U.S. patent application number 13/635732 was filed with the patent office on 2013-03-07 for process for fibrillating lignocellulosic material, fibres and their use.
This patent application is currently assigned to UNIVERSITY OF HELSINKI. The applicant listed for this patent is Pirkko Karhunen, Ilkka Kilpelainen, Alistair King, Jorma Matikainen. Invention is credited to Pirkko Karhunen, Ilkka Kilpelainen, Alistair King, Jorma Matikainen.
Application Number | 20130056165 13/635732 |
Document ID | / |
Family ID | 42074385 |
Filed Date | 2013-03-07 |
United States Patent
Application |
20130056165 |
Kind Code |
A1 |
Kilpelainen; Ilkka ; et
al. |
March 7, 2013 |
PROCESS FOR FIBRILLATING LIGNOCELLULOSIC MATERIAL, FIBRES AND THEIR
USE
Abstract
The invention relates to a process for fibrillating
lignocellulosic material wherein the process comprises treating
lignocellulosic material with ionic liquid and recovering basically
intact fibres of said lignocellulosic material. Another object of
the invention is to provide an activated and/or basically intact
fibre wherein the lignocellulosic material is treated with ionic
liquid and a basically intact fibre of said lignocellulosic
material is recovered. The invention further relates to the use of
the basically intact fibre of the invention in the production of
bio-based materials, preferably bio-plastics, more preferably
conductive polymers, stimuli-responsive polymers, bio-based polymer
composites, ceramics, fabrics, or elastomers. A process for
producing paper, board, pulp or the like from fibers of
lignocellulosic material which have been treated with ionic liquid
and recovered as basically intact fibres is also enclosed.
Inventors: |
Kilpelainen; Ilkka;
(Helsinki, FI) ; King; Alistair; (Helsinki,
FI) ; Karhunen; Pirkko; (Espoo, FI) ;
Matikainen; Jorma; (Helsinki, FI) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Kilpelainen; Ilkka
King; Alistair
Karhunen; Pirkko
Matikainen; Jorma |
Helsinki
Helsinki
Espoo
Helsinki |
|
FI
FI
FI
FI |
|
|
Assignee: |
UNIVERSITY OF HELSINKI
University of Helsinki
FI
|
Family ID: |
42074385 |
Appl. No.: |
13/635732 |
Filed: |
March 18, 2011 |
PCT Filed: |
March 18, 2011 |
PCT NO: |
PCT/FI2011/050234 |
371 Date: |
November 8, 2012 |
Current U.S.
Class: |
162/9 ; 162/100;
162/72 |
Current CPC
Class: |
D21C 9/007 20130101;
D21H 11/18 20130101 |
Class at
Publication: |
162/9 ; 162/72;
162/100 |
International
Class: |
D21B 1/04 20060101
D21B001/04; D21F 11/00 20060101 D21F011/00; D21C 9/00 20060101
D21C009/00 |
Foreign Application Data
Date |
Code |
Application Number |
Mar 18, 2010 |
FI |
20105272 |
Claims
1-15. (canceled)
16. A process for fibrillating lignocellulosic material,
characterized in that said process comprises a) treating
lignocellulosic material with ionic liquid selected from a list
consisting of ##STR00007## and b) recovering basically intact
fibres of said lignocellulosic material.
17. The process according to claim 16 wherein said treating is
performed by heating.
18. The process according to claim 17 wherein said heating is
performed at temperatures between 20.degree. C. and 150.degree.
C.
19. The process according to claim 16 further comprising c)
physical or chemical modification of the basically intact
fibres.
20. The process according to claim 16 characterized in that the
average 2D aspect ratio of said basically intact fibre is at least
5.
21. The process according to claim 20, wherein the average 2D
aspect ratio of said basically intact fibre is at least 20.
22. The process according to claim 20, wherein the average 2D
aspect ratio of said basically intact fibre is at least 50.
23. A basically intact fibre obtained by the process according to
claim 16.
24. The basically intact fibre of claim 23 characterized in that
the surface area of the fibre is increased.
