This document summarizes work from Work Package 2 of the FuBio project, which aims to develop efficient and sustainable methods for biomass fractionation using recyclable ionic liquids. It discusses how ionic liquids enable true homogeneous processing of wood, and highlights results on autohydrolysis pretreatment, fibrillation of wood chips, and the IONCELL process for selective extraction of cellulose and hemicellulose from kraft pulp. It also introduces novel recyclable ionic liquid classes developed within the project, including distillable, switchable, and phase-separable ionic liquids, and evaluates their properties and applicability to lignocellulose processing.

1. FuBio 2 | JR2 | WP2
Novel Ionic Liquids and Fractionation Mechanisms
Alistair W. T. King
University of Helsinki

2. Overview – Work Package Status & Highlights
• Why ionic liquids?
• Wood & Wood Biopolymer Solubility
• Wood & Pulp Fractionation Mechanisms
• Brief Highlights: Autohydrolysis, Fibrillation, IONCELL
• Novel and Recyclable Ionic Liquids
• Conclusions
2

3. WP2: Objectives
• FuBio (Future Biorefinery)
– Research oriented (process development)
– Cellulose
– Joint Research 2
• Work Package 2
– Novel Biomass Fractionation (Ionic Liquids)
• The main objective is to develop efficient and sustainable
methods for biomass fractionation using recyclable ionic
liquids
3Alistair W. T. King

4. What is an Ionic Liquid?
4Alistair W. T. King
‘Ionic Liquids’ are essentially
‘molten salts’ containing one
or more organic ions!
Unsolvated ‘Molten
Salts’ (m.p.)
– NaCl 801 oC
– [mmim]Cl 125 oC
– [emim]Cl 87 oC
– [emim][NTf2] -3 oC
– [emim][OAc] -45 oC

5. Ionic Liquid Anatomy & Cellulose Dissolution
5Alistair W. T. King
N N
Me
Cl-
π−ππ−π
VDV
H
H-bond acidity
H-bond bacisity
COLUMBIC
VDVProperties are dictated by the
interplay of Columbic, Polar, H-bonding
and dispersion interactions
Cellulose dissolution dependent on H-bond basicity &
acidity. Hydrophobic interactions may also play a part

6. What Makes Ionic Liquids Unique?
Cellulose
LigninHemicellulose
Hot Water
Organic
Solvents
Basic Ionic Liquids
Solubility for each component dependent
on entropic component of Gibbs
equation (MW, Temp) and
chemical stability of
components in
the solvents
Alistair W. T. King

7. Wood Processing – Idealised Schemes
7
Dissolution
(Homogeneous)
Degradation
Selective
Precipitation
Chemical
Modification
Regeneration
Extraction
(Heterogeneous)
Chips or
Sawdust
Pure fractions, e.g.
Cellulose, hemis, lignin
+ LCCs
Biofuels &
Chemicals
Pure fractions, e.g.
Cellulose, hemis,
lignin & LCCs
Materials, e.g.
Films,
Fibres,
Composites,
Moldable
Variable degrees
of cellulose
swelling

8. Parameterising Wood Solubility
8
Swell/Dissolve
(90 oC, 18 hr)
Wood Meal +
Ionic Liquid
([amim]Cl)
Phosphitylate
Hydroxyls
Quantitative
31P NMR
Integrate in
Solution-state
• Pre-dissolution/swelling occurs into [amim]Cl under mild conditions
• Quantitative 31P NMR as a measure of wood ‘solubility’
• Kyllönen, et al., On the solubility of wood in ionic liquids., Green
Chem., DOI:10.1039/C3GC41273C, 2013.
Wood
‘solubility’

9. Wood Solubility vs Particle Size (micro)
9
0
2
4
6
8
10
12
-1 4 9 14 19 24
TotalHydroxyls(mmol/g)
Planetary Milling Time (hr)
Spruce
Birch
• Sawdust (0 hr) planetary milled and subjected to 31P NMR
• Both hard and softwoods are not soluble until finely pulverised

10. Birch Wood Solubility vs Chip Size
10
10.7
3.2
1.3
1.7 1.8
0.3 0.0
0.0
2.0
4.0
6.0
8.0
10.0
12.0
PM 24 hr <0.16mm 0.16-0.4mm 0.4-1mm 1-3mm 3-6mm >6mm
TotalHydroxyls(mmol/g)
Planetary Milling Time or Particle Size Range
• As particle size increases towards chip size, solubility decreases drastically

11. Highlight: Autohydrolysis (PHWE)
Alistair W. T. King
University of Helsinki
• Hauru, Sixta et al. RSC Advances, 2013 (‘Enhancement of ionic
liquid-aided fractionation of birchwood. Part 1: Autohydrolysis
pretreatment’)
• Autohydrolysis (pressurised hot water extraction) is an existing
industrial wood pre-treatment method (pre-hydrolysis kraft pulp)

12. Effect of Autohydrolysis on Wood Solubility
12
• Birch chips were autohydrolysed and then Wiley-milled to pass a 1mm sieve
• After autohydrolysis, even very low P-factors increase solubility drastically
10.7
1.4
5.3
11.9 11.5
13.4
11.9
12.6 12.8 12.8
0.0
2.0
4.0
6.0
8.0
10.0
12.0
14.0
16.0
PM 24
hr
0 50 170 260 770 1060 1320 3600 8170
TotalHydroxyls(mmol/g)
Planetary Milling Time or P-Factor

13. Autohydrolysed Wood Solubility vs Chip Size
13
10.7
11.9 11.9
12.6
10.8 10.8
12.0
0.0
2.0
4.0
6.0
8.0
10.0
12.0
14.0
PM 24 hr <0.16mm 0.16-0.4mm 0.4-1mm 1-3mm 3-6mm >6mm
TotalHydroxyls(mmol/g)
Planetary Milling Time or Particle Size Range
• For a P-Factor of 1060, solubility is now consistent over a wide
particle size range, unlike the untreated birch which is essentially
insoluble approaching 1 mm.

14. A Significant FuBio Result
14
• Allow for true homogeneous processing of wood using an
existing pulping pre-treatment (pre-hydrolysis)
• Degradation of the cellulosic fraction is minimised during
this pre-treatment
• An extracted hemicellulose fraction can add value to the
process
• Industrial-sized chips can now be used (sawdust or further
milling not required)

15. Highlight: Fibrillation
Alistair W. T. King
University of Helsinki

16. Fibrillation of Wood Chips in Ionic Liquid
16
• When chips are treated with ionic liquid they
fibrillate, not dissolve.
• Fibre yield is high (typically > 90%)
• Thought to be a result of removal of pectin
from the middle lamella. Lignin is preserved
• Materials are now being assessed by partners
for potential applications
[emim]
[Me2PO4]
140 oC / 6 hr

17. Highlight: IONCELL
Alistair W. T. King
University of Helsinki

18. IONCELL: Kraft Pulp Fractionation
Alistair W. T. King
pure
Cellulose I
+
3 4 5 6 7
0,0
0,5
1,0
1,5
dm/d(logMM)
log MM
Hemi-rich
Kraft pulp
pure Hemi
Ionic Liquid
+ Co-Solvent3 4 5 6 7
0,0
0,5
1,0
1,5
dm/dlog(MM)
log MM
3 4 5 6 7
0,0
0,5
1,0
1,5
dm/d(logMM)
log MM
Poster: IONCELL: Selective xylan extraction with ionic liquids,
A. Roselli, M. Hummel, H. Sixta (Aalto University)
High selectivity of extraction
and recovery of pure fractions

19. Predominant Structures Studied in FuBio
19Alistair W. T. King
Ionic Liquid: Imidazoliums ‘Distillable’ ‘Switchable’
Applicability Cellulose Dissolution & Wood
Chip Fibrillation/ Hemicellulose
Extraction (IONCELL)
Cellulose Dissolution/Wood
Fractionation
Wood Extraction
Thermal Stability Moderate Stability/Variable Unstable Unstable
Recyclability Low Distillable Distillable
Water Miscibility Most Fully Yes Yes
Toxicity Moderate-Low Moderate-Low High-Low
Cost (> ton) High (< 60 €/kg) Low (15-60 €/kg) Low (< 20 €/kg)

20. Alternative Structures Studied in FuBio
20Alistair W. T. King
8/28/13
Ionic Liquid: Hydrophobic & Non-
basic imidazoliums
Phosphonium
Carboxylates
Cholinium
Carboxylates
Applicability Can selectively dissolve lignin
over polysaccharide
DMSO electrolytes dissolve
polysaccharide but neat ILs are
selective for lignin (tuneable)
Known to dissolve lignin
but not cellulose
Thermal Stability Relatively High Stability Highest Stability Lowest Stability
Recyclability Low Phase-separable Low
Water Miscibility Miscible Tunable miscibility Fully Miscible
Toxicity Moderate Toxicity Moderate-High Toxicity Lowest
Cost High High Low
* BASF patent does not cover these structures!

21. Distillable Ionic Liquids (DILs)
Alistair W. T. King
University of Helsinki

22. [emim][OAc] Distillability
8/28/13
22
Kugelrohr
0.3 mbar/170-180 oC
alkylimidazoles recovered
Sublimation Apparatus (wt boiling stones)
0.03 mbar/130-145 oC
‘Pure’ [emim][OAc] recovered
Distillable only
below 170 oC
using short-path
distillation
apparatus
BASF Patent
(WO 09027250)
0.05 mbar / 170 oC

23. Distillable acid-base conjugates
8/28/13
23
King et al,
Distillable acid-base
conjugate ionic liquids
for cellulose
dissolution and
processing.
Angew. Chem. Int. Ed.,
2011, 50, 6301.

