Synthesis of m-Aminophenol


Release time:

2023-11-30

M-Aminophenol (MAP) is an important organic chemical raw materials and intermediates, widely used in medicine, dyes, antioxidants, stabilizers, oil additives, developers, color film production.

Synthesis of m-Aminophenol

m-Aminophenol (MAP) is an important organic chemical raw materials and intermediates, widely used in medicine, dyes, antioxidants, stabilizers, oil additives, developers, color film production.

The synthesis method of m-aminophenol was explored after Baeyei and Caro used tin powder and hydrochloric acid to reduce p-nitrosophenol to synthesize p-aminophenol in 1874. The main methods of industrialization are m-aminobenzenesulfonic acid method and nitrobenzene method. Because these two traditional processes have the disadvantages of long reaction time, high cost and heavy pollution, people are constantly exploring new synthetic methods while constantly improving and perfecting the traditional old process.

From the raw material route, the synthesis method of m-aminophenol is mainly divided into m-aminobenzenesulfonic acid method, nitrobenzene method, m-nitrophenol method and so on.

1. m-Aminobenzenesulfonic acid method

The m-aminobenzenesulfonic acid method is a traditional method for the production of MAP at home and abroad, and it is still used in many countries. The main process is as follows.

The m-aminobenzenesulfonic acid was stirred into a slurry with water, heated to 60 ° C., neutralized with NaOH solution, adjusted to pH = 7-8, filtered and used. Add appropriate amount of prepared NaOH solution into an alkali melting pot, heat to 270-275 ℃, slowly add the above filtrate into it, react at this temperature for 75min, dilute it with water, filter to remove sodium sulfite, wash it with hot water (about 100 ℃) and filter it while it is hot, acidify it with 31% hydrochloric acid to pH = 7-8, cool it, stand still, and filter it after MAP crystal is precipitated, and under the protection of inert gas vacuum refining, drying can be.

2. Nitrobenzene method

Nitrobenzene method is also one of the commonly used methods in the world.

3. m-Nitrophenol Method

Because the traditional process method has many processes, long cycle, high cost, serious pollution and other shortcomings, so chemical workers in various countries are constantly exploring the synthesis method of salary, electrochemical synthesis method was born. It is reported that MAP can be prepared by electrolytic reduction of m-nitrophenol in alcohol acid solution with a dropping mercury electrode. Due to the high toxicity of the electrode, the application of this method is limited. Mr. Gao Quanchang of Xi 'an, China, has developed a new method for synthesizing MAP by electrolytic reduction of m-nitrophenol in alkaline medium with copper as electrode. The current density is 100-200A/m, the temperature is 60 2 ℃, the catholyte is a solution of sodium carbonate with mass fraction of 0.1, 1g of m-nitrophenol is dissolved in 100ml of 10% Na2CO3 solution, and the area of copper cathode is 100 cm2, the yield can reach more than 90%.

Because the method has the advantages of high yield, low pollution and low cost, it has broad prospects for industrialization.