Heterogeneous Ru-Based Catalysts for One-Pot Synthesis of Primary Amines from Aldehydes and Ammonia

Abstract

Abstract:The direct reductive amination of carbonyl compounds with NH3 and H2 is an alternative route to produce primary amines in practical production. The search for efficient and selective catalysts has attracted great interest. In the present work, the reductive amination of heptaldehyde with NH3 was investigated over a Ru-based catalyst. The product selectivities were found to be related with the supports of Ru. The alumina with spinel structure (γ-Al2O3, θ-Al2O3)-supported Ru catalysts exhibited selectivity favoring primary amines (94% yield) at 100% heptaldehyde conversion under optimal conditions. Purely basic (MgO, CaO) and relative acidic (Nb2O5, SnO2, MCM-41, HZSM-5) supports showed relatively poor selectivity towards primary amines (0%-53% yield). The reductive amination mechanism was also proposed. The Schiff base N- [heptylene]heptyl-1-amine was a key intermediate. Ru/γ-Al2O3 was shown to be an excellent hydrogenolysis catalyst to selectively produce primary amine by amination and hydrogenolysis of N- [heptylene]heptyl-1-amine. OPEN ACCESSCatalysts 2015, 5 2259

Selective Synthesis of Furfurylamine by Reductive Amination of Furfural over Raney Cobalt

“…However, after introducing 0.1 MPa ammonia, furfurylamine was obtained over each tested catalyst, which manifested the promotion effect of ammonia on the catalytic hydrogenolysis of the Schiff base. As reported, in the presence of ammonia and hydrogen, the conversion of the Schiff base can also proceed through reacting with ammonia to form a germinal diamine and subsequent hydrogenolysis to produce primary amine (Scheme ). This might be the reason why application of an excess of ammonia is a common technique to increase the selectivity to primary amine.…”

“…However, in the initial stage of the reaction, no desired furfurylamine was detected. This can be ascribed to the stronger nucleophilicity of primary amine than ammonia, resulting in the immediate reaction of the initially‐formed furfurylamine with the remaining furfural to form the Schiff base . With the reaction time up to 15 min, there was no furfural remained and furfurylamine started to accumulate.…”

A high performance catalyst of shape-specific ruthenium nanoparticles for production of primary amines by reductive amination of carbonyl compounds

“…To the best of our knowledge, the Ru-NP catalyst exhibited the highest TOF among the metal catalysts reported to date for the reductive amination of 1a to produce 2a ( Table 2 ). 45 , 47 , 48 Reuse experiments with the Ru-NP catalyst for the reductive amination of 1a (Fig. S7 † ) showed no noticeable decrease in activity, even after four reuses, which indicates the robustness of the catalyst.…”

Characteristics of Carbon Nanotubes/Graphene Coatings on Stainless Steel Meshes Used as Electrodes for Air-Cathode Microbial Fuel Cells

“…A possible explanation is the differences in the surface area of MW-CNTs-and MG-coated SSMs. MW-CNTs and MG are adsorbed on SSM via carbon-metal bonding [38] or van der Waals interaction [22], and a large specific surface area can offer more adsorption sites [39]. In the studied cases, the specific surface areas of MW-CNTs and MG are approximately 60 and 20 m 2 /g, respectively.…”