Carbon-Supported Mg–Al Oxide Hybrid Catalysts for Aqueous Ethanol Conversion into 1-Butanol in a Flow Reactor

Abstract

Carbon-supported Mg–Al oxide (hydrotalcite-derived) hybrid catalysts for aqueous ethanol conversion into 1-butanol were prepared and characterized by X-ray diffraction, scanning electron microscopy, low-temperature nitrogen ad­(de)­sorption, Fourier transform infrared and X-ray photoelectron spectroscopies, and temperature-programmed desorption of NH3, CO2, and H2O. Enhanced catalytic activity and stability of operation over time on stream of the hybrid catalysts versus Mg–Al oxides were achieved using both rectified and aqueous ethanol as feed. Redistribution of the active sites of the Mg–Al oxide phase over a highly dispersed support and increasing their availability for the reagents were suggested to be the causes of the enhanced activity of the hybrid catalysts.

Successive Vapor-Phase Guerbet Condensation of Ethanol and 1-Butanol to 2-Ethyl-1-hexanol over Hydroxyapatite Catalysts in a Flow Reactor

“…A heterogeneous catalyst deactivation is commonly observed during the aldol condensation of AA, and it is most likely to be a result of the formation of high-molecular-weight compounds during the sequential conversion reactions of the obtained aldehyde. ,− This is also confirmed by 1 H and 13 C NMR spectroscopy for HAP catalysts after the reaction (see Figure S9). Moreover, water released in the Guerbet reaction and EtOH dehydration can also block the aldol condensation sites. ,, As we have recently shown, at a temperature of 573 K, the formation and adsorption of H 2 O on the surface of the Guerbet condensation catalyst is the main reason for the decrease in activity with TOS increasing . Nevertheless, the deactivation of the HAP catalyst is reversible, and both the activity and selectivity of the catalyst under study can be fully reproduced after its regeneration at 773 K in the airflow for 1 h.…”

“…31,52,53 As we have recently shown, at a temperature of 573 K, the formation and adsorption of H 2 O on the surface of the Guerbet condensation catalyst is the main reason for the decrease in activity with TOS increasing. 34 Nevertheless, the deactivation of the HAP catalyst is reversible, and both the activity and selectivity of the catalyst under study can be fully reproduced after its regeneration at 773 K in the airflow for 1 h. Initial selectivity in the EtOH-to-BuOH process over the HAP catalysts was compared at the same conversion of ∼20%, achieved by the changing of LHSV, in Table 3. The highest selectivity for BuOH and C 4+ oxygenates is achieved in the presence of Ca-HAP (56.2 and 83.2%) and CaMg2.5-HAP (57.0 and 79.2%).…”

“…32 Recently, the deposition of an active phase on a carbon carrier is shown to reduce the deactivating effect of H 2 O on the indices of Guerbet condensation of ethanol over MgO 33 and MgO−Al 2 O 3 -containing catalyst. 34 However, the potential of using these catalysts for aqueous ethanol conversion remains unclear.…”

“…The presence of H 2 O in the ethanol feed has a significant effect on the catalyst activity during the conversion in both autoclaves and flow reactors . Recently, the deposition of an active phase on a carbon carrier is shown to reduce the deactivating effect of H 2 O on the indices of Guerbet condensation of ethanol over MgO and MgO–Al 2 O 3 -containing catalyst . However, the potential of using these catalysts for aqueous ethanol conversion remains unclear.…”

Synergistic decarboxylation over Ce-doped Na/SiO2 facilitating functionalized monomer production from furfural for manufacturing polymers

“…MgAl, ZnAl, CaMg and MgZr were prepared according to previously reported work, 35,36 and the samples were referred to as MgAl1-2, MgAl1-3, MgAl1-4, ZnAl1-2, CaMg1-2, CaMg1-3, CaMg1-4, MgZr1-2, MgZr1-3, and MgZr1-4, respectively, where 1- x ( x = 2, 3, and 4) represented the Al/Mg, Al/Zn and Zr/Mg molar ratio of 2, 3 and 4. All these samples were calcined in air at 500 °C for 4 h prior to use.…”