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DEVELOPMENT OF SOLID BASE CATALYSTS ACTIVE FOR MICHAEL ADDITIONS AND THEIR RELATED REACTIONS

迈克尔加成活性固体碱催化剂的开发及其相关反应

基本信息

批准号：
09650853
负责人：
HATTORI Hideshi
金额：
$ 2.18万
依托单位：
HOKKAIDO UNIVERSITY
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (C)
财政年份：
1997
资助国家：
日本
起止时间：
1997 至 1998
项目状态：
已结题

项目摘要

A wide variety of solid base catalysts were prepared, and examined their catalytic properties for dimerization of methyl crotonate, addition of nitromethane to usnsaturated carbonyl compounds, and cyanoethylation of alcohols with acrylonitrile for developing hetergenous catalysts active for Michael addition reactions which are important organic synthesis forming C-C bonds.For dimerization of methyl crotonate, only MgO exhibited a high activity among solid bases examined. The reaction is initiated by abstraction of allylic proton by basic sites to form an anionic intermediate which attacks beta-position C atom of a second methyl crotonate. The reaction completes by double bond migration as a final step. A high activity of MgO is suggested to be due to a moderate absorptivity and high density of active sites.For Michael additions of nitromethane to <encircledR>-unsaturated compounds, KF/alumina and KOH/alumina exhibited a high activity, The reaction mechanisms were elucidated, and the reactivity of reactant depended on the charge denstiy of beta-carbon of the reactantFor cyanoethylation of alcohols with acrylonitrile, alkaline earth hydroxides and oxides, KF/alumina, KOH/alumina, and rare earth oxides exhibited a high activity. The reaction rate are determined by a combination of acidity of alcohol with basic strength of active sites. An alcohol of high acidity reacts faster on a weakly basic catalystFor the reactions involving alcohols, a solid based catalyst is scarcely poisoned by water vapor and carbon dioxide, which is caused by a strong interaction of alcohols with basic sites on the catalysts.

制备了多种固体碱催化剂，并检验了它们对巴豆酸甲酯二聚、硝基甲烷与不饱和羰基化合物的加成以及醇与丙烯腈的氰乙基化的催化性能，以开发对迈克尔加成反应具有活性的多相催化剂，迈克尔加成反应是形成 C-C 键的重要有机合成反应。 MgO 在所检测的固体碱中表现出较高的活性。该反应通过碱性位点夺取烯丙基质子来引发，形成阴离子中间体，该中间体攻击第二个巴豆酸甲酯的β-位C原子。作为最后一步，反应通过双键迁移完成。 MgO的高活性被认为是由于其中等的吸收率和高密度的活性位点。对于硝基甲烷与<circledR>-不饱和化合物的迈克尔加成，KF/氧化铝和KOH/氧化铝表现出高活性，阐明了反应机理，反应物的反应性取决于反应物的β-碳的电荷密度。醇与丙烯腈、碱土金属氢氧化物和氧化物、KF/氧化铝、KOH/氧化铝和稀土氧化物的氰乙基化表现出高活性。反应速率由醇的酸性与活性位点的碱性强度的组合决定。高酸度的醇在弱碱性催化剂上反应更快。对于涉及醇的反应，固体催化剂几乎不会被水蒸气和二氧化碳中毒，这是由于醇与催化剂上碱性位点的强烈相互作用造成的。