Cycloaddition of Biomass-Derived Furans for Catalytic Production of Renewable p-Xylene

Abstract

A renewable route to p-xylene from biomass-derived dimethylfuran and ethylene is investigated with zeolite catalysts. Cycloaddition of ethylene and 2,5-dimethylfuran and subsequent dehydration to p-xylene has been achieved with 75% selectivity using H–Y zeolite and an aliphatic solvent at 300 °C. Competitive side reactions include hydrolysis of dimethylfuran to 2,5-hexanedione, alkylation of p-xylene, and polymerization of 2,5-hexanedione. The observed reaction rates and computed energy barriers are consistent with a two-step reaction that proceeds through a bicyclic adduct prior to dehydration to p-xylene. Cycloaddition of ethylene and dimethylfuran occurs without a catalytic active site, but the reaction is promoted by confinement within microporous materials. The presence of Brønsted acid sites catalyzes dehydration of the Diels–Alder cycloadduct (to produce p-xylene and water), and this ultimately causes the rate-determining step to be the initial cycloaddition.

Synthesis of terephthalic acid via Diels-Alder reactions with ethylene and oxidized variants of 5-hydroxymethylfurfural

“…Thus, finding efficient routes to PTA from HMF is of great interest. Diels-Alder routes to PTA from HMF have been investigated, and typically, they require the hydrogenation of HMF to 2,5-dimethylfuran (DMF) (6)(7)(8)(9)(10)(11)(12). It is known that DMF and ethylene can react to form PX in a one-pot Diels-Alder dehydration reaction (7).…”

“…It is known that DMF and ethylene can react to form PX in a one-pot Diels-Alder dehydration reaction (7). This reaction has received much attention recently, and it is catalyzed by homogeneous Lewis acids and a wide variety of heterogeneous Brønsted acid-containing solids (7)(8)(9)(10)(11)(12). Although nearly 100% PX yields from the Diels-Alder dehydration reaction can be achieved, the reduction step to convert HMF to DMF requires expensive metal catalysts and a hydrogen source, making this route challenging to commercially implement (13).…”

High Selectively Catalytic Conversion of Lignin-Based Phenols into para-/m-Xylene over Pt/HZSM-5

“…However, the product distribution significantly changes. For instance, the toluene selectivity increases from 9.8% at 573 K to 39.8% at 673 K and alters a little at higher temperature, while the selectivity of alkanes (including methylcyclohexane, 1,3-dimethylcyclopentane, and C [3][4][5][6] ) sharply declines from 88.2% at 573 K to 4.4% at 723 K. The p-/m-xylene and o-xylene selectivities have similar variation trend as the toluene selectivity, with separately reaching 16.3% and 4.7% at 673 K and changing a little at higher temperature. Selectivities of benzene and polyalkylated benzenes also raise and reach up to 13.8% and 3.3% at 723 K, respectively.…”

“…With depleting stocks of fossil fuels and growing concern on the excessive emission of greenhouse gases, great efforts have been made to develop alternative method of producing sustainable p-/m-xylene from biomass-based compounds [1][2][3][4]. Shiramize and Toste [1] proposed a method to produce p-xylene with 2,5-dimethyfuran (derived from lignocellulosic biomass) and acrolein (from glycerol, a side product of biodiesel production) through four step-reactions with an overall yield of 34%.…”

“…Lyons et al [2] used ethylene (derived from biomass or shale gas) as an alternative feedstock, and synthesized p-xylene through a very complex process involving trimerizaiton, dehydrogenation, Diels-Alder reaction, and further dehydrogenation. Williams et al [3] suggested a renewable route to p-xylene from cycloaddition/dehydration of biomass-based dimethylfuran and ethylene with a high selectivity of 75% using Y zeolite as catalyst. Very recently, Cheng et al [4] reported the production of p-xylene from 2-methylfuran (a product of catalytic fast pyrolysis of lignocellulosic biomass) and propylene using ZSM-5 catalysts.…”