Method for synthesizing piperidine by continuous liquid-phase hydrogenation of pyridine in a microreactor

Abstract

The invention discloses a method for synthesizing piperidine by continuous liquid phase hydrogenation of pyridine in a microreactor, and belongs to the technical field of chemical reaction engineering. This method uses pyridine as raw material and performs catalytic hydrogenation at 1 to 5 MPa and 50 to 150°C to obtain piperidine. This method utilizes microreactor hydrogenation technology to strengthen gas-liquid-solid three-phase mass transfer. The reaction temperature and pressure conditions are milder, the reaction time is greatly shortened, and the hydrogen consumption is lower. At the same time, the process can be continuous and automated, and the process can be It has lower consumption, higher safety, and both product selectivity and pyridine conversion rate reach over 99.5%.

Description

Technical field [0001] The invention relates to the technical field of chemical reaction engineering, and specifically relates to a method for synthesizing piperidine by continuous liquid phase hydrogenation of pyridine in a microreactor. Background technique [0002] Piperidines, the reduction products of pyridine compounds, are important pharmaceutical intermediates and important chemical raw materials, used in pesticides and rubber additives. At present, the preparation of reduction products of piperidine derivatives is mainly achieved by catalytic hydrogenation. The process is as follows: [0003] [0004] Chinese patent CN104725299A discloses a method for preparing 3-hydroxypiperidine by liquid-phase catalytic hydrogenation of 3-hydroxypyridine in a high-pressure reactor. In this method, hydrogen gas is continuously introduced for 14 hours under a high temperature of 140°C and a high pressure of 4.0Mpa to complete the reaction. The intermittent hydrogenation kettle ...

AI Technical Summary

Problems solved by technology

The method has high reaction temperature and pressure, low product selectivity; long reaction time, low production efficiency; low mass transfer efficiency, resulting in a large excess of hydrogen, and its recovery and treatment are more complicated, and bring greater safety hazards

[0006] Patent CN102091638B discloses a hydrogenation reaction method of pyridine or pyridine derivatives to produce piperidine or piperidine derivatives. The reaction temperature is 150°C, the pressure is 8MPa, the molar ratio of hydrogen to pyridine is 150, and there is still energy consumption High and Excess Hydrogen Recovery Disposal Issues

[0007] Patent CN105985300A discloses a method for low-pressure continuous production of piperidine products. A fixed-bed reactor is used to convert the gas-phase pyridine raw materials and hydrogen into piperidine products after being contacted with a hydrogenation catalyst. Pyridine is gasified and then enters the fixed bed for catalytic hydrogenation, resulting in high energy consumption and low production efficiency; the gas phase reaction requires pyridine to maintain a gaseous state under the reaction pressure, and the reaction process requires a higher temperature. Large-scale production needs to be used to achieve a certain production capacity. Larger volume reactor, the intrinsic safety of the reaction process is reduced

[0008] In addition, U.S. Patent US4680283A, US3055840 and US2867628 etc. all need to carry out under higher temperature and pressure, and productive rate is all low

Images