added to 10.0
After dropwise adding g to adjust pH = 4, the mixture was cooled to 25 ° C., and the precipitated crystals were separated by filtration and dried to obtain 66.5 g of 2,4 ′ pure product. The results of analysis by high performance liquid chromatography were 98.2% by weight of 2,4 'form, 1.7% by weight of 4,4' form and 0.1% by weight of water. Two
The purification yield from the 4'-form crude product was 81.0%.

Example 2 30.0 g (0.12 mol) of a crude product of 2,4 'body consisting of 80.0% by weight of 2,4' body and 20.0% by weight of 4,4 'body, 150 ml of water and 48% NaOH aqueous solution 6.
0 g (corresponding to the sum of 0.5 times the molar amount of the 2,4'-form and 1.0 times the molar amount of the 4,4'-form) was added and suspended at 95 ° C for 30 minutes. After that, the mixture was cooled to 30 ° C., and the 1/2 sodium salt of the 2,4 ′ form was filtered off.

The 1/2 sodium salt of the obtained 2,4 'form was 29.0 g, and the water content was 19.9% by weight. (After drying a small amount, the composition was analyzed by high performance liquid chromatography to find that the 2,4'-form of 1/2 sodium salt was 97.4% by weight and the 4,4'-form of monosodium salt was 2.6% by weight. From the results of neutralization titration and elemental analysis of the dried product, it was confirmed that the salt was a salt consisting of 2 molecules of 2,4 'body and Na1 atom.) Then, 2,4' was obtained by filtration. Add the whole body 1/2 sodium salt to 190 ml of water and raise the temperature to 90 ° C.
After 3.3 g of 5% sulfuric acid was added dropwise to adjust the pH to 4,
After cooling to 25 ° C., the precipitated crystals are filtered off and dried,
21.6 g of 2,4 'purified product was obtained. The results of analysis by high performance liquid chromatography were 99.1% by weight of 2,4 'form, 0.8% by weight of 4,4' form and 0.1% by weight of water. Purification yield from 2,4 'crude product is 89.2%
Met.

Example 3 30.0 g (0.12 mol) of a crude product of 2,4'-body consisting of 80.0% by weight of 2,4'-body and 20.0% by weight of 4,4'-body, 150 ml of water and 48% NaOH aqueous solution 6.
0 g (corresponding to the total of 0.5 times the molar amount of the 2,4'-form and 1.0 times the molar amount of the 4,4'-form) was added and suspended at 95 ° C for 15 minutes. After that, 7.5 g of sodium sulfate was added and further suspended at 95 ° C. for 15 minutes and then cooled to 30 ° C., and 1/2 sodium salt of 2,4 ′ form was separated by filtration.

The 1/2 sodium salt of the obtained 2,4 'form was 33.4 g, and the water content was 17.2% by weight. (After drying a small amount, the composition was analyzed by high performance liquid chromatography to find that the 2,4'-form of 1/2 sodium salt was 95.2% by weight and the 4,4'-form of monosodium salt was 4.8% by weight. From the results of neutralization titration and elemental analysis of the dried product, it was confirmed that the salt was a salt consisting of 2 molecules of 2,4 'body and Na1 atom.) Then, 2,4' was obtained by filtration. 30 g of body 1/2 sodium salt was added to 200 ml of water, and the temperature was raised to 90 ° C.
4.1 g of 51% sulfuric acid was added dropwise, the pH was adjusted to pH = 4, the mixture was cooled to 25 ° C., and the precipitated crystals were separated by filtration and dried to obtain 20.7 g of a 2,4 ′ pure product. High-performance liquid chromatography analysis showed that the 2,4 'form was 97.0.
% By weight, 2.9% by weight of 4,4 ′ body and 0.1% by weight of water. The purification yield from the 2,4 'crude product was 93.
It was 0%.

