JP4420430B2 - Method for producing 4-mercaptophenols - Google Patents

Description

  The present invention relates to a method for producing 4-mercaptophenol or a metal salt thereof useful as a developer for heat-sensitive recording materials, a production intermediate for medicine and agricultural chemicals, and the like.

Conventionally, as a method for producing 4-mercaptophenol, a method of reducing bis (4-hydroxyphenyl) polysulfide obtained by the reaction of phenol and sulfur chloride using zinc and hydrochloric acid (Patent Document 1), and metallic water A method of cleaving a disulfide bond of a disulfide compound using an oxide is known (Non-Patent Document 1).
However, the method described in Patent Document 1 has a problem that the post-treatment process becomes complicated because the reduction is performed using zinc. In addition, the method described in Non-Patent Document 1 has a disadvantage in that the yield is poor because arylsulfinic acid and the like are by-produced, and both methods are disadvantageous in industrially mass-producing 4-mercaptophenol. It was.

Japanese Unexamined Patent Publication No. 63-227656 J. et al. Org. Chem. , 32, 2047 (1967).

  This invention is made | formed in view of the actual condition of the above-mentioned prior art, and makes it a subject to provide the method of manufacturing 4-mercaptophenol and its metal salt efficiently and industrially advantageously.

  The inventors of the present invention have intensively studied the reaction using bis (4-hydroxyphenyl) polysulfide as 4-mercaptophenol. As a result, it was found that by reacting bis (4-hydroxyphenyl) polysulfide with a metal hydroxide in the presence of a reducing sugar, a metal salt of 4-mercaptophenol can be obtained in good yield. It came to be completed.

Thus, according to the first aspect of the present invention, there is provided a process for producing a 4-mercaptophenol metal salt, characterized by reacting bis (4-hydroxyphenyl) polysulfide with a metal hydroxide in the presence of a reducing sugar. Is done.
In the method for producing a 4-mercaptophenol metal salt of the present invention, it is preferable to use a bis (4-hydroxyphenyl) polysulfide obtained by a reaction between phenol and sulfur chloride. In a polar solvent, an alkali metal It is more preferable to use what was obtained by reaction of phenol and sulfur chloride in the presence of a halide.

  According to 2nd of this invention, the 4-mercaptophenol metal salt obtained by said 1st invention is further processed with an acid, The manufacturing method of 4-mercaptophenol characterized by the above-mentioned is provided.

  The method for producing 4-mercaptophenol of the present invention includes a step of obtaining bis (4-hydroxyphenyl) polysulfide by reacting phenol with sulfur chloride, bis (4-hydroxyphenyl) polysulfide and metal hydroxide, It is preferable to have a step of obtaining a 4-mercaptophenol metal salt by reacting in the presence of a reducing sugar and a step of treating the obtained 4-mercaptophenol metal salt with an acid, More preferably, the step of obtaining the bis (4-hydroxyphenyl) polysulfide is a step of reacting phenol and sulfur chloride in a polar solvent in the presence of an alkali metal halide.

According to the present invention, by reacting bis (4-hydroxyphenyl) polysulfide with a metal hydroxide in the presence of a reducing sugar, a metal salt of 4-mercaptophenol is produced industrially advantageously in good yield. can do. By treating the resulting metal salt of 4-mercaptophenol with an acid, the desired 4-mercaptophenol can be easily obtained.
In the present invention, when bis (4-hydroxyphenyl) polysulfide obtained from phenol and sulfur chloride is used as a starting material, the desired 4-mercaptophenol can be obtained at a lower production cost.

Hereinafter, the present invention will be described in detail.
1) Method for Producing 4-Mercaptophenol Metal Salt The method for producing 4-mercaptophenol metal salt of the present invention comprises reacting bis (4-hydroxyphenyl) polysulfide with a metal hydroxide in the presence of a reducing sugar. It is characterized by.

(1) Bis (4-hydroxyphenyl) polysulfide The bis (4-hydroxyphenyl) polysulfide used in the present invention is not particularly limited, but is a bis (4-hydroxyphenyl) polysulfide obtained by reaction of phenol and sulfur chloride. Is preferable from the viewpoint of availability and manufacturing cost. As the sulfur chloride used here, disulfur dichloride (S ₂ Cl ₂ ) is preferable because the target product can be obtained with good yield. In this case, a product isolated and purified from a reaction mixture of phenol and sulfur chloride can be used, but without any purification, hydrogen chloride and reaction solvent by-produced by the reaction of phenol and sulfur chloride are removed. It is also possible to use what has been done.

  The bis (4-hydroxyphenyl) polysulfide used in the present invention has the formula (I)

(Wherein x represents 2, 3 or 4), or a mixture of two or more of the compounds represented by When this consists of two or more, it is preferable to use a mixture containing the largest amount of x.

