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

Abstract

The invention discloses a method for synthesizing piperidine through continuous liquid-phase hydrogenation of pyridine in a microreactor, and belongs to the technical field of chemical reaction engineering. According to the method, pyridine is used as a raw material, and catalytic hydrogenation is carried out under 1-5 MPa and 50-150 DEG C to obtain piperidine. According to the method, a micro-reactor hydrogenation technology is utilized, gas-liquid-solid three-phase mass transfer is enhanced, the reaction temperature and pressure conditions are milder, the reaction time is greatly shortened, and the use amount of hydrogen is lower; meanwhile, continuity and automation of the process can be realized, the energy consumption of the process is lower, the safety is higher, and the product selectivity and the conversion rate of pyridine both reach 99.5% or above.

Description

technical field [0001] The invention relates to the technical field of chemical reaction engineering, in particular to a method for synthesizing piperidine through continuous liquid-phase hydrogenation of pyridine in a microreactor. Background technique [0002] The reduction products of pyridine compounds, piperidines, are not only important pharmaceutical intermediates, but also important chemical raw materials, used in pesticides and rubber additives. At present, the reduction products of piperidine derivatives are mainly prepared by catalytic hydrogenation, and the process is shown in the following formula: [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 is fed continuously for 14 hours at a high temperature of 140°C and a high pressure of 4.0Mpa to complete the reaction. The intermittent hydrogenation ta...

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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

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