Example 4 20% by weight was added to 30.0 g (0.12 mol) of a crude product of 2,4 'body consisting of 80.0% by weight of 2,4' body and 20.0% by weight of 4,4 'body. 150 ml of an aqueous methanol solution and 6.0 g of a 48% NaOH aqueous solution (corresponding to a total of 0.5 times the molar amount of the 2,4'-form and 1.0 times the molar amount of the 4,4'-form). In addition, when heated under stirring, it melted at 85 ° C. Then, when the contents were cooled, crystals of 1/2 sodium salt in 2,4 'form were precipitated at 45 ° C. After further cooling, at 25 ° C 1/2 of 2,4 '
26.6 g of the disodium salt was filtered off. This was dried to obtain 21.0 g of a dried product. The composition of the dried product was, by high performance liquid chromatography, 90.9% by weight of 1/2 sodium salt of 2,4'-form and 9.1% by weight of monosodium salt of 4,4'-form. In addition, from the results of neutralization titration and elemental analysis of the dried product, 2 molecules of 2,4 'body and Na
It was confirmed that the salt consisted of one atom. The Na content as determined by elemental analysis was 4.4% (theoretical value: 4.4%).

Next, the 2,4 'body obtained by drying 1/2
Add 15.0 g of sodium salt to 150 ml of water,
The temperature was raised to ℃, 2.6g of 51% sulfuric acid was added dropwise, pH = 4
After adjusting the temperature to 25 ° C., the precipitated crystals were separated by filtration and dried to obtain 14.0 g of 2,4 ′ pure product.
The analysis results by high performance liquid chromatography are 2,
9% by weight of the 4'-form, 7.0% by weight of the 4,4'-form and 0.1% by weight of water. The purification yield from the 2,4 'crude product was 75.9%.

Example 5 30.0 g (0.12 mol) of a crude product of 2,4 'body consisting of 80.0% by weight of 2,4' body and 20.0% by weight of 4,4 'body, 150 ml of water and 48% NaOH aqueous solution 2.
0 g (only a 1.0-fold molar equivalent amount with respect to 4,4 'form) was added, and the mixture was suspended at 95 ° C for 30 minutes, cooled to 30 ° C, and the crystals were separated by filtration.

The obtained crystals weigh 26.7 g and have a water content of 1
It was 0.1% by weight. As a result of neutralization titration and elemental analysis of this dried product, it was confirmed to be a free 2,4 'form. The composition was 98.2% by weight of 2,4'-form and 1.8 of 4,4'-form by high performance liquid chromatography.
% By weight. Purification yield from 2,4 'crude product is 9
It was 8.2%.

Example 6 30.0 g (0.12 mol) of a crude product of 2,4 'body consisting of 65.0% by weight of 2,4' body and 35.0% by weight of 4,4 'body, 150 ml of water and 48% NaOH aqueous solution 5.
2g (0.25 times the molar amount of 2,4 'and 4,4'
This corresponds to the sum of 1.0 times the molar amount of the body. ) Was added and the mixture was melted at 95 ° C. and cooled to 30 ° C. (during cooling, 7
The crystals were precipitated at 9 ° C.) and the crystals were filtered off.

The obtained crystals weighed 17.4 g and had a water content of 9.8% by weight. As a result of neutralization titration and elemental analysis of this dried product, it was confirmed to be a free 2,4 'form. The composition was determined by high performance liquid chromatography to be 93.4% by weight of 2,4 'form and 6.6 of 4,4' form.
% By weight. Purification yield from 2,4 'crude product is 7
It was 5.2%.

Example 7 Example 4 was repeated except that KOH was used instead of NaOH. The analysis results of the obtained purified product of the 2,4'-form by high performance liquid chromatography were 99.0% by weight of the 2,4'-form and 1.0% by weight of the 4,4'-form. The purification yield from the 2,4 'crude product was 95.0%.