  When the bis (4-hydroxyphenyl) polysulfide used in the production method of the present invention is produced by the reaction of phenol and sulfur chloride, phenol and sulfur chloride are added in a polar solvent in the presence of an alkali metal halide. It is preferable to react.

  Examples of polar solvents used include esters such as methyl acetate, ethyl acetate, propyl acetate, butyl acetate, methyl propionate, ethyl propionate, diethyl malonate, and ethyl methyl malonate; nitriles such as acetonitrile, propionitrile, and benzonitrile Amides such as N, N-dimethylformamide and N, N-dimethylacetamide; sulfoxides such as dimethyl sulfoxide; ethers such as diethyl ether, dibutyl ether, tetrahydrofuran, dioxane and dimethoxyethane; Esters are preferred.

Examples of the alkali metal halide to be used include lithium fluoride, rubidium fluoride, lithium chloride, sodium chloride, potassium chloride, rubidium chloride, lithium bromide, sodium bromide, potassium bromide and the like, and lithium chloride is preferable. .
The amount of the alkali metal halide used is usually in the range of 0.01 to 0.5 mol, preferably in the range of 0.05 to 0.2 mol, with respect to 1 mol of phenol.

(2) Metal hydroxide The metal hydroxide used in the present invention includes alkali metal hydroxides such as lithium hydroxide, sodium hydroxide and potassium hydroxide; alkaline earth metals such as magnesium hydroxide and calcium hydroxide. And hydroxides; typical metal hydroxides such as aluminum hydroxide; transition metal hydroxides such as zinc hydroxide; and the like. These metal hydroxides can be used alone or in combination of two or more. Among these, from the viewpoints of reaction yield and production cost, use of alkali metal hydroxide is preferable, and use of sodium hydroxide is particularly preferable.

  In the present invention, it is preferable to use the metal hydroxide by dissolving it in a solvent in advance. The amount of the solvent used is usually 1 to 10 parts by weight, preferably 2 to 1 part by weight of the metal hydroxide. The range is 5 parts by weight.

The usage-amount of a metal hydroxide is 2 mol-20 mol with respect to 1 mol of bis (4-hydroxyphenyl) polysulfide, Preferably it is the range of 2 mol-10 mol.
Moreover, when using the bis (4-hydroxyphenyl) polysulfide obtained by reaction of a phenol and sulfur chloride, the usage-amount of a metal hydroxide is 1 mol-10 mol with respect to 1 mol of phenol, Preferably it is the range of 1 mol-5 mol.

(3) Reducing sugar The reducing sugar used in the present invention includes a reducing sugar having a free aldehyde group or ketone group in its molecule (including those in which these aldehyde group or ketone group forms a hemiacetal. .) Examples thereof include glucose, fructose, mannose, lactose, xylose, sorbose, galactose, and oligosaccharides in which one or more of these reducing sugars form a bond. These can be used individually by 1 type or in mixture of 2 or more types. These reducing sugars may be D-type or L-type, but use of D-glucose is preferred from the viewpoint of availability.

The amount of reducing sugar used is in the range of 0.2 mol to 4 mol, preferably 0.4 mol to 2 mol, with respect to 1 mol of bis (4-hydroxyphenyl) polysulfide.
Moreover, when using the bis (4-hydroxyphenyl) polysulfide obtained by reaction of a phenol and sulfur chloride, the usage-amount of a reducing sugar is 0.1 mol-2 mol with respect to 1 mol of phenol, Preferably it is the range of 0.2 mol-1 mol.

(4) Reaction method The reaction of bis (4-hydroxyphenyl) polysulfide and metal hydroxide can be carried out in a suitable solvent. Moreover, it is preferable to perform reaction in inert gas atmosphere, such as nitrogen gas, argon gas, and helium gas.

  Examples of the solvent to be used include water; alcohols such as methanol, ethanol, n-propanol, isopropanol, n-butanol and t-butanol; amides such as N, N-dimethylformamide and N, N-dimethylacetamide; dimethyl Sulfoxides such as sulfoxide; two-phase mixed solvents such as water-benzene, water-toluene, water-xylene and the like. Among these, use of water is particularly preferable.

  The reaction temperature for producing a 4-mercaptophenol metal salt from bis (4-hydroxyphenyl) polysulfide is usually in the range of 20 ° C to 100 ° C, preferably 30 ° C to 70 ° C.

  In the present invention, the yield of 4-mercaptophenol metal salt is improved by reacting in the presence of reducing sugar, but the yield is improved by appropriately selecting the order of addition of metal hydroxide and reducing sugar. Can do.

