Preparation method of sodium p-nitrophenolate

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 gener