25. The basically intact fibre of claim 23 characterized in that
the average 2D aspect ratio of said basically intact fibre is at
least 5.
26. The basically intact fibre of claim 25, wherein the average 2D
aspect ratio of said basically intact fibre is at least 20.
27. The basically intact fibre of claim 25, wherein the average 2D
aspect ratio of said basically intact fibre is at least 50.
28. The basically intact fibre of claim 23 characterized in that
said lignocellulosic material is activated during the ionic liquid
treatment and/or modified after recovery of the fibre from the
ionic liquid.
29. A method of producing paper, board, pulp or the like or in the
production of bio-based materials, preferably bio-plastics, more
preferably conductive polymers, stimuli-responsive polymers,
bio-based polymer composites, ceramics, fabrics, or elastomers
comprising the process of claim 16.
30. A method of treating lignocellulosic material comprising the
step of contacting lignocellulosic material with ##STR00008##
Description
FIELD OF THE INVENTION
[0001] The invention relates to a process for fibrillating
lignocellulosic material wherein the process comprises treating
lignocellulosic material with ionic liquid and recovering basically
intact fibres of said lignocellulosic material. Typically the
process comprises increasing the surface area of said
lignocellulosic material. Another object of the invention is to
provide an activated and/or basically intact fibre wherein the
lignocellulosic material is treated with ionic liquid and a
basically intact fibre of said lignocellulosic material is
recovered.
[0002] The invention further relates to the use of the basically
intact fibre of the invention in the production of bio-based
materials, preferably bio-plastics, more preferably conductive
polymers, stimuli-responsive polymers, bio-based polymer
composites, ceramics, fabrics, or elastomers. A process for
producing paper, board, pulp or the like from fibers of
lignocellulosic material which have been treated with ionic liquid
and recovered as basically intact fibres is also enclosed.
BACKGROUND OF THE INVENTION
[0003] The treating of lignocellulosic material has become even
more important due to growing energy demands and environmental
concerns. Traditional methods of chemical modification employed for
treating lignocellulosic materials are fibre modification, pulping,
fractionation and depolymerisation.
[0004] The fibre modification method involves enhancement of the
fibre properties by additive functionalization, which means adding
functionalities that demonstrate enhanced properties of the
product. A typical example would be fatty acid (hydrophobic
functionality) functionalization of wood fibre hydroxyl groups in
the production of hydrophobic materials (plastics, hydrophobic
coatings, etc).
[0005] Traditional chemical pulping involves fibrillation of woody
material and selective degradation of the lignin contained within
it. The fibrous quality of the enriched polysaccharide fraction,
which consist mainly of cellulose, is maintained and is essential
for performance in its present applications (mainly paper making).
Typically the depolymerised lignin is collected as a solid material
and burnt to recover raw materials and to produce energy to fuel
the whole process. Apart from chemical pulp, other common forms of
pulp are thermo mechanical pulp (TMP) and chemothermo mechanical
pulp (CTMP). These involve thermo mechanical separation of wood
into fibrous material, with an optional chemical pre-treatment. The
quality of these fibres, as pulp, is generally low, due to their
high lignin content. This material is further upgraded by vigorous
chemical bleaching to afford different grades of pulp.
[0006] Fractionation involves separation of the lignocellulosic
components. This should be distinct from pulping, as pulping
involves depolymerisation of lignin, whereas fractionation should
maintain the molecular weight of the lignin. Methods exist for the
commercial production of high molecular weight lignins and other
components, but these involve depolymerisation of the
polysaccharide components (e.g. organosols lignin).
