Research Progress Of Methl Acetate To Dimethyl Malonate

Dimethyl malonate is an important chemical materials and pharmaceutical intermediates, because of the molecular structural formula contains active methylene are easily replaced by other groups, it can set off alkylation, hydroxyalkyl, amidation and other substitution reaction. In medicine, pesticide and dye industry got very extensive application. Firstly, this paper reviews the synthesis methods of dimethyl malonate, the main of the current method of dimethyl malonate is sodium cyanide, but the process of sodium cyanide method is long, complex process,and the total yield is not high. Production process using poisonous cyanide, great damage to the environment.Makeing the separation of product and post-processing more troublesome, increased the economic burden of subsequent processing, so need to be improved. The current more research is carbonylation method,the Production of carbonylation method need to high temperature and high pressure, the cost of the material is high, operation process is difficult. Although Claisen condensation using green raw materials, experimental yield is low, needs to be improved.Main purpose of this article is under the condition of claisen condensation get higher yield of methyl malonate, with dimethyl carbonate and methyl acetate as raw materials, using the Ultrasonic auxiliary instrument, Respectively analyzed the effect of the alkaline reagents selection and consumption,Reaction time, material ratio, reaction temperature on the yield of the reaction.The experimental results show that:The dosage of alkali reagent LDA is 12.4ml (0.1 mol), the dosage of dimethyl carbonate is 25.2 ml (0.3 mol), the dosage of the solvent of ethanol is 30ml, the amount of methyl acetate is 35.8ml (0.45 mol). Dimethyl carbonate, ethanol and alkaline reagents LDA directly add to the column reactor, stirring and heating activation for a period of time, drops methyl acetate in the column reactor, the reaction time is 30 minutes, the reaction temperature is 70℃, the ultrasonic power is 600W, the yield of dimethyl malonate is 50.68%.