JPS60146866A - Production of 4-hydroxythiophenol - Google Patents

Abstract

PURPOSE:To produce the titled compound useful as a reaction intermediate raw material, easily in high yield, by diazotizing 4-aminothiophenol, and hydrolyzing the product in an aqueous solution of a mineral acid. CONSTITUTION:4-Hydroxythiophenol is produced by diazotizing 4-aminothiophenol, and hydrolyzing the product in an aqueous solution of a mineral acid. The diazotization is carried out e.g. by using sulfuric acid, hydrochloric acid, etc. 4-Aminophenol can be produced by various methods, e.g. by reacting aniline with ammonium thiocyanate, and reducing the resultant 4-thiocyanoaniline with lithium aluminum hydride or hydrolyzing in an alkaline aqueous solution.

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field] The present invention relates to a novel method for producing 4-hydroxythiophenol.

[Prior art]

Conventionally, in order to produce 4-hydroxythiophenol, a method has been known in which 4-aminophenol is diazotized, treated with xanthate, and then hydrolyzed [
Am, Soc, 55, 1224 (1933)), L However, this method has a low yield of less than 50%,
This cannot be said to be an industrially advantageous method. In addition, 4-hydroxychlorobenzene and sodium sulfide were added at 210 to 215
℃ heating method is also known (UK Patent No. 381)
No. 237), this method has a yield of less than 10% and cannot be said to be a practical method. Furthermore, 4,4'-dihydroxydiphenyl disulfide can be added to sodium sulfide (US Pat. No. 1,768,905) or MoS 2 /
A 11203 [:J, Org, Chem, 24.1
958 (1959)), but in these methods, the yield of 4,4'-dihydroxydiphenyl disulfide from phenol and disulfur dichloride is 40 to 78%;
Moreover, the yield of the desired product by cleavage of disulfide is 19 to 75%, which is still not a satisfactory method.

〔the purpose〕

An object of the present invention is to provide a new method for producing 4-hydroxythiophenol simply and with high yield compared to the conventional methods as described above.

〔composition〕

According to the present invention, there is provided a method for producing 4-hydroxythiophenol, which comprises diazotizing 4-aminothiophenol and then hydrolyzing the resulting product in an aqueous mineral acid solution.

In the present invention, diazotization of 4-aminothiophenol is carried out by dissolving 4-aminothiophenol in an aqueous solution of a mineral acid, such as sulfuric acid or hydrochloric acid, at a low temperature, preferably 10°C or less. This can be done by gradually adding an aqueous solution of nitrite such as sodium nitrite. The diazo solution thus obtained is gradually added to an aqueous mineral acid (sulfuric acid, hydrochloric acid, etc.) solution while being heated, and the mixture is heated and stirred at 50 to 90°C for 2 to 10 hours. In this way, a reaction product containing the desired 4-hydroxythiophenol is obtained, but 4-hydroxythiophenol can be separated and purified from this product using an organic solvent such as benzene, toluene, ethyl ether, or ethyl acetate. 4-hydroxythiophenol is extracted by solvent extraction using, for example, 4-hydroxythiophenol, and the organic solvent is removed from this extract by vacuum distillation, followed by rectification under vacuum.

4-aminothiophenol used as a raw material in the present invention can be obtained by various synthetic methods, for example, 4-aminothiophenol obtained by reacting aniline and ammonium thiocyanate.
Thiocyanoaniline can be obtained by reduction with lithium aluminum hydride or by hydrolysis in aqueous alkaline solution. In addition, 4-nitrothiophenol obtained by reacting 4-chloronitrobenzene and sodium sulfide,
Catalytic reduction or zinc-hydrochloric acid reduction treatment can yield 4-aminothiophenol. Furthermore, 4-acetaminothiophenol was synthesized by reducing 4-acetaminobenzenesulfonyl chloride with zinc-hydrochloric acid, and by hydrolyzing this in an acid or alkaline aqueous solution, 4-acetaminothiophenol was synthesized.
- Aminothiophenol can be obtained.

〔effect〕

As described above, according to the present invention, 4-hydroxythiophenol can be produced easily and in high yield. This 4-hydroxythiophenol is used for various purposes as a reaction intermediate raw material.

〔Example〕

Next, the present invention will be explained in more detail with reference to Examples.

Example 1 125 g of 4-aminothiophenol (1,0 mon
) was placed in a 212 flask equipped with a stirrer, and 700 mQ of a 10% aqueous hydrochloric acid solution was added to dissolve it. The flask was cooled with ice to below 10°C. Sodium nitrite 69
g (] , Omo Q ) were gradually added, and the mixture was further stirred at 10° C. or lower for 1 hour. Separately, 700ml of 10% hydrochloric acid aqueous solution
Q was placed in a 3Q flask with a stirrer and heated to 70°C. While stirring, the diazonium solution was added dropwise over 2 hours, and then heated to 90° C. and stirred for 1 hour. After the reaction was completed, the mixture was extracted with benzene, benzene was recovered from the benzene layer, and the residue was distilled under reduced pressure using a 200 mm long Hembel distillation tube under a nitrogen stream. 99-103'C/2
mmt (g fraction), and when left to cool in a refrigerator, it crystallized, yielding 107.2 g of the target product with a melting point of 27-29°C (yield: 8
5.1%).

Example 2 Diazotization was carried out in the same manner as in Example 1. Separately, 700 mQ of a 10% sulfuric acid aqueous solution was placed in a 3Q flask equipped with a stirrer and heated to 70°C. The diazonium solution was added dropwise over 2 hours while stirring. After the dropwise addition, the mixture was heated to 90°C and stirred for 1 hour. After the reaction was completed, extraction was performed with ethyl acetate, ethyl acetate was collected from the ethyl acetate layer, and the ethyl acetate layer was washed for 2 lengths under a nitrogen stream.
The residue was vacuum distilled using a 00 mm Hempel fractionator. 90-bmmHg fraction is collected and left to cool in the refrigerator, crystallizing and producing the desired product with a melting point of 27-29°C 1], 1
．． h (yield 88.4%) was obtained.

Patent applicant Rico Co., Ltd. Representative Patent Attorney Toshiaki Ikeura

Claims (1)

[Claims] (1) A method for producing 4-hydroxythiophenol, which comprises diazotizing 4-aminothiophenol and then hydrolyzing the resulting product in an aqueous mineral acid solution.