JPH06107622A - Production of 2,4'-dihydroxydiphenyl sulfones - Google Patents

Abstract

PURPOSE:To produce 2,4'-dihydroxydiphenyl sulfones useful as a developer for heat-sensitive paper in high selectivity and good yield. CONSTITUTION:The objective method for producing 2,4'-dihydroxydiphenyl sulfones comprises allowing at least one selected from phosphonic acid, phosphinic acid and salts thereof to exist in the reactional system as a catalyst, carrying out reaction in the absence or presence of an aromatic hydrocarbon solvent having 130-200 deg.C boiling point under ordinary pressure in mixing phenols with sulfuric acid, then heating the resultant mixture and producing the objective 2,4'-dihydroxydiphenyl sulfones.

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION The present invention relates to a novel method for producing 2,4'-dihydroxydiphenyl sulfones. More specifically, the present invention relates to a method for efficiently producing 2,4′-dihydroxydiphenyl sulfones useful as a color developer for thermal papers with a high selectivity from phenols and sulfuric acid.

[0002]

2. Description of the Related Art Conventionally, various phenol compounds have been developed as a color developer for thermal paper, and among them, 2,4'-
Dihydroxydiphenyl sulfones are expected as extremely useful developers for thermal paper. However, various attempts have hitherto been made regarding the method for producing 4,4′-dihydroxydiphenylsulfones, and the production of isomers 2,4′-dihydroxydiphenylsulfones is minimized to obtain highly pure 4 Efforts have been made to obtain 4,4'-dihydroxydiphenyl sulfones, but 2,4'-
The fact is that no report has been made so far regarding a production method for increasing the yield of dihydroxydiphenyl sulfones.

[0003]

Under these circumstances, the present invention is useful as a developer for thermal paper, etc.
The present invention has been made for the purpose of providing a method for industrially advantageously producing dihydroxydiphenyl sulfones with a high selectivity.

[0004]

Means for Solving the Problems As a result of intensive studies for achieving the above-mentioned object, the present inventors have found that a specific catalyst is allowed to exist in a reaction system, and it is used in the absence of solvent or in the presence of a specific solvent. By heating phenols and sulfuric acid,
It was found that 4′-dihydroxydiphenyl sulfones can be obtained with a high selectivity and the purpose thereof can be achieved, and the present invention has been completed based on this finding. That is,
According to the present invention, at least one kind selected from phosphonic acid, phosphinic acid and salts thereof is used as a catalyst in producing 2,4′-dihydroxydiphenylsulfones by mixing phenols and sulfuric acid and heating. Is present in the reaction system and has a boiling point of 130 to 200 ° C. under no solvent or at normal pressure.
The present invention provides a method for producing 2,4′-dihydroxydiphenylsulfones, which comprises performing the reaction in the presence of the aromatic hydrocarbon solvent.

The present invention will be described in detail below. In the present invention, as the phenols used as the raw material,
For example, phenol, o-cresol, m-cresol,
2,3-xylenol, 2,5-xylenol, 3,5-
At least one ortho- and para-position such as xylenol, or a mixture of two or more selected from the phenols having no substitution, or one selected from these phenols and p-cresol, Mention may be made, for example, of a mixture of 2,4-xylenol, 2,6-xylenol, 3,4-xylenol and the like, which is selected from two ortho- or para-substituted phenols. With respect to the usage ratio of these phenols and sulfuric acid, it is preferable to use them so that the molar ratio is in the range of 2: 1 to 4: 1. In the method of the present invention, the reaction is carried out by heating without solvent or in an aromatic hydrocarbon solvent having a boiling point of 130 to 200 ° C., and at this time, the catalyst is selected from phosphonic acid, phosphinic acid and salts thereof. It is necessary that at least one kind is present in the reaction system.
The amount of the catalyst used is usually 2% by weight or more, preferably 5 to 10% by weight, based on sulfuric acid. If the amount of this catalyst is less than 2% by weight, the effect of improving the selectivity of 2,4'-dihydroxydiphenylsulfones is not sufficiently exerted, and if it exceeds 10% by weight, the amount of 2,4'-dihydroxy sulfone is 2,4'-dihydroxy. No significant improvement in the selectivity of diphenyl sulfones is observed.

