Preparation method of sodium p-nitrophenolate

Abstract

The invention discloses a preparation method of sodium p-nitrophenolate. The preparation method comprises the following steps: a) heating and melting p-chloronitrobenzene in a melting kettle, and preparing a sodium hydroxide solution in a dissolving kettle; b) repeatedly introducing nitrogen into a system 3-6 times to replace air before a reaction, pumping the heated and molten p-chloronitrobenzene and the sodium hydroxide solution into a micro-reactor by using a feeding valve, uniformly mixing, and carrying out a high-temperature and high-pressure reaction; and c) transferring the solution after the reaction to a cooling crystallization kettle, and cooling to separate out a sodium p-nitrophenolate solid containing crystal water. According to the invention, a hydrolysis reaction is carriedout by adopting a micro-channel, so that the instant uniform mixing and the efficient heat transfer of the raw materials are realized while the equivalence ratio of the materials in the reaction process is reduced, the generation of side reactions and the difficulty in post-treatment are reduced, water can be recycled so as to reduce the energy consumption in production, improve the utilization rate of the raw materials and achieve the environment-friendly production process, the production cost is low, and the reaction time is greatly shortened; and the color of the prepared sodium p-nitrophenolate is faint yellow or orange yellow, and by-products are few.

Description

technical field [0001] The invention relates to the technical field of synthesis methods of fine chemical products, in particular to a preparation method of p-nitrophenol sodium salt. Background technique [0002] p-Nitrophenol is a very important intermediate, mainly used in the production of fine chemicals such as pesticides, medicines, and dyes. Used in the manufacture of phenacetin, paracetamol, developer, rubber anti-aging agent, sulfur dyes, azo dyes and fur dyes, etc. It can also be used in leather antifungal agents, indicators, and can also be used as raw materials to synthesize diaminodiphenyl ether Used in the manufacture of polyimide high-performance engineering plastics. In recent years, with the expansion of industrial production, the demand for p-nitrophenol is also increasing. [0003] Usually p-nitrophenol is produced by the traditional batch method, which is hydrolyzed by p-nitrochlorobenzene under high temperature and high pressure to form p-nitrophenol s...

AI Technical Summary

Problems solved by technology

It is often necessary to invest an excessive amount of alkali to ensure a high conversion rate and a faster reaction rate, which leads to an increase in by-products, making post-treatment more cumbersome and a large amount of pollutant discharge

Chinese patent CN200410041851.7 adopts a continuous hydrolysis process in several reactors in series, which improves the hydrolysis efficiency, but it is still an intermittent reaction in reactors in essence, and a large amount of sewage needs to be treated.

[0004] Chinese patent CN200910251614.6 increases the concentration of sodium hydroxide to increase the production capacity of the hydrolysis kettle, reduce energy consumption, and reduce the discharge of waste water, and has achieved certain results. However, this method is still a batch reaction, and the separation and purification of materials is more complicated. The conversion rate is relatively low, and a large amount of industrial alkaline wastewater will still be produced

However, at present, microchannels are often used for nitrification, oxidation and other reactions, and few are used for hydrolysis reactions.

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