Preparation method of ortho-aminophenol

Abstract

The invention provides a preparation method of ortho-aminophenol, which specifically comprises the following steps: (1) taking water, nitrobenzene and sulfuric acid as raw materials, adding a catalyst, and preparing an initial reaction solution under the condition of introducing hydrogen; (2) carrying out solid-liquid separation on the initial reaction solution, taking a solid substance as the catalyst, and reusing the solid substance in S1, wherein a liquid substance is a mixture solution; and (3) adjusting the pH of the mixture solution by a basic substance to neutrality. According to the preparation method of ortho-aminophenol, nitrobenzene is used for replacing ortho-nitrochlorobenzene, high-pressure hydrolysis and high-temperature and high-pressure reduction are not needed, reaction conditions are mild, the operation process is simple, safety is high, production efficiency is high, productivity is high, the product cost is reduced, and the overall benefit is increased.

Description

technical field [0001] The present invention relates to the field of organic synthesis, in particular to a preparation method of o-aminophenol. Background technique [0002] Ortho-aminophenol (OPA) is an important chemical intermediate widely used in dyestuffs, medicine, printing and other fields. |The traditional process of preparing o-aminophenol is to nitrate phenol at low temperature to obtain a mixture of p-nitrophenol and o-nitrophenol, which is separated and then hydrogenated and reduced (high temperature and high pressure) to obtain o-aminophenol. Its disadvantages are that the safety of the nitration process cannot be guaranteed. In addition to a certain amount of p-nitrophenol produced during the nitration process, there is also a part of tar. The yield is low, the product purity is unstable, it is difficult to deal with environmental protection, and the cost is high. [0003] At present, the domestic market uses o-nitrochlorobenzene and liquid caustic soda to hyd...

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Problems solved by technology

The defect is that the hydrolysis and reduction steps must be high temperature and high pressure, resulting in a large amount of waste brine. Although the product purity can be achieved, the cost of environmental protection treatment is high, because the raw material of ortho-nitrochlorobenzene contains chlorine, and the product has a certain influence when used in pharmaceuticals. The overall synthesis cost is relatively high

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