This document discusses ionic liquids and their applications in wood processing and fiber production. It begins with background on ionic liquids, noting that they are molten salts with organic ions that remain liquid below 100°C. It then discusses experiments dissolving and fractionating wood with ionic liquids, finding they can separate and extract pectins without removing lignin. The document notes this challenges current understanding of wood structure. It also discusses using "next generation" distillable ionic liquids to dissolve cellulose and produce fibers that demonstrate improved mechanical properties compared to other methods like viscose and Lyocell processes. In attendance at the presentation were representatives from universities and industry collaborating on applying ionic liquids for biorefining.

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Ionic liquids
- new process chemistry for heavy industry
Ilkka Kilpeläinen
16.5.2014
Matemaattis-luonnontieteellinen tiedekunta /
Henkilön nimi / Esityksen nimi 1

2. Background – Ionic liquids
2Fig. source: http://acscinf.org/docs/meetings/230nm/presentations/230nm74.pdf
‘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

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Wood ”dissolution”
Trials with wood (Microscope):
-Somewhat later we realized that this has been already patented by Kemira
(V. Myllymaki and R. Aksela, WO Pat, 2005/017001, 2005. )

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Possibilities of ILs – Wood fractionation?
Complete dissolution followed by precipitation by
adding a non-solvent:
-However, it seems that these work only partially (enrichment of
cellulose/lignin/hemicellulose in certain fractions)
Sun, Rahman, Qin, Maxim,
Rodríguez and Rogers,
Green Chem., 2009, 11, 646 - 655,

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Wood Fractionation –ILs
Treatment of wood chips with ILs
IL1
IL2
-Softwood chip treatment
with ILs: No mechanical
stirring (or any agitation)
at 90 oC

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EM of IL-fibrillated
wood
SEM images of spruce latewood treated with
[emim]Me2PO4 - note the “spiral” form

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Softwood (spruce) fibrillation with [emim]Me2HPO4
: No changes in amount or structure of lignin. However, monosaccharide
analysis shows something interesting:
Only pectins have dissolved
– (Lignin is still there.)
225239Total
0.60.7Unknown
1.11.4Unknown
2.83.61,4-bis-O-
MeGlcA
4737Glucose
2315Galactose
87106Mannose
1.710.2Galacturonic
Acid
0.40.0Glucuronic
Acid
1.12.1Rhamnose
5251Xylose
911Arabinose
Fibrillated
Sample 1
Wood ChipsMonomer
225239Total
0.60.7Unknown
1.11.4Unknown
2.83.61,4-bis-O-
MeGlcA
4737Glucose
2315Galactose
87106Mannose
1.710.2Galacturonic
Acid
0.40.0Glucuronic
Acid
1.12.1Rhamnose
5251Xylose
911Arabinose
Fibrillated
Sample 1
Wood ChipsMonomer

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Is our understanding of
wood structure ”complete”?
wikipedia: Lignin fills the spaces in the cell wall between cellulose, hemicellulose,
and pectin components, especially in tracheids, sclereids and xylem. It is
covalently linked to hemicellulose and thereby crosslinks different plant
polysaccharides, conferring mechanical strength to the cell wall and by extension
the plant as a whole.
If lignin is the ”glue”, how
can the removal of pectins
fibrillate wood?

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First generation (Imidazolium-based)
16.5.2014
Matemaattis-luonnontieteellinen tiedekunta /
Henkilön nimi / Esityksen nimi 9
+dissolve cellulose efficiently, so far the “best” one is propably [emim][OAc],
- Expensive
- Difficult to purify (recycling?)
- Almost all atleast somewhat poisonous
- [emim][OAc] restricts carrying out acylation reactions )-> only acetylation (?)
- Side reactions (e.g. With the reducing end of cellulose & hemicellulose
deacetylation)

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Ionic Liquids ”the next generation –
distillable IL’s”
Distillation: > 99 % recovery, > 99 % purity
Dissolves cellulose up to ~20 m-%
Cellulose can be recovered by addition of nonsolvent
(fibers/films), or by direct distillation
16.5.2014 10
‘Distill’
Acid: HA
Base: B
+ IL: [A][BH]
- IL under 100 oC
Mix
Acid: HA
Base: B
+
dissociates
at 140 oC
N N
NH
CH3
CH3
CH3
CH3
CH3
O
OH
[TMGH+][Ac-]
CH3
O
OH
N N
NH
CH3
CH3
CH3
CH3

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[EMIM]OAc/PHK-Euca 20 wt-%
• Textr. = 95ºC
• Vextr. = 0.8 cm3/min
ILHU/PHK-Euca 13 wt-%
• Textr. = 80ºC
• Vextr. = 0.8 cm3/min
NMMO/H2O/PHK-Euca 13 wt-%
• Textr. = 100ºC
• Vextr. = 0.8 cm3/min
BREAK-UP in
the spinning
bath when
stretched
UNSTRETCHED STRETCHED
Fiber spinning –Aalto (Sixta)
11

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Comparison of Fibers
12
Viscose Modal
NMMO
(Tencel®)
ILHU
Titre [dtex] 1.4 1.3 1.3 1.2
Tenacity cond. [cN/dtex] 23.9 33.1 40.2 50.5
Elongation cond. [%] 20.1 13.5 13.0 8.5
Tenacity wet [cN/dtex] 12.5 18.4 37.5 46.4
Elongation wet [%] 22.0 14.1 18.4 9.6
TencelPolynosic Cupro CV CMD[DBNH]OAcNMMO
0
10
20
30
40
50
Tenacity[cN/tex]
Cond. wet
ILHU
NMMO
Commercial fibers Aalto
0
2
4
6
8
10
Titer[dtex]
0 5 10 15 20 25
0
5
10
15
20
25
30
35
40
45
Tenacitycond
[cN/tex]
Elongationcond
[%]
CMD ILHU
CV NMMO
Cupro

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Marimekko
5/16/2014 13

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Persons
Present: Alistair King, Pirkko Karhunen, Jorma
Matikainen, Ashley Holding, Jussi
Helminen, Uula Hyväkkö, Jari
Kavakka, Sara Labaf, Paula Hirsilä
& Collaborators
And many former members