Method for synthesizing polyoxymethylene dimethyl ethers

A technology of dimethyl ether and polyoxymethylene, applied in chemical instruments and methods, preparation of organic compounds, organic chemistry, etc., can solve problems such as low yield of target products, difficult industrialization of processes, poor product selectivity, etc., and achieve good results Heat stability and solvent stability, ease of handling, effect of improving conversion rate

Active Publication Date: 2010-12-01
DONGFANG HONGSHENG NEW ENERGY APPL TECH RES INST +1
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

In this research field, the relevant patents and research literature are very limited, and the existing patents generally have the disadvantages of low target product yield, poor product selectivity, and difficult industrialization of the process.

Method used

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  • Method for synthesizing polyoxymethylene dimethyl ethers
  • Method for synthesizing polyoxymethylene dimethyl ethers
  • Method for synthesizing polyoxymethylene dimethyl ethers

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0048] Fill the reaction tube with 20-40 mesh H 3 PO 4 Modified γ-Al 2 o 3 -P catalyst, the reaction temperature of the first step is controlled at 60°C, the reaction pressure is 0.5MPa, and the molar ratio of materials is m 甲醛(低聚合度多聚甲醛) :m 甲醇 =10:1, liquid volume hourly space velocity (LHSV) 0.5h -1 ; second step m 多聚半缩醛 :m 甲醇 =10: 3, the catalyst adopts active carbon-based organic strong acid bonded phase solid catalyst, the catalyst accounts for 5wt% of the total material, and cyclohexane is used as a water separating agent, the reaction temperature is 80~90°C, the reaction time is 4h, and the methanol is analyzed by gas chromatography The conversion rate was 91.5%. The relative content (product distribution) of methylal with different n values ​​in the product is: n=1, 19.6%; n=2, 7.6%; n=3-8, 60.9%; n>8, 11.9%.

Embodiment 2

[0050] Fill the reaction tube with 40-60 mesh H 3 BO 3 Modified γ-Al 2 o 3 -B catalyst, the reaction temperature of the first step is controlled at 90°C, the reaction pressure is 4.0MPa, and the molar ratio of the materials is m 甲醛(低聚合度多聚甲醇) :m 甲醇 =10:2, liquid volume hourly space velocity (LHSV) 0.5h -1 ; second step m 多聚半缩醛 :m 甲醇 =10: 2, the catalyzer adopts the solid catalyst of silica gel-based organic strong acid bonded phase, the catalyzer accounts for 0.5wt% of the total material, toluene is used as the water separating agent, the reaction temperature is 90~110°C, the reaction time is 4h, and the methanol is analyzed by gas chromatography The conversion rate is 92.7%; the relative content of methylal in the product (product distribution) n=1, 17.8%; n=2, 12.3%; n=3~8 60.1%; n>8, 9.8%.

Embodiment 3

[0052] Fill the reaction tube with 40-60 mesh HF-modified γ-Al 2 o 3 -F catalyst, the reaction temperature of the first stage is controlled at 90°C, the reaction pressure is 4.0MPa, and the molar ratio of materials is m 甲醛(低聚合度多聚甲醛) :m 甲醇 =10:2, liquid volume hourly space velocity (LHSV) 0.5h -1 ; the second paragraph m 多聚半缩醛 :m 甲醇 =10:2, the catalyst adopts silica gel-based organic strong acid bonded phase solid catalyst, the catalyst accounts for 5wt% of the total material, toluene is used as a water separating agent, the reaction temperature is 90~110°C, the reaction time is 4h, and the conversion of methanol is analyzed by gas chromatography The rate is 92.7%; the relative content of methylal in the product (product distribution) n=1, 14.3%; n=2, 9.2%; n=3~8, 67.1%; n>8, 9.4%.

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Abstract

The invention relates to a method for synthesizing polyoxymethylene dimethyl ethers, comprising the following steps: step one, generating hemiacetal by methanol and excessive methanal or paraformaldehyde with low polymerization degree under the existence of a modified alumina catalyst, reacting the hemiacetal with methanal to generate hemiacetal with one more carbon, and successively continuing the above steps to generate poly-hemiacetal with more carbon atoms; and step two, generating the polyoxymethylene dimethyl ethers by the poly-hemiacetal mixture under the existence of methanol and an organic strong acid bonded phase solid catalyst. The invention can achieve the technical targets of improving raw material conversion rate, product selectivity, target product yield and economical efficiency by the two steps of reaction process, adjusts the space velocity by a fixed bed continuous reactor and combines with a catalyst to control the polymerization degree. The synthesis method in the invention has mild reaction conditions and easy control.

Description

technical field [0001] The invention relates to a method for synthesizing polyoxymethylene dimethyl ether with a low degree of polymerization. Background technique [0002] Gasoline and diesel oil are the main energy fuels provided by petroleum raw materials, and the exhaust gas after combustion becomes the main source of pollution of the atmosphere. As a result, environmental problems such as acid rain, photochemical smog, and ozone depletion have been caused. Various countries have continuously put forward new requirements for gasoline and diesel specifications, and formulated corresponding regulations on clean oil products. With the continuous increase of petroleum consumption and the continuous enhancement of people's environmental awareness, the requirements for fuel consumption and environmental protection of internal combustion engines powered by petroleum are becoming increasingly stringent. Therefore, reducing oil consumption and reducing pollution are the main goa...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C07C43/30C07C41/48
Inventor 洪正鹏商红岩
Owner DONGFANG HONGSHENG NEW ENERGY APPL TECH RES INST
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