Oxidative Depolymerization of Lignin Using Supported Niobium Catalysts

Das, Lalitendu; Kolar, Praveen; Sharma-Shivappa, Ratna R.; Classen, John J.; Osborne, Jason A.

doi:10.3390/chemengineering1020017

Cited by 12 publications

(5 citation statements)

References 53 publications

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“…Oxidative approaches to lignin depolymerization, especially utilizing molecular oxygen, hydrogen peroxide, peroxyacids or ozone, have a great potential to become important and economically viable lignin delignification technologies [17], as the reaction pathways can yield valuable chemicals such as simple aldehydes (vanillin, syringaldehyde, p-hydroxybenzaldehyde) or acids (vanillic acid and syringic acid) [18]. Depending on the extent of oxidation, various carboxylic acids having aromatic and non-aromatic structures with mono-or di-carboxyl functional groups can be produced [19].…”

Section: Introductionmentioning

confidence: 99%

Sustainable Process for the Depolymerization/Oxidation of Softwood and Hardwood Kraft Lignins Using Hydrogen Peroxide under Ambient Conditions

et al. 2020

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The present study demonstrated a sustainable and cost-effective approach to depolymerize/oxidize softwood (SW) and hardwood (HW) kraft lignins using concentrated hydrogen peroxide at temperatures ranging from 25 to 35 °C, in the absence of catalysts or organic solvents. The degree of lignin depolymerization could be simply controlled by reaction time, and no further separation process was needed at the completion of the treatment. The obtained depolymerized lignin products were comprehensively characterized by GPC–UV, FTIR, 31P-NMR, TGA, Py-GC/MS and elemental analysis. The weight-average molecular weights (Mw) of the depolymerized lignins obtained from SW or HW lignin at a lignin/H2O2 mass ratio of 1:1 after treatment for 120 h at room temperature (≈25 °C) were approximately 1420 Da. The contents of carboxylic acid groups in the obtained depolymerized lignins were found to significantly increase compared with those of the untreated raw lignins. Moreover, the depolymerized lignin products had lower thermal decomposition temperatures than those of the raw lignins, as expected, owing to the greatly reduced Mw. These findings represent a novel solution to lignin depolymerization for the production of chemicals that can be utilized as a bio-substitute for petroleum-based polyols in polyurethane production.

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Section: Introductionmentioning

confidence: 99%

Sustainable Process for the Depolymerization/Oxidation of Softwood and Hardwood Kraft Lignins Using Hydrogen Peroxide under Ambient Conditions

et al. 2020

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“…Comparison studies revealed that nitrobenzene oxidation process gave higher yields of vanillin than the alkaline aerobic oxidation processes. Surprisingly, adding H 2 O 2 to the reaction mixture led to decreased vanillin production over supported Nb catalysts, caused by further oxidation of vanillin [47].…”

Section: Acetal Formation-assisted Delignification Followed By Cataly...mentioning

confidence: 98%

Towards Lignin-Derived Chemicals Using Atom-Efficient Catalytic Routes

Sudarsanam

Ruijten

Liao

et al. 2020

Trends in Chemistry

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“…There are two different methods of degradation of lignin; one is oxidative and another is reductive. With the help of these methods, lignin is transformed into useful organic compound (Das et al , 2017; Lange et al , 2013; Luo et al , 2016; Nanayakkara et al , 2014; Yanez et al , 2018). These lignin transformations have been used in dye removal (Kong et al , 2015), photo-responsive applications (Duval et al , 2015) and for removal of heavy metals from water (Jin et al , 2017).…”

Section: Introductionmentioning

confidence: 99%

Nano-dispersible azo pigments from lignin: a new synthetic approach and epoxy-polyamine composite coating

Patil

Jadhav

et al. 2022

PRT

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Purpose Here, diazo coupling reaction was imparted on chemically inert lignin isolated from natural resources. Activated lignin was coupled with the diazotised aniline, m-nitroaniline, p-nitroaniline-, and p-anisidine gives organic pigments. Design/methodology/approach The continuous increase in particle size of pigments confirms addition of diazotised salt to lignin by coupling reaction. Further, the dispersing ability of these coloured pigments were exploited in polymer matrix. Epoxy-polyamine cross linking system was doped with difference percentage of pigments and coated on mild steel metal surface. The morphology of these composites was understood by SEM, particle size, differential scanning calorimeter and thermo gravimetric analysis. Findings The synthesised organic pigments were characterised by FT-IR, 1H NMR and UV-visible spectroscopy. It was observed that hiding power of aniline- and m-nitroaniline–based azo pigments was more than p-nitroaniline- and p-anisidine–based azo pigments. Thermal properties as well as water contact angles of coatings were improved with pigment concentration. The chemical resistivity of coating was observed to be improved with the increasing % of lignin-based azo pigment. Originality/value Lignin-based azo pigment has great potential to replace metal oxide pigment and provide strategy for utilisation of lingo-cellulosic biowaste material.

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Oxidative Depolymerization of Lignin Using Supported Niobium Catalysts

Cited by 12 publications

References 53 publications

Sustainable Process for the Depolymerization/Oxidation of Softwood and Hardwood Kraft Lignins Using Hydrogen Peroxide under Ambient Conditions

Sustainable Process for the Depolymerization/Oxidation of Softwood and Hardwood Kraft Lignins Using Hydrogen Peroxide under Ambient Conditions

Towards Lignin-Derived Chemicals Using Atom-Efficient Catalytic Routes

Nano-dispersible azo pigments from lignin: a new synthetic approach and epoxy-polyamine composite coating

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