Mechanistic Understanding of Catalytic Conversion of Ethanol to 1-Butene over 2D-Pillared MFI Zeolite

Yuk, Simuck F.; Lee, Mal‐Soon; Collinge, Greg; Zhang, Junyan; Padmaperuma, Asanga B.; Li, Zhenglong; Polo‐Garzon, Felipe; Wu, Zili; Glezakou, Vassiliki Alexandra; Rousseau, Roger

doi:10.1021/acs.jpcc.0c05585

Cited by 12 publications

(10 citation statements)

References 74 publications

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“…, alumina for ethanol dehydration and nickel/silicoaluminate for ethylene oligomerization); however, the endothermic ethanol dehydration reaction requires significant energy input and the two-step operation leads to increased operating and capital expenses. The single-step approach couples two reaction steps on one single catalyst (generally Brønsted-acidic zeolites − ) and integrates heat generated by the oligomerization step for endothermic ethanol dehydration to reduce both operation and capital costs . This approach, however, catalyzes significant side reactions such as aromatization and hydrogen transfer that lead to considerable aromatic and light paraffin products and decreased C 3+ olefin yields (<50%) …”

Section: Introductionmentioning

confidence: 99%

Isolated Metal Sites in Cu–Zn–Y/Beta for Direct and Selective Butene-Rich C₃₊ Olefin Formation from Ethanol

et al. 2021

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Direct and selective production of C 3+ olefins from bioethanol remains a critical challenge and important for the production of renewable transportation fuels such as aviation biofuels. Here, we report a Cu−Zn−Y/Beta catalyst for selective ethanol conversion to butene-rich C 3+ olefins (88% selectivity at 100% ethanol conversion, 623 K), where the Cu, Zn, and Y sites are all highly dispersed. The ethanol-to-butene reaction network includes ethanol dehydrogenation, aldol condensation to crotonaldehyde, and hydrogenation to butyraldehyde, followed by further hydrogenation and dehydration reactions to form butenes. Cu sites play a critical role in promoting hydrogenation of the crotonaldehyde CC bond to form butyraldehyde in the presence of hydrogen, making this a distinctive pathway from crotyl alcohol-based ethanol-to-butadiene reaction. Reaction rate measurements in the presence of ethanol and acetaldehyde (543 K, 12 kPa ethanol, 1.2 kPa acetaldehyde, 101.9 kPa H 2 ) over monometallic Zn/ Beta and Y/Beta catalysts indicate that Y sites have higher C−C coupling rates than over Zn sites (initial C−C coupling rate, 6.1 × 10 −3 mol mol Y −1 s −1 vs 1.2 × 10 −3 mol mol Zn −1 s −1 ). Further, Lewis-acidic Y-site densities over Cu−Zn−Y/Beta with varied Y loadings are linearly correlated with the initial C−C coupling rates, suggesting that Lewis-acidic Y sites are the predominant sites that catalyze C−C coupling in Cu−Zn−Y/Beta catalysts. Control experiments show that the dealuminated Beta support is important to form higher density of Lewis-acidic Y sites in comparison with other supports such as silica, or deboronated MWW despite similar atomic dispersion of Y sites and Y−O coordination numbers over these supports, leading to more than 9 times higher C−C coupling rate per mole Y over dealuminated Beta relative to other supports. This study highlights the significance of unique combination of metal sites in contributing to the selective valorization of ethanol to C 3+ olefins, motivating for exploring multifunctional zeolite catalysts, where the presence of multiple sites with varying reactivities and functions allows for controlling the predominant molecular fluxes toward the desired products in complex reactions.

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Section: Introductionmentioning

confidence: 99%

Isolated Metal Sites in Cu–Zn–Y/Beta for Direct and Selective Butene-Rich C₃₊ Olefin Formation from Ethanol

et al. 2021

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“…Then, we decrease the temperature of the system gradually from 1000 K to a final target temperature of 850 K running for another 20 ps, respectively. The VDOS was calculated for predicting the spectroscopic characteristics based on the Fourier transform of the velocity autocorrelation function using. , D ( ω ) = prefix∫ 0 ∞ e − i ω t false⟨ υ .25em ( τ ) · υ .25em ( τ + t ) false⟩ τ .25em normald t where υ is the velocity vector and the angular brackets represent the statistical average over all starting times, τ. This allows us to properly describe the anharmonicity of systems at a given temperature.…”

Section: Methodsmentioning

confidence: 99%

Dynamically Formed Active Sites on Liquid Boron Oxide for Selective Oxidative Dehydrogenation of Propane

et al. 2023

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Boron oxide-based catalysts have been shown to be both active and selective for driving the oxidative dehydrogenation of propane (ODHP) without the use of metal promoters. However, this reaction occurs at temperatures where boron oxide melts, challenging experimental identification of the molecular structures within the boron oxide phase under reaction conditions and thus hindering the understanding of its active sites and reaction mechanism(s). By combining density functional theory computations, ab initio molecular dynamics simulations, in situ Raman characterization, and microkinetic modeling, we propose that dimerized di-coordinated boron sites (>B−B<)� dynamically formed in liquid boron oxide�are the active species for O 2 activation under reaction conditions. The resulting peroxylike species (>B−O−O−B<) is then responsible for propane activation but is a moderate oxidant for ODHP and thus inert to propene. These peroxy-like structures rapidly activate propane, homolytically cleaving the >B−O−O−B< bond, producing a propyl radical and a >B−O • dangling bond. These > B−O • originate from the >B−O−O−B< sites as well as the liquid B 2 O 3 structure itself and play a critical role in the abstraction of H atoms from propane and propyl. In fact, microkinetic modeling reveals that the formation of adsorbed C 3 H 7 * radicals is the main rate-controlling step due to the highly endergonic adsorption of propane into the system. Otherwise, the only activated processes were found to be the dehydration steps that lead to water formation, which exhibit an intriguing dependence on the concentration of surface hydroxyl species. These findings provide significant insights into the ODHP mechanisms on boron-based catalysts and emphasize the importance of understanding the liquid nature of the oxide to account for its catalytic activity.

