Routes of degradation of β-O-4 syringyl and guaiacyl lignin model compounds during photobleaching processes

Felı́cio, Cinthia Maria; Machado, Antônio Eduardo da Hora; Castellan, Alain; Nourmamode, Aziz; Perez, Denilson da Silva; Ruggiero, Reinaldo

doi:10.1016/s1010-6030(03)00007-8

Cited by 19 publications

(18 citation statements)

References 36 publications

Supporting

Mentioning

Contrasting

Unclassified

Order By: Relevance

“…Organosolv-derived lignins (OLSW and DL) possess a higher TPC compared to kraft lignins, indicating that the organosolv process maintains a reasonable amount of the phenolic structure in the lignin. As reported in various studies, there is no clear correlation between DPPH inhibition and TPC values, most probably due to the type of phenolics responsible for the antioxidant activity [ 57 ].…”

Section: Resultsmentioning

confidence: 99%

Lignocellulosic Biomass as Source for Lignin-Based Environmentally Benign Antioxidants

et al. 2018

View full text Add to dashboard Cite

Antioxidant activity is an essential aspect of oxygen-sensitive merchandise and goods, such as food and corresponding packaging, cosmetics, and biomedicine. Technical lignin has not yet been applied as a natural antioxidant, mainly due to the complex heterogeneous structure and polydispersity of lignin. This report presents antioxidant capacity studies completed using the 2,2-diphenyl-1-picrylhydrazyl (DPPH) assay. The influence of purification on lignin structure and activity was investigated. The purification procedure showed that double-fold selective extraction is the most efficient (confirmed by ultraviolet-visible (UV/Vis), Fourier transform infrared (FTIR), heteronuclear single quantum coherence (HSQC) and 31P nuclear magnetic resonance spectroscopy, size exclusion chromatography, and X-ray diffraction), resulting in fractions of very narrow polydispersity (3.2–1.6), up to four distinct absorption bands in UV/Vis spectroscopy. Due to differential scanning calorimetry measurements, the glass transition temperature increased from 123 to 185 °C for the purest fraction. Antioxidant capacity is discussed regarding the biomass source, pulping process, and degree of purification. Lignin obtained from industrial black liquor are compared with beech wood samples: antioxidant activity (DPPH inhibition) of kraft lignin fractions were 62–68%, whereas beech and spruce/pine-mixed lignin showed values of 42% and 64%, respectively. Total phenol content (TPC) of the isolated kraft lignin fractions varied between 26 and 35%, whereas beech and spruce/pine lignin were 33% and 34%, respectively. Storage decreased the TPC values but increased the DPPH inhibition.

show abstract

Section: Resultsmentioning

confidence: 99%

Lignocellulosic Biomass as Source for Lignin-Based Environmentally Benign Antioxidants

et al. 2018

View full text Add to dashboard Cite

show abstract

“…C-C) 52 , β-O-4 linkage is commonly selected as the focal point for depolymerization. Oxidative depolymerization of β-O-4 linkage to phenolics initiates via formation of • OH radicals produced during photocatalysis.• OH radical can react with aromatics rings via electrophilic addition to cleave the bond resulting in the substitution of the OH group 53,54. The yield and concentration in terms of TPC for each experiment are reported inTable 2 and Figure 2,respectively.…”

mentioning

confidence: 99%

TiO₂–AgCl Based Nanoparticles for Photocatalytic Production of Phenolic Compounds from Lignocellulosic Residues

et al. 2018

View full text Add to dashboard Cite

Lignocellulosic biomass residues can be used as an interesting resource for the production of biochemicals or sustainable fuels. In this optic, lignin represents an interesting raw material for the production of chemicals, such as aromatic compounds, or fuels. This can contribute in moving away from petroleum-based industries to bio-based industries. The aim of this study was to investigate the application of a photocatalytic process using a commercial solution composed by TiO2 doped with AgCl for wheat straw valorization. The study investigated the effect of pH and catalyst concentrations for optimal phenolic compounds production. It was found that the photocatalytic treatment boosted the phenolic production from wheat straw. The efficiency of the process depended on the initial pH and catalyst concentration. Process optimization towards increased phenolic compounds production was performed. Catalyst concentration of 1 g/L and a treatment time of 1.56 hours in alkaline conditions resulted in the highest phenolics production. Use of the photocatalytic treated wheat straw for anaerobic digestion (AD) was also evaluated. Results showed that the AD microbiome is strongly inhibited by the presence of toxic compounds presented in the catalyst-straw solution and specifically, HNO3 was toxic to methanogenic communities. Hence, to succeed in an efficient biorefinery framework where total phenols and biogas production are combined, the usage of HNO3 for catalyst synthesis should be avoided.

