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近年来,催化CO2合成精细化学品的研究备受关注。本研究在温和条件下利用金属双氮杂环卡宾催化剂实现CO2与末端炔烃的直接羧化反应,并提出合理的催化机理。首先,合成制备了铜基、银基两种金属双氮杂环卡宾催化剂,实验证明银双氮杂环卡宾配合物具有较好催化活性。通过改变环境条件和底物种类,对反应条件及催化剂底物适应性进行了探究,利用核磁共振谱仪表征产物分子结构并计算直接羧化反应的催化产率。结果表明,适宜催化条件为:1.2eq Cs2CO3作为添加剂、1大气压、室温、无水溶剂和1(mmol)%催化剂用量。银基金属催化剂活性较铜基催化剂高并具有广泛的底物适应性,对苯乙炔的催化产率高达93%;对乙炔气体同样具有良好的催化活性。此类催化剂具有优良的催化活性,能催化合成丙炔酸等重要医药中间体,在工业应用上具有极大潜力和广阔前景。
In recent years, catalysis of CO2 synthesis of fine chemicals research has drawn great attention. In this study, the direct carboxylation of CO2 with terminal alkynes was carried out under mild conditions using metal bisazacyclocarbene catalysts and a reasonable catalytic mechanism was proposed. Firstly, Cu-based and Ag-based two-metal bis-azacyclocarbene catalysts were prepared synthetically. The experiments show that the silver bis-aza-heterocyclic carbene complexes have good catalytic activity. By changing the environmental conditions and substrate types, the reaction conditions and the adaptability of the catalyst substrate were explored. The molecular structure of the product was characterized by using a nuclear magnetic resonance spectrometer and the catalytic yield of the direct carboxylation reaction was calculated. The results showed that the suitable catalytic conditions were as follows: 1.2eq Cs2CO3 as additive, 1 atmosphere, room temperature, anhydrous solvent and 1 (mmol)% catalyst. The activity of silver-based metal catalysts is higher than that of copper-based catalysts and has a wide range of substrate adaptability. The catalytic yield of phenylacetylene is as high as 93%. Acetylene gas also has good catalytic activity. Such catalysts have excellent catalytic activity and can catalyze the synthesis of important pharmaceutical intermediates such as propiolic acid and have great potential and broad prospects in industrial applications.