A New Study On The Technical Preparation Of Ethyl Methyl Carbonate

Methyl Ethyl Carbonate (Abbreviation:MEC) is a kind of green chemicals, with unique molecular structure. MEC is one of organic carbonate ester compounds which has asymmetric molecular structure. There are methyl(-CH3), ethyl(-CH2CH3), carbonyl(-CO), methoxy (-CH3O) and ethoxy (-CH3CH2O) in the molecular of EMC. The chemical property of EMC is very active, which has a wide application prospect in many fields.Because EMC can be mixed with organic solvent including alcohol, ketone, esters by arbitrary proportion, it can be simultaneously used as a solvent and organic synthesis intermediates. Compared with the symmetrical carbonate, such as dimethyl carbonate and diethyl carbonate, EMC has incomparable advantages when used as non aqueous electrolyte solvent in lithium ion battery.In this paper, introduced several preparation methods of EMC, such as:phosgenation, oxidative carbonylation and transesterification, and also introduced discussed the used catalyst in the three methods. Based on these Literatures, comparing the several synthesis methods and used catalyst between advantages and disadvantages, the final choice synthesis of EMC process was that dibutyltin oxide catalysis on transesterification of diemthyl carbonate and diethyl ethaneioate to synthesize ethyl methyl carbonate.This paper mainly studied the synthesis technology of methyl ethyl carbonate and diethyl ethaneioate. In this experiment, through research arch catalyst types and dosages, feeding molar ratio, reaction temperature, reaction time of synthetic conditions on the transesterification and the yield of target product, ultimately determine the synthesis process of methyl ethyl Carbonate and optimized the related parameters of this synthesis process.The experimental results show that, the optimal conditions of preparing EMC in transesterification:the feeding molar ratio of methyl ethyl carbonate and diethyl ethaneioate was2.5:1, the catalyst dosage of dibutylin oxide was5%by mass of diethyl ethaneioate, reaction time was5h, reaction temperature was110℃, the yield of methyl ethyl carbonate was32.8%, the purity of the product reached90%. The optimal conditions of preparation diethyl ethaneioate in transesterificat-ion:feeding molar ratio of ethanol and diethyl ethaneioate was3:1, the catalyst dosage of A-15ion exchange resin was5%by mass of methyl ethyl oxalate, reaction time was8h, reaction temperature was130℃the yield of diethyl ethaneioate was42.3%, the purity of products was90%.In this paper, the life time of the catalyst on the two kinds of transeserification were also tested. The experimental results show that, dibutyltin oxide catalysis on transesterification to synthesize ethyl methyl carbonate under optimal conditions, the life time was3times. A-15ion exchange resin catalysis on transesterification to synthesize diethyl ethaneioate was4times.