固体碱催化合成乙酰乙酸甲酯

SYNTHESIS OF METHYL ACETOACETATE BY METHOXYCARBONYLATION OF ACETYLACETONE WITH DIMETHYL CARBONATE OVER SOLID BASES

以固体碱为催化剂,研究了碳酸二甲酯(DMC)与乙酰丙酮羰基甲氧基化合成乙酰乙酸甲酯的反应,并考察了反应温度、反应时间、催化剂用量和原料摩尔配比等因素对反应的影响。结果表明,固体酸催化剂对羰基甲氧基化反应不利,而具有强碱性位的CaO对反应具有较好的催化性能。当以CaO为催化剂,反应温度为240℃,反应时间5 h,催化剂用量为反应物总质量的1.0%,n(乙酰丙酮):n(DMC)=1:6时,乙酰丙酮的转化率和乙酰乙酸甲酯的选择性分别达99.1%和48.9%。

A novel route for the synthesis of methyl acetoacetate from acetylacetone and dimethyl carbonate over solid base catalysts was developed. The results showed that no products were detected if the catalyst were not present, and solid acids such as Al2O3 and SiO2 produced diacetone alcohol and 2- methoxypropene as major products, which suggested that solid acid catalysts were inactive towards the methoxycarbonylaton reactions. As for solid base, CaO, which possesses strong basic strength, exhibited higher catalytic activity and methyl acetoacetate selectivity than other catalysts, i.e. ZrO2, La2O3, MgO. Over CaO catalyst, the optimal reaction conditions were obtained as follows： temperature 240 ℃, time 5 h, catalyst mass fraction （based on the total mass of reactant） 1.0%, n（acetylacetone） ： n（DMC）=1 ： 6. Under these conditions, the conversion of acetylacetone and the selectivity of methyl acetoacetate reached 99.1% and 48.9 %, respectively.