A New Strategy For Organic Electro-synthesis Of Monoethyl Malonate

The rapid development of global economy caused people to the growing demandfor energy, and thus bring such problems as environmental pollution, greenhouseeffect which is the test of the human. How to effectively protect the survivalenvironment of human, and to control or reduce the extent of environmental pollutionhave been attracting more and more attention.Monoethyl malonate is an important organic synthetic material. It has beenwidely used in the synthesis of natural products and other organic material. However,the single traditional synthesis process of monoethyl malonate is from diethylmalonate through saponification, hydrolysis and acidification steps. This process isnot only time consuming, but also strict to the reaction conditions, and will have sidereactions occur, which will pollute the environment. Therefore, the study on a kind ofgreen and efficient method to synthesize monoethyl malonate has important practicalsignificance.Currently, many studies on the electro-carboxylation of halogenatedhydrocarbon with CO2have been reported, but ethyl chloroacetate as the substrate ofthe research is still blank. Used the green synthesis method, therefore, under mildconditions to electro-carboxylation of ethyl chloroacetate and CO2for the synthesis ofmonoethyl malonate (one of important drug intermediates) has important practicaland innovative value. Research content of this paper is mainly divided into two parts:one is research on the mechanism of ethyl chloroacetate reaction with CO2byelectrochemistry and characterization of monoethyl malonate product; the other one isoptimization research on the synthesis of monoethyl malonate process.In the first part, the cyclic voltammetry is used to research the electrochemicalreduction of ethyl chloroacetate behavior. The results showed that the electrochemicalreduction of ethyl chloroacetate on Ag, Cu, and Ss electrode have all good response.The cyclic voltammograms after CO2passes into shows that there are some reactionstaking place between CO2and ethyl chloroacetate. And then the reaction mechanismof the electrocarboxylation of ethyl chloroacetate with CO2was speculated, the The product monoethyl malonate was characterized.In the second part, the impact of the raw material concentration, solvents,supporting electrolyte salts, electrode materials, current density, electric quantity,temperature and other electrolytic reaction factors on the electrocarboxylation of ethylchloroacetate were discussed. Found that, in a one room type electrolytic cell withaluminum(Al) as the sacrificial anode for the electrolysis at constant current, the onlytarget product monoethyl malonate was obtained.The optimized reaction conditions are as follows: acetonitrile as the solvent,0.1mol/L TBAB as supporting electrolyte salt, Ag as cathode, Al as anode, thetemperature at0℃and current densitywas25mA/cm2. Under the optimized reactionconditions, the yield of monoethyl malonate was up to81.45%with the theoreticalelectric quantity.