Method for synthesizing o-amino p-tert-butylphenol by nitration of p-tert-butylphenol

Abstract

The invention discloses a method for synthesizing o-amino-p-tert-butylphenol by nitration of p-tert-butylphenol, which comprises the following steps.Catalytic hydrogenation reaction is carried out ina high-pressure reaction kettle by taking o-nitro-p-tert-butylphenol as a raw material, methanol as a solvent and Raney nickel as a catalyst, wherein the ratio m / v of the o-nitro-p-tert-butylphenolmass to the methanol volume is 1: (10-12), the mass ratio of the catalyst to the o-nitro-p-tert-butylphenol is 1: (20-30), the reaction pressure is 0.4-0.6Mpa, the reaction temperature is 30-40 DEG C, and the reaction time is 6-8h.The system is cooled to be20-30DEG C, and filtered, concentrated, crystallized, centrifuged, and dried to obtain the o-amino-p-tert-butylphenolin white powder under the protection of inert gas. According to the method, the o-amino-p-tert-butylphenol with higher purity and yield can be obtained through the reaction under the conditions of lower temperature and lower pressure. The method has the advantages that oxidation is not easy to occur in the production process, the chromaticity of the product is ensured, the amount of waste water is small, the solvent methanolcan be recycled, the pollution is small, the controllability is achieved, and the like.

Description

technical field [0001] The invention belongs to the technical field of organic synthesis, and relates to a synthesis method of o-amino-p-tert-butylphenol, in particular to a method for synthesizing o-amino-p-tert-butylphenol by hydrogenation of o-nitro-p-tert-butylphenol. Background technique [0002] o-amino-p-tert-butylphenol, which has the molecular formula C 10 h 15 The structural formula of NO is as follows: [0003] [0004] Pure o-amino-p-tert-butylphenol is a white powder, and the color will gradually darken and turn gray when exposed to the air for a long time. Its melting point is 164~166°C. It is an important organic chemical intermediate and chemical raw material. The key intermediate for the synthesis of fluorescent whitening agent 2,5-bis[5-tert-butyl-2-phenylbutazolyl]thiophene (OB). [0005] The quality of o-amino-p-tert-butylphenol is directly related to the quality of OB. The quality of optical brightener OB in my country is not stable, and the main r...

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Problems solved by technology

[0007] (1) Sulfide reduction method: use p-tert-butylphenol as raw material, nitrate with mixed acid and then reduce it with alkali sulfide to obtain o-amino-p-tert-butylphenol; due to the use of mixed acid and sulfide, a large amount of p-tert-butylphenol will be produced The waste water is seriously polluted, which is not conducive to the realization of industrialized production;

[0008] (2) Electrolytic reduction method: p-tert-butylphenol is electrolytically reduced in an electrolytic cell, and the intermediate product p-tert-butylhydroxyaniline is rearranged to obtain o-amino-p-tert-butylphenol; this method consumes a lot of power and the production cost is too high , not conducive to industrial production;

[0009] (3) Iron powder reduction method: o-nitro-p-tert-butylphenol is reduced by iron powder in an acidic aqueous solution, and after filtering to remove iron sludge, sodium pyronitrite is added to the mother liquor, followed by cooling, recrystallization, drying, etc. Obtain product o-amino-p-tert-butylphenol afterward; Although this method process is simple, because produce a lot of wastes that are difficult to handle, pollution is serious, be unfavorable for suitability for industrialized production;

[0010] (4) Hydrazine hydrate reduction method: Use hydrazine hydrate with strong reducibility to reduce the nitro group in o-nitro-p-tert-butylphenol to amino group, and then obtain o-amino-p-tert-butylphenol after cooling, recrystallization, drying, etc. phenol; although this method has the advantages of easy reaction, high yield, and less pollution, but because hydrazine hydrate is a high-risk compound, and its price is too high, the scale-up production cost is high and has a very high risk. Not conducive to industrial production;

However, because the ammonia in the raw material has a strong pungent smell and is difficult to control, it is very harmful to people and the environment. Even if companies with such technologies barely operate, they will be shut down by the Environmental Protection Bureau. This law not only pollutes the ecological environment It also causes a great waste of production materials and equipment, and the laboratory test is acceptable, but the applicability and promotion value of industrial production are relatively poor

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