Tunable Synthesis of Ethanol or Methyl Acetate via Dimethyl Oxalate Hydrogenation on Confined Iron Catalysts

Abstract

Oxygenated chemicals are essential to modern industries. However, selective syntheses with controllable products are still challenging over a single heterogeneous catalyst. Herein, a confined iron catalyst is designed for balanced syntheses of ethanol and methyl acetate via dimethyl oxalate (DMO) hydrogenation. With the characteristic structure of a microsphere, the Fe@C catalyst promotes the enrichment of hydrogen to reach a tunable selectivity of ethanol (84.3%) and methyl acetate (77.9%). The highest selectivity of methyl acetate is reached at a H2/DMO molar ratio as low as 20, which is the lowest among catalysts reported for DMO hydrogenation by now. The molecule-level mechanism of DMO hydrogenation is further investigated. It proves that Fe5C2 in Fe@C is the main active center of DMO hydrogenation and Fe3O4 promotes the conversion of the intermediate especially in a low H2/DMO molar ratio. This work provides a strategy for tuning targeted oxygenated chemicals.

Enhanced Effect of the Mesoporous Carbon on Iron Carbide Catalyst for Hydrogenation of Dimethyl Oxalate to Ethanol

“…In C 1s spectrogram, a weak peak at 283.5 eV for CÀ Fe bond can be observed on these catalysts, indicating the existence of iron ChemCatChem carbides species on the catalyst surface. In Fe 2p regions, 707.6, 709.8 and 712.1 eV are assigned to Fe x C, Fe 2 + and Fe 3 + , respectively, [28] which proves the coexistence of different iron oxides and iron carbides on surface of the three catalysts. Sun et al [28] believe the Fe 2 O 3 has no obvious activity on DMO conversion, and Fe 3 O 4 promotes conversion of MG in low H 2 / DMO molar ratio.…”

“…In Fe 2p regions, 707.6, 709.8 and 712.1 eV are assigned to Fe x C, Fe 2 + and Fe 3 + , respectively, [28] which proves the coexistence of different iron oxides and iron carbides on surface of the three catalysts. Sun et al [28] believe the Fe 2 O 3 has no obvious activity on DMO conversion, and Fe 3 O 4 promotes conversion of MG in low H 2 / DMO molar ratio. However, Fe 3 O 4 cannot further convert MG to ethanol according to Sun's work.…”

“…[24][25] Different carbon materials or structural properties could influence the formation of iron carbides. [26,27] By using microsphere structure to enrich hydrogen, Sun et al [28] designed an Fe@C catalyst and obtained a selectivity of ethanol (84.3 %) when weight liquid hourly space velocity (WHSV) is 0.19 h À 1 . This work gave a meaningful instruction for fabricating an efficient iron carbide catalyst.…”

3D Interconnected Honeycomb-Like Multifunctional Catalyst for Zn–Air Batteries

“…Numerous studies have shown that morphology regulation can effectively construct electrocatalytic materials with large specific surface area microstructures, such as hollow nanotube structured materials with remarkable bifunctional oxygen electrocatalytic properties prepared by self-template synthesis method [18]. Among these different structures, hollow core-shell sphere structure can provide high specific surface area and load more active sites [19], for example, using carbon layer as a substrate to fix the nanoparticles (NPs) or sub nanostructures has been widely reported [20][21][22][23]. Such hollow structure is helpful to stabilize the active sites and accelerate the mass transfer process in the electrochemical process [13].…”

Highly selective hydrogenation of dimethyl oxalate to methyl glycolate and ethylene glycol over an amino-assisted Ru-based catalyst

“…1,6 In recent years, silver and copper based catalysts have been extensively researched for the heterogenetic reaction of DMO hydrogenation. 7–9 The Ag-based catalysts have been confirmed with high MG selectivity and stability at a reaction temperature of 473 K; however, the production rate was low due to the low activity of Ag metal towards CO bonds. 10,11 Copper-based catalysts could gain a high yield of EG and ethanol at the reaction temperature of 473 K and 553 K, respectively.…”