Graphical A dynamic double kinetic resolution (DDKR) strategy under the co-catalysis of Raney nickel and Candida antarctica lipase B (CAL-B) was established for the one-pot simultaneous resolution of primary amines and secondary alcohols. Herein, we have established a dynamic double kinetic resolution (DDKR) strategy under the co-catalysis of Raney nickel and Candida antarctica lipase B (CAL-B) for the one-pot simultaneous resolution of primary amines and secondary alcohols (or esters). The DDKR strategy was successfully applied to the resolution of a series of racemic amines and secondary alcohols (or esters) as well as mexiletine, an important antiarrhythmic agent. The catalysts could be recycled and reused several times with the same high activity. Scale-up experiments were also successful. As a more atom-economical and efficient process than traditional simple kinetic resolutions, the DDKR strategy can be widely used to prepare optically pure amines and alcohols.
Yulu Wang,Xuejun Pan,Yueyuan Ye,Shuirong Li,Duo Wang,Yun-Quan Liu
Liquefaction co-catalyzed by Raney nickel and NaOH in isopropanol (2-PrOH)/H 2 O is an efficient method for transforming lignocellulosic biomass into bio-oil. The present study investigated the effect of reaction temperature, residence time, and dosage of the catalysts on the yield and composition of bio-oil. To understand the liquefaction mechanism, the transformation of lignin and cellulose at the same conditions was investigated as well. The results indicated that 240 °C was the optimum temperature in terms of bio-oil yield. It was also found that residence time had a great effect on not only the bio-oil yield but also the composition and higher heating value (HHV) of the bio-oil. Increasing the dosage of the catalysts also improved the yield and HHV of bio-oil. Most phenols in bio-oil were originated from lignin, while most ketones and hydrocarbons were produced by cellulose.
Yuan Sheng,Wenxing Zhu,Zhijian Li,Shuo Li,Liangbin Shao,Jianguo Wang
Green hydrogen production by alkaline water electrolysis is an important technology in the decarbonization of the current industry. However, its large-scale application is limited by mediocre performance of conventional Raney Ni electrocatalysts. Herein, high-performance NiMoZn alloy catalysts of the Raney Ni type are developed by pulse electrodeposition for the hydrogen evolution reaction (HER). The optimized catalyst, NMZ-CA, exhibits an overpotential of 37 mV at 10 mA⋅cm −2 and a Tafel slope of 27 mV⋅dec −1 in 1 mol·L –1 KOH. Tafel slope measurements, X-ray photoelectron spectroscopy, and H 2 temperature-programmed desorption experiments show that the incorporation of Mo and Zn in Ni weakens the binding of HER intermediate (H ads ) on strongly adsorbing sites, leading to improved electrochemical kinetics. Electron microscopy and X-ray diffraction study reveals that a phase-pure Mo-doped Ni 2 Zn 11 intermetallic precatalyst formed via pulse electrodeposition and subsequent heat treatment is key to the structure integrity and performance of the catalyst after activation by alkaline leaching. Modification of NMZ-CA with PTFE enhances its HER performance by facilitating gas removal and improving structure integrity. A practical alkaline water electrolyzer built on the modified NMZ/PTFE-CA electrode delivers 2.0 A⋅cm −2 at 1.92 V cell voltage and operates for 250 h without decay. This work provides insights into the synergy between Ni, Mo, and Zn in Raney Ni-type catalysts, and demonstrates the hydrophobic modification as an effective strategy for electrode development in high-performance alkaline water electrolysis.
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