阅读说明：本技术 一种硒催化乙酸甲酯氧化制电解液溶剂碳酸二甲酯的方法 (Method for preparing electrolyte solvent dimethyl carbonate by oxidizing methyl acetate under catalysis of selenium ) 是由 俞磊 王琪远 李培梓 于 2020-06-05 设计创作，主要内容包括：本发明涉及一种硒催化乙酸甲酯氧化制电解液溶剂碳酸二甲酯的方法,其步骤为：将硒催化剂、三氟化铁、乙酸甲酯按照质量比0.001～0.005：0.0002～0.0006：1的比例混合,在0.5～1.0MPa氧气压力下,100～140<Sup>o</Sup>C加热4～8小时,通过蒸馏可分离获得碳酸二甲酯产物。该方法合成碳酸二甲酯,反应原料廉价安全,整体路线清洁,是合成碳酸二甲酯的全新合成工艺。(The invention relates to a method for preparing electrolyte solvent dimethyl carbonate by oxidizing methyl acetate under the catalysis of selenium, which comprises the following steps: mixing a selenium catalyst, ferric trifluoride and methyl acetate according to a mass ratio of 0.001-0.005: 0.0002 to 0.0006: 1, under the oxygen pressure of 0.5-1.0 MPa, 100-140 o And C, heating for 4-8 hours, and distilling to obtain the dimethyl carbonate product. The method for synthesizing the dimethyl carbonate has the advantages of cheap and safe reaction raw materials and clean overall route, and is a brand new synthesis process for synthesizing the dimethyl carbonate.)

1. A method for preparing electrolyte solvent dimethyl carbonate by catalyzing methyl acetate oxidation by selenium is characterized by comprising the following steps: methyl acetate is adopted as a raw material, a selenium catalyst and ferric trifluoride are adopted as a catalytic system, and the reaction is carried out for a period of time in an oxygen atmosphere, so as to obtain a dimethyl carbonate product.

2. The method of claim 1, wherein: the preparation method of the selenium catalyst comprises the following steps: : stirring and mixing an ethanol solution of sodium borohydride and selenium powder at the temperature of 0 +/-1 ℃, and then adding a mixture consisting of sugar, dodecyl ammonium bromide, triethyl ammonium bromide and diethyl ammonium bromide, diisopropyl ammonium bromide to obtain a mixed system; heating the mixed system to 20-60 ℃ under the stirring condition for reaction, obtaining a precipitate after the reaction is finished, and calcining at the temperature of 450-550 ℃ after suction filtration to obtain the nano selenium material; the molar ratio of selenium powder, sugar, dodecyl triethyl ammonium bromide, diethyl diisopropyl ammonium bromide and sodium borohydride in the ethanol solution of sodium borohydride is 100: 1000: 8.20: 2.60: 100.

3. The method of claim 1, wherein: the mass ratio of the selenium catalyst to the methyl acetate is 0.001-0.005: 1, preferably 0.003: 1.

4. The method of claim 1, wherein: the mass ratio of ferric trifluoride to methyl acetate is 0.0002-0.0006: 1, preferably 0.0004: 1.

5. The method of claim 1, wherein: reacting under the oxygen pressure of 0.5-1.0 MPa, preferably 0.8 MPa.

6. The method of claim 1, wherein: heating and reacting for 4-8 hours at 100-140 ℃.

7. The method of claim 1, wherein: the reaction was heated at 120 ℃ for 6 hours.

8. The method of claim 1, wherein: after the reaction is finished, the dimethyl carbonate product is obtained by distillation separation.

Technical Field

The invention relates to a method for preparing electrolyte solvent dimethyl carbonate by oxidizing methyl acetate under the catalysis of selenium, belonging to the technical field of chemical synthesis.

