Search

Your search keyword '"Feng, Yi-Si"' showing total 300 results
Start Over Author "Feng, Yi-Si"
300 results on '"Feng, Yi-Si"'

56. Selective Conversion of Furfural to Cyclopentanone and Cyclopentanol by Magnetic Cu‐Fe3O4 NPs Catalyst.

Author

Pan, Pan, Xu, Wen‐Yi, Pu, Tong‐Jun, Wang, Xu–Dong, Pei, Xiao‐Jun, Tang, Fei, and Feng, Yi−Si

Subjects
FURFURAL, CYCLOPENTANONES, IRON oxide nanoparticles
Abstract

Series of magnetic Cu/Fe3O4 nanoparticles (NPs) with different Cu loading were prepared by co‐precipitation method and studied as catalysts for the conversion of furfural to cyclopentanone (CPO) or cyclopentanol (CPL), respectively in aqueous phase. It is found that the product distribution was affected by the hydrogen pressure, reaction temperature, reaction time and the loading of active metals. X‐ray diffraction (XRD), X‐ray photoelectron spectroscopy (XPS) and Transmission electron microscope (TEM) were used to characterize the catalysts. The results showed that active metals Cu and Fe had obvious interaction. XPS analysis suggested that the electron binding energy of Cu and Fe exhibited a strong interaction, which may be the main reason for the high selectivity of the catalyst to CPO and CPL. The highest yield of CPO was 91% at 3 MPa H2, 10% Cu/Fe3O4, 443 K and 4 h. Furthermore, the highest yield of 82% CPL was obtained when 50% Cu/Fe3O4 was employed. Importantly, it was found that the catalyst had no obvious loss of activity in the five cycles. The catalyst was easy to recycle because of its magnetism. [ABSTRACT FROM AUTHOR]

Published
2019
Full Text
View/download PDF

57. Cadmium Sulfide Quantum‐Dot‐Photocatalyzed Cascade Cyclization of Functionalized Difluoromethyl Chlorides with Unactivated Olefins.

Author

Hu, Jinglin, Pu, Tong‐Jun, Xu, Zhuo‐Wei, Xu, Wen‐Yi, and Feng, Yi‐Si

Subjects
ALKENES, PHOTOCATALYSIS, CADMIUM sulfide, RING formation (Chemistry), DIFLUOROMETHYL compounds, QUANTUM dots
Abstract

A cadmium sulfide quantum‐dot‐photocatalyzed C(sp3)−Cl bond cleavage of ethyl chlorodifluoroacetate and cascade cyclization with unactivated olefins is described herein. This reaction provides a cost‐efficient method for synthesizing a wide range of CF2‐containing azaheterocycles from a variety of functionalized difluoromethyl chlorides. Furthermore, the results of a preliminary anti‐proliferative activity study indicate an in vitro anti‐proliferative activity superior to that of doxorubicin with IC50 values of 1.140 μM on triple negative breast cancer (MDA‐MB‐231) and 2.129 μM on lung (A549) carcinoma cells. [ABSTRACT FROM AUTHOR]

Published
2019
Full Text
View/download PDF

64. Metal‐Free, Visible‐Light‐Mediated Direct C−H Trifluoromethylation of Hydrazones with NADH Coenzyme Model Catalyst.

Author

Huang, Bei, Bu, Xiao‐Song, Xu, Jun, Dai, Jian‐Jun, Feng, Yi‐Si, and Xu, Hua‐Jian

Subjects
METALS, METHYLATION, HYDRAZONES
Abstract

Abstract: A metal‐free, visible‐light‐mediated direct C−H bond trifluoromethylation of N,N‐dialkylhydrazones with an NADH coenzyme model catalyst has been developed. The use of NADH coenzyme model makes this reaction more meaningful. Advantages of this reaction include avoidance of transition metal catalysts, high levels of functional group tolerance, and mild reaction conditions. This reaction represents a method to synthesize substituted hydrazones. [ABSTRACT FROM AUTHOR]

Published
2018
Full Text
View/download PDF

65. Preparation and Optical Properties of SnO 2 /SiO 2 Nanocomposite

Author

Feng Yi-si, Yao Ri-sheng, and Zhang Li-De

Subjects
Materials science, Nanocomposite, Absorption edge, Chemical engineering, Annealing (metallurgy), General Physics and Astronomy, Nanoparticle, Tin oxide, Mesoporous material, Amorphous solid, Blueshift
Abstract

SnO2/SiO2 nanocomposites have been prepared by the soaking-thermal-decomposing method, tin oxide nanoparticles are uniformly dispersed in the mesopores of silica. The optical absorption edge of the obtained nanocomposite presents a redshift compared with bulk tin oxide. With the increasing annealing temperature during the procedure of the sample preparation, the optical absorption edge of the sample moves to shorter wavelength (blueshift). These optical properties can be ascribed to the amorphous structure and band defects of surface layers of the tin oxide nanoparticles.

Published
2004

87. Directed alkynylation of unactivated C(sp3)–H bonds with ethynylbenziodoxolones mediated by DTBP.

Author

Cheng, Zhi-Fei, Feng, Yi-Si, Rong, Chun, Xu, Tao, Wang, Peng-Fei, Xu, Jun, Dai, Jian-Jun, and Xu, Hua-Jian

Subjects
*ALKYNES, *CHEMICAL reactions, *CARBON-hydrogen bonds, *CHEMICAL symbiosis, *RADICALS (Chemistry), *FUNCTIONAL groups
Abstract

A general and efficient method for the direct alkynylation of unactivated C(sp3)–H bonds under metal-free conditions is described. The reaction performs smoothly under mild conditions and shows excellent functional-group tolerance. Initial mechanistic investigation indicates that the reaction may involve a radical pathway. [ABSTRACT FROM AUTHOR]

Published
2016
Full Text
View/download PDF

Catalog

Books, media, physical & digital resources
See catalog results