Polymer-Supported Raney Nickel Catalysts for Sustainable Reduction Reactions

Hydrogenation of Adiponitrile to Hexamethylenediamine over Raney Ni and Co Catalysts

Hexamethylenediamine (HMDA), a chemical for producing nylon, was produced on Raney Ni and Raney Co catalysts via the hydrogenation of adiponitrile (ADN). HMDA was hydrogenated from ADN via 6-aminohexanenitrile (AHN). For the two catalysts, the effects of five different reaction parameters (reaction temperature, H2 pressure, catalyst loading, and ADN/HMDA ratio in the reactant) on the hydrogenation of ADN were investigated. Similar general trends demonstrating the dependence of ADN hydrogenation on the reaction conditions for both catalysts were observed: higher temperature (60–80 °C) and H2 pressure, as well as lower ADN/catalyst and ADN/HMDA ratios, led to higher HMDA yields. A further increase in temperature from 80 to 100 °C increased the HMDA yield from 90.5 to 100% for the Raney Ni catalyst, but did not affect the HMDA yield (85~87%) for the Raney Co catalyst. A 100% HMDA yield (the highest yield reported to date) was also achieved via ADN hydrogenation over the Raney Ni catalyst, with a high HMDA content in the reactant (e.g., ADN/HMDA volumetric ratio of 0.06). No sign of metal leaching into the product solution was found, meaning that the Raney Ni and Raney Co catalysts were stable during ADN hydrogenation.

Carbon-Supported Raney Nickel Catalyst for Acetone Hydrogenation with High Selectivity

Catalysts with high selectivity play key roles in green chemistry. In this work, a granular Raney Ni catalyst using carbon as support (Raney Ni/C) was developed by mixing phenolic resin with Ni-Al alloy, conducting carbonization at high temperature, and leaching with alkaline liquor. The as-prepared Raney Ni/C catalyst is suitable for use in fix-bed reactors. Moreover, it shows high activity and selectivity for catalytic acetone hydrogenation. For instance, at the reaction temperature of 120 °C, the conversion of acetone can reach up to 99.9% and the main byproduct methyl isobutylcarbinol (MIBC) content can be diminished to 0.02 wt%. The Raney Ni/C may represent a new type of shaped Raney metal catalysts, which are important fix-bed catalysts in chemical industry.