Structural Requirements for Chemoselective Ammonolysis of Ethylene Glycol to Ethanolamine over Supported Cobalt Catalysts

Abstract

Ethylene glycol is regarded as a promising C2 platform molecule due to the fast development of its production from sustainable biomass. This study inquired the structural requirements of Co-based catalysts for the liquid-phase ammonolysis of ethylene glycol to value-added ethanolamine. We showed that the rate and selectivity of ethylene glycol ammonolysis on γ-Al2O3-supported Co catalysts were strongly affected by the metal particle size within the range of 2–10 nm, among which Co nanoparticles of ~4 nm exhibited both the highest ethanolamine selectivity and the highest ammonolysis rate based on the total Co content. Doping of a moderate amount of Ag further promoted the catalytic activity without affecting the selectivity. Combined kinetic and infrared spectroscopic assessments unveiled that the addition of Ag significantly destabilized the adsorbed NH3 on the Co surface, which would otherwise be strongly bound to the active sites and inhibit the rate-determining dehydrogenation step of ethylene glycol.

Glycerol Electrocatalytic Reduction Using an Activated Carbon Composite Electrode: Understanding the Reaction Mechanisms and an Optimization Study

“…Figure 3B illustrates diethylene glycol yield was enhanced with the increase of reaction time and the maximum value was 6.0 C mol%. It proves dehydration reaction occurred with the aid of Amberlyst-15 (rich in Brønsted acid sites) under high temperature similar to Lei et al (2021) work, where diethylene glycol was observed as a by-product on Co/γ-Al 2 O 3 catalyst that consisted high Brønsted acid sites. In Figure 3C, acetol appeared as the only product until the fourth hour with the maximum yield of 2.6 C mol%.…”

The Acquisition of Primary Amines from Alcohols through Reductive Amination over Heterogeneous Catalysts

“…This is because excess NH3 promotes the reductive am nation of acetone, which increases selectivity for isopropylamine. Lei et al [87] prepared a Co catalyst supported on γ-Al2O3 for the liquid-phase am monolysis of ethylene glycol to produce high-value-added ethanolamine and explored th effect of different metal Co particle sizes on the selectivity of ethanolamine in the reductiv amination of ethylene glycol. Among the sizes analyzed, Co nanoparticles above 4 n From the above studies, it can be seen that temperature, H 2 pressure, NH 3 pressure, the structure of the substrate alcohol, catalysts, and other factors all have important effects on the catalytic reaction in the reductive amination of alcohols with NH 3 to produce primary amines.…”

“…Among the sizes analyzed, Co nanoparticles above 4 nm showed the highest ethanolamine selectivity (73.6%) and the highest ammonolysis rate based on the total Co content (Figure 6a). Smaller Co nanoparticles (above 2 nm) were not Lei et al [87] prepared a Co catalyst supported on γ-Al 2 O 3 for the liquid-phase ammonolysis of ethylene glycol to produce high-value-added ethanolamine and explored the effect of different metal Co particle sizes on the selectivity of ethanolamine in the reductive amination of ethylene glycol. Among the sizes analyzed, Co nanoparticles above 4 nm showed the highest ethanolamine selectivity (73.6%) and the highest ammonolysis rate based on the total Co content (Figure 6a).…”

Amination of Ethylene Glycol to Ethylenediamine Catalyzed by Co‐Cu/γ‐Al2O3

“…Xie et al [9,32] prepared unsupported monometallic catalysts for catalyzing amination of ethylene glycol; a 33.9 % ethylene glycol conversion, a 28.2 % ethanolamine selectivity and a 15.3 % ethylenediamine selectivity were obtained. In the research of Lei et al, [10] the catalytic activity of CoÀ Ag/γ-Al 2 O 3 was improved by doping a moderate amount of Ag. The ethylene glycol conversion was 20 % and the ethanolamine selectivity reached 73.6 %, but the ethylenediamine selectivity was still unsatisfactory.…”

“…Lei et al [10] found that CoÀ Ag/γ-Al 2 O 3 showed a better catalytic performance for ethylene glycol amination. Under a reaction temperature of 180 °C, a hydrogen pressure of 3.0 MPa, an ammonia gas pressure of 0.6 MPa, the conversion of ethylene glycol was 20 %, and the selectivity of ethanolamine reached 73.6 %, but the selectivity of ethylenediamine was still low.…”