Catalysis Center for Energy Innovation for Biomass Processing: Research Strategies and Goals

Vlachos, Dionisios G.; Chen, Jingguang G.; Gorte, Raymond J.; Huber, George W.; Tsapatsis, Michael

doi:10.1007/s10562-010-0455-4

Cited by 41 publications

(26 citation statements)

References 36 publications

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“…1,2 Coinciding with the increased research effort into biomass-derived fuels and chemicals, shale gas production has also greatly expanded in the United States. This newly tapped energy source has the potential to provide vast quantities of C 1 and C 2 hydrocarbons but lacks the ability to provide larger olefins and aromatic chemicals.…”

Section: Introductionmentioning

confidence: 99%

Kinetic Regime Change in the Tandem Dehydrative Aromatization of Furan Diels–Alder Products

et al. 2015

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Renewable production of p-xylene from [4 + 2] Diels− Alder cycloaddition of 2,5-dimethylfuran (DMF) and ethylene with H−Y zeolite catalyst in n-heptane solvent is investigated. Experimental studies varying the solid acid catalyst concentration reveal two kinetic regimes for the p-xylene production rate: (i) a linear regime at low acid site concentrations with activation energy E a = 10.8 kcal/mol and (ii) a catalyst-independent kinetic regime at high acid site concentrations with activation energy E a = 20.1 kcal/mol. We carry out hybrid QM/MM calculations with a three-layer embedded cluster ONIOM model to compute the energetics along the main reaction pathway, and a microkinetic model is constructed for the interpretation of the experimental kinetic data. At high solid acid concentrations, p-xylene production is limited by the homogeneous Diels−Alder reaction, whereas at low acid concentrations, the overall rate is limited by the heterogeneously catalyzed dehydration of the Diels−Alder cycloadduct of DMF and ethylene because of an insufficient number of acid sites, despite the dehydration reaction requiring significantly less activation energy. A reduced kinetic model reveals that the production of p-xylene follows the general kinetics of tandem reactions in which the first step is uncatalyzed and the second step is heterogeneously catalyzed. Reaction orders and apparent activation energies of quantum mechanical and microkinetic simulations are in agreement with experimental values.

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Section: Introductionmentioning

confidence: 99%

Kinetic Regime Change in the Tandem Dehydrative Aromatization of Furan Diels–Alder Products

et al. 2015

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“…Across the chemical industry there is a push to discover new sources for the fuels and chemicals currently derived from fossil resources, and biomass is an ideal feedstock for a number of renewable monomers . As inexpensive natural gas liquids (shale gas) are pushing naphtha feedstocks aside, the development of alternative routes for the production of aromatics from renewables is receiving considerable attention .…”

Section: Introductionmentioning

confidence: 99%

Tandem Diels–Alder Reaction of Dimethylfuran and Ethylene and Dehydration to para‐Xylene Catalyzed by Zeotypic Lewis Acids

et al. 2017

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The zeotypic Lewis acids Sn‐BEA, Zr‐BEA, and Ti‐BEA have recently been reported to catalyze the synthesis of p‐xylene by dehydrative aromatization of the Diels–Alder product between 2,5‐dimethylfuran and ethylene. Although it has been shown that these Lewis acids can catalyze the dehydration of the Diels–Alder cycloadduct, the tandem scheme precludes decoupling of the two steps needed to infer whether these same catalysts can catalyze the Diels–Alder step. We have employed electronic structure calculations and microkinetic modelling to investigate the Diels–Alder aromatization of 2,5‐dimethylfuran and ethylene to p‐xylene over the Lewis‐acidic zeotypes Sn‐, Zr‐, and Ti‐BEA. We show that there is only minor catalysis of the Diels–Alder reaction, solely attributable to confinement phenomena varying with the translational freedom allowed to the species inside the zeolite. Microkinetic modelling and sensitivity analysis of the computed rates show that the heterogeneous Diels–Alder pathway does not contribute to the overall rate, and that the homogeneous cycloaddition is rate‐limiting at high acid site concentrations. Only the partially hydrolyzed (“open”) Lewis acid sites are found to be catalytically active, with moderately Brønsted‐acidic silanol groups formed, which catalyze 2,5‐dimethylfuran hydrolysis. Of the Lewis acids tested in this work, Zr‐BEA and Sn‐BEA have similar activities, in agreement with experiment, whereas Ti‐BEA is found to be inactive, suggesting that the recently reported Ti‐BEA activity was likely a result of Brønsted‐acidic defect sites.

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“…Biomass represents sustainable alternative carbon sources for producing fuels and chemicals instead of from the traditional petroleum feedstock. [1][2][3] One of the difficulties in processing biomass for fuel applications is related to its high oxygen content [4,5] with oxygen being present in the functional groups such as carbonyl and/or carboxyl groups. Hydrodeoxygenation (HDO) is a promising way to remove the extra oxygen in biomass-derived oxygenate molecules because an ideal HDO process selectively cleaves the C-O/C=O bonds of the oxygenates while keeping the C-C/C=C bonds intact, which is particularly important for fuel applications.…”

Section: Introductionmentioning

confidence: 99%

Reaction pathways of furfural, furfuryl alcohol and 2-methylfuran on Cu(111) and NiCu bimetallic surfaces

2016

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Hydrodeoxygenation (HDO) is an important reaction for converting biomass-derived furfural to value-added 2-methylfuran, which is a promising fuel additive. In this work, the HDO of furfural to produce 2-methylfuran occurred on the NiCu bimetallic surfaces prepared on either Ni(111) or Cu(111). The reaction pathways of furfural were investigated on Cu(111) and Ni/Cu(111) surfaces using density functional theory (DFT) calculations, temperature programmed desorption (TPD) and high resolution electron energy loss spectroscopy (HREELS) experiments. These studies provided mechanistic insights into the effects of bimetallic formation on enhancing the HDO activity. Specifically, furfural weakly adsorbed on Cu(111), while it strongly adsorbed on Ni/Cu(111) through an η 2 (C,O) configuration which led to the HDO of furfural on Ni/Cu(111). The ability to dissociate H 2 on Ni/Cu(111) is also an important factor for enhancing the HDO activity over Cu(111).

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Catalysis Center for Energy Innovation for Biomass Processing: Research Strategies and Goals

Cited by 41 publications

References 36 publications

Kinetic Regime Change in the Tandem Dehydrative Aromatization of Furan Diels–Alder Products

Kinetic Regime Change in the Tandem Dehydrative Aromatization of Furan Diels–Alder Products

Tandem Diels–Alder Reaction of Dimethylfuran and Ethylene and Dehydration to para‐Xylene Catalyzed by Zeotypic Lewis Acids

Reaction pathways of furfural, furfuryl alcohol and 2-methylfuran on Cu(111) and NiCu bimetallic surfaces

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