Title: Kinetic regimes in the tandem reactions of H-BEA catalyzed formation of p-xylene from dimethylfuran

Abstract

Reaction kinetics and pathways of p-xylene formation from 2,5-dimethylfuran (DMF) and ethylene via cascade reactions of Diels–Alder cycloaddition and subsequent dehydration over H-BEA zeolite (Si/Al = 12.5) were characterized. Two distinct kinetic regimes were discovered corresponding to the rate limiting reaction, namely Diels–Alder cycloaddition and cycloadduct dehydration, as the concentration of Brønsted acid sites decreases. At catalyst loadings with effective acid site concentrations exceeding a critical value (~2.0 mM), the rate of formation of Diels–Alder products becomes constant. Under these conditions, the measured activation energy of 17.7 ± 1.4 kcal mol^-1 and reaction orders correspond to the [4 + 2] Diels–Alder cycloaddition reaction of DMF and ethylene. Conversely, at catalyst loadings below the critical value, the formation rate of p-xylene becomes first order in catalyst loading, and the measured activation energy of 11.3 ± 3.5 kcal mol^-1 is consistent with dehydration of the Diels–Alder cycloadduct to p-xylene. Experimental comparison between H-BEA and H-Y zeolite catalysts at identical conditions indicates that the micropore structure controls side reactions such as furan dimerization and hydrolysis; the latter is supported via molecular simulation revealing a substantially higher loading of DMF within H-Y than within H-BEA zeolites at reaction conditions.

Authors:

Williams, C. Luke ^[1]; Vinter, Katherine P. ^[1]; Chang, Chun-Chih ^[1]; Xiong, Ruichang  ^[2];

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Green, Sara K. ^[1]; Sandler, Stanley I. ^[2]; Vlachos, Dionisios G. ^[2]; Fan, Wei ^[1]; Dauenhauer, Paul J. ^[1]

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+ Show Author Affiliations

1. Amherst College, MA (United States). Dept. of Chemical Engineering; Catalysis Center for Energy Innovation, Newark, DE (United States)
2. Univ. of Delaware, Newark, DE (United States). Dept. of Chemical and Biomolecular Engineering

Publication Date:

2015-10-25

Research Org.:

Energy Frontier Research Centers (EFRC) (United States). Catalysis Center for Energy Innovation (CCEI)

Sponsoring Org.:

USDOE Office of Science (SC), Basic Energy Sciences (BES)

OSTI Identifier:

1387605

Grant/Contract Number:  

SC0001004

Resource Type:

Accepted Manuscript

Journal Name:

Catalysis Science and Technology

Additional Journal Information:

Journal Volume: 6; Journal Issue: 1; Related Information: CCEI partners with the University of Delaware (lead); Brookhaven National Laboratory; California Institute of Technology; Columbia University; University of Delaware; Lehigh University; University of Massachusetts, Amherst; Massachusetts Institute of Technology; University of Minnesota; Pacific Northwest National Laboratory; University of Pennsylvania; Princeton University; Rutgers University; Journal ID: ISSN 2044-4753

Publisher:

Royal Society of Chemistry

Country of Publication:

United States

Language:

English

Subject:

09 BIOMASS FUELS; 37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY; catalysis (homogeneous); catalysis (heterogeneous); biofuels (including algae and biomass); bio-inspired; hydrogen and fuel cells; materials and chemistry by design; synthesis (novel materials), synthesis (self-assembly); synthesis (scalable processing)