Continuous synthesis of 4-bromo-3-methylanisole in modular microreaction system

XIE Pei1 WANG Kai1 DENG Jian1 LUO Guangsheng1

(1.The State Key Laboratory of Chemical Engineering, Tsinghua University, Beijing, China 100084)

【Abstract】With the development of microreaction technology and the key issues of liquid-liquid batch bromination process for the synthesis of 4-bromo-3-methylanisole, a modular microreaction system was constructed by taking microreactor and microbead-packed bed as the major functional microdevice units to intensify the bromination of 3-methylanisole. And in this modular microreaction system, the liquid-liquid heterogeneous continuous bromination of 4-bromo-3-methylanisole was studied. The following optimized conditions were obtained, concentration of Br217.5 wt%, molar ratio of Br2 to 3-methylanisole1.01, initial reaction temperature (T): 0 °C, residence time (τ): 0.78 min, with yield of 4-bromo-3-methylanisole more than 98%, and percentage of polybrominated side product less than 1%. Compared with the conventional batch process, the continuous microreaction technology has obvious advantages. For example, it can change the traditional batch process to a continuous one with a significant increase in productivity (space time yield: 6.5 × 104 kg/(m3·h)). Besides, since this process is mainly controlled by mass transfer, the modular microreaction system with excellent mass transfer could reduce 50% of polybrominated side product. The study might provide a good foundation for the continuously controllable synthesis of 4-bromo-3-methylanisole in safety.

【Keywords】 microreactor; static mixer; 3-methylanisole; bromination; continuous synthesis; process control;

【DOI】

【Funds】 National Key Research and Development Program of China (2017YFB0307102) Major Program of the National Natural Science Foundation of China (21991100, 21991104)

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(Translated by LIN LY)

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This Article

ISSN:0438-1157

CN: 11-1946/TQ

Vol 71, No. 09, Pages 4168-4176

September 2020

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Article Outline

Abstract

  • Introduction
  • 1 Experimental
  • 2 Results analysis and discussion
  • 3 Conclusion
  • References