Exploration On Synthesis Of Carbonic Acid,2ethoxyethyl Methyl Ester By Transesterification

Carbonic acid,2ethoxyethyl methyl ester is one of important derivatives in finechemical of coal. It can be used as a new additive of Synthetic diesel fuel,because ofthe high content of oxygen and perfect performance of combustion.What’s more, itcan also used as Paint remover, Degreasing agent, Rubber adhesive, printing inks andso on.The mixtures of carbonic acid,2ethoxyethyl methyl ester and other Alkylcarbonate can be used to replace the material of cyclohexanone, ethylene glycoldimethyl ether and methyl acetate and nylon and can be used as nitro spray, syntheticresins and coatings, because it can improve the film ductility, adhesion, aesthetics,etc. Therefore it can be applied in different fields, widely.This paper discussed the synthesis of Carbonic acid,2ethoxyethyl methyl esterpreliminary by transesterification, in which dimethyl carbonate and ethylene glycolether were used as raw materials and Solid base was catalyst. The detail work is listedas follows:The reaction system was analyzed by thermodynamic analysis.The standardenthalpy of formation,the standard formation entropy and heat capacity of dimethylcarbonate,glycol ether and2ethoxyethyl methyl ester were calculated byBenson-group contribution.The changes of enthalpy,the free energy,and theequilibrium constant were evaluated according to the chemical thermodynamicsprinciple at direct synthesis of carbonic acid,2ethoxyethyl methyl ester with dimethylcarbonate and glycol ether.The results showed that this reaction is exothermal,thechang of free energy is negative,and the equilibrium constant is small,the temperaturehas little influence on the equilibrium constant K.The reaction can be proceeded atrelative low temperature.This work mainly focus on the research of catalyzed transesterification, in whichthe Carbonic acid,2ethoxyethyl methyl ester was synthesized by the catalyst ofPotassium hydroxide. The product of Carbonic acid,2ethoxyethyl methyl ester wascharacterized by the boiled point, IR,1HNMR,13CNMR and other methods. Theresults indicated that the Carbonic acid,2ethoxyethyl methyl ester which is synthesized was the objective compound.By orthogonal and single factor experiments, the effect of factors on conversionof ethylene glycol ether and yield of Carbonic acid,2ethoxyethyl methyl ester wasinvestigated such as the amount of catalyst, reaction temperature, reaction time andthe ratio of raw materials and others. Optimal experimental conditions are as follows:reaction time is3h;the ratio of n (DMC): n (glycol ether) is4:1(0.05mol glycol etheras a standard),reaction temperature is100℃, the amount of potassium hydroxide is0.6g (mass fraction is2.7%of reaction substrate). A parallel experiment wasperformed for three times in optimal condition. The results showed that the averageyield of Carbonic acid,2ethoxyethyl methyl esterwas74.15%and the averageconversion of and glycol ether was87.15%.Recycled of catalyst was inspected.Theyield of Carbonic acid,2ethoxyethyl methyl ester was more than70%, after thecatalyst recycled for five times.By product was Identified,expounds the problems of raw material recovery andthe yield of purpose separation. And the separation yield can reaches47.26%.What’s more, the carrier of activated carbon, activated alumina, silica gel,molecular sieves for potassium hydroxide was studied,and the catalytic actives werealso investigated. The results demonstrated that silica gel and molecular sieve ascarrier of catalyst were poor; catalytic activity of KOH/C was in general for constantyield of product was the same almost; Na-γ/Al2O3-KOH as a supported catalyst hadthe best catalytic propersity, and the yield of product was up to89.7%. However,sodium metal is expensive and is difficult to be used in experimental synthesisbecause of the existed risks. Also, yield of product was up to85.32%by the catalystof KOH/γ/Al2O3,and the reproducibility of the catalyst was very well.