Efficient reductive depolymerization of hardwood and softwood lignins with Brookhart's iridium(<scp>iii</scp>) catalyst and hydrosilanes

Monsigny, Louis; Féghali, Elias; Berthet, Jean‐Claude; Cantat, Thibault

doi:10.1039/c7gc03743k

Cited by 33 publications

(20 citation statements)

References 33 publications

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“…and 16 h were needed to depolymerize PLA with a slight excess of Et3SiH and 5 mol% 3 at room temperature, while the same reaction was achieved within 3 h with PET 14. As already observed with natural polymers,22 catalyst 4 proved less reactive than B(C6F5)3 requiring longer reaction times and higher temperatures for both PLA and PET.Nevertheless, B(C6F5)3 in presence of excess silane favored rapid (24 h) cleavage of all the C-O bonds at room temperature with formation of alkanes and siloxane as the sole products. The iridium catalyst 4 exhibits a higher selectivity allowing the conservation of functionalities, such as silylethers.…”

supporting

confidence: 61%

Depolymerization of Waste Plastics to Monomers and Chemicals Using a Hydrosilylation Strategy Facilitated by Brookhart’s Iridium(III) Catalyst

Monsigny

Berthet

Cantat

2018

ACS Sustainable Chem. Eng.

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115

111

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Plastic waste management is a major concern. While the societal demand for sustainability is growing, landfilling and incineration of waste plastics remain the norm and methods able to efficiently recycle these materials are desirable. Herein, we report the depolymerization, under mild conditions, of oxygenated plastics in the presence of hydrosilanes with the cationic pincer complex [Ir(PCP)H(THF)][B(C6F5)4] (PCP = 1,3-(tBu2P)2C6H3)) as catalyst. The iridium catalyst, with a low loading (0.3-1 mol%), proves selective toward the formation of silyl ethers or the corresponding alkanes depending only on the reaction temperature. It is noteworthy that the depolymerization of real household waste plastics such as PET (from plastic bottles) and polylactic acid (PLA) from 3D printer filaments is not altered by the presence of dye or other plastic's additives.

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confidence: 61%

Depolymerization of Waste Plastics to Monomers and Chemicals Using a Hydrosilylation Strategy Facilitated by Brookhart’s Iridium(III) Catalyst

Monsigny

Berthet

Cantat

2018

ACS Sustainable Chem. Eng.

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115

111

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“…The depolymerization of lignin into well-defined mono-aromatic chemicals suitable for downstream processing would be an important starting point for the valorization of lignin as well as the promotion of the economics of biorefineries [17,18]. Recently, the direct reductive catalytic fractionation (RCF) of lignocellulosic biomass was emerged as a new protocol for biomass fractionation and lignin depolymerization [15,19].…”

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confidence: 99%

Total utilization of lignin and carbohydrates in Eucalyptus grandis: an integrated biorefinery strategy towards phenolics, levulinic acid, and furfural

Chen

Zhang

Xiao

et al. 2020

Biotechnol Biofuels

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Background: Lignocellulosic biomass, which is composed of cellulose, hemicellulose and lignin, represents the most abundant renewable carbon source with significant potential for the production of sustainable chemicals and fuels. Current biorefineries focus on cellulose and hemicellulose valorization, whereas lignin is treated as a waste product and is burned to supply energy to the biorefineries. The depolymerization of lignin into well-defined mono-aromatic chemicals suitable for downstream processing is recognized increasingly as an important starting point for lignin valorization. In this study, conversion of all three components of Eucalyptus grandis into the corresponding monomeric chemicals was investigated using solid and acidic catalyst in sequence. Results: Lignin was depolymerized into well-defined monomeric phenols in the first step using a Pd/C catalyst. The maximum phenolic monomers yield of 49.8 wt% was achieved at 240 °C for 4 h under 30 atm H 2. In the monomers, 4-propanol guaiacol (12.9 wt%) and 4-propanol syringol (31.9 wt%) were identified as the two major phenolic products with 90% selectivity. High retention of cellulose and hemicellulose pulp was also obtained, which was treated with FeCl 3 catalyst to attain 5-hydroxymethylfurfural, levulinic acid and furfural simultaneously. The optimal reaction condition for the co-conversion of hemicellulose and cellulose was established as 190 °C and 100 min, from which furfural and levulinic acid were obtained in 55.9% and 73.6% yields, respectively. Ultimately, 54% of Eucalyptus sawdust can be converted into well-defined chemicals under such an integrated biorefinery method. Conclusions: A two-step process (reductive catalytic fractionation followed by FeCl 3 catalysis) allows the fractionation of all the three biopolymers (cellulose, hemicellulose, and lignin) in Eucalyptus biomass, which provides a promising strategy to make high-value chemicals from sustainable biomass.

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“…N° D135550). Lignin purified from poplar, plane tree and wheat straw was kindly provided by Louis Monsigny [ 34 ] and oak wood extractive by Melanie Morel.…”

Section: Methodsmentioning

confidence: 99%

Lignin Degradation and Its Use in Signaling Development by the Coprophilous Ascomycete Podospora anserina

Dicko¹,

Ferrari

Tangthirasunun

et al. 2020

JoF

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The filamentous fungus Podospora anserina is a good model to study the breakdown of lignocellulose, owing to its ease of culture and genetical analysis. Here, we show that the fungus is able to use a wide range of lignocellulosic materials as food sources. Using color assays, spectroscopy and pyrolysis–gas chromatography mass spectrometry, we confirm that this ascomycete is able to degrade lignin, primarily by hydrolyzing β–O-4 linkages, which facilitates its nutrient uptake. We show that the limited weight loss that is promoted when attacking Miscanthus giganteus is due to a developmental blockage rather than an inefficiency of its enzymes. Finally, we show that lignin, and, more generally, phenolics, including degradation products of lignin, greatly stimulate the growth and fertility of the fungus in liquid cultures. Analyses of the CATΔΔΔΔΔ mutant lacking all its catalases, pro-oxidants and antioxidants indicate that improved growth and fertility of the fungus is likely caused by augmented reactive oxygen species levels triggered by the presence of phenolics.

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Efficient reductive depolymerization of hardwood and softwood lignins with Brookhart's iridium(iii) catalyst and hydrosilanes

Abstract: Efficient catalytic reduction of lignin model molecules and reductive depolymerization of softwood and hardwood lignins is presented with the iridium based Brookhart's catalyst and hydrosilanes R3SiH as reductant.

Cited by 33 publications

References 33 publications

Depolymerization of Waste Plastics to Monomers and Chemicals Using a Hydrosilylation Strategy Facilitated by Brookhart’s Iridium(III) Catalyst

Depolymerization of Waste Plastics to Monomers and Chemicals Using a Hydrosilylation Strategy Facilitated by Brookhart’s Iridium(III) Catalyst

Total utilization of lignin and carbohydrates in Eucalyptus grandis: an integrated biorefinery strategy towards phenolics, levulinic acid, and furfural

Lignin Degradation and Its Use in Signaling Development by the Coprophilous Ascomycete Podospora anserina

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