Preparation method of thiophenol

A technology of thiophenols and compounds, which is applied in the field of preparation of thiophenols, can solve problems such as environmental pollution, increase production costs, and increase separation costs, and achieve the effects of reducing production costs, simplifying separation processes, and high chemical selectivity

Inactive Publication Date: 2013-02-27
ZHEJIANG UNIV
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Problems solved by technology

There is bibliography to prepare thiophenol (JP03170456,1991) with zinc reduction benzene sulfonic acid, also has bibliography to prepare thiophenol with the method (Tetrahedron Lett.1999,40,3179-3182) of zinc reduction sulfonyl chloride; But this type of method produces A large number of heavy metal ions not only increase the workload of post-processing, but also cause pollution to the environment. Among them, the reduction of benzenesulfonic acid also needs to use cerium chloride as a catalyst, which increases the production cost
It has been reported that sodium borohydride can be used to reduce sulfonyl chloride to obtain thiophenol (Chem.Pharm.Bull.1987,35,1770-1776), or to reduce sulfonic acid to obtain thiophenol (Tetrahedron Lett.1982,23,4701 -4704), but the price of reducing agent used in this type of method is higher, and the reaction needs to be carried out in an organic solvent, which increases the separation cost; someone uses iodine reduction sulfonic acid to prepare thiophenol (Tetrahedron Lett.1980,21,4921-4924) , but the price of reducing agent is higher; there are also reports using phosphorus chloride as reducing agent to reduce sulfonic acid (Pol.J.Chem.1982,56,799-803), but phosphorus chloride will pollute the environment

Method used

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  • Preparation method of thiophenol
  • Preparation method of thiophenol

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Experimental program
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Effect test

Embodiment 1

[0013] Embodiment 1: the preparation of 4-methylthiophenol

[0014] Mix 8.5g of 4-methylbenzenesulfonamide (about 0.05mol) with 12.0g of ammonium formate (about 0.19mol), heat to 180°C for 5 hours, and distill off the water generated during the reaction. After the reaction, the temperature of the reaction liquid was lowered to 80° C., and the pH of the reaction liquid was adjusted to 2 by adding dilute hydrochloric acid with a mass concentration of 10%. Then rectification was performed to obtain 4.5 g of 4-methylthiophenol.

[0015] The conversion rate of 4-methylbenzenesulfonamide was 73.2%, and the yield of 4-methylthiophenol was 71.8%.

Embodiment 2

[0016] Embodiment 2: the preparation of 4-hydroxybenzenethiol

[0017] Mix 8.7g of 4-hydroxybenzenesulfonamide (about 0.05mol) with 15.0g of ammonium formate (about 0.24mol), heat to 200°C for 4 hours, and distill the water generated during the reaction. After the reaction, the temperature of the reaction solution was lowered to 80° C., and 10% dilute sulfuric acid was added to adjust the pH to 2, followed by rectification to obtain 4.7 g of 4-hydroxythiophenol.

[0018] The conversion rate of 4-hydroxybenzenesulfonamide was 75.5%, and the yield of 4-hydroxybenzenethiophenol was 74.1%.

Embodiment 3

[0019] Embodiment 3: Preparation of 4-fluorothiophenol

[0020] Mix 8.7g of 4-fluorobenzenesulfonamide (about 0.05mol) with 15.0g of potassium formate (about 0.18mol), heat to 210°C for 6 hours, and distill off the water generated during the reaction. After the reaction, the temperature of the reaction liquid was lowered to 80° C., and 10% dilute sulfuric acid was added to adjust the pH to 2, followed by rectification to obtain 5.3 g of 4-fluorothiophenol.

[0021] The conversion rate of 4-fluorobenzenesulfonamide was 84.3%, and the yield of 4-fluorobenzenethiol was 82.4%.

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Abstract

The invention discloses a preparation method of thiophenol. The preparation method comprises the following steps of: reacting a chemical compound presented in formula II with ammonium formate / methanoic acid at 160-230 DEG C for 3-10 hours, and removing steam generated during the reaction, wherein the mole ratio of the chemical compound presented in the formula II to the ammonium formate / the methanoic acid is 1:3-6, and in the formula II, R1, R2, R3, R4 and R5 are hydrogen, halogen, hydrocarbyl, alkoxy, hydroxyl, amidogen, amidogen, nitryl, carboxyl, aldehyde group, carbonyl, acylamino, ester group or nitrile group; after reaction, cooling the reaction liquid to 75-85 DEG C, then adding dilute acid to adjust pH to 1.8-2.2; and then rectifying the acid-treated reaction liquid to obtain the thiophenol presented in formula I.

Description

technical field [0001] The invention relates to a preparation method of thiophenol. Background technique [0002] Thiol is a chemical synthesis intermediate, which is an important raw material for the synthesis of some medicines, pesticides, and dyes. Thiophenol can be prepared by reducing sulfonic acid or sulfonic acid chloride. There is bibliography to prepare thiophenol (JP03170456,1991) with zinc reduction benzene sulfonic acid, also has bibliography to prepare thiophenol with the method (Tetrahedron Lett.1999,40,3179-3182) of zinc reduction sulfonyl chloride; But this type of method produces A large amount of heavy metal ions will not only increase the workload of post-processing, but also cause pollution to the environment. Among them, the reduction of benzenesulfonic acid also needs to use cerium chloride as a catalyst, which increases the production cost. It has been reported that sodium borohydride can be used to reduce sulfonyl chloride to obtain thiophenol (Chem...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): C07C319/02C07C321/26C07C323/09C07C323/20C07C323/34C07C323/62C07C323/32C07C323/22
Inventor 陈新志周少东钱超
Owner ZHEJIANG UNIV
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