Energy-saving method for preparing amine compound by continuous hydrogenation of nitrile compound

An amine compound and compound technology, which is applied in the field of energy-saving nitrile compound continuous hydrogenation to prepare amine compound, can solve the problems of reduced catalyst life, reduced production cost, reduced selectivity and catalyst life, etc.

Pending Publication Date: 2021-03-23
WANHUA CHEM GRP CO LTD
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  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

In addition, the verification experiment also found that replacing 5% of the solvent with the outlet material of the reactor will cause the selectivity of the target amine to drop to about 95%. If the ratio of outlet material replacement is continued to increase to 10%, the conversion rate will drop to 94.5% while the selectivity decreases. % or so, at the same time the catalyst life is significantly reduced
Therefore, although part of the reaction solution is recycled back to the reactor inlet, although the proportion of solvent added is reduced, the selectivity and catalyst life are also significantly reduced, and the by-product of aminonitrile is increased, which significantly increases the energy consumption of downstream separation. Overall, the production cost is not high. no significant reduction

Method used

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  • Energy-saving method for preparing amine compound by continuous hydrogenation of nitrile compound
  • Energy-saving method for preparing amine compound by continuous hydrogenation of nitrile compound
  • Energy-saving method for preparing amine compound by continuous hydrogenation of nitrile compound

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0079] Prepare m-xylylenediamine (MXDA) by continuous hydrogenation of isophthalonitrile (MXPN), and its flow process of the preparation method adopted is as follows image 3 As shown, the marks 1-15 marked in the figure are the numbers of material streams.

[0080] The size of a single trickle bed reactor is D=0.1m, TL=2m. Catalyst (cat-1) is randomly packed in the upper section of the reactor, and the upper and lower ends are piled up with ceramic balls at a height of 0.3m to prevent the loss of the catalyst, and then the catalyst and the ceramic balls are fixed in the straight section with wire mesh. Two multi-point multi-branch thermocouple temperature probes are evenly inserted into the reactor bed to measure the temperature change of the hot spot of the bed in real time. An annular tube gas collector is installed horizontally in the lower section of the reactor, and the diameter of the annular tube is calculated as Φ15mm according to the pressure drop of 100 meters not ...

Embodiment 2

[0125] The preparation method refers to Example 1, the only difference is that the catalyst cat-1 is replaced by cat-3, the raw material is still MXPN, the solvent is liquid ammonia, the feed ratio, feed space velocity, cyanamide ratio, reaction temperature and pressure Consistent with Example 1, the reactor has a volume of 100ml, a length of 1m, an inner diameter of 20mm, and a catalyst loading capacity of 50ml. The feed rate of raw materials is 375ml / h, and the results of running for 840h are shown in Table 8. It can be found that when magnesium oxide is not added to the catalyst, the catalyst activity is relatively stable for the first 504 hours, but as the reaction time continues, the surface of the catalyst is gradually attached by heavy components, and the catalyst activity gradually decreases, resulting in an increase in aminonitriles, and the overhydrogenation product 1.3 cyclohexyl The gradual increase of the dimethylamine content shows that the specificity of the cat...

Embodiment 3

[0130] The preparation method refers to Example 1, the only difference is that the catalyst cat-1 is replaced by cat-5. The reaction conditions such as feed composition and ratio, space velocity, cyanamide ratio, reaction temperature and pressure are consistent with those in Example 1. The reactor has a volume of 100ml, a length of 1m, an inner diameter of 20mm, and a catalyst loading of 50ml. The raw material feed rate is 375ml / h, and the results of running for 72 hours are shown in Table 9. It can be found that compared with Example 1, the conversion rate of MXPN has no significant change, but the product selectivity decreases significantly, and the by-product benzylamine light components (comprising 1.3-cyclohexanedimethylamine, methylbenzylamine, benzylamine, etc.) ) significantly increased, and by-product amide heavy components such as dicondensate and tricondensate increased significantly.

[0131] Table 9

[0132]

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Abstract

The invention relates to an energy-saving method for preparing an amine compound by continuous hydrogenation of a nitrile compound. The method comprises the following steps: 1) mixing a nitrile compound with an ammonia-containing organic solvent, feeding the mixture into a reactor filled with a catalyst, introducing hydrogen at the same time, and carrying out a hydrogenation reaction in a catalystfilling layer; 2) separating the material after the hydrogenation reaction in the step 1) into a gas phase and a liquid phase, and then separately leading the gas phase and the liquid phase out of the reactor; (3) separating the gas phase led out of the reactor in the step (2) to recover the ammonia-containing organic solvent, then replacing part of a fresh ammonia-containing organic solvent in the step (1) with the recovered ammonia-containing organic solvent, mixing the ammonia-containing organic solvent with the nitrile compound, and then circulating the mixture back to the reactor; and 4)removing the solvent from the liquid phase led out of the reactor in the step 2) to obtain the amine compound. According to the method, the solvent separation load is reduced by 40% or more on the basis of maintaining high conversion rate of raw materials and high selectivity of products, and the production energy consumption and equipment investment are greatly reduced.

Description

technical field [0001] The present invention relates to a method for preparing amine compounds by continuous hydrogenation of energy-saving nitrile compounds, in particular to the preparation of nitriles (especially isophorone nitrile or phthalonitrile) by high-pressure continuous hydrogenation in the presence of liquid ammonia Amines (isophoronediamine or xylylenediamine) method. Background technique [0002] In industry, the hydrogenation of nitriles to produce amines mainly includes continuous fixed-bed and continuous (or batch) tank-type production processes, comprehensive catalyst life, reaction conversion rate and selectivity, equipment investment and operational complexity and other factors. Major manufacturers are currently Both adopt high-pressure fixed-bed production process. However, there are still many problems to be solved in the fixed bed production process due to harsh reaction conditions, large proportion of solvent, expensive catalyst and short life. [0...

Claims

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Application Information

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IPC IPC(8): C07C211/27C07C209/48C07C209/86C07C211/36B01J23/847B01J23/887B01J23/755B01J23/83B01J35/10
CPCC07C209/48C07C209/86B01J23/8472B01J23/002B01J23/8871B01J23/755B01J23/83C07C2601/14B01J35/40B01J35/615B01J35/647C07C211/27C07C211/36Y02P20/584
Inventor 朱洪亮蒋玉鑫王静胡展乔小飞
Owner WANHUA CHEM GRP CO LTD
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