Method for preparing high-purity adipic acid dimethyl ester by catalytic gas stripping coupling technology

A technology of dimethyl adipate and adipic acid, which is applied in the field of preparation of dimethyl adipate, can solve the problems of increased production cost, limited acid conversion rate, complex process, etc., to avoid corrosion and post-processing Complex, high-purity effects

Active Publication Date: 2013-06-05
WANHUA CHEM GRP CO LTD +1
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

The tower still liquid still contains a certain amount of unreacted acid, which needs to pass through a fixed-bed reactor equipped with an esterification catalyst together with excess alcohol, and further react to remove the unreacted acid, and finally obtain practically unreacted acid. For acid-containing ester products, the conversion rate of the acid in this method is still limited, and in order to solve the unreacted acid and excess alcohol, new equipment needs to be added, which makes the process more complicated and increases the production cost
[0007] Generally speaking, it is difficult to directly obtain esters with sufficient purity by adopting kettle-type or fixed-bed esterification processes. It is feasible to refine them through subsequent rectification and other processes, but the cost is very high

Method used

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  • Method for preparing high-purity adipic acid dimethyl ester by catalytic gas stripping coupling technology
  • Method for preparing high-purity adipic acid dimethyl ester by catalytic gas stripping coupling technology
  • Method for preparing high-purity adipic acid dimethyl ester by catalytic gas stripping coupling technology

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0042] The stripping tower with a tower diameter of 100mm adopts a plate tower with deflectors, operated at normal pressure, with 15 stages of trays (the condenser and the tower kettle are regarded as the first and 15th stage trays respectively), and the plate spacing is 60mm , The thickness of the liquid layer on the plate is 50mm, and the liquid holding capacity of each stage of the plate is about 200-245ml. There are strong acid ion exchange resin catalysts scattered on the 3-13 stage trays, and the D008 type dimethyl adipate special catalyst is used. The dry weight of the catalyst on each stage tray is about 15% of the liquid mass on each stage tray . The feeding rate of the liquid phase of adipic acid composed of adipic acid and dimethyl adipate is 500mol / h, the molar content of adipic acid is 20%, the feeding temperature is 110°C, and it is fed from the third stage tray. The molar ratio of methanol to adipic acid is 15 times, and it is fed from below the 12-stage tray, ...

Embodiment 2

[0049] N with a flow rate of 500mol / h 2 Air stripping is carried out, the reflux ratio at the top of the tower is 0.11, adipic acid is fed into 4 plates, methanol is fed into 12 plates, and catalysts are installed on 4-13 plates. Other experimental conditions are the same as in Example 1. The results are shown in Table 2.

[0050] Table 2 Results of Example 2

[0051]

[0052] The reaction section is reduced, and N is stripped 2 The flow rate decreases, the conversion rate of adipic acid can still reach 99.99%, and the purity of dimethyl adipate obtained in the tower still can reach 99.98%.

Embodiment 3

[0054] The top of the tower is refluxed with pure methanol at 20°C, 220mol / h. Other experimental conditions are identical with example 2. The results are shown in Table 3.

[0055] Table 3 Results of Example 3

[0056]

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Abstract

The invention discloses a method for preparing high-purity adipic acid dimethyl ester by catalytic gas stripping coupling technology. The method comprises the following steps: carrying out countercurrent contact on adipic-acid-containing liquid phase, methanol gas and inert gas in a gas stripping tower and carrying out reaction to generate water which is gas-stripped to the gas phase and recovered from the top of the gas stripping tower; obtaining high-purity adipic acid dimethyl ester from the tower bottom. The method of the invention features simple process, high purity of produced adipic acid dimethyl ester, no need of further refining and direct application as raw material for preparing 1,6-hexanediol.

Description

technical field [0001] The invention relates to a method for preparing dimethyl adipate, in particular to a method for preparing high-purity dimethyl adipate through a reaction-air stripping coupling process in a reactor. Background technique [0002] The esterification reaction is a typical reversible reaction, which generally needs to be esterified by the corresponding acid or acid anhydride and alcohol under the catalysis of an acidic catalyst, such as sulfuric acid. Due to the limitation of chemical balance, it is generally impossible to obtain a high single-pass yield at one time, and subsequent refining is required to achieve the required purity, and unreacted raw materials need to be recycled. The esterification reactor generally adopts a tank reactor or a tubular reactor, and operates intermittently or continuously. [0003] CN200410020789.3 discloses a method for preparing dimethyl adipate, the method uses an esterification catalyst supported on activated carbon, t...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): C07C69/44C07C67/08
Inventor 何岩王玉启任娇娇赵文娟黎源员玫李浩王静隋东武
Owner WANHUA CHEM GRP CO LTD
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