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Sakirler F, Wong HW. Cellulose Fast Pyrolysis Activated by Intramolecular Hydrogen Bonds. J Phys Chem A 2022; 126:7806-7819. [PMID: 36263959 DOI: 10.1021/acs.jpca.2c03669] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
The conversion of inedible biomass by fast pyrolysis is a promising route for sustainable production of renewable fuels and value-added chemicals, but low selectivity toward desired products hampers its economic viability. Understanding the molecular-level reaction pathways of biomass fast pyrolysis could be the key to overcoming this challenge. However, the effects of intramolecular and interchain hydrogen bonds near the reaction center have not been thoroughly explored. In this work, the reaction pathways and kinetics of fast pyrolysis of cellulose, a major component of biomass, were investigated using the density functional theory. A new intramolecular hydroxyl-activated mechanism is presented for cellulose activation. Our calculations incorporating noncovalent interactions accurately captured the activation energy of 50.8 kcal mol-1, agreeable with the apparent activation energy measured experimentally. The findings of cellulose pyrolysis provide insights into the investigation of interactions during real-life biomass pyrolysis.
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Affiliation(s)
- Fuat Sakirler
- Department of Chemical Engineering, University of Massachusetts Lowell, One University Avenue, Lowell, Massachusetts 01854, United States
| | - Hsi-Wu Wong
- Department of Chemical Engineering, University of Massachusetts Lowell, One University Avenue, Lowell, Massachusetts 01854, United States
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SriBala G, Vargas DC, Kostetskyy P, Van de Vijver R, Broadbelt LJ, Marin GB, Van Geem KM. New Perspectives into Cellulose Fast Pyrolysis Kinetics Using a Py-GC × GC-FID/MS System. ACS ENGINEERING AU 2022; 2:320-332. [PMID: 35996395 PMCID: PMC9389586 DOI: 10.1021/acsengineeringau.2c00006] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
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Cellulose pyrolysis
is reportedly influenced by factors such as
sample size, crystallinity, or different morphologies. However, there
seems to be a lack of understanding of the mechanistic details that
explain the observed differences in the pyrolysis yields. This study
aims to investigate the influence of particle size and crystallinity
of cellulose by performing pyrolysis reactions at temperatures of
673–873 K using a micropyrolyzer apparatus coupled to a GC
× GC-FID/TOF-MS and a customized GC-TCD. Over 60 product species
have been identified and quantified for the first time, including
water. Crystalline cellulose with an average particle size of 30–50
× 10–6 m produced 50–60 wt % levoglucosan.
Predominantly amorphous cellulose with an average particle size of
10–20 × 10–6 m resulted in remarkably
low yields (10–15 wt %) of levoglucosan complemented by higher
yields of water and glycolaldehyde. A detailed kinetic model for cellulose
pyrolysis was used to obtain mechanistic insights into the different
pyrolysis product compositions. The kinetics of the mid-chain dehydration
and fragmentation reactions strongly influence the total yields of
low-molecular weight products (LMWPs) and are affected by cellulose
chain arrangement. Levoglucosan yields are very sensitive to the activation
of parallel cellulose decomposition reactions. This can be attributed
to the mid-chain reactions forming smaller chains with the levoglucosan
ends, which remain in the solid phase and react further to form LMWPs.
Direct quantification of water helped to improve the description of
the dehydration, giving further indications of the dominant role of
mid-chain reaction pathways in amorphous cellulose pyrolysis.
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Affiliation(s)
- Gorugantu SriBala
- Laboratory for Chemical Technology, Ghent University, Technologiepark 125, Ghent 9052, Belgium
- Department of Chemical and Biological Engineering, Northwestern University, Evanston, Illinois 60208, United States
| | - Diana C. Vargas
- Laboratory for Chemical Technology, Ghent University, Technologiepark 125, Ghent 9052, Belgium
| | - Pavlo Kostetskyy
- Department of Chemical and Biological Engineering, Northwestern University, Evanston, Illinois 60208, United States
| | - Ruben Van de Vijver
- Laboratory for Chemical Technology, Ghent University, Technologiepark 125, Ghent 9052, Belgium
| | - Linda J. Broadbelt
- Department of Chemical and Biological Engineering, Northwestern University, Evanston, Illinois 60208, United States
| | - Guy B. Marin
- Laboratory for Chemical Technology, Ghent University, Technologiepark 125, Ghent 9052, Belgium
| | - Kevin M. Van Geem
- Laboratory for Chemical Technology, Ghent University, Technologiepark 125, Ghent 9052, Belgium
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