show abstract

“…In the present study, microwave radiation and the reactive radical species such as •OH and O 2 • − radicals from H 2 O 2 dissociation induce these reactions to occur. Importantly, hydroxyl radicals can react with benzene ring via electrophilic addition and cause the cleavage of α-O-4 or β-O-4 ether links in lignin [63]. As a result, OH group substitution is achieved.…”

Section: The Proposed Mechanism Of Oxidative Depolymerization Of Efb Derived Lignin With Mixed Metal Oxides Cu-fe Catalystmentioning

confidence: 99%

Lignin-Derived Syringol and Acetosyringone from Palm Bunch Using Heterogeneous Oxidative Depolymerization over Mixed Metal Oxide Catalysts under Microwave Heating

et al. 2021

View full text Add to dashboard Cite

Biomass valorization to building block chemicals in food and pharmaceutical industries has tremendously gained attention. To produce monophenolic compounds from palm empty fruit bunch (EFB), EFB was subjected to alkaline hydrothermal extraction using NaOH or K2CO3 as a promotor. Subsequently, EFB-derived lignin was subjected to an oxidative depolymerization using Cu(II) and Fe(III) mixed metal oxides catalyst supported on γ-Al2O3 or SiO2 as the catalyst in the presence of hydrogen peroxide. The highest percentage of total phenolic compounds of 63.87 wt% was obtained from microwave-induced oxidative degradation of K2CO3 extracted lignin catalyzed by Cu-Fe/SiO2 catalyst. Main products from the aforementioned condition included 27.29 wt% of 2,4-di-tert-butylphenol, 19.21 wt% of syringol, 9.36 wt% of acetosyringone, 3.69 wt% of acetovanillone, 2.16 wt% of syringaldehyde, and 2.16 wt% of vanillin. Although the total phenolic compound from Cu-Fe/Al2O3 catalyst was lower (49.52 wt%) compared with that from Cu-Fe/SiO2 catalyst (63.87 wt%), Cu-Fe/Al2O3 catalyst provided the greater selectivity of main two value-added products, syringol and acetosyrigone, at 54.64% and 23.65%, respectively (78.29% total selectivity of two products) from the NaOH extracted lignin. The findings suggested a promising method for syringol and acetosyringone production from the oxidative heterogeneous lignin depolymerization under low power intensity microwave heating within a short reaction time of 30 min.

show abstract

Routes of degradation of β-O-4 syringyl and guaiacyl lignin model compounds during photobleaching processes

Cited by 19 publications

References 36 publications

Lignocellulosic Biomass as Source for Lignin-Based Environmentally Benign Antioxidants

Lignocellulosic Biomass as Source for Lignin-Based Environmentally Benign Antioxidants

TiO₂–AgCl Based Nanoparticles for Photocatalytic Production of Phenolic Compounds from Lignocellulosic Residues

Lignin-Derived Syringol and Acetosyringone from Palm Bunch Using Heterogeneous Oxidative Depolymerization over Mixed Metal Oxide Catalysts under Microwave Heating

Contact Info

Product

Resources

About

Routes of degradation of β-O-4 syringyl and guaiacyl lignin model compounds during photobleaching processes

Cited by 19 publications

References 36 publications

Lignocellulosic Biomass as Source for Lignin-Based Environmentally Benign Antioxidants

Lignocellulosic Biomass as Source for Lignin-Based Environmentally Benign Antioxidants

TiO2–AgCl Based Nanoparticles for Photocatalytic Production of Phenolic Compounds from Lignocellulosic Residues

Lignin-Derived Syringol and Acetosyringone from Palm Bunch Using Heterogeneous Oxidative Depolymerization over Mixed Metal Oxide Catalysts under Microwave Heating

Contact Info

Product

Resources

About

TiO₂–AgCl Based Nanoparticles for Photocatalytic Production of Phenolic Compounds from Lignocellulosic Residues