Valorisation of 2,5-dimethylfuran over zeolite catalysts studied by on-line FTIR-MS gas phase analysis

Christopher Sauer,Andreas Schaefer,Anders Lorén,Per-Anders Carlsson

doi:10.1039/d1cy01312b

Christopher Sauer, Andreas Schaefer + Show 2 more

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https://doi.org/10.1039/d1cy01312b

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Abstract

The valorisation of 2,5-dimethylfuran over zeolites under catalytic fast pyrolysis conditions was analysed by on-line FTIR-MS. BTX and olefins correlate and decrease with time on stream, whereas the isomerisation of 2,5-dimethylfuran increases.

Highlights

For the catalytic conversion of furans to BTX, MFI and beta type zeolites have been identified as promising catalyst candidates due to their shape selectivity.[13,14] As examples, the selectivity towards BTX has been reported to be 20%,15 35%16 and ca. 50%.17,18 Among the BTX compounds, the p-xylene is the product with highest market value because of its use as a precursor for terephthalic acid, the monomor used for PET production.[19]The selective production of p-xylene as well as other compounds in the BTX family has been studied extensively using high-pressure reactors operated in batch mode
The development of absolute concentrations during time on stream (TOS) at the three temperatures 300, 400 and 500 °C are found in Fig. 1 to 3 and Fig. S10 and S11.† We deepen the discussion by mechanistic interpretations of the flowreactor results using the results from the temperature programmed desorption measurements and in situ diffuse reflectance infrared Fourier transform spectroscopy (DRIFTS) characterisation
The valorisation of 2,5-dimethylfuran over Cu- and H-ZSM-5 and beta zeolite has been studied in a continuous flow reactor under catalytic fast pyrolysis (CFP) conditions

Summary

Introduction

Among the BTX compounds, the p-xylene is the product with highest market value because of its use as a precursor for terephthalic acid, the monomor used for PET production.[19]. The selective production of p-xylene as well as other compounds in the BTX family has been studied extensively using high-pressure reactors operated in batch mode. With an aliphatic solvent such as n-heptane, an ethene pressure of approximately 50 bar and catalysts such as H-BEA, tin phosphate, or others, selective production (≥90%) of p-xylene has been demonstrated.[20,21,22] The reaction has been proposed to proceed through a Diels–Alder cycloaddition with subsequent dehydration (DACD).[3,23] This reaction pathway is highly desirable because it builds on the natural chemical complexity of the 5-membered furan ring so as to produce the 6-membered carbon rings, with the only byproduct being benign water.[3] It has been found that the DA reaction is catalysed by Lewis acid sites (LAS) but not Brønsted acid sites (BAS),[3,24] whereas the dehydration of the bicyclic intermediate, which cannot occur in reasonable rates uncatalysed, is facilitated by

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