A Review on the Recent Advances in the Reductions of Carbon–Carbon/Oxygen Multiple Bonds Including Aromatic Rings Using Raney Ni–Al Alloy or Al Powder in the Presence of Noble Metal Catalysts in Water

Abstract

Over the last few years, heterogeneous catalysts have attracted much attention with a view to lowering reaction temperatures and improving the selectivity of many organic syntheses. When designing or optimizing a catalyst, attention is devoted to the nature of the active sites, and how they interact with the reactants, intermediates and products of the catalytic process. It has become clear that the structural and electronic features of an active site are usually affected by the chemical environment in which it operates. Raney Ni-Al alloy and noble metal catalysts such as Ru/C, Rh/C, Pd/C and Pt/C are employed in the selective and complete hydrogenation of various functional groups and aromatic rings in presence of water in a sealed tube. Al powder was found to be capable of reducing a carbonyl group, an alkyne group and the aromatic ring of biphenyl, fluorene, 9,10-dihydroanthracene, polyarenes and N-heterocycles using noble metal catalysts in water under mild reaction conditions.

The formation of active phases in Pt-containing catalysts for bicyclohexyl dehydrogenation in hydrogen storage

“…The synergistic effect of interaction between platinum and transition metals in composite active clusters can significantly increase the activity and selectivity of catalytic reactions. 15–20…”

In Situ Evolution of Ru4Al13 Crystals into a Highly Active Catalyst for the Hydrogen Evolution Reaction

“…Bulk Ru–Al intermetallic compounds are particularly attractive targets as they alloy an HER-active metal catalyst (Ru) with a corrosion-susceptible metal (Al) and therefore are capable of evolving in acid to change composition and morphology. The most ubiquitous example of this synthetic strategy, using Al-based alloys, has been through the development of Raney Ni, which is a widely used hydrogenation catalyst synthesized by leaching the Al in Ni–Al alloys under alkaline conditions. − Raney nickel-based materials have seen use as both catalysts and supports for carrying out water-splitting reactions. , Al leaching has also been used to transform MoAlB single crystals into MoAl 1– x B, which has accessible pores that expose catalytically active basal planes that were buried within the crystal prior to removal of Al . In addition, this Al dealloying strategy has been used to produce “Raney Ru” catalysts, which are typically used for ammonia and methanol synthesis. − Nanoporous Ru catalysts made through dealloying of sputtered Ru–Al films have also been shown to facilitate the production of hydrogen from the hydrolysis of sodium borohydride or ammonia borane. , …”

Visible-Light-Induced Hydrogenation of C═C Bonds by Hydrazine over Ultrathin Layered Double Hydroxide Nanosheets

“…Hydrogenation of carbon–carbon or carbon–oxygen multiple bonds (CC, CC, and CO) in alkenes, alkynes, and carbonyl compounds to valuable products is of great importance in the synthesis of fine chemicals. − During the traditional hydrogenation reaction, heterogeneous catalysts containing noble metals such as Au, Pt, and Rh are widely used, and hydrogen (H 2 ) is usually necessary as the reductant in the hydrogenation reaction. − However, the use of noble metal catalysts is restricted by the limited resources and costs. In addition, the flammable hydrogen gas as a reducing agent may pose a safety accident, especially under harsh reaction conditions.…”