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

C. Luke Williams,Katherine P. Vinter,Chun-Chih Chang,Dionisios G. Vlachos,Wei Fan,Sara K. Green,Paul J. Dauenhauer,Ruichang Xiong,Stanley I. Sandler

doi:10.1039/c5cy01320h

C. Luke Williams, Katherine P. Vinter + Show 7 more

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https://doi.org/10.1039/c5cy01320h

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Abstract

Tandem Diels–Alder cycloaddition and subsequent dehydration of dimethylfuran and ethylene produces renewablep-xylene with an H-BEA zeolite catalyst.

Highlights

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
We evaluate the kinetics of the reaction of dimethylfuran and ethylene with H-BEA zeolite and demonstrate a reaction pathway of tandem homogeneous Diels– Alder cycloaddition followed by Brønsted acid catalyzed dehydration to p-xylene, consistent with the overall mechanism occurring in H-Y zeolite
The chemical potential values required for the CB-GCMC simulations were calculated with the ASPEN Plus® commercial software package using the Soave–Redlich– Kwong–Kabadi–Danner (SRK–KD) equation of state (EOS), which is suitable for calculating the phase behavior of mixtures of hydrocarbons and water.[41]

Summary

Introduction

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. 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. Diels–Alder reactions of biomass-derived furans have recently demonstrated potential for producing renewable sixcarbon aromatic chemicals, including p-xylene and PTA. It has recently been proposed that oxidized variants of HMF can undergo Diels–Alder (DA) addition of ethylene, producing six-carbon ring aromatic chemicals with

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