Method for synthesizing dimethyl carbonate under catalysis action of ionic liquid

A technology of dimethyl carbonate and ionic liquid, which is applied in the field of synthesis of dimethyl carbonate, can solve problems such as the complexity of the preparation process, and achieve high catalytic activity, simple synthesis operation, and high catalytic activity

Active Publication Date: 2019-05-03
NANKAI UNIV +1
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  • Application Information

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Problems solved by technology

[0009] Aiming at the relatively complicated preparation process of the existing ionic liquid used for catalytic synthesis of dimethyl carbonate, the purpose of the present invention is to provide a kind of ionic liquid that is easy to prepare, anion and cation can synergistically activate reactants, has high catalytic activity and can be recycled and reused. Ionic liquid catalytic system for the preparation of dimethyl carbonate

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  • Method for synthesizing dimethyl carbonate under catalysis action of ionic liquid

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Embodiment 1

[0024] To operate under normal pressure reflux conditions, in a 50mL round bottom flask, add ethylene carbonate (0.8806g, 10mmol), methanol (3.204g, 100mmol) and ionic liquid catalyst [DBUH][TFA] (3mol%, 0.3 mmol), under the condition of a stirring rate of 800r / min, the reaction temperature was raised to 60°C to start the reaction, and the reaction time was 7h. After the reaction was completed, the reaction system was analyzed by gas chromatography to obtain a conversion rate of ethylene carbonate of 45% and a yield of dimethyl carbonate of 20% (internal standard method, 1,3,5-trimethoxybenzene internal standard). The catalyst is separated from the reaction system by distillation under reduced pressure, and the catalyst is recovered.

Embodiment 2

[0026]To operate under normal pressure reflux conditions, the raw material ethylene carbonate (0.8806g, 10mmol), methanol (9.612g, 300mmol) and ionic liquid catalyst [DBUH][TFE] (0.1mol%, 0.01mmol) were sequentially added to a 50mL circle In the bottom flask, the reaction temperature was raised to the reflux temperature of the system at 70° C. under the condition of a stirring rate of 1000 r / min to start the reaction, and the reaction time was 12 hours. After the reaction was completed, the reaction system was analyzed by gas chromatography to obtain a conversion rate of ethylene carbonate of 85% and a yield of dimethyl carbonate of 83% (internal standard method, 1,3,5-trimethoxybenzene internal standard). The catalyst is separated by distillation under reduced pressure, and the catalyst is recovered.

Embodiment 3

[0028] Under normal pressure reflux condition, add raw material ethylene carbonate (0.8806g, 10mmol), methanol (1.602g, 50mmol) and ionic liquid catalyst [DBUH]Cl (2mol%, 0.2mmol) successively in 50mL round bottom flask , the reaction temperature was raised to 40° C. under the condition that the stirring rate was 600 r / min, and the reaction time was 2 h. After the reaction was completed, the reaction system was analyzed by gas chromatography to obtain a conversion rate of ethylene carbonate of 64% and a yield of dimethyl carbonate of 15% (internal standard method, 1,3,5-trimethoxybenzene internal standard). The catalyst is separated by distillation under reduced pressure, and the catalyst is recovered.

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Abstract

The invention discloses a method for synthesizing dimethyl carbonate under the catalysis action of an ionic liquid. The bifunctional ionic liquid is adopted as a catalyst, a transesterification reaction is performed between ethylene carbonate and methanol, wherein when the use amount of the catalyst is 0.5-10 mol% of ethylene carbonate, the molar ratio of ethylene carbonate to methanol is 1:(5-30), the reaction temperature is 40-70 DEG C, and the reaction time is 2-12 h, so that dimethyl carbonate and ethylene glycol are synthesized with a high conversion rate and high selectivity. The methodhas the following advantages: (1) the bifunctional ionic liquid adopted as the catalyst has the effect of a homogeneous reaction and the characteristic of a heterogeneous catalyst, the shortcomings ofconventional solid catalysts and the homogeneous catalysts are overcome, and high catalytic activity, easy separation, recyclability and no pollution to the environment are achieved; (2) since the bifunctional ionic liquid is applied to the reaction system, reactants can be activated under the synergistic action of anions and cations of the catalyst, higher catalytic activity is achieved, and synthesis operation of the catalyst is simple and easy.

Description

technical field [0001] The invention relates to a method for synthesizing dimethyl carbonate, in particular to a method for preparing dimethyl carbonate by using a bifunctional ionic liquid to catalyze the transesterification of ethylene carbonate and methanol. Background technique [0002] Among the chain carbonates, dimethyl carbonate (DMC) is particularly widely used. It is a commonly used solvent and can also be used as a thickener for fuel. In addition, as a green carbonylation reagent and methylation reagent, it can replace highly toxic phosgene, methyl chloroformate, and dimethyl sulfate Esters, etc. can be used to prepare diphenyl carbonate, isocyanate, tetramethoxysilane, and aromatic polycarbonate can also be synthesized. Therefore, it is a green chemical product with great development prospects. [0003] The current synthesis methods of dimethyl carbonate mainly include phosgene synthesis, methanol oxidative carbonylation, urea alcoholysis, CO 2 And methanol as...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C07C68/06C07C69/96
CPCY02P20/584
Inventor 宋禹李红茹何兴叶峰崔晓莹何良年
Owner NANKAI UNIV
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