New crown ether complex cation ionic liquids with N-heterocycle anions: preparation and application in CO2 fixation
New crown ether complex cation ionic liquids with N-heterocycle anions: preparation and application in CO2 fixation
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DOI：
10.1039/c7qo00829e
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发表时间：
2018-02
影响因子：
5.4
通讯作者：
Jinyuan Wang;Y. Liang;Da‐Gang Zhou;Jiangping Ma;Huanwang Jing
中科院分区：
文献类型：
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作者：
Jinyuan Wang;Y. Liang;Da‐Gang Zhou;Jiangping Ma;Huanwang Jing
设计、合成了一系列冠醚配合物阳离子液体（CECILs），并通过NMR、IR、元素分析和TGA-DSC等手段对CECILs进行了表征。这些新的CECIL（[18-C-6 K]+Y−和[15-C-5 Na]+Y−，Y− =咪唑啉、吡唑啉、1，2，4-三唑啉、苯并[d]咪唑啉、苯并[d]三唑啉）在常压和无溶剂条件下作为有效的催化剂用于环氧化物和二氧化碳的环加成反应。结果表明，催化剂的活性与其结构特征密切相关。在最佳反应条件下，[18-C-6 K]+Y−的CECIL性能上级[15-C-5 Na]+Y−。用[18-C-6 K][Im]和[15-C-5 Na][Im]催化剂对该反应进行了初步的动力学研究。所得活化能与反应速率一致。结合新型催化剂的特点和实验结果，提出了一种阴-阳离子协同催化机理，并通过DFT计算得到了证实。
A series of crown ether complex cation ionic liquids (CECILs) have been devised, synthesized and characterized by NMR, IR, elemental analysis and TGA-DSC. These new CECILs ([18-C-6K]+Y− and [15-C-5Na]+Y−, Y− = imidazolide, pyrazolide, 1,2,4-triazolide, benzo[d]imidazolide, benzo[d]triazolide) were applied as efficient catalysts to the cycloaddition of epoxides and carbon dioxide without a co-catalyst under atmospheric pressure and solvent-free conditions. The results showed that the activity of catalysts deeply relies on their structural features. The CECILs of [18-C-6K]+Y− are superior to [15-C-5Na]+Y− under optimal reaction conditions. A preliminary kinetic study of this reaction was carried out using [18-C-6K][Im] and [15-C-5Na][Im] catalysts. The obtained activation energies are consistent with their reaction rates. An anion–cation synergistic catalytic mechanism has been carefully proposed in light of the features of the new catalysts and experimental results, which was confirmed as well by DFT calculations.