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金属配合物在离子液体中催化醇的氧化反应研究

Study on Catalytic Oxidation of Alcohols in Ionic Liquid by Metal Complexes

【作者】 刘翀

【导师】 韩金玉;

【作者基本信息】 天津大学 , 化学工艺, 2008, 博士

【摘要】 离子液体是由阴阳离子组成的室温成液态的盐,采用金属配合物与离子液体相结合催化醇的氧化反应,不仅可以使催化剂能够重复使用,而且对于开发绿色化工过程具有重要意义和应用价值。本文对乙酰丙酮铜在离子液体中催化醇的氧化反应进行了研究,通过考察一系列影响反应的因素,确定出乙酰丙酮铜/[bmim]PF6为适宜的催化体系,得到适宜的反应条件为:2 mmolα-苯乙醇,10 mmol t-BuOOH,3 mol% Cu(acac)2,[bmim]PF6 1 mL,室温反应5h,在此条件下,α-苯乙醇的转化率和乙酰苯的产率分别达到93%和87%。在此催化体系下,以t-BuOOH为氧化剂,脂肪醇和芳香醇的仲醇均能被氧化成相应的酮,而伯醇有一部分被过氧化为相应的羧酸。反应体系在重复使用5次后,活性仅有微小的降低。以乙酰丙酮铜为原型,通过改变配体结构分别合成了乙酰丙酮-氨基酸-金属配合物和水杨醛-氨基酸-金属配合物来研究配体的改变对配合物催化性能的影响,通过红外光谱、热重分析、元素分析、核磁共振等定性分析方法,确定了其分子结构式。通过对反应影响因素的考察,确定出乙酰丙酮-亮氨酸-铜和水杨醛-酪氨酸-锰两个催化体系具有较好的催化活性。乙酰丙酮-亮氨酸-铜体系不仅能够将脂肪醇和芳香醇的仲醇氧化成相应的酮,而且也能将伯醇全部氧化成相应的羧酸。同时,相应的离子液体催化体系在重复使用5次后,其活性没有明显降低。结果表明氨基酸的引入大大提高了催化剂对伯醇的选择性。而水杨醛-酪氨酸-锰体系对产物的选择性与乙酰丙酮铜类似,但反应结束后催化体系不能重复使用。合成了带有离子液体支链的金属配合物功能型离子液体,以期提高催化体系的重复使用性,通过红外光谱、热重分析、元素分析、核磁共振等定性分析方法,确定了其分子结构式。实验结果表明,经过改性的功能型离子液体的催化活性得到了较大程度的提高,但催化剂的重复使用性仍有待提高。[bmim]BF4/NaClO组成的催化体系能够有效地催化脂肪醇和芳香醇的氧化反应,不仅可将仲醇氧化成相应的酮,而且也能将伯醇氧化成相应的醛。同时催化体系在重复使用5次后,其催化活性没有明显降低。

【Abstract】 Ionic liquids are liquid salts at room temperature which are composed by anions and cations. Oxidations of alcohols are catalyzed by the method based on metal compounds and ionic liquids, which not only make catalysts reusably, but also have important meaning and application for the green chemical engineering.Catalyzed oxidation of alcohols by copper acetylacetonate in ionic liquid was studied. For optimizing the reaction condition, the influence of several factors on reaction was studied, and then a satisfied reaction condition was obtained in 5 hours at room temperature with 2 mmol 1-Phenylpropan-1-ol, 10 mmol t-BuOOH, 3 mol% copper acetylacetonate and 1 mL [bmim]PF6. In this condition, the conversion and yield of 1-Phenylpropan-1-ol was 93% and 87%. The sec-alcohols of benzylic and aliphatic alcohols were all oxidized to the corresponding ketones with t-BuOOH as oxygen resource in this catalytic condition. The catalytic system can be recycled and reused for five runs without any significant loss of catalytic activity.N-acac-amino acid-M and Sal-amino acid-M were synthesized by changing structure of complexes based on copper acetylacetonate in order to study the influence between catalyzed ability and complexes. The molecular structures were confirmed by FT-IR, TGA, EA and NMR, etc. N-acac-amino acid-Cu and Sal-amino acid-Mn were satisfied catalytic system by studying the factors on reactions. The N-acac-amino acid-Cu system oxidized not only the sec-alcohols of benzylic and aliphatic alcohols to corresponding ketones, but also the primary alcohol to the corresponding carboxylic acid. The catalytic system can be recycled and reused for five runs without any significant loss of catalytic activity. The selectivity of primary alcohols was improved due to introduced amino acid to metal complexes. For the Sal-amino acid-Mn catalytic system, the selectivity of products was the same as the copper acetylacetonate catalytic system, but it cannot be reused.Metal complexes task-special ionic liquids with ionic liquid tags were synthesized in order to improved the reusability of catalytic system. The molecular structures were confirmed by FT-IR, TGA, EA and NMR, etc. It should be noted that the catalytic ability was greatly improved by these Metal complexes task-special ionic liquids, but the reusability still needed to improve.Oxidations of benzylic and aliphatic alcohols were catalyzed efficiently by [bmim]BF4/NaClO system. This system oxidized not only the sec-alcohols to the corresponding ketones, but also the primary alcohols to the corresponding carboxylic acid. What’s more, the catalytic system can be recycled and reused for five runs without any significant loss of catalytic activity.

  • 【网络出版投稿人】 天津大学
  • 【网络出版年期】2009年 07期
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