Comparative Example 1 30.0 g (0.12 mol) of a 2,4'-form crude product consisting of 80.0% by weight of the 2,4'-form and 20.0% by weight of the 4,4'-form, 150 ml of water and 48% NaOH aqueous solution 1
3.0 g (1.3 for 2,4 'and 4,4' bodies
This corresponds to a double molar amount. ) Was added and suspended at 95 ° C. for 30 minutes, then cooled to 30 ° C., and the 1/2 sodium salt of the 2,4 ′ form was filtered off.

The 1/2 sodium salt of the obtained 2,4'-form was 15.0 g, and the water content was 14.0% by weight. (After drying a small amount, the composition was analyzed by high performance liquid chromatography. As a result, it was found that the 1,4'-form of the 1/2 sodium salt was 96.2% by weight and the 4,4'-form of the monosodium salt was 3.8% by weight. From the results of neutralization titration and elemental analysis of the dried product, it was confirmed that the salt was a salt composed of 2 molecules of 2,4 'body and Nal atom.) Then, 2,4' was obtained by filtration. Add the whole body 1/2 sodium salt to 100 ml of water and raise the temperature to 90 ° C.
After 1.7 g of 5% sulfuric acid was added dropwise to adjust the pH to 4,
After cooling to 25 ° C., the precipitated crystals are filtered off and dried,
11.3 g of 2,4 'purified product was obtained. The results of analysis by high performance liquid chromatography were 98.4% by weight of 2,4 'form, 1.5% by weight of 4,4' form and 0.1% by weight of water. Purification yield from 2,4 'crude product is 45.2%
Met.

Comparative Example 2 30.0 g (0.12 mol) of a 2,4'-form crude product consisting of 80.0% by weight of 2,4'-form and 20.0% by weight of 4,4'-form, 150 ml of water and 48% NaOH aqueous solution 1.
6 g (only a 0.8-fold molar equivalent amount with respect to 4,4'-form) was added, and the mixture was suspended at 95 ° C for 30 minutes, cooled to 30 ° C, and the crystals were separated by filtration.

The crystals obtained were 28.0 g, and the water content was 9.6% by weight. As a result of neutralization titration and elemental analysis of this dried product, it was confirmed to be a free 2,4 'form. The composition was determined by high performance liquid chromatography to be 88.3% by weight of 2,4'-form and 4,4'-form of 11.
It was 7% by weight. The purification yield from the 2,4 'crude product was 93.1%.

[0048]

According to the method of the present invention, since an aqueous solvent that is easy to manage is used, it is easy to handle, has no safety and occupational hygiene problems, and has a high purity of 2,4'-dihydroxydiphenyl sulfone. Can be obtained with a high purification yield.

Front page continued (58) Fields surveyed (Int.Cl. ⁷ , DB name) C07C 317/00 C07C 315/00 CA (STN) REGISTRY (STN)

Claims (3)

(57) [Claims] 1. A 2,4'-dihydroxydiphenyl sulfone crude product is dissolved or suspended in an aqueous solution of a basic alkali metal compound to give 2,4'-dihydroxydiphenyl sulfone or its 1/2 alkali metal salt. Is precipitated and separated, and then, if necessary, this is treated with an acid .
A method for purifying 4'-dihydroxydiphenyl sulfone.
The amount of basic alkali metal compound used is
2,4'-dihydroxydiphenylsulfur in terms of genus atoms
2,4'-dihydroxydiphe contained in hong crude product
0 to 1.0 equivalent relative to nyl sulfone, 4,4'-diene
Hydroxydiphenyl sulfone and trihydroxy
1.0 equivalent to the total amount of Liphenyldisulfone
A method for purifying 2,4'-dihydroxydiphenyl sulfone, characterized in that 2. The purification method according to claim 1, wherein the crude 2,4′-dihydroxydiphenyl sulfone product is dissolved or suspended in an aqueous solution of a basic alkali metal compound and then salted out. . 3. The purification method according to claim 1 or 2 , wherein the aqueous solution of the basic alkali metal compound is an aqueous solution of the basic alkali metal compound or an aqueous alcoholic solution.