Oxidative conversion of lignin over cobalt-iron mixed oxides prepared via the alginate gelation

Hdidou, Loubna; Kouisni, Lamfeddal; Manoun, Bouchaib; Hannache, Hassan; Solhy, Abderrahim; Barakat, Abdellatif

doi:10.1016/j.catcom.2018.08.027

Cited by 6 publications

(3 citation statements)

References 29 publications

(29 reference statements)

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“…In most lignin degradation strategies, the macromolecule first ruptures into small fragments and then specific functional groups may selectively be removed or regenerated to produce higher quality products. However, specifically designed catalysts could directly convert lignin into these products while breaking specific chemical bonds and functionalities at once. ,− Due to the complex chemical structure of lignin, simple model compounds are typically used to facilitate the understanding of the lignin chemistry. − In this work, we selected guaiacylglycerol-β-guaiacyl ether (GG) and veratrylglycerol β-guaiacyl ether (VG) model compounds to investigate lignin and UL oxidative depolymerization over heterogeneous catalysts (Scheme a). ,− They represent two of the most popular and widely used phenolic and non-phenolic lignin model compounds (with C γ –OH) featuring the β- O -4-aryl ether bond, dominating up to 50% of interunit linkages in softwood lignins. ,,− These lignin-related model structures comprise carbon–carbon (e.g., C α –C β and C α –C ph ) and carbon–heteroatom (e.g., C β –OPh) bonds (Scheme a). The phenolic GG molecule is more reactive than the non-phenolic VG fragment because of the hydroxyl group on the benzene ring .…”

Section: Resultsmentioning

confidence: 99%

Gas–Solid Oxidation of Unwashed Lignin to Carboxylic Acids

et al. 2020

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The availability and multifunctionality of lignin makes it a desirable, renewable alternative to petroleum for specialty and bulk chemicals. However, recovering lignin from black liquor is expensive, thus lowering its prospect as a raw material source. Direct conversion of unwashed lignin (UL) to chemicals eliminates unit operations and reaction steps, which makes it a more likely feedstock. We compared the selective oxidation of lignin and UL to produce carboxylic acids over vanadium pyrophosphate (VPP), HZSM-5 zeolite, and VPP/HZSM-5 catalysts at atmospheric pressure and varying temperature (from 140 to 650 °C), steam concentration (from 0 to 20%), and oxygen (from 0 to 15.5%). The main acids produced were formic acid, acetic acid, and malonic acid. VPP/HZSM-5 produced 5% more acids with UL compared to treated lignin. The catalytic reaction network comprises both anaerobic and aerobic pathways for oxidation-based valorization of free phenolic guaiacylglycerol-β-guaiacyl ether (GG) and non-phenolic veratrylglycerol β-guaiacyl ether (VG) model lignin compounds. The three main reaction types include selective catalytic oxidative depolymerization with interunit bond breakage (e.g., alkyl–O–aryl bonds), alkyl side chain modification (e.g., Cα–OH to CαO ketone), and aromatic ring oxidation and ring opening to produce benzoquinones and dicarboxylic acids.

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Section: Resultsmentioning

confidence: 99%

Gas–Solid Oxidation of Unwashed Lignin to Carboxylic Acids

et al. 2020

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“…Therefore, main catalytic approaches for the up-grading of lignin involve a reacting atmosphere, either reductive (H2) to produce deoxygenated aromatics for energy use, or oxidative (O2, air) to produce oxygenated aromatics for fine chemistry [81]. As far as heterogeneous catalysis is concerned, oxygenated aromatics can be obtained particularly with perovskites [82], mixed-metal oxides such as FeCoO as demonstrated by Barakat and co. [83], all giving global yields into aromatic aldehydes (vanillin, syringal-dehyde…) in the 15-20 wt% range. Systems with supported metals have also been investigated with Co, Au, and Pd.…”

Section: Transformation Of Lignin Under Oxidative Atmospherementioning

confidence: 99%

A Landscape of Lignocellulosic Biopolymer Transformations into Valuable Molecules by Heterogeneous Catalysis in C’Durable Team at IRCELYON

et al. 2021

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This review article highlights part of the research activity of the C’Durable team at IRCELYON in the field of sustainable chemistry. This review presents a landscape of the work performed on the valorization of lignocellulosic biopolymers. These studies intend to transform cellulose, hemicellulose and lignin into valuable molecules. The methodology usually consists in evaluating the behavior of the biopolymers in the absence of catalyst under various conditions (solvent, temperature), and then to assess the influence of a catalyst, most often a heterogeneous catalyst, on the reactivity. The most significant results obtained on the upgrading of cellulose and lignin, which have been mainly investigated in the team, will be presented with an opening on studies involving raw lignocellulose.

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“…36 Recently, considerable efforts were achieved in order to develop sustainable and eco-friendly procedures for oxides design. [37][38][39] Surya et al, prepared TiO 2 by using Jatropha curcas leaf extracts for the photocatalytic degradation of tannery wastewater. 40 Moreover, TiO 2 was synthesized from Cymbopogon proximus in order to use it for Rhodamine B photodegradation and the study suggested its possible use for drinking water purication.…”

Section: Introductionmentioning

confidence: 99%