Propanol Amination over Supported Nickel Catalysts: Reaction Mechanism and Role of the Support

Abstract

Ni-supported hydroxyapatite catalyst (Ni/ HAP) was characterized and evaluated for propanol amination to propylamine at 423 K. The reaction proceeds via dehydroamination, a process that involves sequential dehydrogenation, condensation, and hydrogenation. Kinetic and isotopic studies indicate that α-H abstraction from propoxide species limits the rate of the dehydrogenation step and hence the overall rate of reaction. The rate of propanol dehydrogenation depends on the composition of the support and on the concentration of Ni sites located at the interface between Ni nanoparticles and the support. Ni/HAP is an order of magnitude more active than Ni/SiO 2 and displays a higher selectivity toward the primary amine. The superior performance of Ni/HAP is attributed to the high density of basic sites on HAP, which are responsible for stabilizing alkoxide intermediates and suppressing the disproportionation and secondary amination of amines.

Effective synthesis of 5-amino-1-pentanol by reductive amination of biomass-derived 2-hydroxytetrahydropyran over supported Ni catalysts

“…Firstly, 2-HTHP is equilibrated with its ring-opened tautomer (5-HP) [17], which is then rapidly condensed with NH3 to form the reactive imine intermediate . Imines are reported to be the key intermediates in the amination of both alcohols and carbonyl compounds for the synthesis of primary amines [2,11,26,[30][31][32]. The 5-IP intermediate is readily hydrogenated to the target 5-AP product over metallic active sites in the presence of sufficient H2.…”

Switchable Structure Promoted Leaching Free Atomically Dispersed Pt Catalyst for Low Carbon Biomass Polyol Oxidation

“…Therefore, Pt precursor can be uniformly doped into the crystal of HAP during crystallization 43,44 .…”

Boosting Amination of 1‐Octanol to 1‐Octylamine via Metal‐Metal Oxide Interactions in NixFe1/Al2O3 Catalysts

“…It is reported that the acidic and basic characteristics of the catalyst are important for the reductive amination reaction. [13,15,25] NH 3 À TPD and CO 2 À TPD experiments were conducted to investigate the acid-base properties of the catalyst. As shown in Figure 4a, Ni/Al 2 O 3 exhibited a similar amount of weak acid (200-280 °C) but an increased amount of medium acid (300-400 °C) in comparison with pure Al 2 O 3 .…”

“…Consequently, nickel oxide of the catalyst was easy to reduce, which enhanced the catalytic activity. Ho et al [15] studied the Ni-supported hydroxyapatite catalyst (Ni/HAP) for propanol amination to propylamine. The high density of basic sites on HAP gave superior catalytic performance.…”