  For example, reducing sugars and metal hydroxides are dissolved in a solvent by distilling off hydrogen chloride and by-products produced by distillation of bis (4-hydroxyphenyl) polysulfide obtained by the reaction of phenol and sulfur chloride. Add food. Then, a yield improves by slowly dripping what dissolved the metal hydroxide in the solvent. In this case, the amount of the metal hydroxide added first is usually in the range of 0.5 to 5 mol, preferably 1 to 2 mol, relative to 1 mol of phenol. Moreover, the usage-amount of the metal hydroxide dripped after adding a reducing sugar is 0.1-5 mol normally with respect to 1 mol of phenol, Preferably it is the range of 1-3 mol.

  According to the present invention, 4-mercaptophenol metal salt can be produced in a high yield by carrying out the reaction in the presence of a reducing sugar. Although details of this reaction are not clear, it is considered that the reaction proceeds as shown in the following reaction formula (II).

(Wherein R represents an alkyl group or an aryl group)
That is, disulfide compounds (R-S-S-R ) hydroxide ions ^- reacted ^{with, R-S-O (OH} ) -, R-S - and water _(H 2 O) is produced. Then, the R-S-O ^- reacts with disulfide compounds (R-S-S-R ), R-S (→ O) -S-R and R-S ^- and to produce. Furthermore, this R—S (→ O) —S—R reacts with a hydroxide ion (OH ⁻ ) to react with a sulfinate (R—S (═O) —O ⁻ ), R—S ^— and water ( H ₂ O) is considered to be generated.

According to the above reaction formula, the desired 4-mercaptophenol metal salt is produced in a maximum amount of 1.5 moles per mole of the disulfide compound. Although not described in the above reaction scheme, sulfinate (R-S (= O) -O -) - and is further oxidized to sulfonate _{(R-S (= O)} 2 -O) In this case, a maximum of 1.625 mol of 4-mercaptophenol metal salt is produced per 1 mol of the disulfide compound.

On the other hand, it is considered that sulfenate and thiolsulfinate produced from a disulfide compound and a metal hydroxide are reduced by adding a reducing sugar to the reaction system.
According to the method of the present invention, the formation of sulfinate and sulfonate is suppressed, and the desired 4-mercaptophenol metal salt can be obtained almost quantitatively with respect to bis (4-hydroxyphenyl) polysulfide. it can.

2) Method for Producing 4-Mercaptophenol The method for producing 4-mercaptophenol of the present invention is characterized in that the 4-mercaptophenol metal salt obtained by the invention of 1) is further treated with an acid.
Examples of the acid to be used include inorganic acids such as hydrochloric acid, sulfuric acid, nitric acid and phosphoric acid; organic acids such as acetic acid and propionic acid, and the use of inorganic acids is preferred. Moreover, what was diluted with water etc. can also be used as an acid. The amount of acid added is usually a neutralization amount.

  Examples of the method for treating the 4-mercaptophenol metal salt with an acid include a method of adding an acid to a solution of the 4-mercaptophenol metal salt, such as water. When the acid is added dropwise to the solution of the 4-mercaptophenol metal salt, it is preferable to sufficiently stir the solution and to cool the solution as desired.

  After the treatment with an acid, extraction with an appropriate organic solvent is performed, and the desired 4-mercaptophenol can be isolated by a known separation / generation means such as a distillation method. In this case, in order to prevent oxidation of 4-mercaptophenol, it is also preferable to perform an acid treatment or a post-treatment operation of the reaction in an inert gas atmosphere.

  EXAMPLES Hereinafter, although an Example demonstrates this invention still in detail, this invention is not limited to the following Example.

Synthesis Example 1 Production of 4,4′-dihydroxydiphenyl disulfide To a 1 L 4-neck flask was added 36.5 g (0.27 mol) disulfur dichloride, 2.6 g (0.06 mol) lithium chloride and 318 ml ethyl acetate at room temperature. Stir for 30 minutes. Thereafter, the internal temperature was cooled to 10 to 15 ° C., and 47.5 g (0.5 mol) of molten phenol was added dropwise over 1 hour using a dropping funnel while maintaining the temperature. After completion of the dropwise addition, the mixture was further stirred at the same temperature for 3 hours, and then heated to the reflux temperature, and the hydrogen chloride gas was sufficiently removed while refluxing. Thereafter, the reaction solution was concentrated under normal pressure and reduced pressure to obtain 76.5 g of 4,4′-dihydroxydiphenyl disulfide as an oily substance.

