| 摘要 |
PURPOSE:To minimize the loss of the titled compound in the preparation using a catlyst comprising an alcohol or acetone solution of cobalt tetracarbonyl anion, by decreasing the amount of water for the extraction of Co salt and NaCl as far as possible. CONSTITUTION:Monochloroacetic ester is made to react with carbon monoxide, sodium carbonate and an alcohol in the presence of a catalyst comprising an alcohol or acetone solution of cobalt tetracarbonyl anion to obtain a reaction liquid containing malonic acid diester. The catalyst is decomposed by adding concentrated sulfuric acid and oxygen to the reaction liquid, and the excess alcohol is removed by distillation. The resultant concentrated liquid is admixed with 0.1-0.5pt.wt. of water 1pt.wt. of the liquid, and the mixture is separated into an aqueous layer containing sodium chloride and Co salt and an organic layer composed mainly of the objective compound. The organic layer is distilled and the objective compound is obained as the distillate. The monoester in the still residue is diesterified to obtain the objective compound. The separated aqeous layer is diluted with water to dissolve sodium chloride, and the Co salt is converted to a water-insoluble compound, recovered and used for the preparation of the catalyst. |
