Process for preparing polyoxymethylene dimethyl ether

A technology of polyoxymethylene dimethyl ether and dimethyl ether, which is applied in chemical instruments and methods, preparation of organic compounds, organic chemistry, etc., can solve the problems of poor economy, lack of large-scale industrialization, and high cost

Active Publication Date: 2012-08-01
INST OF CHEM CHINESE ACAD OF SCI +1
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

The cost of paraformaldehyde is high, and the economy of its preparation method is poor
These methods all face the problem of high cost in industrialization, so they have not yet achieved large-scale industrialization.

Method used

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  • Process for preparing polyoxymethylene dimethyl ether
  • Process for preparing polyoxymethylene dimethyl ether
  • Process for preparing polyoxymethylene dimethyl ether

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0031] Step 1: Heat and stir 500 g of methanol, 200 g of paraformaldehyde and triethylamine (the mass ratio of triethylamine to paraformaldehyde is 13:1000) at 80° C. until it forms a homogeneous mixed solution to obtain poly The homogeneous mixed solution formed by formaldehyde monomethyl ether and methanol is neutralized by adding equimolar hydrochloric acid with triethylamine to obtain a neutral solution. At 50°C, methanol was distilled off by vacuum distillation to obtain a polyoxymethylene monomethyl ether solution containing a small amount of methanol.

[0032] Second step: 30g of the polyoxymethylene monomethyl ether solution prepared above, 120g of methylal, an acid catalyst and a dehydrating agent were mixed, stirred and reacted at room temperature and normal pressure for 4 hours, and obtained polyoxymethylene dimethyl ether (DMM) containing Mixed solution, the obtained product was analyzed by gas chromatography, and the results are shown in Table 1.

[0033] The DMM...

Embodiment 2-16

[0036] The polymerization process was the same as in Example 1, only the types and ratios of the acidic catalyst and water-absorbing agent were changed. The results are shown in Table 1.

[0037] Table 1

[0038]

[0039]

Embodiment 17-23

[0041] The first step reaction is the same as in Example 1, the second step reaction temperature is 50°C, the reaction time is shortened to 2 hours, and the types and ratios of the acidic catalyst and water-absorbing agent are changed. Others are the same as in Example 1, and the results are shown in Table 2.

[0042] Table 2

[0043]

[0044]

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Abstract

The invention provides a process for preparing polyoxymethylene dimethyl ether represented by general formula (1). The process for preparing the polyoxymethylene dimethyl ether is characterized by subjecting methanol, methylal and /or dimethyl ether and formaldehyde and /or paraformaldehyde to reaction under the action of an acid catalyst and a water absorbing agent. The general formula (1) is as follows.

Description

technical field [0001] The invention relates to a method for preparing polyoxymethylene dimethyl ether, in particular to a method for preparing polyoxymethylene dimethyl ether in the presence of a dehydrating agent. Background technique [0002] Polyoxymethylene dimethyl ether has a structure such as H 3 C(OCH 2 ) n OCH 3 of homologues. Polyoxymethylene dimethyl ether has been proven to be used as a blending component of diesel to promote the combustion of diesel, reduce the smoke in diesel emissions, and increase the cetane number of diesel, becoming a new type of energy. Polyoxymethylene dimethyl ether used for vehicle diesel requires n=3 to 8. When n is less than 3, it is difficult to meet the standards and requirements of cetane number, flash point, solubility and other aspects. Polyoxymethylene dimethyl ether is solid and difficult to mix with diesel. Therefore, a high-efficiency, low-cost method for synthesizing polyoxymethylene dimethyl ethers with n=3-8 has rec...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C07C43/303C07C41/48
Inventor 李化毅方勇方世壁张英伟胡友良张新志
Owner INST OF CHEM CHINESE ACAD OF SCI
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