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Method for purifying polyoxymethylene dimethyl ether

A technology of dimethyl ether and polyoxymethylene, which is applied in chemical instruments and methods, preparation of organic compounds, organic chemistry, etc., can solve problems affecting the continuous and stable operation of the separation process of polyoxymethylene dimethyl ether, unfavorable expansion of production, and processing time. long and other issues

Active Publication Date: 2018-12-28
CHINA PETROLEUM & CHEM CORP +1
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

However, this method needs to be condensed and refluxed for 2 hours, and the processing time is long, which is not conducive to expanding production
[0008] Therefore, the separation of formaldehyde is a technical bottleneck affecting the continuous and stable operation of the separation process of polyoxymethylene dimethyl ether

Method used

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  • Method for purifying polyoxymethylene dimethyl ether
  • Method for purifying polyoxymethylene dimethyl ether
  • Method for purifying polyoxymethylene dimethyl ether

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0039] The reaction mixture obtained by catalytic reaction using paraformaldehyde and methylal as raw materials is firstly rectified by the first rectification tower under normal pressure to remove the first fraction, and the first tower still liquid with a temperature of 105°C is obtained. The first tower still liquid enters the purification tank to contact and react with the chemical treatment liquid; the chemical treatment liquid is a 40% alkali aqueous solution configured with a mass ratio of 1:1 NaOH and KOH solid mixture and water; the dosage is 10% of the first tower still liquid %. The reaction temperature of the purification tank is 90°C, the stirring reaction time is 20min, and then the chemical treatment liquid is separated to obtain PODE containing 2-5 Purified feed liquid. The purified feed liquid enters the second rectification tower and is rectified under normal pressure. The temperature at the top of the tower is 80°C. The third rectification tower and the fo...

Embodiment 2

[0043] The reaction mixture obtained by catalytic reaction using paraformaldehyde and methylal as raw materials is firstly rectified by the first rectification tower under normal pressure to remove the first fraction, and the first tower still liquid with a temperature of 105°C is obtained. The first tower still liquid enters the purification tank and reacts with the chemical treatment liquid; the used chemical treatment liquid is a NaOH aqueous solution with a concentration of 40%, and the consumption is 10% of the first tower still liquid. The reaction temperature of the purification tank is 90°C, the stirring reaction time is 20min, and then the chemical treatment liquid is separated to obtain PODE containing 2-5 Purified feed liquid. The purified feed liquid enters the second rectification tower and is rectified under normal pressure. As a result, it is found that a white solid is precipitated from the top of the second rectification tower after about 4 hours. Component a...

Embodiment 3

[0045] The reaction mixture obtained by catalytic reaction using paraformaldehyde and methylal as raw materials is firstly rectified by the first rectification tower under normal pressure to remove the first fraction, and the first tower still liquid with a temperature of 105°C is obtained. The first tower still liquid enters the purification tank and reacts with the chemical treatment liquid; the used chemical treatment liquid is a KOH aqueous solution with a concentration of 40%, and the consumption is 10% of the first tower still liquid. The reaction temperature of the purification tank is 90°C, the stirring reaction time is 20min, and then the chemical treatment liquid is separated to obtain PODE containing 2-5 Purified feed liquid. The purified feed liquid enters the second rectification tower and is rectified under normal pressure. As a result, it is found that a white solid is precipitated from the top of the second rectification tower after about 3 hours. Component an...

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Abstract

The technical problem to be solved by the invention is that it is difficult to carry out long-term continuous production operation caused by the presence of formaldehyde in the process of purifying polyoxymethylene dimethyl ether by a rectification method. The method adopted includes the following steps that a reaction equilibrium mixture is obtained by a reaction synthesis unit, and firstly methylal is removed in a first separation tower to obtain first tower bottoms; the first tower bottoms enter a purification kettle, and is contacted with chemical treatment liquid to obtain purification liquid containing PODE 2-8; the purification liquid enters a second distillation tower, a second fraction comprising methanol and water is separated from the top, and second tower bottoms are obtained in a tower kettle; the second tower bottoms enter a third distillation tower, a high-purity PODE2 product fraction is separated from the top of the third distillation tower, and third tower bottoms areobtained; the third tower bottoms enter a fourth distillation tower, and a fourth distillation tower product fraction is separated from the top of the fourth distillation tower; the fourth distillation tower product fraction is PODE3-4 or PODE3-5.

Description

technical field [0001] The invention relates to a method for purifying polyoxymethylene dimethyl ether, in particular to preparing high-purity PODE from a reaction mixture containing polyoxymethylene dimethyl ether obtained from a reaction in which paraformaldehyde is a raw material 3～4 Product or PODE 3～5 product 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 value is less...

Claims

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Application Information

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IPC IPC(8): C07C41/58C07C43/30
CPCC07C41/58C07C43/30
Inventor 裴义霞顾军民张斌
Owner CHINA PETROLEUM & CHEM CORP
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