[0007] Depolymerisation of lignocellulosic material, or
fractionated/enriched materials, is a method whereby the polymeric
structures are degraded to low molecular weight species. This may
be selective degradation of certain components or structures for
the production of commodity chemicals (bioethanol, monosaccharide,
disaccharides, oligosaccharides, phenols, catechols, LGO,
furanoids, hydroxyalcohols, etc) or indiscriminate degradation of
components for the production of mixtures of chemicals, tars and
oils, liquid biofuel or wood gas (syngas). This may involve the
catalysed degradation of components in solution (e.g. aqueous-acid
catalysis), anaerobic thermal degradation of material in solution
or solid state (pyrolysis) or aerobic thermal degradation of
material (gasification). All these methods have in common the
degradation of the fibrous properties of the material. This
degradation may allow for more efficient fractionation, however,
the nature of the resulting polysaccharide materials is changed so
drastically that it is rendered useless for traditional pulping
applications.
[0008] The present invention surprisingly shows that ionic liquids
can be used for fibrillating lignocellulosic materials under mild
conditions, compared to the conditions used in traditional methods
for treating lignocellulosic materials, in order to receive a novel
type of fibres.
[0009] Ionic liquids are ambient temperature molten salts. They
usually have melting points below 100.degree. C. and are seemingly
composed of ions, with no additional molecular solvent present to
render the mixture liquid (i.e. as opposed to aqueous salt
solutions). Ionic liquids have been described, for example, in US
patent application US 20080190321 A1, which discloses the
preparation of ionic liquids and a method for dissolving cellulose
into a solution comprising an ionic liquid. German patent
application DE 102005062608 A1 also discloses the preparation of
ionic liquids and their use as dissolution systems for
celluloses.
[0010] Further uses of ionic liquids for different purposes are
known from US patent application US 20070215300 A1, which relates
to a method for the treatment of a lignin-containing material with
an ionic liquid to extract lignin there from. The lignin is
recovered from the ionic liquid. US patent application US
20080185112 A1 relates to thermolysis of lignocellulosic materials
where ionic liquids are used for pre-treatment of lignocelluloses
and US patent application US 20080190013 A1 describes a method for
converting lignocellulosic material into biofuel. Ionic liquids are
used for pre-treatment by dissolution of the lignocellulosic
materials in the ionic liquid. WO 2008119770 A1 relates to a method
for modifying the structure of a cellulose material and dissolution
of lignocellulosic material is described in WO 2005017001 A1.
[0011] It should be noted that all documents cited in this text
("herein cited documents") as well as each document or reference
cited in each of the herein-cited documents, and all manufacturer's
literature, specifications, instructions, product data sheets,
material data sheets, and the like, as to the products and
processes mentioned in this text, are hereby expressly incorporated
herein by reference.
SUMMARY OF THE INVENTION
[0012] The invention relates to a process for fibrillating
lignocellulosic material, such as wood chips, wherein the process
comprises treating lignocellulosic material with ionic liquid to
produce basically intact fibres of the lignocellulosic material,
with minimal degradation. The fibrillation may also be combined
with mechanical treatment, such as a thermomechanical or
chemithermomechanical treatment. Typically the process of the
invention comprises increasing the surface area of said
lignocellulosic material by the fibrillation.
[0013] Another object of the invention is to provide a basically
intact fibre which is obtained by treating lignocellulosic material
with ionic liquid and by recovering the basically intact fibre. The
present invention further relates to a process for producing paper,
board, pulp and the like from the basically intact fibres of the
invention.
[0014] A further object of the present invention is application of
the fibrillated material of the invention in the production of
bio-based materials such as conductive polymers, stimuli-responsive
polymers, bio-based polymer composites, ceramics, fabrics,
elastomers and bio-plastics in general from the fibres.
[0015] Another embodiment of the invention provides a refined and
efficient lignocellulose functionalization, for the production of
novel materials. This feature of the treatment, in combination with
the wide range of chemical or physical modification, allows for
tuning of the physiochemical properties to produce high value
materials for a given application with increased yields. The
modification is used to effect changes in hydrophobicity,
electrical conductivity/resistance, stimuli response, rheological
properties, visual properties, solvent (e.g. water)
absorbtivity/barrier properties, swelling properties, elasticity,
tensile properties or thermal resistance of the fibres. One
preferred application is inclusion of hydrophobic functionalities,
such as fatty acid esters derived from rosin acids, tall oil fatty
acids (TOFA) or alkyl ketene dimer (AKD) sizing reagents. This can
help to "compatibilize" the material for the formation of composite
materials with traditional hydrophobic polymers.
