Method for synthesizing cyclohexylamine with aniline by means of gas-phase catalytic hydrogenation

A technology for catalytic hydrogenation and cyclohexylamine, applied in chemical instruments and methods, preparation of organic compounds, preparation of amino compounds, etc. The effect of reducing reactions and ensuring production safety

Active Publication Date: 2013-08-21
SHANDONG WEIJIAO GRP
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0004] The production technique of prior art also needs to be further optimized, and this is because: one, when reaction temperature is high, reaction rate becomes faster, and product output improves, but side reaction increases, product yield is lower, and when reaction temperature is low, reaction The rate slows down, the product output decreases, but the side reactions decrease and the product yield increases, see Table 1 for details; 2. The hydrogen consumption is too high; 3. There is still a large room for improvement in the product yield

Method used

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  • Method for synthesizing cyclohexylamine with aniline by means of gas-phase catalytic hydrogenation
  • Method for synthesizing cyclohexylamine with aniline by means of gas-phase catalytic hydrogenation
  • Method for synthesizing cyclohexylamine with aniline by means of gas-phase catalytic hydrogenation

Examples

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Effect test

Embodiment 1

[0027] Mix fresh hydrogen with circulating hydrogen containing 1wt% ammonia, then mix the mixed hydrogen with aniline at a molar ratio of 19:1, and then add it to the aniline evaporator to vaporize the aniline, and the vaporized mixed gas In the fixed-bed hydrogenation reactor pre-installed with the catalyst, the catalytic hydrogenation reaction is carried out under the conditions of 165℃ and 0.24MPa pressure. The materials after the hydrogenation reaction are heat exchanged, condensed and cooled into the separator for gas After separation, crude cyclohexylamine is obtained, which is then rectified to obtain cyclohexylamine product.

[0028] The gas separated in the separator is hydrogen containing ammonia, part of the mixed gas is used as circulating hydrogen, and the other part is continuously vented as tail gas; the step of continuous tail gas venting is to perform online detection of the ammonia concentration of circulating hydrogen Then, according to the detection result, th...

Embodiment 2

[0032] Mix fresh hydrogen with circulating hydrogen containing 2wt% ammonia, then mix the mixed hydrogen with aniline at a molar ratio of 18:1, then add it to the aniline evaporator to vaporize the aniline, and the vaporized mixed gas In a fixed-bed hydrogenation reactor with a pre-installed catalyst, the catalytic hydrogenation reaction is carried out at 170°C and 0.26MPa pressure. After the hydrogenation reaction, the materials after the hydrogenation reaction are subjected to heat exchange, condensation and cooling, and then enter the separator for gas After separation, crude cyclohexylamine is obtained, which is then rectified to obtain cyclohexylamine product.

[0033] The gas separated in the separator is hydrogen containing ammonia, part of the mixed gas is used as circulating hydrogen, and the other part is continuously vented as tail gas; the step of continuous tail gas venting is to perform online detection of the ammonia concentration of circulating hydrogen Then, acco...

Embodiment 3

[0037] Mix fresh hydrogen with circulating hydrogen containing 6wt% ammonia, then mix the mixed hydrogen with aniline at a molar ratio of 16:1, and then add it to the aniline evaporator to vaporize the aniline, and the vaporized mixed gas In the fixed-bed hydrogenation reactor with pre-installed catalyst, the catalytic hydrogenation reaction is carried out under the conditions of 175℃ and 0.3MPa pressure. The materials after the hydrogenation reaction are heat exchanged, condensed and cooled into the separator for gas After separation, crude cyclohexylamine is obtained, which is then rectified to obtain cyclohexylamine product.

[0038] The gas separated in the separator is hydrogen containing ammonia, part of the mixed gas is used as circulating hydrogen, and the other part is continuously vented as tail gas; the step of continuous tail gas venting is to perform online detection of the ammonia concentration of circulating hydrogen Then, according to the detection results, the ex...

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Abstract

The invention discloses a method for synthesizing cyclohexylamine with aniline by means of gas-phase catalytic hydrogenation, which includes the steps: 1) mixing fresh hydrogen with circulating hydrogen; 2) mixing mixed hydrogen with the aniline according to the molar ratio of 15:1-19:1 in an aniline evaporator to enable vaporization of the aniline; 3) carrying out a hydrogenation reaction of vaporized mixed gas in a fixed bed hydrogenation reactor prefilled with cobalt-ruthenium catalyst or nickel-ruthenium catalyst at the reaction temperature of 165-179 DEG C and under the reaction pressureof 0.2-0.3MPa; and 4) materials which are subjected to the hydrogenation reaction enter a separator by means of heat exchange, condensation and cooling, performing gas separation to obtain crude cyclohexylamine, and then rectifying so that a cyclohexylamine product is prepared. By the aid of the method, production cost is effectively reduced, product yield is increased, and the service life of the catalyst is prolonged.

Description

Technical field [0001] The invention relates to the technical field of cyclohexylamine synthesis methods, in particular to a method for synthesizing cyclohexylamine by gas-phase catalytic hydrogenation of aniline. Background technique [0002] Cyclohexylamine is an important chemical raw material and fine chemical intermediate. There are four main synthesis methods: aniline catalytic hydrogenation, nitrocyclohexylamine reduction, cyclohexanol catalytic ammonolysis and cyclohexanone catalysis In the ammonolysis method, the catalytic hydrogenation of aniline is divided into gas phase and liquid phase. The gas phase hydrogenation method is further divided into normal pressure hydrogenation and high pressure hydrogenation. Because the gas-phase atmospheric catalytic hydrogenation method has the advantages of simple process, easy operation, high safety, easy availability of raw materials, stable quality, etc., it is currently the most commonly used method for the synthesis of cyclohex...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): C07C211/35C07C209/72
Inventor 刘良玉王读升亓乐祥于海生刘春胜王读福
Owner SHANDONG WEIJIAO GRP
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