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33 results on '"Qian, Jun"'

31. Catalytic behavior of a ZnO/TiO 2 composite in the synthesis of polycarbonate diol.

Author

Chong R, Qian F, Sun ZH, Wei MJ, Zhou WY, Zhang J, He MY, Chen Q, and Qian JF

Abstract

ZnO/TiO 2 catalysts with different ZnO contents have been prepared through equal volume impregnation method, characterized by XRD, SEM, Py-IR, ICP, XPS, NH 3 -TPD and N 2 adsorption/desorption, and evaluated in the synthesis of polycarbonate diol (PCDL) through transesterification. The results showed that titanium zinc oxide formed in these catalysts, and the content of acidic sites varied with the ZnO content, and ZnO/TiO 2 (10%) has the highest acid amount. The ZnO/TiO 2 (20%) with medium acidic sites showed the highest catalytic activity. The synthesis process of polycarbonate glycol was also optimized. Under the optimal reaction conditions, the yield of PCDL was 72.5%, and the M n reached 4829 g mol -1 with a PDI of 1.6., Competing Interests: The authors declare no conflict of interest., (This journal is © The Royal Society of Chemistry.)

Published
2023
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32. Metal-free synthesis of C2-quaternary indolinones by (NH 4 ) 2 S 2 O 8 mediated oxidative dearomatization of indoles.

Author

Dong Y, Qian JH, Chen XL, Jiang H, Li X, Zhou Q, Mei T, Shi ZC, Li ZH, and He B

Abstract

An efficient metal-free, (NH 4 ) 2 S 2 O 8 mediated oxidative dearomatization of indoles for the construction of C2-quaternary indolinones was disclosed. A series of C2-quaternary indolinones derivatives with good functional group tolerance were obtained in moderate to excellent yields. This methodology provides an alternative approach for the direct generation of all-carbon quaternary centers at the C2 position of indoles. This catalytic approach represents a step-economic and convenient strategy for the oxidative dearomatization of indoles., Competing Interests: There are no conflicts to declare., (This journal is © The Royal Society of Chemistry.)

Published
2022
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33. Preparation of perovskite CsPb(Br x I 1- x ) 3 quantum dots at room temperature.

Author

Li Y, Qian J, Zhao D, and Song R

Abstract

Here, we propose a method for preparing red perovskite CsPb(Br x I 1- x ) 3 quantum dots (QDs) at room temperature. The PL emission peak of the QDs is close to 650 nm, and the full width at half maximum reaches 61 nm. The red CsPb(Br x I 1- x ) 3 QDs with higher water stability are obtained successfully at room temperature by adjusting the proportion of halogen elements and incorporating polystyrene. At the same time, the red QDs are combined with a blue light-emitting diode to prepare a white light-emitting device (WLED). Compared with the WLED based on the Ce-doped Yttrium Aluminum Garnet (YAG:Ce) phosphor alone, the new WLED based on QDs exhibits a reduced correlated color temperature of 2976 K, while achieving a lumen efficiency of 55.3 lm W -1 , which provides a feasible solution for future research on light-emitting diodes (LEDs)., Competing Interests: There are no conflicts to declare., (This journal is © The Royal Society of Chemistry.)

Published
2021
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