Depolymerization of Lignin at Low Pressure Using Lewis Acid Catalysts and under High Pressure Using Hydrogen Donor Solvents

Davoudzadeh, Faegh; Smith, Blair; Avni, E.; Coughlin, Robert W.

doi:10.1515/hfsg.1985.39.3.159

Cited by 39 publications

(23 citation statements)

References 4 publications

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“…In addition, the reaction temperature used is in the range of 300-600°C, which is fairly lower than those applied in thermolysis [24]. Hydrogenation is performed either by treating lignin in an active hydrogen-donating solvent, such as tetralin [34,60,[62][63][64], sodium formate [61], and formic acid [65], or in gaseous hydrogen [66,67].…”

Section: Hydrogenolysismentioning

confidence: 99%

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Lignin Depolymerization and Conversion: A Review of Thermochemical Methods

2010

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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...

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Section: Hydrogenolysismentioning

confidence: 99%

“…Davoudzadeh et al [63] used tetralin with phenol as solvent for lignin hydrogenolysis. An increase in the liquid yield compared to neat pyrolysis was observed.…”

Section: Hydrogen-donating Solventsmentioning

confidence: 99%

Lignin Depolymerization and Conversion: A Review of Thermochemical Methods

2010

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“…A number of thermochemical conversion methods have been proposed to deploymerize lignin to low-molecular weight compounds [25][26][27][28][29][30][31][32][33][34][35]. Among them, base-catalyzed depolymerization, pyrolysis (lignin to liquid, LtL), and Lewis acid-catalyzed solvolysis have received a considerable amount of attention.…”

Section: Thermochemical Lignin Depolymerization Methodsmentioning

confidence: 99%

“…Despite the low yield (>10%), more than a dozen phenol monomers were identified in the product mixture but recovery of these monomers required multiple steps of separation [35]. Degrading isolated lignin by solvolysis in the presence of Lewis acid catalysts (e.g., AlCl 3 , FeCl 3 , NiCl 2 , and BF 3 ) has also been proposed [28,30]. This reaction leads to a simultaneous depolymerization and hydrogenation of lignin.…”

Section: Thermochemical Lignin Depolymerization Methodsmentioning

confidence: 99%

Routes to Potential Bioproducts from Lignocellulosic Biomass Lignin and Hemicelluloses

2011

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“…It has long been known that the presence of phenols or cresols decreases condensation reactions and leads to higher yields of monomeric phenols (see, for instance, Section 111.2.1 for aqueous alkali medium data and more recently, Davoudzadeh et al 1985). Extensive work at the Noguchi Institute and at Crown-Zellerback Corp. (see Section II.…”

Section: B) Solvent/vehiclementioning

confidence: 99%

Liquid Fuels from Lignins: Annual Report

Chum¹,

Johnson²

1986

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Depolymerization of Lignin at Low Pressure Using Lewis Acid Catalysts and under High Pressure Using Hydrogen Donor Solvents

Cited by 39 publications

References 4 publications

Lignin Depolymerization and Conversion: A Review of Thermochemical Methods

Lignin Depolymerization and Conversion: A Review of Thermochemical Methods

Routes to Potential Bioproducts from Lignocellulosic Biomass Lignin and Hemicelluloses

Liquid Fuels from Lignins: Annual Report

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