[0016] The invention is based on the finding that ionic liquids can
be used for fibrillating lignocellulosic materials under mild
conditions, compared to the conditions of the traditional methods
for treating lignocellulosic materials, in order to receive a novel
type of fibers. The present invention can further be used as an
ionic liquid-mediated fibrillation pre-treatment from where
components of the remaining fibrous material are more easily
degradated.
[0017] One advantage of the invention is that ionic liquids affords
a media which do not contribute to environmentally polluting
volatile organic compound (VOC) emissions. This is in part due to
the extremely low volatility of most ionic liquid media. The ionic
liquid technology research is a rapidly expanding area of materials
science. Ionic liquids seem to offer potential sustainable
technology platforms for some environmentally benign new and
alternative processes.
[0018] A further advantage of the invention is that the basically
intact fibres are closer to their native structure and molecular
weight, than those obtained from traditional pulping, fractionation
or extraction processes. During the ionic liquid treatment, the
treated fibres maintain their advantageous fibrous properties and
yet retain a practically similar mass compared to the mass of the
starting lignocellulosic material.
[0019] Several advantages are further achieved when the present
invention is used for pre-treatment of wood, for example before
chemical pulping, such as Kraft pulping. The ionic liquid treatment
allows for milder cooking, for example influences the cooking
temperature and time and therefore reduces the energy consumption.
The process according to the invention also increases the surface
area of the lignocellulosic material for the delignification
process. Further mild delignification under aqueous basic
conditions is achieved, even in the absence of sulphur, yielding a
sulphur-free lignin. This is an advantage compared to traditional
pulping due to reduced catalyst poisoning during cracking, lower
sulphur emissions during combustion or easier reagent recovery.
[0020] Furthermore, according to one embodiment of the invention,
small portions of wood components, such as polymeric and oligomeric
polysaccharides (pectins or hemicelluloses) in particular, are
regenerated from the ionic liquid, for example by precipitation
with a co-solvent. Typically these components are extracted into
the ionic liquid mixture during the fibrillation process.
Therefore, one benefit of the invention is the increased efficiency
of extraction of extractives or particular polysaccharide
components, such as pectins or hemicelluloses, from the
lignocellulosic material. Pectins and hemicelluloses are
particularly useful as food additives and their scope is expanding.
Extractives may have wide ranging applications as commodity
chemicals or as intermediates or drug candidates for agrochemical
or pharmaceutical applications.
[0021] In research related to wood, the use of ionic liquids for
fibrillation opens up new possibilities also for studies of wood
components and structures with the aim of increased utilization of
natural renewable wood reserves. One advantage of the invention is
the mild deconstruction and optionally reconstruction of the native
lignocellulosic material with other bio-based materials. Due to
more detailed knowledge of wood structure and the physical and
chemical properties of ionic liquids, increased efficiency of the
process and an increased quality of product are achieved.
[0022] The objectives of the invention are accomplished with a
process and product having the characteristics as mentioned in the
independent claims. The preferred embodiments of the invention are
presented in the independent claims.
BRIEF DESCRIPTION OF THE DRAWINGS
[0023] FIG. 1, A schematic view of one embodiment of the process of
the invention.
[0024] FIG. 2, .sup.31P NMR analysis of the [mmim]Me.sub.2PO.sub.4
residue from pine fibrillation according to Example 4.
DETAILED DESCRIPTION OF THE INVENTION
[0025] The present invention relates to a process for fibrillating
lignocellulosic material wherein the process comprises treating
lignocellulosic material with ionic liquid and recovering basically
intact fibres of said lignocellulosic material.
[0026] In the present specification and claims, the following terms
have the meanings defined below.
[0027] The term "fibrillation" refers to changes in the fibre
structure of the lignocellulosic material, i.e. the fibre walls,
whereby a number of fibrils or tracheids are completely or
partially separated and the binding between the remaining fibrils
or tracheids is weakened, to the state of being reduced to fibres
with high aspect ratio. The removal of pectins from the lumen by
ionic liquid significantly contributes to the fibrillation process,
but the fibre structure and aspect ratio are maintained.
[0028] The term "basically intact fibre" refers to the fibres of
lignocellulosic material having a basically intact cell structure.
Typically the average 2D aspect ratio of the fibres is >5, more
preferably >20 and most preferably >50. Dissolution on the
other hand generally results in recovery of non-fibrous material,
which should be regarded as no longer "basically intact".
[0029] The term "activated" as used in the present specification
and claims refers to fibres of lignocellulosic material which have
been activated in the sense that the surface area for reaction is
increased, due to fibrillation or swelling of the fibre surface.
This affords a material that is more easily subjected to further
treatments, such as different kinds of modification, for example
chemical functionalization.
[0030] The term "modification" in the present specification and
claims refers to chemical or physical modification of the fibre
material. For example chemical functionalization, involving
breakage or formation of chemical bonds, comprises adding
functionalities which afford enhanced properties of the fibrous
material, for example physiochemical properties such as
hydrophobicity, electrical conductivity/resistance, rheological
properties, visual properties, solvent (e.g. water)
adsorbtivity/absorbtivity, swelling properties, elasticity, tensile
properties or thermal resistance. For example increasing the
resistance to oxidation of the remaining lignin diminishes the
requirement for bleaching or ageing of the material and results in
a high yield of a product. Further examples of modification
comprise increasing the molecular weight and fragmentation or
depolymerization of the lignocellulosic material. Fragmentation
and/or depolymerization is useful in the production of enriched
biopolymer preparations, such as lignin, or monomeric and low
molecular weight materials to be used as bulk chemicals, commodity
chemicals or bio-based fuels. Physical modification may involve
physical formation or defomation of the material. For example a
process of grinding, as is used in the production of TMP, or
shearing, as is used for the production of microfibrillar cellulose
(MFC), may be used. The modification can take place in the presence
of another solid, liquid or gaseous material to affect some
chemical, morphological or physical transformation in general.
[0031] The term "wood chips" refers to pieces of wood most of which
are bigger than 1 cm.times.0.5 cm.times.0.1 mm, preferably at least
50% of the wood chips are bigger than 1 cm.times.0.5 cm.times.0.1
mm, more preferably at least 80%, most preferably at least 95%.
[0032] The term "lignocellulosic material" in the present
specification and claims refers to a natural material comprising
cellulose, hemicellulose and lignin that has not been subjected to
previous pulping or fibrillation processes. The lignocellulosic
material may be close to its native (unprocessed) form, or it can
be partially processed using typical harvesting and pre-treatment
techniques. The material may also contain "extractives" which are a
range of different low molecular weight compounds and are of value
in the forestry product chain. For example carbohydrate polymers
(pectins, cellulose and hemicelluloses) are tightly bound to the
lignin, by hydrogen and covalent bonds. Hemicelluloses are embedded
in the cell walls of plants--they bind with pectin and lignin to
cellulose to form a network of cross-linked fibres. The
lignocellulosic material also refers to biomass of different types,
such as wood residues (including sawmill and paper mill discards),
agricultural residues (including corn stover and sugarcane
bagasse), dedicated energy crops (which are mostly composed of fast
growing tall, woody grasses), and trees (felled for pulp,
construction, materials, chemicals or energy). According to the
present invention lignocellulosic materials can for example be
obtained from vascular plants such as hardwood, softwood, straws,
grasses (e.g., rice, esparto, wheat and sabai), canes, reeds (e.g.,
bagasses or sugar cane), bamboo, bast fibres (e.g., jute, flax,
kenaf, linen, ramie, cannabis) and/or leaf fibres (e.g., agaba,
minila hemp, sisal). Preferably the lignocellulosic material is
wood, such as softwood or hardwood, for example in the form of wood
chips.
