阅读说明：本技术 利用乙二醇二甲醚合成乙烯基甲醚的方法 (Method for synthesizing vinyl methyl ether by using ethylene glycol dimethyl ether ) 是由 刘海超 何鑫 于 2020-07-03 设计创作，主要内容包括：本发明公开了一种利用乙二醇二甲醚合成乙烯基甲醚的方法。所述合成方法包括如下步骤：在固体碱的催化作用下,乙二醇二甲醚发生消去反应得到乙烯基甲醚和甲醇；所述固体碱为氧化镁、二氧化铈、氧化钙或钙镁混合氧化物；所述钙镁混合氧化物中,钙与镁的摩尔比为0.1～4。本发明提供的以固体碱催化乙二醇二甲醚制备乙烯基甲醚的方法,原料来源广泛且绿色；催化剂高效,廉价稳定性好；目标产物的收率能够达到80％；副产物甲醇可循环利用制备反应原料；且该方法对设备要求低,投资小,具有相当重要的实际应用价值。(The invention discloses a method for synthesizing vinyl methyl ether by using ethylene glycol dimethyl ether. The synthesis method comprises the following steps: under the catalytic action of solid alkali, ethylene glycol dimethyl ether undergoes elimination reaction to obtain vinyl methyl ether and methanol; the solid alkali is magnesium oxide, cerium dioxide, calcium oxide or calcium magnesium mixed oxide; in the calcium-magnesium mixed oxide, the molar ratio of calcium to magnesium is 0.1-4. The method for preparing vinyl methyl ether by catalyzing glycol dimethyl ether with solid base has wide and green raw material sources; the catalyst is efficient, cheap and good in stability; the yield of the target product can reach 80 percent; the byproduct methanol can be recycled to prepare reaction raw materials; the method has low requirements on equipment, small investment and quite important practical application value.)

1. A method for synthesizing vinyl methyl ether comprises the following steps:

under the catalytic action of solid alkali, ethylene glycol dimethyl ether undergoes elimination reaction to obtain vinyl methyl ether and methanol.

2. The method of synthesis according to claim 1, characterized in that: the solid alkali is magnesium oxide, cerium dioxide, calcium oxide or calcium magnesium mixed oxide.

3. The method of synthesis according to claim 2, characterized in that: in the calcium-magnesium mixed oxide, the molar ratio of calcium to magnesium is 0.1-4.

4. A synthesis method according to any one of claims 1-3, characterized in that: the elimination reaction is carried out in a miniature fixed bed reactor;

the elimination reaction is carried out under normal pressure.

5. The method of synthesis according to claim 4, characterized in that: the ethylene glycol dimethyl ether is introduced into the fixed bed reactor in the form of bubbling;

nitrogen is used as bubbling and balance gas;

the entrance airspeed of the ethylene glycol dimethyl ether is 1.0-10 h^-1。

6. The method of synthesis according to any one of claims 1-5, characterized in that: the temperature of the elimination reaction is 375-425 ℃.

Technical Field

The invention relates to a method for synthesizing vinyl methyl ether by using ethylene glycol dimethyl ether, belonging to the field of chemical synthesis.

Background

Vinyl methyl ether is the simplest ether compound containing a carbon-carbon double bond. Because of containing active carbon-carbon double bonds, vinyl methyl ether can generate polymerization reaction like vinyl acetate and vinyl chloride, and synthesize various multifunctional high molecular materials, such as polyvinyl methyl ether with temperature sensitivity, polyvinyl ether-maleic anhydride copolymer with biocompatibility and the like. In addition, vinyl methyl ether is also an important organic synthesis intermediate, and is industrially one of important raw materials for synthesizing glutaraldehyde. Meanwhile, vinyl methyl ether can also be used for preparing other vinyl ether derivatives through alcohol exchange.

