Method for preparing 3-nitro-4-chlorobenzotrifluoride through continuous adiabatic nitration and micro-reaction equipment

Abstract

The invention discloses a method for preparing 3-nitro-4-chlorobenzotrifluoride through continuous adiabatic nitrification and micro-reaction equipment. The method comprises the following steps: (1) under a stirring state, adding concentrated sulfuric acid into concentrated nitric acid, and cooling the reaction liquid to obtain a mixed acid material; (2) respectively preheating the mixed acid material and p-chlorobenzotrifluoride to a reaction temperature, simultaneously and continuously conveying into a micro-reaction system, continuously flowing through a micro-sieve pore reactor, a static mixer and a reaction delay tube, and carrying out a continuous nitration reaction; and (3) carrying out phase separation, extraction and washing to obtain the product 3-nitro-4-chlorobenzotrifluoride. The micro-reaction equipment comprises a micro-sieve pore reactor, and one end of an outlet of the micro-sieve pore reactor is sequentially communicated with a static mixer and a reaction delay tube; and the static mixer is filled with small stainless steel balls. The reaction rate is not reduced at the later stage of the reaction, so that the reaction conversion rate is effectively improved. And the production process is safe, controllable, short in time and high in product content.

Description

technical field [0001] The invention relates to the technical field of organic synthesis, in particular to a preparation method of 3-nitro-4-chlorobenzotrifluoride. Background technique [0002] 3-nitro-4-chlorobenzotrifluoride is mainly used in organic synthesis in industry, it is an intermediate for the synthesis of 3,5-dinitro-4-chlorobenzotrifluoride, and industrially prepares 3-nitro-4- Chlorotrifluorotoluene adopts a batch still production process, as shown in chemical reaction formula 1. The traditional batch kettle production process takes a long time, the temperature is not easy to control, the yield is low, the by-products are more, and the safety risk is high, which is not in line with the development of society. Therefore, the intrinsically safe continuous adiabatic nitrification process came into being under this background. [0003] [0004] The nitrification reaction is an exothermic reaction. The higher the temperature, the faster the nitrification react...

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Problems solved by technology

At the same time, for some heterogeneous reactions, after the droplets are dispersed through the microreactor, they may gradually coalesce along the reaction delay tube, and the droplets of the organic phase and the acid phase gradually become larger, eventually leading to the separation of the two phases, thereby reducing the nitrification reaction rate. Significant decline or termination, the result is to cause the reaction conversion rate to significantly reduce, using the microreactor of prior art, the conversion rate of p-chlorobenzotrifluoride<90%

[0005] Therefore, the significant decrease in the nitrification reaction rate currently existing in the microreactor is a major technical problem restricting the industrial production of the microreactor system.

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