Kinetics of Vanillin Production from Kraft Lignin Oxidation

Fargues, Claire; Mathias, Álvaro Luiz; Rodrigues, Alírio E.

doi:10.1021/ie950267k

Cited by 145 publications

(131 citation statements)

References 6 publications

Supporting

Mentioning

123

Contrasting

Unclassified

Order By: Relevance

“…Reports in the literature indicated that treatment of lignin in alkaline solution at elevated temperatures and under oxygen atmosphere led to the formation of aromatic aldehyde cleavage products. 13 Here, however, changing the reaction atmosphere to oxygen or argon had a negligible influence on the yields affording 4 in 58% and 61%, respectively (entries 11 and 12). Furthermore, we were able to demonstrate that the good yield of veratrol was maintained when the reaction was performed on a 2 mmol scale (entry 10).…”

Section: Resultsmentioning

confidence: 86%

Base-catalysed cleavage of lignin β-O-4 model compounds in dimethyl carbonate

et al. 2015

View full text Add to dashboard Cite

A base-catalysed transformation and cleavage of lignin β-O-4 model compounds in dimethyl carbonate is reported. The reaction system consists of readily available bases and inexpensive dimethyl carbonate as a solvent and reagent, affording methoxy benzene or 2-aryloxyvinyl benzene derivatives in good to very good yields. The applicability of the system for the bond cleavage in an organosolv lignin sample was demonstrated.

show abstract

Section: Resultsmentioning

confidence: 86%

Base-catalysed cleavage of lignin β-O-4 model compounds in dimethyl carbonate

et al. 2015

View full text Add to dashboard Cite

show abstract

“…Villar et al [33] attributed the low yield value to the condensed nature of kraft lignin and the decomposition of aldehydes to lower-molecular-weight acids. However, under comparable conditions, Fargues et al [86] have reported obtaining a vanillin yield of around 10 wt-%. They also studied the dependency of vanillin and syringaldehyde yield on temperature, reaction time, oxygen pressure and alkaline condition.…”

Section: Oxidation For Aldehyde Productionmentioning

confidence: 91%

“…A further increase in oxidation time and temperature causes vanillin to undergo degradation [83]. Fargues et al [86] observed that the addition of copper and cobalt catalysts did not have a considerable influence on the conversion and aldehyde yields, which is in contrast to the results of Xiang and Lee [36] who found a mixture of Cu 2+ and Fe 3+ to be an effective catalyst increasing the yield of aldehydes from 7.9 to 11.1 wt-%. Wu and Heitz [85] and Zhang et al [87] also reported the effectiveness of catalysts in increasing the yield of aldehydes.…”

Section: Oxidation For Aldehyde Productionmentioning

confidence: 95%

Lignin Depolymerization and Conversion: A Review of Thermochemical Methods

2010

View full text Add to dashboard Cite

The structure of lignin suggests that it can be a valuable source of chemicals, particularly phenolics. However, lignin depolymerization with selective bond cleavage is the major challenge for converting it into value-added chemicals. Pyrolysis (thermolysis), gasification, hydrogenolysis, chemical oxidation, and hydrolysis under supercritical conditions are the major thermochemical methods studied with regard to lignin depolymerization. Pyrolytic oil and syngases are the primary products obtained from pyrolysis and gasification. A significant amount of char is also produced during pyrolysis. Thermal treatment in a hydrogen environment seems very promising for converting lignin to liquid fuel and chemicals like phenols, while oxidation can produce phenolic aldehydes. Reaction severity, solvents, and catalysts are the factors of prime importance that control yield and composition of the product. IntroductionThe depleting stocks of fossil fuels and the growing concern over the excessive emission of greenhouse gases have forced researchers to investigate renewable, abundant and comparably cleaner alternatives to liquid fuels and chemicals produced from petroleum [1][2][3]. Biomass appears to be a promising alternative and a renewable source for fuels and chemicals. Significant achievements have already been made in the production of ethanol fuel from biomass, primarily starch and sugarrich components. However, research on second-generation bioethanol is focused on a more abundant [4,5] and often relatively cheap [6][7][8] biomass feedstock known as lignocellulosic biomass. Lignocellulosic biomass consists of three basic components: cellulose, hemicellulose, and lignin. Cellulose is a linear polymer of glucose consisting of parts with crystalline structure and parts with amorphous structure [9], while hemicellulose is an amorphous, heterogeneously branched polymer of pentoses and hexoses, mainly xylose, arabinose, mannose, galactose, and glucose. Lignin is an amorphous and highly branched polymer of phenylpropane units, which can account for up to 40 % of the dry biomass weight [10]. The concept of a biorefinery that integrates processes and technologies for biomass conversion demands efficient utilization of all three components [11]. Most of the biorefinery schemes, however, are focused on utilizing easily convertible fractions while lignin remains relatively underutilized to its potential [11]. The lignocellulosics-to-ethanol process makes use of the cellulose and hemicelluloses, leaving lignin as waste. In addition, pulp and paper refineries also generate huge amounts of lignin. Presently, lignin is being utilized as a low-grade boiler fuel to provide heat and power to the process [3]. However, the chemical structure of lignin suggests that it may be a good source of valuable chemicals if it could be broken into smaller molecular units [7].Several studies have been done to convert lignin to more value-added products. These include attempts to convert lignin to liquid fuel additives and commercially important chem...

show abstract

“…It may be noted that in our research, the pH of the system was around 8 as we did not adjust the pH of the reactants. Several researchers, including [45][46][47], have noted the role of pH in lignin oxidation into chemicals. From an oxidation perspective, an increase in pH will promote oxidation of lignin [48].…”

Section: Future Directionsmentioning

confidence: 99%

Oxidative Depolymerization of Lignin Using Supported Niobium Catalysts

et al. 2017

View full text Add to dashboard Cite

Abstract:Valorization of lignin into aromatics has driven researchers for decades. In this research, niobium was deposited on oyster shells (OSNC) and carbon rods (CRNC) and tested as a catalyst for depolymerization of lignin. Catalysts (2%, 5%, and 8% loading) were synthesized via wet impregnation. Batch experiments were performed at 95 • C, using 8 g of lignin, and 1 g of catalyst. Our research indicates that niobium supported catalysts are effective in partial oxidation of lignin. Maximum vanillin concentration for OSNC was found to be 86.25 mg L −1 (0.1 wt%) at 5% niobium whereas, as for CRNC, maximum vanillin concentration was found to be 139.40 mg L −1 (0.17 wt%) at 2% niobium loading. Addition of hydrogen peroxide into the batch reactor decreased the concentration of vanillin production.

show abstract

Kinetics of Vanillin Production from Kraft Lignin Oxidation

Cited by 145 publications

References 6 publications

Base-catalysed cleavage of lignin β-O-4 model compounds in dimethyl carbonate

Base-catalysed cleavage of lignin β-O-4 model compounds in dimethyl carbonate

Lignin Depolymerization and Conversion: A Review of Thermochemical Methods

Oxidative Depolymerization of Lignin Using Supported Niobium Catalysts

Contact Info

Product

Resources

About