Example 1 Production of 4-mercaptophenol (1)
In Synthesis Example 1, except that the reaction scale was 1/10, 7.60 g of 4,4′-dihydroxydiphenyl disulfide oily substance obtained by the same method as in Synthesis Example 1 was added to 3.60 g of D-glucose ( 0.02 mol) and 60.0 g (0.15 mol) of a 10% aqueous sodium hydroxide solution were added, and the mixture was stirred at 50 ° C. for 5 hours under a nitrogen stream to obtain a sodium salt of 4-mercaptophenol.

Thereafter, the reaction solution was cooled to 5 to 10 ° C., and this was put into a mixed solution of 35.4 g (0.17 mol) of 17.5% hydrochloric acid and 100 ml of methylene chloride. The obtained mixture was separated to separate the organic layer. The aqueous layer was extracted again with 100 ml of methylene chloride. The organic layers were combined and the whole volume was concentrated under reduced pressure to obtain 6.10 g of 4-mercaptophenol as a reddish brown oily substance.
This material was quantitatively analyzed by liquid chromatography and found to contain 73.2% by weight of 4-mercaptophenol. The two-stage yield from phenol was 70.8%.

Example 2 Production of 4-mercaptophenol (2)
In Synthesis Example 1, except that the reaction scale was reduced to 1/10, 6.60 g of 4,4′-dihydroxydiphenyl disulfide oily substance obtained by the same method as in Synthesis Example 1 was added to 3.60 g of D-glucose ( 0.02 mol) and 20.0 g (0.05 mol) of 10% aqueous sodium hydroxide solution were added, and the temperature was raised to 50 ° C. with stirring under a nitrogen stream. After confirming that the solution was completely dissolved, 40.0 g (0.10 mol) of 10% aqueous sodium hydroxide solution was added dropwise over 1 hour, and the mixture was further stirred for 3 hours to obtain a sodium salt of 4-mercaptophenol.

Thereafter, the reaction solution was cooled to 5 to 10 ° C., and this was neutralized by pouring it into a mixed solution of 31.3 g (0.15 mol) of 17.5% hydrochloric acid and 100 ml of methylene chloride. The mixture was separated and the organic layer was separated. The aqueous layer was extracted again with 100 ml of methylene chloride, and the resulting organic layers were combined and concentrated under reduced pressure to obtain 6.18 g of 4-mercaptophenol as a reddish brown oily substance.
This material was quantitatively analyzed by liquid chromatography and found to contain 76.3% by weight of 4-mercaptophenol. The two-stage yield from phenol was 74.8%.

Comparative Example 1 Production of 4-mercaptophenol 76.5 g of the oily substance of 4,4′-dihydroxydiphenyl disulfide obtained in Synthesis Example 1 was dissolved in 800.0 g (2.0 mol) of a 10% aqueous sodium hydroxide solution. The mixture was stirred at 80 ° C. for 4 hours under an air stream to obtain a sodium salt of 4-mercaptophenol. The reaction solution was cooled to 5 to 10 ° C., and this was neutralized by introducing it into a mixed solution of 416.7 g of 17.5% hydrochloric acid and 200 ml of methylene chloride. The mixture was separated and the organic layer was separated. The aqueous layer was extracted again with 200 ml of methylene chloride. The obtained organic layers were combined and concentrated under reduced pressure to obtain 54.85 g of 4-mercaptophenol as a pale yellow oily substance.
This material was quantitatively analyzed by liquid chromatography and found to contain 63.0% by weight of 4-mercaptophenol. The two-stage yield from phenol was 54.7%.

Claims (6)

  A method for producing a 4-mercaptophenol metal salt, comprising reacting bis (4-hydroxyphenyl) polysulfide with a metal hydroxide in the presence of a reducing sugar.   The method for producing a 4-mercaptophenol metal salt according to claim 1, wherein the bis (4-hydroxyphenyl) polysulfide is obtained by a reaction between phenol and sulfur chloride.   The 4-mercapto according to claim 1, wherein the bis (4-hydroxyphenyl) polysulfide is obtained by reaction of phenol and sulfur chloride in a polar solvent in the presence of an alkali metal halide. A method for producing a phenol metal salt.   The 4-mercaptophenol metal salt obtained by the reaction according to claim 1 is further treated with an acid.   By reacting phenol with sulfur chloride to obtain bis (4-hydroxyphenyl) polysulfide, and reacting bis (4-hydroxyphenyl) polysulfide with metal hydroxide in the presence of reducing sugar. The manufacturing method of 4-mercaptophenol which has the process of obtaining 4-mercaptophenol metal salt, and the process of processing the obtained 4-mercaptophenol metal salt with an acid. 6. The process according to claim 5, wherein the step of obtaining the bis (4-hydroxyphenyl) polysulfide is a step of reacting phenol and sulfur chloride in a polar solvent in the presence of an alkali metal halide. A method for producing mercaptophenol.