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Method for refining polyoxymethylene dimethyl ether

A technology of dimethyl ether and polyoxymethylene, applied in chemical instruments and methods, preparation of organic compounds, organic chemistry, etc.

Active Publication Date: 2019-08-06
CHINA PETROLEUM & CHEM CORP +1
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

[0008] The technical problem to be solved in the present invention is the problem that in the purification process of purifying polyoxymethylene dimethyl ether by rectification, the material clogs the top of the rectification tower and makes it difficult to operate continuously for a long time. A method for refining polyoxymethylene dimethyl ether is provided , this method overcomes the shortcoming of accumulation at the top of the rectification tower, and is conducive to the long-term continuous operation of the production

Method used

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  • Method for refining polyoxymethylene dimethyl ether
  • Method for refining polyoxymethylene dimethyl ether
  • Method for refining polyoxymethylene dimethyl ether

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0033]The neutral reaction mixture obtained by the reaction unit is firstly passed through the first rectification tower to remove the first fraction DMM by rectification at 0.1 MPa, a reflux ratio of 1, and a tower bottom temperature of 105°C. The two-phase extractant composed of water and cyclohexane in a ratio of 1:1, enters the extraction tower with the ratio of 2:1 with the liquid in the first tower, and the extracted phase enters the second rectification tower. The operating conditions are 0.08MPa, The reflux ratio is 8, the temperature of the tower bottom is 150°C, the second fraction containing cyclohexane solvent and n=2 polyoxymethylene dimethyl ether is obtained from the top of the tower, and the polyoxymethylene dimethyl ether containing n=3-8 is obtained from the tower bottom The second tower still liquid. The second fraction enters the solvent recovery tower, and is rectified under the conditions of normal pressure, reflux ratio of 2, and tower bottom temperature...

Embodiment 2

[0037] The neutral reaction mixture obtained by the reaction unit is firstly passed through the first rectification tower to remove the first fraction DMM by rectification under the conditions of 0.05MPa, reflux ratio of 3, and tower bottom temperature of 88°C. A two-phase extractant composed of NaOH-containing aqueous solution and n-hexane at a ratio of 0.2:1, enters the extraction tower at a ratio of 1:5 with the bottom liquid of the first tower, and the extracted phase enters the second rectification tower at an operating condition of 0.05 MPa, the reflux ratio is 4, the temperature of the tower bottom is 130 °C, the second fraction containing n-hexane solvent and n=2 polyoxymethylene dimethyl ether is obtained from the top of the tower, and the polyoxymethylene dimethyl ether containing n=3-8 is obtained from the tower bottom The second tower bottom liquid of ether. The second fraction enters the solvent recovery tower and is rectified under the conditions of 0.1MPa, reflu...

Embodiment 3

[0039] Using paraformaldehyde and methylal as raw materials, the reaction mixture obtained after acid catalysis is firstly passed through the first rectification tower to remove the first distillate DMM by rectification at 0.15MPa, reflux ratio of 0.5, and tower bottom temperature of 125°C The two-phase extractant that water and normal heptane form with the ratio of 3:1 enters the extraction and separation pump with the ratio of 4:1 with the first tower bottom liquid, obtains the extraction phase and enters the second rectifying tower, and the operating condition is 0.03MPa , the reflux ratio is 1, the temperature of the tower bottom is 116 ° C, the second fraction containing n-heptane solvent and n=2 polyoxymethylene dimethyl ether is obtained at the top of the tower, and the polyoxymethylene dimethyl ether containing n=3-8 is obtained from the tower bottom The second tower bottom liquid of ether. The second fraction enters the solvent recovery tower and is rectified under th...

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Abstract

The present invention provides a polyformaldehyde dimethyl ether refinement method. The technical scheme comprises that a reaction mixture is separated in a first rectification tower to remove a first distillate mainly containing methylal; the first tower kettle liquid is extracted with a double phase extractant containing an organic solvent and a water phase in an extraction unit to obtain an extraction phase containing polyformaldehyde dimethyl ether having n of 2-8 and an organic solvent, wherein the raffinate phase is a water phase containing formaldehyde; a second distillate containing an organic solvent and polyformaldehyde dimethyl ether having n of 2 and a second tower kettle liquid containing polyformaldehyde dimethyl ether having n of 3-8 are obtained in a second rectification tower from the extraction phase; a solvent recovery tower kettle liquid distillate containing high-purity polyformaldehyde dimethyl ether having n of 2 is obtained in a solvent recovery tower kettle from the second distillate; and the second tower kettle liquid is rectified in a third rectification tower to obtain a product distillate containing polyformaldehyde dimethyl ether having n of 3-4 and a third tower kettle material containing a polyformaldehyde dimethyl ether high polymer having n of more than or equal to 5.

Description

technical field [0001] The invention relates to a separation process of polyoxymethylene dimethyl ether, in particular to the preparation of polyoxymethylene dimethyl ether with high purity n=3-4 from the reaction mixture containing polyoxymethylene dimethyl ether obtained in the reaction of paraformaldehyde as a raw material ether method. Background technique [0002] With the sharp increase of energy consumption in modern society, the increasing shortage of petroleum resources, and the increasing pressure on the environment, it is urgent to develop new clean diesel fuels. The use of oxygen-containing compounds as diesel additives is a convenient and effective measure without adding additional devices or changing the engine structure, and has become a new idea for the development of the petroleum industry. [0003] Polyoxymethylene dimethyl ether (PODE) is an oxygen-containing compound with the general formula: CH 3 O(CH 2 O)nCH 3 , where n is an integer ≥ 1 (generally ...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): C07C43/30C07C41/58
CPCC07C41/58C07C43/30
Inventor 裴义霞顾军民赵精彩田立达
Owner CHINA PETROLEUM & CHEM CORP
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