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Title: Inverse Temperature-Dependent Pathway of Cellulose Decrystallization in Trifluoroacetic Acid

Abstract

Abstract An unusual inverse temperature-dependent pathway was observed during cellulose decrystallization in trifluoroacetic acid (TFA). Decreasing the TFA treatment temperature accelerated the cellulose decrystallization process. It took only 100 minutes to completely decrystallize cellulose at 0 °C in TFA, a result not achieved in 48 hours at 25°C in the same medium. There was neither cellulose esterification nor a change of cellulose macrofibril morphology by TFA treatment at 0 °C. Our IR data suggest that TFA molecules are present as cyclic dimers when they penetrate into crystalline cellulose regions, transforming crystalline cellulose to amorphous cellulose. The TFA cyclic dimer does not form strong hydrogen bonds with cellulose since the IR vibration frequency of the carbonyl group of the dimer molecule remained unchanged after the dimer diffused into the cellulose matrix. On the other hand, the rate of TFA penetration into the cellulose matrix was greatly retarded at higher temperatures where monomeric TFA esterification took place on the external surface of crystalline cellulose. At elevated temperatures esterification of TFA monomers with cellulose, as well as water released from the esterification reaction, inhibit the diffusion rate of TFA into the cellulose crystalline region and decreases the TFA swelling capability. Based on experimentalmore » observations, our study indicates that cellulose decrystallization does not require that solvent molecules form strong hydrogen bonds with cellulose.« less

Authors:
; ; ;
Publication Date:
Research Org.:
Pacific Northwest National Lab. (PNNL), Richland, WA (United States). Environmental Molecular Sciences Lab. (EMSL)
Sponsoring Org.:
USDOE
OSTI Identifier:
912510
Report Number(s):
PNNL-SA-50485
16307; 16691; TRN: US200801%%1061
DOE Contract Number:  
AC05-76RL01830
Resource Type:
Journal Article
Journal Name:
Journal of Physical Chemistry B, 111(19):5295-5300
Additional Journal Information:
Journal Volume: 111; Journal Issue: 19
Country of Publication:
United States
Language:
English
Subject:
08 HYDROGEN; CARBONYLS; CELLULOSE; DIFFUSION; DIMERS; ESTERIFICATION; HYDROGEN; MONOMERS; MORPHOLOGY; SOLVENTS; SWELLING; WATER; biorefinery; biomass; decrystallization; combinatorial catalysis; Environmental Molecular Sciences Laboratory

Citation Formats

Zhao, Haibo, Holladay, John E, Kwak, Ja Hun, and Zhang, Z Conrad. Inverse Temperature-Dependent Pathway of Cellulose Decrystallization in Trifluoroacetic Acid. United States: N. p., 2007. Web. doi:10.1021/jp070253f.
Zhao, Haibo, Holladay, John E, Kwak, Ja Hun, & Zhang, Z Conrad. Inverse Temperature-Dependent Pathway of Cellulose Decrystallization in Trifluoroacetic Acid. United States. https://doi.org/10.1021/jp070253f
Zhao, Haibo, Holladay, John E, Kwak, Ja Hun, and Zhang, Z Conrad. 2007. "Inverse Temperature-Dependent Pathway of Cellulose Decrystallization in Trifluoroacetic Acid". United States. https://doi.org/10.1021/jp070253f.
@article{osti_912510,
title = {Inverse Temperature-Dependent Pathway of Cellulose Decrystallization in Trifluoroacetic Acid},
author = {Zhao, Haibo and Holladay, John E and Kwak, Ja Hun and Zhang, Z Conrad},
abstractNote = {Abstract An unusual inverse temperature-dependent pathway was observed during cellulose decrystallization in trifluoroacetic acid (TFA). Decreasing the TFA treatment temperature accelerated the cellulose decrystallization process. It took only 100 minutes to completely decrystallize cellulose at 0 °C in TFA, a result not achieved in 48 hours at 25°C in the same medium. There was neither cellulose esterification nor a change of cellulose macrofibril morphology by TFA treatment at 0 °C. Our IR data suggest that TFA molecules are present as cyclic dimers when they penetrate into crystalline cellulose regions, transforming crystalline cellulose to amorphous cellulose. The TFA cyclic dimer does not form strong hydrogen bonds with cellulose since the IR vibration frequency of the carbonyl group of the dimer molecule remained unchanged after the dimer diffused into the cellulose matrix. On the other hand, the rate of TFA penetration into the cellulose matrix was greatly retarded at higher temperatures where monomeric TFA esterification took place on the external surface of crystalline cellulose. At elevated temperatures esterification of TFA monomers with cellulose, as well as water released from the esterification reaction, inhibit the diffusion rate of TFA into the cellulose crystalline region and decreases the TFA swelling capability. Based on experimental observations, our study indicates that cellulose decrystallization does not require that solvent molecules form strong hydrogen bonds with cellulose.},
doi = {10.1021/jp070253f},
url = {https://www.osti.gov/biblio/912510}, journal = {Journal of Physical Chemistry B, 111(19):5295-5300},
number = 19,
volume = 111,
place = {United States},
year = {Thu May 17 00:00:00 EDT 2007},
month = {Thu May 17 00:00:00 EDT 2007}
}