Furfural offers a promising, rich platform for lignocellulosic biofuels. These include methylfuran and methyltetrahydrofuran, valerate esters, ethylfurfuryl and ethyltetrahydrofurfuryl ethers as well as various C(10)-C(15) coupling products. The various production routes are critically reviewed, and the needs for improvements are identified. Their relative industrial potential is analysed by defining an investment index and CO(2) emissions as well as determining the fuel properties for the resulting products. Finally, the most promising candidate, 2-methylfuran, was subjected to a road trial of 90,000 km in a gasoline blend. Importantly, the potential of the furfural platform relies heavily on the cost-competitive production of furfural from lignocellulosic feedstock. Conventional standalone and emerging coproduct processes-for example, as a coproduct of cellulosic ethanol, levulinic acid or hydroxymethyl furfural-are expensive and energetically demanding. Challenges and areas that need improvement are highlighted. In addition to providing a critical review of the literature, this paper also presents new results and analysis in this area.

Furfural—A Promising Platform for Lignocellulosic Biofuels

http://www.chtf.stuba.sk/~szolcsanyi/education/files/Chemia%20heterocyklickych%20zlucenin/Prednaska%207/Doplnkove%20studijne%20materialy/Hydroxymethylfurfural/Conversion%20of%20biomass%20platform%20molecules%20into%20fuel%20additives%20and%20liquid%20hydrocarbon%20fuels.pdf

Conversion of biomass platform molecules into fuel additives and liquid hydrocarbon fuels

The production of future transportation fuels and chemicals requires the deployment of new catalytic processes that transform biomass into valuable products under competitive conditions. Furfural has been identified as one of the most promising chemical platforms directly derived from biomass. With an annual production close to 300 kTon, furfural is currently a commodity chemical, and the technology for its production is largely established. The aim of this review is to discuss the most relevant chemical routes for converting furfural to chemicals, biofuels, and additives. This review focuses not only on industrially produced chemicals derived from furfural, but also on other not yet commercialised products that have a high potential for commercialisation as commodities. Other chemicals that are currently produced from oil but can also be derived from furfural are also reviewed. The chemical and engineering aspects such as the reaction conditions and mechanisms, as well as the main achievements and the challenges still to come in the pursuit of advancing the furfural-based industry, are highlighted.

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Furfural: a renewable and versatile platform molecule for the synthesis of chemicals and fuels

Increasing demand for sustainable chemicals and fuels has pushed academia and industry to search for alternative feedstocks replacing crude oil in traditional refineries. As a result, an immense academic attention has focused on the valorisation of biomass (components) and derived intermediates to generate valuable platform chemicals and fuels. Zeolite catalysis plays a distinct role in many of these biomass conversion routes. This contribution emphasizes the progress and potential in zeolite catalysed biomass conversions and relates these to concepts established in existing petrochemical processes. The application of zeolites, equipped with a variety of active sites, in Bronsted acid, Lewis acid, or multifunctional catalysed reactions is discussed and generalised to provide a comprehensive overview. In addition, the feedstock shift from crude oil to biomass involves new challenges in developing fields, like mesoporosity and pore interconnectivity of zeolites and stability of zeolites in liquid phase. Finally, the future challenges and perspectives of zeolites in the processing of biomass conversion are discussed.

/pdf/potential-and-challenges-of-zeolite-chemistry-in-the-2jjml8ecsr.pdf

Potential and challenges of zeolite chemistry in the catalytic conversion of biomass

http://www.chtf.stuba.sk/~szolcsanyi/education/files/Chemia%20heterocyklickych%20zlucenin/Prednaska%207/Doplnkove%20studijne%20materialy/Hydroxymethylfurfural/Catalytic%20dehydration%20of%20C6%20carbohydrates%20for%20the%20production%20of%20HMF.pdf

Catalytic dehydration of C6 carbohydrates for the production of hydroxymethylfurfural (HMF) as a versatile platform chemical

This work was supported by Consilider Ingenio 2009 CDS 00050. O.d.l.T. is grateful to the Spanish Ministry of Science and Innovation for a doctoral grant (FPU). We also thank E. Ponce and Dr. D. Penno for discussions and technical assistance.

Production of High-Quality Diesel from Biomass Waste Products

The Sylvan (2-methylfuran) diesel process involves the conversion of pentose biopolymers into premium diesel via furfural, by means of hydroxyalkylation/alkylation and hydrodeoxygenation reactions. In the hydroxyalkylation/alkylation step two Sylvan molecules are reacted with an aldehyde or a ketone to yield C12+ oxygenated intermediate molecules. Thus, the manuscript describes first the performance of the hydroxyalkylation/alkylation step with different soluble and solid catalysts, and among solids delaminated zeolites were identified as promising catalysts. The scope of the process has also been studied by reacting Sylvan with different aldehyde and ketone molecules. It has been found that for the one-step trimerization of Sylvan, sulfuric acid appears the most adequate catalyst and can be reused. The final hydrodeoxygenation step is studied in detail starting with C14 intermediates generated from two Sylvan and one butanal molecules as well as with the product generated by direct trimerization of Sylvan to yield the final corresponding mono-branched paraffinic diesel product. The Sylvan diesel process is an environmentally friendly process able to produce a high yield (87%) of a premium diesel with a cetane number of >70 and upper pour point of −75 °C from non-food biomass.

Production of high quality diesel from cellulose and hemicellulose by the Sylvan process: catalysts and process variables

High-quality diesel from hexose- and pentose-derived biomass platform molecules.

The epoxide rearrangement of β-pinene oxide into myrtanal was studied in the presence of solid Lewis-acid catalysts. Different metals such as Zr, Sn, Ti, Nb, Ta, Al, and Ga have been incorporated within network positions of zeolite Beta by isomorphous substitution. The materials have been characterized by powdered X-ray diffraction (XRD), IR spectroscopy and by in situ IR spectroscopy on adsorbed molecules (cyclohexanone and pyridine). Among the studied catalysts Zr-Beta gave the best selectivity (up to 94%) in acetonitrile as solvent at practically complete conversion. In this epoxide rearrangement the solvent has to be selected to balance the competitive adsorption of the product. Product desorption is enhanced with acetonitrile which results in a selectivity increase with only a small penalty on the rate of reaction. Zr-Beta has been reused in the batch mode and in a fixed-bed reactor for several times and analysis of the reused catalyst indicated that Zr-Beta is a robust catalyst for the epoxide rearrangement. Leaching of the metal or crystal degradation has not been detected.

Biomass to chemicals: Rearrangement of β-pinene epoxide into myrtanal with well-defined single-site substituted molecular sieves as reusable solid Lewis-acid catalysts

Olalla de la Torre

Papers

Production of High-Quality Diesel from Biomass Waste Products

Production of high quality diesel from cellulose and hemicellulose by the Sylvan process: catalysts and process variables

High-quality diesel from hexose- and pentose-derived biomass platform molecules.

Biomass to chemicals: Rearrangement of β-pinene epoxide into myrtanal with well-defined single-site substituted molecular sieves as reusable solid Lewis-acid catalysts