The vinyl ether is prepared by Reppe vinylation reaction in industry, namely acetylene and alcohol are catalyzed by liquid-phase strong base at 150-180 ℃. Since the reaction is strongly exothermic, the reaction proceeds easily. However, the use of liquid phase bases and the relatively hazardous reaction starting materials limit the utility of the process. Another common method is to prepare vinyl methyl ether by thermal decomposition of acetal derivatives, wherein the acetal derivatives are used as raw materials, phosphate is used as a catalyst, and vinyl ether with the yield of more than 90% can be obtained at 300-350 ℃. The thermal decomposition method of acetal derivatives requires expensive raw materials and limited sources, and is not economical. Therefore, the development of a more green, safe and economic vinyl methyl ether preparation method has great commercial value and scientific research significance.

Disclosure of Invention

The invention aims to provide a method for synthesizing vinyl methyl ether by using ethylene glycol dimethyl ether, which is to obtain high-yield vinyl methyl ether by a method of eliminating one molecule of methanol by using ethylene glycol dimethyl ether under the catalysis of solid base.

The synthesis method of vinyl methyl ether provided by the invention comprises the following steps:

under the catalytic action of solid alkali, ethylene glycol dimethyl ether undergoes elimination reaction to obtain vinyl methyl ether and methanol.

In the above synthesis method, the solid base may be magnesium oxide, cerium oxide, calcium oxide or calcium magnesium mixed oxide, and is diluted with quartz sand before use to eliminate local overheating caused by local exothermic reaction.

In the above synthesis method, the molar ratio of calcium to magnesium in the calcium-magnesium mixed oxide may be 0.1 to 4, for example, 0.5, 1 or 2;

the calcium-magnesium mixed oxide can be prepared by the following method: preparing a mixed solution by taking calcium acetate and magnesium acetate as precursors, adding an excessive ammonium carbonate precipitator, stirring, filtering, washing with deionized water, drying overnight, and then roasting in a muffle furnace in a nitrogen atmosphere to obtain the catalyst.

In the above synthesis method, the elimination reaction is carried out in a miniature fixed bed reactor;

the elimination reaction is carried out under normal pressure.

In the above synthesis method, the ethylene glycol dimethyl ether is introduced into the fixed bed reactor in the form of bubbling;

nitrogen is used as bubbling and balance gas;

the introduction airspeed of the ethylene glycol dimethyl ether can be 1.0-10 h^-1E.g. 1.0 to 1.2h^-1、1.0h^-1Or 1.2h^-1。

In the above synthesis method, the temperature of the elimination reaction is 375 to 425 ℃, such as 380 to 400 ℃, 380 ℃ or 400 DEG C

Ethylene glycol is a chemical with wide source and low price, and can be prepared by biomass catalytic conversion, so that the ethylene glycol is a green chemical raw material, and the ethylene glycol dimethyl ether is an important derivative of the ethylene glycol, and has the characteristics of wide source and green.

The method for preparing vinyl methyl ether by catalyzing glycol dimethyl ether with solid base has wide and green raw material sources; the catalyst is efficient, cheap and good in stability; the yield of the target product can reach 80 percent; the byproduct methanol can be recycled to prepare reaction raw materials; the method has low requirements on equipment, small investment and quite important practical application value.

Detailed Description

The experimental procedures used in the following examples are all conventional procedures unless otherwise specified.

Materials, reagents and the like used in the following examples are commercially available unless otherwise specified.

The following examples produce vinyl methyl ether from ethylene glycol dimethyl ether.

The catalytic reaction of ethylene glycol dimethyl ether in the following examples was carried out on a fixed bed microreactor at atmospheric pressure.

The catalyst is diluted with quartz sand to eliminate local overheating caused by local exothermic reaction.

The raw material glycol dimethyl ether is introduced into a reaction system in a bubbling mode, and high-purity nitrogen is used as bubbling and equilibrium gas. To prevent the feed and product condensation from blocking the lines, all gas lines were kept at temperatures above 120 ℃ by heating tape.

The reaction raw materials and products are analyzed on line by Shimadzu GC-2010 gas chromatography, which is a double-gas path and double-detector configuration. One path is a TCD detector which is mainly used for detecting inert gas nitrogen and the like, and chromatographic columns are Porapak Q and 13X molecular sieve packed columns; the other path is a FID detector, and a chromatographic column is LZP35, which is used for quantitative analysis of ethylene glycol dimethyl ether, methanol and vinyl methyl ether.

The conversion and selectivity are calculated as follows: