b - acumen - The University of Alabama

207 Pages·2010·3.28 MB·English

by  Ning Sun

DISSOLUTION AND PROCESSING OF CELLULOSIC MATERIALS WITH IONIC
LIQUIDS: FUNDAMENTALS AND APPLICATIONS

by

NING SUN

A DISSERTATION

Submitted in partial fulfillment of the requirements
for the degree of Doctor of Philosophy
in the Department of Chemistry
in the Graduate School of
The University of Alabama

TUSCALOOSA, ALABAMA

2010
Copyright Ning Sun 2010
ALL RIGHTS RESERVED
ABSTRACT
With the inevitable depletion of petroleum-based resources, there has been an increasing
worldwide interest in renewable resources such as biomass. One reason for the current
approaches being taken to utilize biomass is the difficulty in processing lignocellulosic materials
and the energy needed for separation of the components. The three major components of
biomass are covalently bonded together, which makes dissolution and further separation of the
three major components difficult and this has been recognized as the grand challenge for biomass
utilization.
This dissertation describes research efforts in processing of lignocellulosic biomass
using ionic liquids (ILs) as solvents. ILs are salts with melting points below 100 oC, which
possess many advantage properties. Cellulose composite fibers have been prepared based on IL
solution with dispersion of the additives. Wood and bagasse have been completely dissolved in
ILs. Partial separation of the components has been obtained using selected reconstitution
solvents. High temperature and fast dissolution was found to be an efficient method for both
dissolution and separation of biomass components. Biomass composite fibers can be prepared
directly from such biomass solutions. With selected catalysts in solution, improved dissolution
and separation has been achieved, making the delignification and pulp yield comparable to the
kraft pulping process.
ii
DEDICATION
This dissertation is dedicated to my husband Li Ding, my son Terry Haoyang Ding, my
parents Jimin Sun and Peirong Zhu, and my brother Jie Sun. Their love and belief in me made
this possible.

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LIST OF ABBREVIATIONS AND SYMBOLS
IL Ionic liquid
[C mim] 1-alkyl-3-methylimidazolium (n = number of carbons in the
n
alkyl chain)
[Amim] 1-allyl-3-methylimidazolium
[C mPy] 1-butyl-3-methylpyridinium
4
[Bu P] Tetrabutylphosphonium
4
OAc Acetate
XS Xylenesulfonate
[RCH OPO ] Alkanephosphonate (R: alkyl chain)
3 2
POM Polyoxometalate
HPAs Heterpoly acids
DP Degrees of polymerization
CRM Cellulose-rich material
NMMO N-methylmorpholine-N-oxide
DMSO Dimethyl sulfoxide
PB Pretreated biomass
OW Original wood
C Cellulose content in original wood
ow
C Cellulose content in pretreated wood
pw
L Lignin content in original wood
ow
L Lignin content in pretreated wood
pw
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LHC Loss of hemicellulose
PY Pulp yield
LY Lignin yield
CY Carbohydrate yield
LC Loss of carbohydrate
LL Loss of lignin
NMR Nuclear magnetic resonance
SEM Scanning electron microscopy
TEM Transmission electron microscopy
ATR Attenuated total reflectance
MCC Microcrystalline cellulose
PXRD Powder X-ray Diffraction
TGA Thermogravimetric Analysis
GC/MS Gas chromatography/mass spectrometry
T Glass transition temperature
g
M Remanence magnetization
r
M Saturation magnetization
s
H Coercivity
c

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ACKNOWLEDGEMENTS
I would like to express my gratitude to my research advisor, Dr. Robin D. Rogers, for
giving me a chance to join his group and providing guidance, advice, and encouragement during
the past five years. He has given me the confidence and ability to think and work
independently.
I would also like to acknowledge my committee members Dr. Shane C. Street, Dr. Carolyn
J. Cassady, Dr. Arunava Gupta, and Dr. Christopher S. Brazel for their valuable suggestions and
comments. They are great scientific educators and made me a better prepared chemist.
I would like to thank Dr. Richard P. Swatloski and Dr. Scott Spear for helping me to start
my project. Thanks are also extended to Dr. Mustafizur Rahman, Dr. Ying Qin, Dr. Xinyu
Jiang, Dr. Xingmei Lu, Mirela L. Maxim, and Weiying Li for working together with me on the
related projects. They have been both great colleagues and friends at the same time, making my
work and life more enjoyable. I thank Dr. Héctor Rodríguez and Dr. Andreas Metlen for great
help with writing papers and Dr. Gabriela Gurau, Dr. Marcin Smiglak, and David M. Drab for
always being there and offering help on my presentations and proposals. I also thank Dr. Ken
Belmore for his assistance with NMR characterization, and Dr. Qiaoli Liang for her assistance
with GC/MS.
I would like to acknowledge my family and all my friends for their support, love, and faith
in me. This research would not have been possible without them.

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Lastly, I would like to thank The Department of Chemistry and The University of Alabama
for giving me the opportunity to be here and BASF, North America for initially funding this
project. Finally I would like to thank The University of Alabama Graduate Council for
providing me a fellowship which allowed me to finish my dissertation.

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CONTENTS
ABSTRACT ............................................................................................................................... ii
DEDICATION .......................................................................................................................... iii
LIST OF ABBREVIATIONS AND SYMBOLS ...................................................................... iv
ACKNOWLEDGEMENTS ....................................................................................................... vi
LIST OF TABLES .................................................................................................................. xiii
LIST OF SCHEMES AND FIGURES .................................................................................... xiv
CHAPTER 1 INTRODUCTION .............................................................................................. 1
1.1 Ionic liquids (ILs), what are they really? ................................................ 1
1.2 Biomass and sustainability ...................................................................... 4
1.3 Dissolution of cellulose in ILs ................................................................ 7
1.4 A question of Graneacher: a detective story ......................................... 15
1.5 If you can easily dissolve cellulose in ILs, what can you do with it? ... 19
1.5.1 Bioactive supports ................................................................. 21
1.5.2 Membrane sensors ................................................................. 22
1.5.3 Cellulose matrices with particulates incorporated ................. 23
1.5.4 Cellulose/polymer blends ...................................................... 24
1.5.5 Hydrolysis of cellulose .......................................................... 26
1.6 Beyond cellulose: other biomacromolecules ........................................ 28

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1.7 Can ionic liquids dissolve wood? ......................................................... 29
1.7.1 Wood dissolution in IL .......................................................... 32
1.7.2 Functionalization of dissolved lignocellulose ....................... 35
1.8 Conclusions ........................................................................................... 35
1.9 Acknowledgements ............................................................................... 37
1.10 Summary of the chapters ...................................................................... 37
1.11 References ............................................................................................. 40
CHAPTER 2 MAGNETITE EMBEDDED CELLULOSE FIBERS
PREPARED FROM IONIC LIQUIDS ............................................................ 47
2.1 Introduction ........................................................................................... 47
2.2 Experimental ......................................................................................... 49
2.2.1 Materials ................................................................................ 49
2.2.2 Preparation of cellulose fibers ............................................... 49
2.2.3 Characterization of fibers ...................................................... 51
2.3 Results and discussion .......................................................................... 53
2.3.1 Analysis of cellulose fibers without magnetite ...................... 55
2.3.2 Analysis of magnetite-embedded cellulose fibers ................. 60
2.4 Conclusions ........................................................................................... 66
2.5 Acknowledgements ............................................................................... 66
2.6 References ............................................................................................. 67

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