When the reaction is carried out without using a solvent, it is carried out under reduced pressure, preferably under reduced pressure of 600-50 mmHg, at 140-
It is desirable to heat and react at a temperature in the range of 170 ° C. When the reaction is carried out in the presence of a solvent, an aromatic hydrocarbon having a boiling point of 130 to 200 ° C. at atmospheric pressure is used as the reaction solvent. Examples of the aromatic hydrocarbon include xylene, ethylbenzene, butylbenzene, diethylbenzene, mesitylene, cymene, cumene, pseudocumene, Shellsol A [trade name, manufactured by Shell Chemical Co., Ltd.], Shellsol AB [trade name, manufactured by Shell Chemical Company, etc.] These may be used alone or in combination of two or more. It is also possible to use an aromatic petroleum solvent having a boiling point in the range of 130 to 200 ° C at atmospheric pressure. When the reaction is carried out using these solvents, a method is generally used in which the reaction product water is azeotropically distilled off under normal pressure or weak pressure while being distilled out of the reaction system. In the method using such a solvent, after the reaction is completed, the by-product phenolsulfonic acid can be easily separated from the dihydroxydiphenylsulfone by filtration without neutralization, and the phenolsulfonic acid and the solvent can be separated from each other. Can be reused.

In the conventional method for producing 4,4'-dihydroxydiphenylsulfone, when it is attempted to obtain a dihydroxydiphenylsulfone isomer mixture in a yield of 80 mol% or more, 2,4'-dihydroxydiphenyl produced as a by-product. The production rate of sulfone is suppressed to about 20% by weight or less. On the other hand, if the production rate of 2,4′-dihydroxydiphenylsulfone is increased to 20% by weight or more, the yield of the dihydroxydiphenylsulfone isomer mixture is reduced. Therefore, it is economically extremely disadvantageous to apply such a conventional method to the production of 2,4'-dihydroxydiphenyl sulfones. On the other hand, according to the production method of the present invention, for example, when phenol is used as a raw material, the production ratio of 2,4′-dihydroxydiphenylsulfone and 4,4′-dihydroxydiphenylsulfone is close to 50:50 by weight. The yield of the dihydroxydiphenyl sulfone isomer mixture can be increased to 80 mol% or more. Further, when 5-methyl-2,4'-dihydroxydiphenyl sulfone is produced using phenol and p-cresol as a raw material, or 3,5-dimethyl-2,4 is produced using phenol and 2,4-xylenol. In the case of producing'-dihydroxydiphenylsulfone, the production ratio of 2,4'-dihydroxy compound can be increased to 80% by weight or more, and the yield of the isomer mixture of dihydroxydiphenylsulfone derivative can be increased to 80% by mole or more. be able to. If desired, the isomer mixture of dihydroxydiphenylsulfones obtained by the method of the present invention is further purified to a highly pure 2,4′-dihydroxydiphenylsulfone by a suitable purification method, for example, a purification method using a solvent. be able to.

[0008]

EXAMPLES The present invention will be described in more detail by way of examples, which should not be construed as limiting the invention thereto. Example 1 A reactor was charged with 793 g of phenol, 334 g of sulfuric acid and 16.5 g of phosphonic acid, and dehydration reaction was carried out at 150 to 165 ° C. for 3 hours under a reduced pressure of 560 to 260 mmHg. When 250 g of effluent was obtained, 165 g of phenol was added. Add 2
The dehydration reaction was performed for 2 hours under reduced pressure of 60 to 100 mmHg to obtain 180 g of effluent. Further, 165 g of phenol was added and dehydration reaction was carried out for 2 hours under a reduced pressure of 260 to 100 mmHg. When the effluent amounted to 140 g, the reaction was terminated, the phenolsulfonic acid was removed by washing with water, and then dried. A dihydroxydiphenyl sulfone isomer mixture was obtained with a yield of 85 mol%. As a result of analysis by high performance liquid chromatography, the composition was 49 wt% of 2,4′-dihydroxydiphenyl sulfone, 50 wt% of 4,4′-dihydroxydiphenyl sulfone, and 1 wt% of other components.

