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Title: Kinetic Studies of Lignin Solvolysis and Reduction by Reductive Catalytic Fractionation Decoupled in Flow-Through Reactors

Abstract

Reductive catalytic fractionation (RCF) is an effective active-stabilization strategy to selectively extract and depolymerize lignin into aromatic monomers. Here, the kinetics of RCF were investigated by using flow-through reactors to decouple the two limiting mechanistic steps, namely lignin solvolysis and reduction. When operating in a solvolysis-limited regime, apparent energy barriers of 63 ± 1 and 64 ± 2 kJ mol –1 were measured for the solvent mediated lignin extraction of poplar using particle diameters of 0.5 < d < 1 mm and 0.075 < d < 0.25 mm, respectively. In contrast, when using mechanically stirred batch reactors, apparent barriers of 32 ± 1 and 39 ± 3 kJ mol –1 were measured for particle diameters of 0.5 < d < 1 mm and 0.075 < d < 0.25 mm, respectively. The difference of activation barriers between flow and batch reactors indicated that lignin extraction under typical RCF conditions in a 100 mL batch reactor stirred at 700 rpm was mass-transfer limited. In the reduction-limited regime, cleavage of the β-O-4 bond in a model compound exhibited an apparent activation barrier of 168 ± 14 kJ mol –1. This study demonstrates RCF occurs by two limiting processes that can be independently controlled.more » Furthermore, both controlling which process limits RCF and verifying if transport limitations exist, are critical steps to develop a mechanistic understanding of RCF and to design improved catalysts.« less

Authors:
 [1];  [1]; ORCiD logo [1]; ORCiD logo [2]; ORCiD logo [1]
  1. Massachusetts Inst. of Technology (MIT), Cambridge, MA (United States). Chemical Engineering
  2. National Renewable Energy Lab. (NREL), Golden, CO (United States)
Publication Date:
Research Org.:
National Renewable Energy Lab. (NREL), Golden, CO (United States); Massachusetts Inst. of Technology (MIT), Cambridge, MA (United States)
Sponsoring Org.:
USDOE Office of Energy Efficiency and Renewable Energy (EERE), Bioenergy Technologies Office (EE-3B); National Science Foundation (NSF)
OSTI Identifier:
1436364
Alternate Identifier(s):
OSTI ID: 1462319
Report Number(s):
NREL/JA-2A00-72048
Journal ID: ISSN 2168-0485
Grant/Contract Number:  
AC36-08GO28308; 1454299; AC36?08GO28308
Resource Type:
Journal Article: Published Article
Journal Name:
ACS Sustainable Chemistry & Engineering
Additional Journal Information:
Journal Volume: 6; Journal Issue: 6; Journal ID: ISSN 2168-0485
Publisher:
American Chemical Society (ACS)
Country of Publication:
United States
Language:
English
Subject:
09 BIOMASS FUELS; biomass pretreatment; flow-through extraction; lignin conversion; lignin first; lignin kinetics; reductive catalysis; semicontinuous processing

Citation Formats

Anderson, Eric M., Stone, Michael L., Hulsey, Max J., Beckham, Gregg T., and Roman-Leshkov, Yuriy. Kinetic Studies of Lignin Solvolysis and Reduction by Reductive Catalytic Fractionation Decoupled in Flow-Through Reactors. United States: N. p., 2018. Web. doi:10.1021/acssuschemeng.8b01256.
Anderson, Eric M., Stone, Michael L., Hulsey, Max J., Beckham, Gregg T., & Roman-Leshkov, Yuriy. Kinetic Studies of Lignin Solvolysis and Reduction by Reductive Catalytic Fractionation Decoupled in Flow-Through Reactors. United States. doi:10.1021/acssuschemeng.8b01256.
Anderson, Eric M., Stone, Michael L., Hulsey, Max J., Beckham, Gregg T., and Roman-Leshkov, Yuriy. Tue . "Kinetic Studies of Lignin Solvolysis and Reduction by Reductive Catalytic Fractionation Decoupled in Flow-Through Reactors". United States. doi:10.1021/acssuschemeng.8b01256.
@article{osti_1436364,
title = {Kinetic Studies of Lignin Solvolysis and Reduction by Reductive Catalytic Fractionation Decoupled in Flow-Through Reactors},
author = {Anderson, Eric M. and Stone, Michael L. and Hulsey, Max J. and Beckham, Gregg T. and Roman-Leshkov, Yuriy},
abstractNote = {Reductive catalytic fractionation (RCF) is an effective active-stabilization strategy to selectively extract and depolymerize lignin into aromatic monomers. Here, the kinetics of RCF were investigated by using flow-through reactors to decouple the two limiting mechanistic steps, namely lignin solvolysis and reduction. When operating in a solvolysis-limited regime, apparent energy barriers of 63 ± 1 and 64 ± 2 kJ mol–1 were measured for the solvent mediated lignin extraction of poplar using particle diameters of 0.5 < d < 1 mm and 0.075 < d < 0.25 mm, respectively. In contrast, when using mechanically stirred batch reactors, apparent barriers of 32 ± 1 and 39 ± 3 kJ mol–1 were measured for particle diameters of 0.5 < d < 1 mm and 0.075 < d < 0.25 mm, respectively. The difference of activation barriers between flow and batch reactors indicated that lignin extraction under typical RCF conditions in a 100 mL batch reactor stirred at 700 rpm was mass-transfer limited. In the reduction-limited regime, cleavage of the β-O-4 bond in a model compound exhibited an apparent activation barrier of 168 ± 14 kJ mol–1. This study demonstrates RCF occurs by two limiting processes that can be independently controlled. Furthermore, both controlling which process limits RCF and verifying if transport limitations exist, are critical steps to develop a mechanistic understanding of RCF and to design improved catalysts.},
doi = {10.1021/acssuschemeng.8b01256},
journal = {ACS Sustainable Chemistry & Engineering},
number = 6,
volume = 6,
place = {United States},
year = {Tue Apr 24 00:00:00 EDT 2018},
month = {Tue Apr 24 00:00:00 EDT 2018}
}

Journal Article:
Free Publicly Available Full Text
Publisher's Version of Record at 10.1021/acssuschemeng.8b01256

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