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Purification method of 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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  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

[0008] The technical problem to be solved by 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 for long-term continuous production and operation. A kind of purification of polyoxymethylene dimethyl ether is provided. method, which overcomes the shortcoming of accumulation at the top of the rectification tower, and is conducive to the production of long-term continuous operation

Method used

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  • Purification method of polyoxymethylene dimethyl ether
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  • Purification method of polyoxymethylene dimethyl ether

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0031]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 0.1MPa, reflux ratio of 1, and tower bottom temperature of 105°C The two-phase extractant that water and hexanaphthene are formed in the ratio of 1:1 enters the extraction tower with the ratio of 2:1 with the first tower still liquid, obtains the extraction phase and enters the second rectifying tower, at normal pressure, reflux The ratio is 2, and the temperature of the bottom of the tower is 115°C, and the second fraction mainly containing cyclohexane solvent is obtained at the top of the tower, which is returned to the two-phase extraction agent; containing polyoxymethylene dimethyl ether with n=2-8 The liquid in the second tower of the second tower enters the third rectifying tower and the fourth rectifying tower for rectification under vacuum successively...

Embodiment 2

[0035] 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 0.05MPa, reflux ratio of 3, and tower bottom temperature of 88°C. ; The aqueous solution containing NaOH and normal hexane form the two-phase extractant with the ratio of 0.2:1, enter the extraction tower with the ratio of 1:5 with the first tower bottom liquid, obtain the extraction phase and enter the second rectifying tower, at 0.1MPa , the reflux ratio is 5, and the temperature of the tower bottom is rectified under the condition of 110°C, and the second fraction mainly containing n-hexane solvent is obtained at the top of the tower, which is returned to the two-phase extractant; it contains polyoxymethylene dimethyl with n=2-8 The second tower bottom liquid of ether enters the third rectification tower and the fourth rectification tower vacuum rectificat...

Embodiment 3

[0037] 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 n-heptane are formed with the ratio of 3:1 enters the extraction separation pump with the ratio of 4:1 with the first tower still liquid, obtains the extraction phase and enters the second rectifying tower, at 0.05MPa, reflux The ratio is 8, and the temperature of the tower bottom is rectified under the condition of 90°C, and the second fraction mainly containing n-heptane solvent is obtained at the top of the tower, which is returned to the two-phase extractant; containing polyoxymethylene dimethyl ether with n=2-8 The liquid in the second tower of the second tower enters the third rectifying tower and the fourth rectifying tower for rectification unde...

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Abstract

The invention aims to solve the technical problem that long-term continuous production operation is difficult due to the fact that materials block the tops of rectifying towers in the PODE (polyoxymethylene dimethyl ether) purification process with a rectification method. The adopted technical scheme comprises steps as follows: (a) a reaction mixture obtained by a reaction synthesis unit firstly enters a first rectifying tower, a first fraction mainly containing methylal is removed through separation, and first tower bottoms are obtained; (b) the first tower bottoms enter an extraction unit and are subjected to extraction with a two-phase extraction agent containing an organic solvent and an aqueous phase, an extract phase containing PODEn (n=2-8) and an organic solvent is obtained, and a raffinate phase is an aqueous phase containing formaldehyde; (c) the extract phase sequentially enters a second rectifying tower, a third rectifying tower and a fourth rectifying tower for rectification, and a second fraction containing an organic solvent, a third fraction containing high-purity PODEn (n=2) and a fourth fraction containing PODEn (n=3-5) are obtained respectively.

Description

technical field [0001] The invention relates to a process for purifying polyoxymethylene dimethyl ether, in particular to preparing polyoxymethylene dimethyl ether with high purity n=3-5 from the reaction mixture containing polyoxymethylene dimethyl ether obtained in the reaction of paraformaldehyde as a raw material base 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 the ...

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 裴义霞顾军民张斌韩诚康
Owner CHINA PETROLEUM & CHEM CORP
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