固体碱碱性位对丙酮和碳酸二甲酯反应的影响

Effect of Solid Basic Sites on Reaction of Acetone with Dimethyl Carbonate

考察了固体碱不同的碱性位对丙酮和碳酸二甲酯反应的影响,并对反应在不同碱性位上的反应机理进行了推测.实验结果表明,由表面羟基引起的弱碱位有利于丙酮自身缩合反应的进行,主产物为二丙酮醇、4-甲基-3-戊烯-2-酮和4-甲基-4-戊烯-2-酮;Lewis酸碱离子对有利于碳酸二甲酯的甲基化反应的发生,主产物为2-甲氧基丙烯;而由固体碱表面配位不饱和的O2-所造成的强碱位有利于碳酸二甲酯的甲氧基羰基化产物的生成,主产物为乙酰乙酸甲酯;同时发现各种产物的收率与对应的各碱性位的碱量之间均具有较好的线性关系.

The effect of solid basic sites on the reaction of acetone and dimethyl carbonate was investigated. The results showed that the weak basic sites caused by hydroxyl groups favored the condensation of acetone, and the major products were diacetone alcohol, 4-methyl-3-penten-2-one and 4-methyl-4- penten-2-one. The moderate base sites caused by Lewis acid base ions pairs favored the formation of the methylation product （2-methoxypropene） as the main product. The strong basic sites caused by isolated O^2- ions facilitated the methoxycarbonylation reactions with methyl acetoacetate as the major product. For MgO-based catalysts with different calcined temperature, good linear correlations were observed between the products yields and the amount of corresponding basic sites. Furthermore, the possible reaction mechanisms over different basic sites were also proposed.