Cu-loaded zeolites enable the selective activation of ethane to ethylene at low temperatures and pressure

Abstract

Cu-zeolites are found to activate the C-H bond of ethane already at 150 °C in a cyclic protocol and form ethylene with a high selectivity. Both the zeolite topology and...

Selective Oxidative Dehydrogenation of Ethane and Propane over Copper‐Containing Mordenite: Insights into Reaction Mechanism and Product Protection

“…Both mechanisms have been suggested for the oxidative dehydrogenation of alkanes over vanadia‐based catalysts [12,13] . For the reaction of ethane with copper(II)‐containing mordenite, the formation of a stable ethoxy intermediate, which dehydrates to ethylene, was proposed recently [31] . According to our data (Figure 2B), the corresponding alkoxy intermediates were found only for ethane conversion at temperatures below 423 K (Figure 2B).…”

“…[12,13] For the reaction of ethane with copper(II)-containing mordenite, the formation of a stable ethoxy intermediate, which dehydrates to ethylene, was proposed recently. [31] According to our data (Figure 2B), the corresponding alkoxy intermediates were found only for ethane conversion at temperatures below 423 K (Figure 2B). At the same time, in the conversion of ethane at higher temperature and propane activation in the studied temperature range the only detected products are olefin-Cu I πcomplexes.…”

“…As was shown by means of FTIR spectroscopy, the reaction of propane with copper‐containing MFI zeolite at 573 K leads to the formation of a small amount of adsorbed propylene [30] . Later on, it was demonstrated that copper‐containing MOR enables ethane conversion to ethylene in a stepwise process [31] . While several attempts have been made to tackle the problem of C 2+ alkane activation over copper‐containing zeolites, the most important questions remain and require careful examination.…”

“…[30] Later on, it was demonstrated that copper-containing MOR enables ethane conversion to ethylene in a stepwise process. [31] While several attempts have been made to tackle the problem of C 2 + alkane activation over copper-containing zeolites, the most important questions remain and require careful examination. First, the mechanism of alkane transformation to olefin is unclear, and yet this is of utmost importance both for the fundamental understanding of the reaction and for the design of better-performing materials.…”

Understanding C–H activation in light alkanes over Cu-MOR zeolites by coupling advanced spectroscopy and temperature-programmed reduction experiments

“…Nonetheless, during both C 2 H 6 - and CO-TPR, additional Cu I species were found. Cu I _b , observed at T > 300 °C during C 2 H 6 -TPR is again a quasi-linear Cu I , likely with a slightly different geometry/siting with respect to Cu I _a. Considering the recent findings about ethane-to-ethylene conversion over Cu-MOR, 93 both the reactant and the formed hydrocarbons could trigger long-range interactions leading to certain distortion in the Cu I centers local coordination, especially in the high-temperature portion of the TPR. The Cu I _c species found during CO-TPR was established herein as a chemisorbed Cu I –CO intermediate by the combination of results from XAS and FT-IR.…”