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以碳酸二甲酯(DMC)与丙酮为原料,在固体碱上合成乙酰乙酸甲酯,并考察了反应温度、反应时间、催化剂用量和原料摩尔比等因素对反应结果的影响。结果表明,以固体酸为催化剂时,无乙酰乙酸甲酯的生成,而具有中强碱位的K/MgO对反应具有较好的催化性能。当以K/MgO为催化剂,在反应温度为240℃,反应时间5h,催化剂用量为反应物总质量的1.5%,原料摩尔比为n(丙酮)∶n(DMC)=1∶4时,丙酮的转化率和乙酰乙酸甲酯的选择性分别达到41.2%和50.3%。反应的主要副产物为丙酮自身缩合的产物(二丙酮醇、4-甲基-3-烯基-2-戊酮、4-甲基-4-烯基-2-戊酮)以及醚化产物(2-甲氧基丙烯)等。
Methyl acetoacetate was synthesized on solid base with dimethyl carbonate (DMC) and acetone. The effects of reaction temperature, reaction time, amount of catalyst and molar ratio of raw materials on the reaction results were investigated. The results showed that the formation of methyl acetoacetate was not observed when solid acid was used as catalyst, while the K / MgO with strong base showed good catalytic activity. When using K / MgO as catalyst, the reaction temperature is 240 ℃, the reaction time is 5h, the amount of catalyst is 1.5% of the total mass of the reactants and the molar ratio of raw materials is n (acetone): n Conversion and methyl acetoacetate selectivity reached 41.2% and 50.3%, respectively. The main byproduct of the reaction is the product of self condensation of acetone (diacetone alcohol, 4-methyl-3-alkenyl-2- pentanone, 4-methyl-4-alkenyl-2-pentanone) (2-methoxypropene) and the like.