Heterogeneous Catalytic Conversion of Biobased Chemicals into Liquid Fuels in the Aqueous Phase

Abstract

Different biobased chemicals are produced during the conversion of biomass into fuels through various feasible technologies (e.g., hydrolysis, hydrothermal liquefaction, and pyrolysis). The challenge of transforming these biobased chemicals with high hydrophilicity is ascribed to the high water content of the feedstock and the inevitable formation of water. Therefore, aqueous-phase processing is an interesting technology for the heterogeneous catalytic conversion of biobased chemicals. Different reactions, such as dehydration, isomerization, aldol condensation, ketonization, and hydrogenation, are applied for the conversion of sugars, furfural/hydroxymethylfurfural, acids, phenolics, and so on over heterogeneous catalysts. The activity, stability, and reusability of the heterogeneous catalysts in water are summarized, and deactivation processes and several strategies are introduced to improve the stability of heterogeneous catalysts in the aqueous phase.

Ketone Formation from Carboxylic Acids by Ketonic Decarboxylation: The Exceptional Case of the Tertiary Carboxylic Acids

“…(1)]. [3][4][5][6][7][8] The last oxygen atom in the ketone can be removed by hydrodeoxygenation via alcohol and olefin to producel inear alkanes, which can serve as fuels or lubricants. Furthermore, this reaction is highly suited for the selective removal of the oxygen content of chemical compounds because only one carbon atom is eliminated together with three oxygen atoms out of four.T his fact makes it particularly relevant for the upgrade of biomass-derived product mixtures.…”

Production of furfural from xylose and corn stover catalyzed by a novel porous carbon solid acid in γ-valerolactone

“…[4][5][6] Lignocellulosic biomass is comprised of three primary components -cellulose, hemicellulose, and lignin -where each component has distinct characteristics and properties that allows it to be tailored to a unique purpose. 7 Furfural is a versatile chemical derived from pentosane-rich agricultural and forestry residues such as corn cobs, corn stover, saw dust, and straw.…”

Enhancement of furfural–cyclopentanone aldol condensation using binary water–ethanol mixtures as solvent

“…In spite of the well‐known disadvantages of using homogeneous catalysts, and the wide use of solid base catalysts for these reactions there are few works dealing with the heterogeneously catalyzed cyclopentanone‐furfural condensation . In our previous work, preliminary results using Mg‐Zr mixed oxide as catalyst were reported, combining mild conditions (303–323 K) and aqueous media .…”

“…Hronec et al studied this reaction using homogeneous catalyst (NaOH), with more than 95% of the second adduct yield (C15) in less than 2 h. 13 Deng et al reported selectivities higher than 85% (in solid phase) after 2 h but working in solvent-free condensation and using NaOH as catalyst. 14 In spite of the well-known disadvantages of using homogeneous catalysts, 15 and the wide use of solid base catalysts for these reactions 7,16,17 there are few works dealing with the heterogeneously catalyzed cyclopentanone-furfural condensation. 18 In our previous work, preliminary results using Mg-Zr mixed oxide as catalyst were reported, combining mild conditions (303-323 K) and aqueous media.…”