preparation | (1), condensation reaction between chloropentane and formaldehyde under acidic conditions, catalyzed by Zn/Co/Sb composite catalyst, reaction temperature 60°C, reaction time 5h, preparation of peronone, the ratio between the sum of the substances of each component in the Zn/Co/Sb composite catalyst and the amount of chloropentane is 3:50;(2), using pyrenone, sodium hydride and dimethyl carbonate as raw materials, toluene as solvent, at 55~60°C, stirring and reacting, cooling, at pH = 4, preparing 4, crude methyl 4-dimethyl-3-oxo-valerate, with water content <0.2fft.% and water content of toluene <0.2Wt.%;(3) The crude methyl 4-dimethyl-3-oxo-valerate was distilled at a vacuum degree of less than 1mm Hg and a temperature of 90°C, and the purity of methyl 4, 4-dimethyl-3-oxo-valerate obtained was high, the yield is high, the main content is above 98%, and the total yield is 96%. |