The application of deep eutectic solvents has been demonstrated for the first time in promiscuous lipase-catalysed aldol reactions. The model reaction between 4-nitrobenzaldehyde and acetone was examined in depth, with excellent compatibility being found between porcine pancreas lipase and choline chloride/glycerol mixtures for the formation of the aldol product in high yields. The system was compatible
Carbon Quantum Dots with Photoenhanced Hydrogen-Bond Catalytic Activity in Aldol Condensations
作者:Yuzhi Han、Hui Huang、Hengchao Zhang、Yang Liu、Xiao Han、Ruihua Liu、Haitao Li、Zhenhui Kang
DOI:10.1021/cs401118x
日期:2014.3.7
Carbon quantum dots (CQDs) were synthesized by an electrochemical etching method. The CQDs are well-dispersed with uniform size about 5 nm. FT-IR spectra suggest the presence of many hydroxyl groups on the surface of CQDs. Here, CQDs with diameter approximately 5 nm, directly used as effective heterogeneous nanocatalysts for H-bond catalysis in aldol condensations, show excellent photo-enhanced catalytic ability (89% yields when 4-cyanobenzaldehyde is used). It demonstrated that aldol condensation between acetone and aromatic aldehydes resulted in higher yields with visible light irradiation than in the dark, confirming visible light is necessary for good conversion. The H-bond catalytic activities of CQDs can be significantly enhanced with visible light irradiation. The high catalytic activities of CQDs are due to highly efficient electron-accepting capabilities. Repeated catalytic experiments suggest that the CQD catalyst can be easily recycled as a heterogeneous catalyst with a long catalyst life.