Method for removing hexaldehyde and 2-heptanone in cyclohexanone

A technology of cyclohexanone and hexanal, applied in the field of organic chemical purification, can solve the problems of high energy consumption and material consumption

Inactive Publication Date: 2012-06-13
黄燕
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0003] The purpose of the present invention is to solve the problem of high energy consumption and high material consumption in the traditional chemical fiber grade cyclohexanone technology for producing caprolactam, and propose a method to remove hexanal and 2-heptanone impurities from solvent-type cyclohexanone with solid adsorbent , and control the sum of the two contents below 40mg / kg, and can desorb the adsorbate well, so that the adsorption and desorption can be continuously operated online

Method used

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  • Method for removing hexaldehyde and 2-heptanone in cyclohexanone
  • Method for removing hexaldehyde and 2-heptanone in cyclohexanone

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Effect test

Embodiment 1

[0025] Use 1226gHZSM-5 type molecular sieve to adsorb cyclohexanone whose hexanal content is 106mg / kg and 2-heptanone is 57mg / kg, and use the flow pump to control the flow rate to be 66ml / min. figure 1 In the shown adsorption column (height 1000mm, inner diameter 50mm, volume 1.96L), the bottom feed, the adsorbed cyclohexanone flows out from the top of the adsorption column, and another stainless steel bucket collects it. Every two hours, samples were taken from the top of the adsorption column and the contents of hexanal and 2-heptanone were analyzed by gas chromatography. It is found that the molecular sieve can ensure that the total content of hexanal and 2-heptanone is less than 40 mg / kg within 10 hours at one volume space velocity, fully meeting the requirements of chemical fiber grade cyclohexanone. Experiments also show that molecular sieves also have a certain adsorption effect on other impurities, such as cyclohexanol and pentanol.

[0026] 1226g strip molecular siev...

Embodiment 2

[0039] static adsorption dynamic desorption

[0040]At 30°C, use HZSM-5 type molecular sieve to adsorb the cyclohexanone solution with hexanal content of 116mg / kg and 2-heptanone of 87mg / kg, and control the molecular sieve mass and cyclohexanone volume ratio to 0.08g / ml When the adsorption time is 12h, the removal rate of hexanal reaches 100%, and the removal rate of 2-heptanone reaches more than 99%; To 10MPa, the temperature is 40°C, the supercritical gas flow rate is 16m3 / h, and the desorption time is 4 hours. Then carry out decompression separation and desorption with supercritical carbon dioxide gas. Due to the super-diffusion of supercritical gas, molecules can diffuse into the deep capillary pores of molecular sieves. -Heptanone dissolves, and in the separator, when the system pressure becomes normal pressure, carbon dioxide returns to the original storage tank from the top in the form of gas, while hexanal and 2-heptanone are in liquid form and can be discharged from...

Embodiment 3

[0042] On-line Desorption Test Using Activated Carbon Adsorption

[0043] At 20°C, use 1300g of granular activated carbon to adsorb cyclohexanone solution with hexanal content of 116mg / kg and 2-heptanone of 77mg / kg, and use a convection pump to control the flow rate to 68ml / min. figure 1 At the bottom of the adsorption column shown (height 1000mm, inner diameter 50mm, volume 1.96L), the adsorbed cyclohexanone flows out from the top of the adsorption column, and an empty stainless steel barrel collects it. Every two hours, samples were taken from the top of the adsorption column and analyzed for hexanal and 2-heptanone. Using gas chromatography analysis, it is found that activated carbon can ensure that the total content of hexanal and 2-heptanone in the outlet is less than 40mg / kg within 10h under one volume space velocity, and the concentration of hexanal and 2-heptanone in the outlet exceeds 40mg / kg. kg, the desorption can begin if the product quality requirements cannot ...

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Abstract

The invention relates to a method for removing hexaldehyde and 2-heptanone in cyclohexanone. As a traditional technology for producing chemical fibre level cyclohexanone of caprolactam has the problems of high energy consumption and high material consumption, the invention discloses a method; the method comprises the following steps of: using solid adsorben to remove hexanal and 2-heptanone impurities from solvent-based cyclohexanone; controlling the content of the two in the cyclohexanone to be lower than 40mg/kg, and using supercritical gas carbon dioxide to desorb the adsorbate, so that the absorption and the desorption can be continuously on-line. The method has the characteristics of low energy consumption and low material consumption.

Description

technical field [0001] The invention belongs to the technical field of organic chemistry purification, in particular to a method for removing hexanal and 2-heptanone in cyclohexanone. Background technique [0002] In the current domestic cyclohexanone market, the supply of solvent-type cyclohexanone exceeds the demand, while the supply of chemical fiber-grade cyclohexanone used to produce caprolactam is in short supply, which directly leads to fierce competition in the market for solvent-type cyclohexanone, making cyclohexanone manufacturers Must seize the chemical fiber grade cyclohexanone market. The difficulty in the production of chemical fiber grade cyclohexanone is to control the content of hexanal and 2-heptanone, and generally the sum of the two needs to be controlled below 40mg / kg. Because the boiling points of these two substances and cyclohexanone are very close, it is difficult to completely remove these two impurities by conventional rectification methods to m...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C07C49/403C07C45/79
CPCY02P20/54
Inventor 黄燕
Owner 黄燕
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