Purification method for polymethoxydimethyl ether

A technology of polyoxymethylene dimethyl ether and methanol, which is applied in the reaction mixture containing polyoxymethylene dimethyl ether to prepare high-purity PODE3-4 products and PODE3-5 products, which can solve the problem of unfavorable expansion of production and the impact of polymethoxyl dimethyl ether Problems such as continuous and stable operation and long processing time of oxydimethyl ether separation process

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 polyoxymethylene dimethyl ether separation process

Method used

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  • Purification method for polymethoxydimethyl ether
  • Purification method for polymethoxydimethyl ether
  • Purification method for polymethoxydimethyl ether

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Experimental program
Comparison scheme
Effect test

Embodiment 1

[0041] 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 of the bottom of the tower is 155° C., and the second fraction containing ...

Embodiment 2

[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 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

[0047] 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 invention relates to a purification method for polymethoxydimethyl ether. The purification method aims at solving the problem that it is difficult to carry out long-term continuous production operation due to the presence of formaldehyde in the process of purifying polymethoxydimethyl ether by means of a rectification method. According to the adopted technical scheme, the purification method includes the following steps that methylal of a reaction equilibrium mixture obtained in a reaction synthesis unit is removed first in a first separation tower to obtain a first tower bottom liquid; the first tower bottom liquid enters a purification kettle to be in contact with a chemical treatment liquid to obtain a purified feed liquid containing PODE2 to PODE8; the purified feed liquid enters asecond rectification tower, a second fraction comprising PODE2, methanol and water is separated out from the top, and a second tower bottom liquid is obtained at the tower bottom; the second fractionenters a third rectification tower, and a third fraction containing methanol and water is separated out from the top of the third rectification tower to obtain a third tower bottom liquid, namely a high-purity PODE2 product; the second tower bottom liquid enters a fourth rectification tower, and a fourth rectification tower product fraction, namely PODE3 to PODE4 or PODE 3 to PODE5, is separatedout from the top of the fourth rectification tower.

Description

technical field [0001] The invention relates to a method for purifying polyoxymethylene dimethyl ether, in particular to preparing high-purity PODE from a polyoxymethylene dimethyl ether-containing reaction mixture 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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Patent Type & Authority Applications(China)
IPC IPC(8): C07C41/58C07C43/30
CPCC07C41/58C07C43/30
Inventor 裴义霞顾军民吕国强
Owner CHINA PETROLEUM & CHEM CORP
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