Condensed-phase low temperature heterogeneous hydrogenation of CO₂ to methanol

Abstract

A low-temperature CH3OH synthesis was achieved at 120–170 °C using tertiary amine and alcohol in the presence of a Cu/ZnO/Al2O3 catalyst by CO2 hydrogenation.

Mechanistic Insights into Ruthenium-Pincer-Catalyzed Amine-Assisted Homogeneous Hydrogenation of CO2 to Methanol

“…Methanol synthesis from CO 2 is traditionally carried out at high temperatures and pressures with heterogeneous catalysts such as Cu/ZnO/Al 2 O 3 and modifications thereof. , Recently, however, less harsh conditions have been reported, with both homogeneous and heterogeneous catalysts to access low-temperature methanol synthesis from CO 2 . − In this regard, homogeneous catalysis holds certain advantages by enabling researchers to systematically investigate the catalyst’s molecular structure in order to improve its efficiency and selectivity toward methanol formation. The homogeneous reduction of gaseous CO 2 by molecular H 2 to methanol has been challenging due to the kinetic and thermodynamic stability of CO 2 .…”

Recent Progress in Materials Exploration for Thermocatalytic, Photocatalytic, and Integrated Photothermocatalytic CO2‐to‐Fuel Conversion

“…Delightedly, a low‐temperature (120−170 °C) CO 2 ‐to‐CH 3 OH conversion with nearly 100% yield was realized using tertiary amine and alcohol through the condensed‐phase hydrogenation of alkylcarbonate, accompanied by the generation of ammonium formate and alkylformate intermediates. [ 31 ] The incorporation of alkaline metal oxides (e.g., MgO, CaO, SrO, and BaO) into Cu/Al 2 O 3 catalysts contributes to a higher Cu + /Cu 0 ratio and surface area, which show a higher MeOH production rate and suppress the competing RWGS reaction. [ 32 ] Evidenced by DFT, DRIFT, and kinetic Monte Carlo (KMC) simulations, the reduced Zr 3+ sites at the interface of Cu/ZrO2 catalysts preferably absorb the *CO 2 , *CO, *HCO, and *H 2 CO intermediates, which moderately promote methanol synthesis on Cu.…”

CO2 Reduction to Methanol in the Liquid Phase: A Review

“…[30,31] The subsequent hydrogenation of alkyl carbonate ions could be faster since the CO 2 molecule has been activated chemically, resulting in a higher yield of formate ( Figure 20C). [32,91] The formate salt can undergo dehydration with alcohol to obtain the alkyl formate, which could easily be hydrogenated to methanol and the corresponding alcohol. [93] The hydrogenation of alkyl formate undergoes the formation of the ethoxymethoxy group and formaldehyde.…”

“…In the presence of amine and alcohol, the alkyl carbonate ions are first formed (Figure 20B), which has been demonstrated to be more active than the dissolved CO 2 in the alcohol solvent [30,31] . The subsequent hydrogenation of alkyl carbonate ions could be faster since the CO 2 molecule has been activated chemically, resulting in a higher yield of formate (Figure 20C) [32,91] . The formate salt can undergo dehydration with alcohol to obtain the alkyl formate, which could easily be hydrogenated to methanol and the corresponding alcohol [93] .…”