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“…4 Biomass fermentation-derived ethanol, another useful platform chemical, has been studied extensively to synthesize butenes over zeolite catalysts. 5,6 Other biomass-derived small platform chemicals, such as 1-propanol, 7 1-butanol, 8 and acetone, 9 are also good candidates for synthesizing propene and butenes. Besides these opportunities, 2,3-butanediol ( received significant interests because of its potential to be synthesized in a high titer owing to its low toxicity to producing microorganisms.…”

Section: ■ Introductionmentioning

confidence: 99%

“…Biomass-derived γ-valerolactone (GVL) has been identified as an important platform molecule to make butenes via ring-opening and decarboxylation reactions, where various solid acid catalysts have been studied, including heteroatom modified zeolites, Ni 2 P/MCM-41, and amorphous SiO 2 /Al 2 O 3 . Biomass fermentation-derived ethanol, another useful platform chemical, has been studied extensively to synthesize butenes over zeolite catalysts. , Other biomass-derived small platform chemicals, such as 1-propanol, 1-butanol, and acetone, are also good candidates for synthesizing propene and butenes. Besides these opportunities, 2,3-butanediol (2,3-BDO) is another important C 4 platform chemical, which has recently received significant interests because of its potential to be synthesized in a high titer owing to its low toxicity to producing microorganisms .…”

Section: Introductionmentioning

confidence: 99%

Direct 2,3-Butanediol Conversion to Butene-Rich C₃₊ Olefins over Copper-Modified 2D Pillared MFI: Consequence of Reduced Diffusion Length

Adhikari

Zhang

Unocic

et al. 2022

ACS Sustainable Chem. Eng.

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2,3-Butanediol (2,3-BDO), a critical C 4 platform chemical derived from biomass, syngas, or CO 2 , can be converted to C 3+ olefins, serving as important renewable feedstocks for producing sustainable aviation fuels to decarbonize the hard-toelectrify air transportation sector. Herein, we report a bifunctional Cu-modified diffusion-free 2D pillared MFI catalyst (Cu/PMFI) which can selectively catalyze 2,3-BDO conversion to butene-rich C 3+ olefins (95% selectivity at 97% conversion, 523 K). 2,3-BDO conversion to butenes over Cu/PMFI primarily occurs via methyl ethyl ketone intermediate while 2-methyl propanal is also observed as another minor dehydration product that leads to butene formation. In comparison with a control mesoporous Cu/ZSM-5 sample prepared by the postsynthetic approach, Cu/PMFI shows favorable C 3+ olefin selectivity (95% over Cu/PMFI vs 80% over Cu/ZSM-5 at ∼5.1 h TOS). The coke formation over Cu/PMFI is dramatically suppressed by >50% in contrast to Cu/ZSM-5 in 90 h 2,3-BDO conversion due to the reduced diffusion length. Cu/PMFI also favors butene formation and minimizes nonbutene C 3+ olefins by inhibiting the downstream oligomerization and cracking reactions. This study highlights the usefulness of the diffusion-free 2D PMFI materials in catalytic conversion of biomass-derived platform molecules and the significance of diffusion impact on catalyst coke formation and product distributions.

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Mechanistic Understanding of Catalytic Conversion of Ethanol to 1-Butene over 2D-Pillared MFI Zeolite

Cited by 12 publications

References 74 publications

Isolated Metal Sites in Cu–Zn–Y/Beta for Direct and Selective Butene-Rich C₃₊ Olefin Formation from Ethanol

Isolated Metal Sites in Cu–Zn–Y/Beta for Direct and Selective Butene-Rich C₃₊ Olefin Formation from Ethanol

Dynamically Formed Active Sites on Liquid Boron Oxide for Selective Oxidative Dehydrogenation of Propane

Direct 2,3-Butanediol Conversion to Butene-Rich C₃₊ Olefins over Copper-Modified 2D Pillared MFI: Consequence of Reduced Diffusion Length

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Mechanistic Understanding of Catalytic Conversion of Ethanol to 1-Butene over 2D-Pillared MFI Zeolite

Cited by 12 publications

References 74 publications

Isolated Metal Sites in Cu–Zn–Y/Beta for Direct and Selective Butene-Rich C3+ Olefin Formation from Ethanol

Isolated Metal Sites in Cu–Zn–Y/Beta for Direct and Selective Butene-Rich C3+ Olefin Formation from Ethanol

Dynamically Formed Active Sites on Liquid Boron Oxide for Selective Oxidative Dehydrogenation of Propane

Direct 2,3-Butanediol Conversion to Butene-Rich C3+ Olefins over Copper-Modified 2D Pillared MFI: Consequence of Reduced Diffusion Length

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Isolated Metal Sites in Cu–Zn–Y/Beta for Direct and Selective Butene-Rich C₃₊ Olefin Formation from Ethanol

Isolated Metal Sites in Cu–Zn–Y/Beta for Direct and Selective Butene-Rich C₃₊ Olefin Formation from Ethanol

Direct 2,3-Butanediol Conversion to Butene-Rich C₃₊ Olefins over Copper-Modified 2D Pillared MFI: Consequence of Reduced Diffusion Length