ReaxFF Study of the Oxidation of Lignin Model Compounds for the Most Common Linkages in Softwood in View of Carbon Fiber Production

Beste, Ariana

doi:10.1021/jp410454q

Cited by 69 publications

(84 citation statements)

References 71 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…4g in Ref. 51 ), thus validating that we are not substantially diverging from previous computational studies through incorporation of a steering force. In the second case, the transferred hydrogen atom originated either from a neighboring alcohol group or directly from the adjacent carbon atom, leading to either aldehyde or enol products (for a total of three overall pathways).…”

Section: A Dimer Studiessupporting

confidence: 81%

Ab Initio Screening Approach for the Discovery of Lignin Polymer Breaking Pathways

Mar¹,

Qi²,

Liu

et al. 2015

J. Phys. Chem. A

View full text Add to dashboard Cite

The directed depolymerization of lignin biopolymers is of utmost relevance for the valorization or commercialization of biomass fuels. We present a computational and theoretical screening approach to identify potential cleavage pathways and resulting fragments that are formed during depolymerization of lignin oligomers containing two to six monomers. We have developed a chemical discovery technique to identify the chemically relevant putative fragments in eight known polymeric linkage types of lignin. Obtaining these structures is a crucial precursor to the development of any further kinetic modeling. We have developed this approach by adapting steered molecular dynamics calculations under constant force and varying the points of applied force in the molecule to diversify the screening approach. Key observations include relationships between abundance and breaking frequency, the relative diversity of potential pathways for a given linkage, and the observation that readily cleaved bonds can destabilize adjacent bonds, causing subsequent automatic cleavage.

show abstract

Section: A Dimer Studiessupporting

confidence: 81%

Ab Initio Screening Approach for the Discovery of Lignin Polymer Breaking Pathways

Mar¹,

Qi²,

Liu

et al. 2015

J. Phys. Chem. A

View full text Add to dashboard Cite

show abstract

“…3 Quantum chemical studies have examined bond dissociation enthalpies relevant to lignin deconstruction, [40][41][42][43][44] radical coupling reactions in lignin biosynthesis [45][46][47] and dilignol interaction energies with ionic liquid ions. 3 Quantum chemical studies have examined bond dissociation enthalpies relevant to lignin deconstruction, [40][41][42][43][44] radical coupling reactions in lignin biosynthesis [45][46][47] and dilignol interaction energies with ionic liquid ions.…”

Section: Discussionmentioning

confidence: 99%

Why genetic modification of lignin leads to low-recalcitrance biomass

Carmona

Langan

Smith

et al. 2015

Phys. Chem. Chem. Phys.

View full text Add to dashboard Cite

Genetic modification of plants via down-regulation of cinnamyl alcohol dehydrogenase leads to incorporation of aldehyde groups in the lignin polymer. The resulting lignocellulosic biomass has increased bioethanol yield. However, a molecular-scale explanation of this finding is currently lacking. Here, we perform molecular dynamics simulation of the copolymer with hemicellulose of wild type and the genetically modified lignin, in aqueous solution. We find that the non-covalent association with hemicellulose of lignin containing aldehyde groups is reduced compared to the wild-type. This phase separation may increase the cell wall porosity in the mutant plants, thus explaining their easier deconstruction to biofuels. The thermodynamic origin of the reduced lignin-hemicellulose association is found to be a more favorable self-interaction energy and less favorable interaction with hemicellulose for the mutant lignin. Furthermore, reduced hydration water density fluctuations are found for the mutant lignin, implying a more hydrophobic lignin surface. The results provide a detailed description of how aldehyde incorporation makes lignin more hydrophobic and reduces its association with hemicellulose, thus suggesting that increased lignin hydrophobicity may be an optimal characteristic required for improved biofuel production.

show abstract

“…Previous computational efforts have focused on studying model compounds that contain the abundant β-O-4 ether lignin linkage by evaluating homolytic bond dissociation energies [35][36][37][38][39] , mechanical properties [40][41][42][43] , intramolecular hydrogen bonding 44 . More recently, some kinetic modeling and analysis has been carried out, particularly to model fast pyrolysis [45][46][47][48][49][50] . Both specific 51 and general catalysis of lignin depolymerization has been investigated computationally by studying the effect of transition metal catalysts [52][53][54][55] and ionic liquids [56][57] on lignin degradation.…”

Section: Introductionmentioning

confidence: 99%

Depolymerization Pathways for Branching Lignin Spirodienone Units Revealed with ab Initio Steered Molecular Dynamics

Mar

Kulik

2017

J. Phys. Chem. A

View full text Add to dashboard Cite

Lignocellulosic biomass is an abundant, rich source of aromatic compounds, but direct utilization of raw lignin has been hampered by both the high heterogeneity and variability of linking bonds in this biopolymer. Ab initio steered molecular dynamics (AISMD) has emerged both as a fruitful direct computational screening approach to identify products that occur through mechanical depolymerization (i.e., in sonication or ball-milling) and as a sampling approach. By varying the direction of force and sampling over 750 AISMD trajectories, we identify numerous possible pathways through which lignin depolymerization may occur in pyrolysis or through catalytic depolymerization as well. Here, we present eight unique major depolymerization pathways discovered via AISMD for the recently characterized spirodienone lignin branchinglinkage that may comprise around 10% weight of all lignin in some softwoods. We extract representative trajectories from AISMD and carry out reaction pathway analysis to identify energetically favorable pathways for lignin depolymerization. Importantly, we identify dynamical effects that could not be observed through more traditional calculations of bond dissociation energies. Such effects include thermodynamically favorable recovery of aromaticity in the dienone ring that leads to near-barrierless subsequent ether cleavage and hydrogen bonding effects that stabilize newly formed radicals. Some of the most stable spirodienone fragments that reside at most 1 eV above the reactant structure are formed with only 2 eV barriers for C-C bond cleavage, suggesting key targets for catalyst design to drive targeted depolymerization of lignin.2

show abstract

ReaxFF Study of the Oxidation of Lignin Model Compounds for the Most Common Linkages in Softwood in View of Carbon Fiber Production

Cited by 69 publications

References 71 publications

Ab Initio Screening Approach for the Discovery of Lignin Polymer Breaking Pathways

Ab Initio Screening Approach for the Discovery of Lignin Polymer Breaking Pathways

Why genetic modification of lignin leads to low-recalcitrance biomass

Depolymerization Pathways for Branching Lignin Spirodienone Units Revealed with ab Initio Steered Molecular Dynamics

Contact Info

Product

Resources

About