化工进展 ›› 2022, Vol. 41 ›› Issue (9): 5022-5028.DOI: 10.16085/j.issn.1000-6613.2021-2284

• 精细化工 • 上一篇    下一篇

微管反应器中硝基氯苯的连续合成

张晓啸(), 尚振华, 张向京()   

  1. 河北科技大学化学与制药工程学院,河北 石家庄 050018
  • 收稿日期:2021-11-08 修回日期:2021-12-26 出版日期:2022-09-25 发布日期:2022-09-27
  • 通讯作者: 张向京
  • 作者简介:张晓啸(1994—),男,硕士研究生,研究方向为制药工程。E-mail:zxx5496@163.com
  • 基金资助:
    河北省重点研发计划(20311201D)

Continuous flow synthesis of nitrochlorobenzene in microtubular reactor

ZHANG Xiaoxiao(), SHANG Zhenhua, ZHANG Xiangjing()   

  1. School of Chemical and Pharmaceutical Engineering, Hebei University of Science and Technology, Shijiazhuang 050018, Hebei, China
  • Received:2021-11-08 Revised:2021-12-26 Online:2022-09-25 Published:2022-09-27
  • Contact: ZHANG Xiangjing

摘要:

芳香族化合物的硝化是快速、强放热反应,采用连续硝化工艺可降低间歇操作可能引起的潜在风险。本文采用可视化方法和计算流体力学(CFD)模拟研究微管内流动状况的基础上,在体积为10mL的微管反应器中进行了氯苯连续硝化反应,探究了停留时间、温度、混酸比(硝酸与硫酸的摩尔比)、相比(硝酸与氯苯的摩尔比)对反应转化率、收率、产物邻对比和选择性的影响。结果表明,氯苯和混酸两相在内径为1mm的微通道内呈现出的Taylor流流型可以强化传质传热的效率,提高宏观反应速率。在停留时间为8min、温度80℃、混酸比=1∶1.5、相比=1∶1时,产物中邻对比在0.7~0.8之间,氯苯单程转化率为81.24%,一硝基氯苯的选择性为93.77%。采用连续硝化后,反应停留时间大幅降低,一硝基氯苯的邻对比明显提高。相比于传统釜式工艺,微管反应器内连续硝化更加安全、高效。

关键词: 氯苯硝化, 微管反应器, 连续流动, 硝基氯苯

Abstract:

The nitration of aromatic compounds is a rapid and strong exothermic reaction, and continuous process can reduce the potential risk caused by batch operations. The continuous nitration of chlorobenzene was carried out in a 10mL microtubular reactor on basis of the flow condition study by the visualization method and computational fluid dynamics (CFD) simulation. Some effects on the reaction conversion, yield, o-/p-nitrochlorobenzene ratio and selectivity were investigated, such as the residence time, temperature, mixed acid ratio (the molar ratio of nitric acid to sulfuric acid) and phase ratio (the molar ratio of nitric acid to chlorobenzene). The results showed that the chlorobenzene and mixed acid phases in a microchannel with an inner diameter of 1mm exhibited the Taylor flow pattern, which can enhance the efficiency of mass and heat transfer, leading to increase the macro reaction rate. When the residence time was 8min, the temperature was 80℃, the mixed acid ratio was 1∶1.5 and the molar ratio of nitric acid to chlorobenzene was 1∶1, the ratio of o-/p-nitrochlorobenzene was between 0.7—0.8, the single-pass conversion of chlorobenzene was 81.24% and the selectivity of mononitrochlorobenzene was 93.77%. The continuous nitrification can greatly shorten the residence time and significantly improve the o-/p-nitrochlorobenzene ratio. Compared with conventional kettle process, the continuous nitration of chlorobenzene in microtubular reactor was safer and more efficient.

Key words: chlorobenzene nitration, microtubular reactor, continuous flow, nitrochlorobenzene

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