Background

Dimethyl carbonate (namely DMC) is an important chemical solvent with low toxicity, environmental protection and safety. It can be used as a solvent in battery electrolytes. With the rise of the lithium battery industry, the market demand of DMC is increasingly expanding, and the DMC has good development prospect. The conventional production route for DMC is the phosgene process, but this route is gradually being phased out due to the high toxicity and corrosivity of phosgene and environmental problems caused by sodium chloride emissions. Currently, there are three synthetic routes commonly used: copper chloride or nitric oxide is used as a catalyst for oxidative carbonylation, propylene carbonate and methanol transesterification, and urea methanolysis. However, the above three methods still have problems such as the use of nitrogen oxides which destroy the ozone layer, the high toxicity of allyl alcohol which is a by-product, and the production of odorous ammonia gas by alcoholysis of urea. Overcomes the problems, develops a new green and clean production route and has good application value.

Disclosure of Invention

The invention aims to provide a method for preparing dimethyl carbonate serving as an electrolyte solvent by catalyzing methyl acetate oxidation through selenium, wherein cheap and easily-obtained methyl acetate is used as a raw material, and the dimethyl carbonate is prepared by catalyzing oxygen oxidation through nano selenium-ferric trifluoride.

In order to solve the technical problems, the technical scheme provided by the invention is as follows: a method for preparing electrolyte solvent dimethyl carbonate by oxidizing methyl acetate under the catalysis of selenium comprises the following steps: mixing a selenium catalyst, ferric trifluoride and methyl acetate according to a mass ratio of 0.001-0.005: 0.0002 to 0.0006: 1, heating for 4-8 hours at 100-140 ℃ under the oxygen pressure of 0.5-1.0 MPa, and distilling to obtain the dimethyl carbonate product.

In the invention, the selenium catalyst is prepared by the following steps: : stirring and mixing an ethanol solution of sodium borohydride and selenium powder at the temperature of 0 +/-1 ℃, and then adding a mixture consisting of sugar, dodecyl ammonium bromide, triethyl ammonium bromide and diethyl ammonium bromide, diisopropyl ammonium bromide to obtain a mixed system; heating the mixed system to 20-60 ℃ under the stirring condition for reaction, obtaining a precipitate after the reaction is finished, and calcining at the temperature of 450-550 ℃ after suction filtration to obtain the nano selenium material; the molar ratio of selenium powder, sugar, dodecyl triethyl ammonium bromide, diethyl diisopropyl ammonium bromide and sodium borohydride in the ethanol solution of sodium borohydride is 100: 1000: 8.20: 2.60: 100.

In the invention, the mass ratio of the selenium catalyst to the methyl acetate is 0.001-0.005: 1. wherein 0.003:1 is preferred, at which ratio the selenium catalyst can be utilized to the maximum extent;

in the present invention, iron trifluoride is used as a co-catalyst. The mass ratio of the methyl acetate to the methyl acetate is 0.0002-0.0006: 1, wherein preferably 0.0004: 1. under the condition, the conversion rate of the raw materials can be improved, and the reduction of selectivity caused by side reaction due to the use of excessive cocatalyst can be avoided.

In the present invention, the reaction is carried out in an oxygen gas of 0.5 to 1.0MPa, preferably 0.8 MPa. Oxygen at this pressure can promote the full conversion of the raw material and avoid the reduction of product selectivity caused by transitional oxidation

In the invention, the reaction temperature is 100-140 ℃, preferably 120 ℃, so that the raw materials can be fully converted, and the product selectivity is high.

In the present invention, the reaction time is 4 to 8 hours, and preferably 6 hours. Sufficient conversion of the starting materials is ensured at this reaction time.

Compared with the prior art, the invention has the beneficial effects that:

the invention provides a method for preparing electrolyte solvent dimethyl carbonate by catalyzing methyl acetate to oxidize by selenium. The reaction raw materials are cheap, the reaction process is environment-friendly and mild, and no waste is generated. And because toxic and harmful reactants and solvents are not used, the synthesis process is safer and more reliable.

Detailed Description

In the invention, a selenium catalyst (see patent No. ZL201610899676.8 of invention patent of 'a method for synthesizing nano-selenium material' developed before the inventor is used), a proper amount of ferric trifluoride cocatalyst is used, cheap and easily available methyl acetate is used as a raw material under a certain pressure, and the dimethyl carbonate is prepared by catalyzing oxygen oxidation through selenium-ferric trifluoride.

The following examples illustrate the invention in more detail, but do not limit the invention further.