Example 2 A reactor was charged with 793 g of phenol, 334 g of sulfuric acid and 16.5 g of phosphinic acid, and dehydration reaction was carried out at 150 to 165 ° C. for 3 hours under a reduced pressure of 560 to 260 mmHg to obtain 240 g of effluent. Add 165 g of phenol and 2
The dehydration reaction was performed for 2 hours under reduced pressure of 60 to 100 mmHg to obtain 170 g of effluent. Further, 165 g of phenol was added, and dehydration reaction was carried out for 2 hours under a reduced pressure of 260 to 100 mmHg. When the amount of effluent reached 125 g, the reaction was terminated, the phenolsulfonic acid was removed by washing with water, and then dried. 82 mol% of dihydroxydiphenyl sulfone isomer mixture
It was obtained with a yield of. As a result of analysis by high performance liquid chromatography, the composition was 40% by weight of 2,4′-dihydroxydiphenylsulfone, 58% by weight of 4,4′-dihydroxydiphenylsulfone, and 2% by weight of other components. Example 3 A reactor was charged with 793 g of phenol, 334 g of sulfuric acid, 950 ml of mesitylene and 16.5 g of phosphonic acid, a dehydration reaction was carried out under reflux for 6 hours, and then the mixture was cooled to room temperature and filtered to remove phenolsulfonic acid. Dried. A dihydroxydiphenyl sulfone isomer mixture was obtained with a yield of 85 mol%. As a result of analysis by high performance liquid chromatography, the composition was 51% by weight of 2,4′-dihydroxydiphenylsulfone, 48% by weight of 4,4′-dihydroxydiphenylsulfone, and 1% by weight of other components. Example 4 Phenol 793 g, sulfuric acid 334 g, Shel in a reactor
lsol A950 ml and phosphonic acid 16.5
After adding g, the mixture was dehydrated under reflux for 6 hours, cooled to room temperature, filtered to remove phenolsulfonic acid, and then dried. A dihydroxydiphenyl sulfone isomer mixture was obtained with a yield of 80 mol%. As a result of analysis by high performance liquid chromatography, the composition was 52% by weight of 2,4′-dihydroxydiphenylsulfone, 47% by weight of 4,4′-dihydroxydiphenylsulfone, and 1% by weight of other components.

EXAMPLE 5 Phenol 793 g, sulfuric acid 334 g, Shel were placed in a reactor.
940 g of lsol AB and 16.5 g of phosphonic acid were charged and dehydration reaction was carried out under reflux for 6 hours to obtain a predetermined dehydration amount. The reaction solution was cooled to room temperature, and the precipitated crystals were washed by filtration and dried. The filtrate was neutralized and washed, desolvated and dried to give crystals. A dihydroxydiphenyl sulfone isomer mixture was obtained with a yield of 82 mol%. As a result of analysis by high performance liquid chromatography, the composition was 51% by weight of 2,4'-dihydroxydiphenylsulfone, 47% by weight of 4,4'-dihydroxydiphenylsulfone, and 2% by weight of other components. Example 6 p-Cresol 368 g, sulfuric acid 334 g, Sh
2000 ml of ellsol A and 16.5 g of phosphonic acid were charged, dehydration reaction was carried out under reflux for 2 hours, and then 384 g of phenol was added and dehydration reaction was carried out for 4 hours. Next, the mixture was cooled to room temperature, the precipitated crystals were collected by filtration, washed with a dilute alkaline solution, washed with water to remove phenolsulfonic acid, and dried. An isomer mixture of dihydroxydiphenyl sulfone derivatives was obtained with a yield of 81 mol%. As a result of analysis by high performance liquid chromatography,
90 wt% of 5-methyl-2,4'-dihydroxydiphenyl sulfone (mp.179 ° C), 10 wt% of other components
The composition was. Example 7 2,4-xylenol (416 g) and sulfuric acid (334 g) were placed in a reactor.
g, Shellsol AB (2000 ml) and phosphonic acid (16.5 g) were charged, dehydration reaction was performed under reflux for 3 hours, and then 384 g of phenol was added and dehydration reaction was performed for 4 hours. After cooling to room temperature, the precipitated crystals were collected by filtration, washed with a dilute alkaline solution, washed with water to remove phenolsulfonic acid, and dried. An isomer mixture of dihydroxydiphenyl sulfone derivatives was obtained with a yield of 80 mol%. As a result of analysis by high performance liquid chromatography, the composition was 3,5-dimethyl-2,4'-dihydroxydiphenylsulfone (mp.176 ° C) of 87 wt% and the other components of 13 wt%.

