In this work, a tubular reactor with a micromixer was introduced in attempt to enhance the amination reaction of 4-nitrochlorobenzene in terms of the process efficiency and safety. It was found that the reaction system containing a large excess of ammonia water can become homogeneous at high temperature. Thus, as both micromixing and the heat transfer performance were guaranteed, the set-up combining a micromixer and a microtube reactor enabled the reaction to exhibit homogeneous reaction characteristics, meeting the demands of efficiency and reliability. Furthermore, using a multi-channel sampling system connected behind the micromixer, the reaction kinetics were studied in a modified “stop flow” mode, which is adaptable for in-situ fast homogenization, high temperature, and high pressure. The reaction conditions were screened and a kinetic model was developed. Accordingly, we propose and verify a self-circulation strategy to reduce the burden of ammonia separation and recovery in a continuous tubular reactor system.
DOI：https://doi.org/10.1016/j.cep.2021.108636
Highlights
• Reveal homogeneous reaction window under suitable conditions.
• Investigate reaction kinetics with multi-channeled sampling system.
• Develop kinetic model for homogeneous reaction design.
• Introduce self-circulation to achieve flow production with less NH3 recovery cost.