24. [TMGH][OAc] Extract Distillation
8/28/13
24
• [emim][OAc] distillation:
• 130 oC / 0.05 mbar
• [TMGH][OAc] distillation
• 130 oC / 5 mbar!
[TMGH][OAc] Pine extract distilled at JBEI

25. Switchable Ionic Liquids (SILs)
Alistair W. T. King
University of Helsinki

26. Switchable Ionic Liquids (SILs):
The Concept
26
§ Solvent before and after switching mixed with Nile red dye to
show the transformation from low polarity to high polarity
§ Solvent is ‘switched’ back again by bubbling N2 or heating.
+ CO2

27. Switchable Ionic Liquids (SILs):
The Concept
27
N
N
+
NH
+
N
CO2+
CO2-NH2
OH
NH2
O
O
O
-
Gas flow in
Gas flow
out
MEA SIL
Poster: Different pre-treatment methods and their effects
before SIL wood fractionation, I. Anugwom, P. Virtanen, P.
Mäki-Arvela, J-P. Mikkola (Åbo Akademi University)
DBU

28. Phase-Separable Ionic Liquids
(PSILs)
Alistair W. T. King
University of Helsinki

29. Hydrophobic ‘Phase-Separable’
Ionic Liquids (PSILs)
29
Chlorides, provided by CYTEC,
were converted to the acetates
using ion exchange resin.

30. HSQC of MCC Dissolved in [P8881][OAc]/
d6-DMSO (7 % MCC, 50 oC)
8/28/13
30

31. 1H NMR of MCC Dissolved in [P8881]
[OAc]/d6-DMSO (7 % MCC, 50 oC)
31
C1
C6
C3
C4
C5
C2
Polymeric AGU C1-1H
Anomeric Glu C1-1H
(reducing end)
Terminal Glu C1-1H

32. Assignment of C1-1H NMR Resonances
32
Based on 2D NMR
assignments of low to high DP
samples:
• Cellobiose (DP 2)
• sc-H2O extracted MCC (DP 15)
• MCC & Avicel (DP 100)
• Bahia PHK pulp (DP 500)
• Borregaard Super VS sulfite
pulp (DP 1000)

33. 8/28/13
33
Matemaattis-luonnontieteellinen tiedekunta / Henkilön nimi / Esityksen nimi
% Recovery of [P8881][OAc] Per Cycle
at Different Co-Solvent Compositions

34. Gibbs Diagram: [P8881][OAc],
DMSO & Water
34
Poster: An NMR study of wood and
wood biopolymers dissolved in phase-
separable ionic liquids (PSILs), A.
Holding, V. Mäkelä, J. Helminen, L.
Tolonen, H. Sixta, I. Kilpeläinen, A. King
(Aalto & U. Helsinki)

35. Conclusions
35
• Basic ionic liquids are highly effective media for
homogeneous processing of wood
• True homogeneous processing requires pre-treatment
methods such as pre-hydrolysis/autohydrolysis
• It is possible to fibrillate wood chips upon treatment with
certain ionic liquids
• It is possible to convert kraft pulp to high purity cellulose
and xylan with ionic liquid-co-solvent treatments (IONCELL)
• New recyclable ionic liquids for lignocellulose processing
have been developed: Switchable (SIL), distillable (DIL),
phase-separable (PSIL)
• PSIL-DMSO electrolytes are excellent media for cellulose
dissolution and NMR analysis.

36. Acknowledgements
8/28/13
36
• Ilkka Kilpeläinen (University of Helsinki)
• Ionic Liquid Development
• Arno Parviainen, Ashley Holding, Somdatta Deb, Pirkko
Karuhnen, Jorma Matikainen, Laura Lemetti, Tia Kakko,
Valtteri Mäkelä
• Herbert Sixta (Aalto University)
• Fractionation Scheme Development
• Application of ILs for fibre spinning
• Yibo Ma, Lasse Tolonen, Lauri Hauru, Michael Hummel, Anne
Michud, Annariika Roselli
• Jyri-Pekka Mikkola (Åbo Akademi University)
• Switchable Ionic Liquids
• Ikenna Anugwom, Valerie Eta, Pasi Virtanen, Paivi Mäki-
Arvela
• Martin Lawoko (Wallenberg Wood Science Center, KTH)
• Seema Singh (Joint Bioenergy Institute, CA, USA)
PROC ESS
C HEMISTRY
C ENTRE ÅAÅBO
AKADEMI
UNIV E R SITY