Comparative Example 1 A reactor was charged with 628 g of phenol and 334 g of sulfuric acid,
Under a reduced pressure of 560 to 260 mmHg, dehydration reaction was performed at 150 to 165 ° C. for 3 hours, and when effluent 160 g was obtained, 165 g of phenol was added and a reduced pressure of 260 to 100 mmHg,
The dehydration reaction was performed for 2 hours to obtain 120 g of effluent. Further, 120 g of phenol was added and dehydration reaction was carried out for 2 hours under a reduced pressure of 260 to 100 mmHg. When the effluent reached 90 g, the reaction was terminated, the phenolsulfonic acid was removed by washing with water, and then dried. A dihydroxydiphenyl sulfone isomer mixture was obtained with a yield of 76 mol%. High-performance liquid chromatography analysis revealed that 2,4'-dihydroxydiphenyl sulfone was 18 wt%, 4,4'-dihydroxydiphenyl sulfone was 77 wt%, and other components were 5 wt%.
The composition was.

[0012]

According to the method of the present invention, 2,4'-dihydroxydiphenyl sulfones can be obtained in high yield from phenols and sulfuric acid with high selectivity. The 2,4′-dihydroxydiphenyl sulfones are useful as a developer having good storage stability and can replace diaryldihydroxydiphenyl sulfones and 4-isopropoxy-4′-hydroxydiphenyl sulfones.

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Claims (6)

[Claims] 1. At least one selected from phosphonic acid, phosphinic acid and salts thereof as a catalyst when 2,4'-dihydroxydiphenyl sulfone is produced by mixing phenols and sulfuric acid and heating them. The seed is present in the reaction system and has a boiling point of 130 to 200 ° C. without a solvent or at normal pressure.
The method for producing 2,4′-dihydroxydiphenyl sulfones, which comprises performing the reaction in the presence of the aromatic hydrocarbon solvent. 2. A solvent-free, 140-170 ° C. under reduced pressure.
The method for producing 2,4′-dihydroxydiphenylsulfones according to claim 1, wherein the reaction is carried out by heating to the temperature of. 3. The 2,4 ′ according to claim 1, wherein the reaction is carried out by using an aromatic hydrocarbon solvent having a boiling point of 130 to 200 ° C. at atmospheric pressure and distilling out the water produced by the reaction by azeotropic distillation. -Method for producing dihydroxydiphenyl sulfones. 4. The 2,4′-dihydroxydiphenyl sulfone according to claim 1, 2 or 3 which is 2,4′-dihydroxydiphenyl sulfone obtained from phenol as a raw material. Manufacturing method. 5. The 2,4′-dihydroxydiphenyl sulfone is 5-methyl-2,4′-dihydroxydiphenyl sulfone obtained by using phenol and p-cresol as raw materials. A method for producing 2,4'-dihydroxydiphenyl sulfones. 6. The 2,4′-dihydroxydiphenyl sulfone is 3,5-dimethyl-2,4′-dihydroxydiphenyl sulfone obtained by using phenol and 2,4-xylenol as raw materials. Or 2 of 3,
A method for producing 4'-dihydroxydiphenyl sulfones.