Raney Ni as a Versatile Catalyst for Biomass Conversion

Abstract

Raney Ni is a class of fine-grained heterogeneous catalysts composed mostly of nickel that is widely applied in organic synthesis and a large number of industry processes. In the past 10 years, various excellent research achievements have been obtained due to the emerging field of biomass conversion, which opened another dimension to this catalyst. This review starts with a brief introduction to the history of Raney Ni from its creation to its development. The subsequent sections provide a comprehensive discussion of the synthetic strategies and their controls from the perspective of structure and composition. We focus especially on the current applications in biomass conversion, including the catalytic upgrading of raw biomass resources and the derived platform chemicals. In this review, we try to gain a great understanding of this unique catalyst and its special role in biomass conversion in comparison with supported Ni catalysts. The outstanding catalytic performance of Raney Ni may inspire researchers to explore more elegant preparation methods and emerging applications.

One‐Pot Catalytic Conversion of Lignin‐Derivable Guaiacols and Syringols to Cyclohexylamines

“…In using Raney Ni, however, this could be significantly improved to an overall 7A yield of 87.3 %. This suggests a unique capability of Raney Ni to perform not only hydrogenation but also demethoxylation, as was also shown by recent work of Wang and Rinaldi, and alcohol amination, which is in line with previous work by our group [31,36,47–49] . We attribute the high required catalyst loading to the presence of inactive Ni oxide in Raney Ni as well as inaccessible Ni in the bulk of the catalyst.…”

“…This suggests a unique capability of Raney Ni to perform not only hydrogenation but also demethoxylation, as was also shown by recent work of Wang and Rinaldi, and alcohol amination, which is in line with previous work by our group. [31,36,[47][48][49] We attribute the high required catalyst loading to the presence of inactive Ni oxide in Raney Ni as well as inaccessible Ni in the bulk of the catalyst. Also, commercial Raney Ni is typically characterized by the presence of a substantial amount of water ( � 20 wt %).…”

Fully lignocellulose-based PET analogues for the circular economy

“…2C and Supplementary Table 3 ), in line with excellent previous work of Rinaldi and coworkers 44 using this solvent/catalyst combination for transfer hydrogenation purposes. Thus, we attribute this higher rate of catalytic funneling towards PC to the high transfer hydrogenation activity of Raney Ni as well as its lower tendency for aromatic ring hydrogenation compared to noble metal catalysts 46 (Supplementary Note 5 ). Optimization led to an 84.8% yield of PC at 120 °C for 2 h, applying 10 bar H 2 (Fig.…”

Primary amines from lignocellulose by direct amination of alcohol intermediates, catalyzed by RANEY® Ni

“…Overalkylation of 1G amine to 1G dimer amine was only detected in very small amounts (Table S1, † entry The high catalytic reactivity was mainly ascribed to the fact that RANEY® Ni is highly efficient in a range of hydrogen transfer transformations, including amination by hydrogen-borrowing reactions. 41 It has to be noticed that using atmospheric pressure of NH 3 shifted towards the production of 4-ethyl guaiacol, with a selectivity of >99%. (Table S4 †) Therefore this catalyst system was selected for detailed optimization over a wide temperature range (120-160 °C), the results having been summarized in Fig.…”