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

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...

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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

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