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Caprolactam hydrofining method

A caprolactam, hydrofining technology, applied in the field of caprolactam hydrofining treatment, can solve the problem of high energy consumption

Active Publication Date: 2015-04-29
CHINA PETROLEUM & CHEM CORP +1
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0005] The inventors of the present invention have found through a large number of experiments that when the crystallized crystal slurry in the preparation process of caprolactam is not subjected to solid-liquid separation, but is directly washed in countercurrent with a solvent that can be used for crystallization, it does not need to be separated and directly undergoes hydrogenation refining. It can make up for the deficiencies in the existing technology of using caprolactam aqueous solution or molten caprolactam to carry out hydrofining, and under the same situation of improving the PM value of the product, solve the problem of solid-liquid separation and the hydrofining of caprolactam aqueous solution due to water entering the system and subsequent distillation. High energy consumption of water and problems with water triggering caprolactam polymerization in the system

Method used

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Examples

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Effect test

Embodiment 1

[0025] Put 150g of caprolactam crystals (see Table 1 for specifications) and 150g of isopropyl ether into a 500ml pressure reactor, then add 40-100 mesh 2%Pd-1%La 2 o 3 / Activated carbon strip catalyst 1.5g, close the reactor, replace it with hydrogen, raise the temperature of the reactor to 90°C at a heating rate of 2°C / min, the hydrogen flow rate is 200ml / min, and the pressure of the reaction system is controlled at 0.7MPa, at 90°C Keep the temperature constant for 60 minutes. After the reaction is completed, stop stirring and heating, and take off the insulation cover to quickly cool down. When the temperature is lowered to 55°C, the reactor is opened, the solvent is evaporated to dryness, and then it is made into a 50% aqueous solution of ethyl alcohol, which is then filtered and then analyzed and evaluated for product quality.

Embodiment 2-3

[0027] The hydrogenation conditions are the same as in Example 1, but the hydrogenation solvent is changed, and the hydrogenation solvents in Examples 2 and 3 are replaced by a mixed solvent of n-heptane, n-heptane and isopropyl ether (mass ratio is 3:1), and the hydrogenation product See Table 1 for quality.

Embodiment 4

[0029] Embodiment 4 conditions are the same as embodiment 1, difference is that used hydrogenation catalyst is 1%Pd-3.5%La 2 o 3 / Activated carbon strip catalyst. The quality of hydrogenation products is shown in Table 1.

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Abstract

The invention relates to a caprolactam hydrofining method. The caprolactam hydrofining method is characterized in that an organic solution of caprolactam is in contact with hydrogen in the presence of a hydrogenation catalyst under hydrofining reaction conditions. In the catalytic hydrogenation reaction conditions, the reaction temperature is 50 DEG C-150 DEG C, the pressure is 0.1-5MPa, and the molar ratio of caprolactam to hydrogen is 1:(0.001-0.25). By adopting the caprolactam hydrofining method provided by the invention, under the situation of upgrading the PM (particulate matter) value of a product to the same extent, the shortcomings of using a caprolactam water solution or molten-state caprolactam to perform hydrofining in the prior art can be overcome, the problems that water enters a system, high energy consumption is caused by subsequent water evaporation and polymerization of caprolactam is initiated by the water in the system are avoided, and after hydrofining, the purity of caprolactam is above 99.9950%, the PM value is more than 10000s and the extinction value is less than 0.05.

Description

technical field [0001] The invention relates to a method for refining caprolactam, more particularly to a method for hydrofining caprolactam. Background technique [0002] Caprolactam is an important monomer for nylon-6 synthetic fibers and nylon-6 engineering plastics. The current industrial production method of caprolactam is mainly the liquid-phase Beckmann rearrangement process of cyclohexanone oxime under the catalysis of oleum. This process has low reaction temperature and high selectivity, but there are also many shortcomings: one is to consume ammonia and oleum with high economic value, and produce a large amount of low-value and low-efficiency fertilizer ammonium sulfate by-product, and produce 1 ton of caprolactam to produce 1.6 tons Ammonium sulfate; Second, there is equipment corrosion and environmental pollution. Liquid-phase Beckmann rearrangement reaction produces crude caprolactam, which needs to be separated and purified through rearrangement neutralizatio...

Claims

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Application Information

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IPC IPC(8): C07D223/10C07D201/16C07D201/04
CPCC07D201/04C07D201/16C07D223/10
Inventor 谢丽张树忠程时标宗保宁
Owner CHINA PETROLEUM & CHEM CORP
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