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368 results on '"Xu, Bao-Hua"'

27. Co(dppbsa)-catalyzed reductive N,N-dimethylation of nitroaromatics with CO2 and hydrosilane.

Author

Ma, Shuang-Shuang, Sun, Rui, Zhang, Zi-Heng, Guan, Peng-Xin, Lin, Jin-Qing, Li, Chun-Shan, and Xu, Bao-Hua

Subjects
NITROAROMATIC compounds, CATALYTIC reduction, SILYL ethers, CATALYTIC activity
Abstract

In this study, a novel half-sandwich phosphinesulfonate cobaltic complex (Co(dppbsa)) was prepared and characterized, which surprisingly enabled the chemoselective N,N-dimethylation of nitroaromatics with CO2 using NaBArF4 as the promotor and a combination of PhSiH3 and Et3SiH as the reductant. Further studies demonstrated that the catalytic activity for reduction of nitroaromatics and CO2 could be modulated, respectively, by using a specific structure and composition of hydrosilanes. The semi-reduction products nitrosoarene and silyl formate are the key intermediates affording the most efficient C–N coupling for the N,N-dimethylation of nitroaromatics with CO2. [ABSTRACT FROM AUTHOR]

Published
2023
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39. HZSM‐5‐Catalyzed Vapor‐Phase Conversion of Dimethyl Adipate to Adiponitrile: The Influence of the SiO2/Al2O3 Ratio on Reactivity.

Author

He, Lin‐Jie, Wang, Yao‐Feng, Guan, Peng‐Xin, Niu, Qing‐Shan, Liu, Hong‐Ying, and Xu, Bao‐Hua

Subjects
ETHANES, ACID catalysts, ZEOLITES, DESORPTION, ADSORPTION (Chemistry)
Abstract

The vapor‐phase nitrilation of dimethyl adipate (DMA) with ammonia (NH3) is an environmentally benign route leading to adiponitrile (ADN) with great application value. In this study, the performance of HZSM‐5 zeolites, widely used in industry as the solid acid catalysts, was investigated. It exhibits a strong correlation between the SiO2/Al2O3 ratio (SAR) in HZSM‐5 zeolites and the reactivity (both activity and selectivity). The influence of Al density closely related to the value of SAR on the reactivity of HZSM‐5 was thus elucidated by mechanistic experiments. As a result, the introduction of Al element to the framework is beneficial to the activation of ester functionality, thus improving the activity, especially at a high liquid hourly space velocity (LHSV). However, a high Al density will lead to poor selectivity and deactivation due to too strong adsorption of esters and intermediates (e. g., amides). Herein, the balanced adsorption/desorption capability was reached on HZSM‐5 with SAR as 631 (i. e., HZSM‐5‐631), which provides the best selectivity to nitriles (SADN+MCP, 92.5 %) at a high single‐pass conversion of DMA (CDMA, 98.0 %). [ABSTRACT FROM AUTHOR]

Published
2023
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43. The Combination of Red and Blue Light, Radiofrequency and Intense Pulsed Light for the Treatment of Facial Postacne Erythema [Letter]

Author

Zhang,Jia-Yu, Xu,Bao-Hua, Zhang,Jia-Yu, and Xu,Bao-Hua

Abstract

Jia-Yu Zhang, Bao-Hua Xu China-Japan Friendship Hospital (Institute of Clinical Medical Sciences), Chinese Academy of Medical Sciences & Peking Union Medical College, Beijing, People’s Republic of ChinaCorrespondence: Bao-Hua Xu, Chinese Academy of Medical Sciences & Peking Union Medical College, China-Japan Friendship Hospital, 2 Cherry Blossom Garden East Street, Chaoyang District, Beijing, 100029, People’s Republic of China, Email drbaohuaxu@163.com

Published
2022

44. Factors Predicting Positive Sentinel Lymph Node Biopsy in Clinically Node-Negative Breast Cancer [Letter]

Author

Zhang,Jia-Yu, Xu,Bao-Hua, Zhang,Jia-Yu, and Xu,Bao-Hua

Abstract

Jia-Yu Zhang,1 Bao-Hua Xu1,2 1China-Japan Friendship Hospital (Institute of Clinical Medical Sciences), Chinese Academy of Medical Sciences & Peking Union Medical College, Beijing, People’s Republic of China; 2China-Japan Friendship Hospital Stomatology Center, Beijing, People’s Republic of ChinaCorrespondence: Bao-Hua Xu, China-Japan Friendship Hospital, 2 Cherry Blossom Garden East Street, Chaoyang District, Beijing, 100029, People’s Republic of China, Email drbaohuaxu@163.com

Published
2022

50. Covalent Organic Frameworks Boost the Silver-Electrocatalyzed Reduction of CO2: The Electronic and Confinement Effect

Author

Yang, Xian-Xia, Du, Yi-Ran, Li, Xiao-Qiang, Duan, Guo-Yi, Chen, Yong-Mei, and Xu, Bao-Hua

Abstract

The electrocatalytic reduction of CO2to CO with high efficiency is one of the most promising approaches for CO2conversion due to its considerable economic feasibility and broad application prospects. In this study, three Ag@COF-R (R = −H, −OCH3, −OH) hybrids were facilely fabricated by impregnating silver acetate (AgOAc) into respective covalent organic frameworks (COFs) prepared in advance. They differ significantly in the crystallinity, porosity, distribution, size, and electronic configuration of AgOAc species, which thereby influences both the activity and the selectivity of electrolytic CO2-to-CO transformation. Impressively, Ag@COF-OCH3provided a high FECOof 93.0% with a high jCOof 213.9 mA cm–2at −0.87 V (vs reversible hydrogen electrode, RHE) in 1 M KOH using a flow cell. In addition, it exhibited long-term durability at 100 mA cm–2for 30 h.

Published
2023
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