Highly Selective Oxidative Dehydrogenation of Ethane to Ethylene via Chemical Looping with Oxygen Uncoupling through Structural Engineering of the Oxygen Carrier

Abstract

The oxidative dehydrogenation of ethane (ODH) to produce ethylene offers advantages compared to the industry standard steam cracking, but its industrial application is hindered by costly air separation units needed to supply oxygen. A chemical‐looping‐based oxidative dehydrogenation (CL‐ODH) scheme is presented, in which oxygen carriers supply gaseous oxygen in situ, which then reacts with ethane in the presence of a catalyst at a comparatively low temperature (500 °C). A common challenge of chemical looping processes beyond combustion is to suppress the overoxidation of hydrocarbons to COx to enable high product yields. It is demonstrated that the overoxidation of ethane can be eliminated completely through structural engineering of the perovskite oxygen carrier involving alkali‐metal‐based carbonate coatings, while maintaining the materials’ ability to generate oxygen. Through CL‐ODH, higher ethylene selectivity (≈91%) and yields (≈39%) are achieved compared to the conventional ODH scheme without oxygen carrier and cofeeding air/ethane. 18O‐labeling experiments demonstrate that the carbonate layer functions like a diffusion barrier for ethane while being permeable for oxygen. Both the CL‐ODH scheme and the material design strategy can be extended to other catalytic oxidation or dehydrogenation reactions requiring oxygen at different temperatures, offering enormous potential to intensify such processes.

Uncovering the CO2 Capture Mechanism of NaNO3-Promoted MgO by 18O Isotope Labeling

“…O-enriched NaNO 3 was synthesized according to a previously described method. 52 Briefly, 100 μL of 70% HNO 3 was equilibrated with 140 μL of 97% 18 O-enriched water for 3 days at 100 °C in a closed vial. Afterward, the solution was neutralized with 82.4 mg Na 2 CO 3 .…”

Mixed oxides as multi-functional reaction media for chemical looping catalysis

“…A similar strategy has also been recently adopted by a few other researchers in the context of CL-ODH and methane oxydehydroaromatizations. 96,97,118,166 In all cases, higher H 2 combustion selectivity were observed after promoting the oxide surface with the “inert” molten salt. This further demonstrates the feasibility of the Type 1 catalyst architecture.…”

“…52–94 Furthermore, marrying the chemical looping strategy with oxidative catalysis offers a unique opportunity to intensify the production of a few important commodity chemicals with substantially decreased energy consumption and CO 2 emissions. 95–136 Given that separation processes consume ∼60% of the total energy usage in chemical and petroleum industries and heterogeneous catalysts are responsible for >80% of all chemical products worldwide, chemical looping catalysis (CLCa) in this article, has the potential to facilitate process intensification throughout the chemical manufacturing sector by combining catalytic reactions with separations. 120,137–142 The abovementioned chemical looping process types are summarized in Table 1.…”

Production of Acetaldehyde via Oxidative Dehydrogenation of Ethanol in a Chemical Looping Setup

“…CL offers increased safety in oxidative catalytic reactions, removing the need to mix O 2(g) with flammable reactants and eliminating the problem of costly separation of depleted air from the products. Originally proposed for combustion and effective CO 2 capture, CL has been shown to be effective and selective in catalytic processes, for example, epoxidation of olefins and oxidative dehydration of alkanes. , CL for oxidative dehydrogenation of ethanol has been suggested by Zhu et al in their recent perspective paper, but until now, the process has not been demonstrated experimentally.…”