[0033] The term "treatment" in the present specification and claims
refers to treatment of lignocellulosic material with ionic liquid
and may involve one or more common treatments such as heating,
vacuum, pressure, stirring, vibration, microwave, ultrasound, or
other common methods of agitation of mixtures.
[0034] The term "ionic liquid", is commonly defined as molten
salts, which are comprised of ions and are liquids at certain
temperatures. In the present specification and claims, the term
"ionic liquid" refers to molten salts with melting point ranges
between -100.degree. C. to 200.degree. C. or even up to 300.degree.
C. The ionic liquids comprise one or more anions and one or more
cations. In a further extension of the definition according to the
present invention, ionic liquids should be regarded as molten salts
at any suitable process conditions. The present definition of ionic
liquids includes "room temperature ionic liquids" which are molten
salts with melting points below room temperature
(.about.17-25.degree. C. in most laboratory settings). Under the
present definition of ionic liquids, the fact that the ions may be
closely paired or clustered in the solution state (by columbic
interaction, hydrogen bonding or weaker interactions), does not
exclude them from being classed as ionic liquids.
[0035] The terms "phosphate", "phosphonate", "sulfate", "sulfonate"
and "carboxylate" in the present specification and claims refer to
anions of ionic liquids and can mean any homologues of substituted
phosphate, phosphonate, sulfate, sulfonate and carboxylate anions
respectively. For example, methylhydrogenphosphonate can be refered
to as a phosphonate. Homologues containing alkyl, aryl and
partially or perhalogenated substituents are also included under
this definition.
[0036] The present invention relates to a process for fibrillating
lignocellulosic material wherein the process comprises treating
lignocellulosic material with ionic liquid and recovering basically
intact fibres of said lignocellulosic material. Typically the
treatment involves heating (by standard methods), vacuum, pressure,
stirring, vibration, microwave, ultrasound, or other common methods
of agitation of mixtures to enhance the fibrillation. The heating
typically involves using process temperatures between 20.degree. C.
and 150.degree. C., preferably between 50.degree. C. and
120.degree. C., more preferably between 75.degree. C. and
120.degree. C. Microwaves and ultrasound have in the prior art been
found to aid dissolution of cellulose with ionic liquids. However,
the use of microwaves and/or ultrasound to enhance fibrillation
according to one embodiment of the present invention requires
appropriate control of the fibrillation conditions, not to dissolve
material. According to another embodiment, the treatment to
facilitate fibrillation involves heating in combination with
mechanical treatment. Such a treatment is for example used in the
production of thermomechanical pulp or chemothermomechanical
pulp.
[0037] According to one embodiment of the invention the basically
intact fibre fibrillated according to the process of the invention
has an average 2D aspect ratio at least 5, more preferably at least
20 and most preferably at least 50. According to other preferred
embodiments the average 2D aspect ratio of the basically intact
fibre of the invention is at least 10, at least 15, at least 25, at
least 30, at least 35, at least 40, at least 45 or at least 55.
[0038] According to another embodiment of the invention the
basically intact fibre is activated during the treatment of the
lignocellulosic material and/or modified after the recovery of the
basically intact fibres. Such a modification of the basically
intact fibre is preferably made by chemical or physical
modification or upgrading of the fibres. Examples of chemical
modifications are esterification, redox reactions, etherifications,
carbamate formations, carbonate formation, crosslinking and/or
other reactions where covalent linkages are formed. Examples of
physical modification are grinding, as is used in the production of
TMP or CTMP, or shearing, as is used for the production of MFC.
According to one aspect of the invention the fibrillated
lignocellulosic material can be modified after recovery from the
ionic liquid media but according to another aspect of the invention
the fibrillated lignocellulosic material is modified in the ionic
liquid media before recovery. According to one option of the
present invention the fibres, which are present in the ionic liquid
or which have been recovered from the ionic liquid, are in an
activated state.
[0039] According to one embodiment the basically intact fibre of
the invention is chemically modified by additive chemical
functionalization. Such functionalization involves modification of
functional groups on the surface or through the fibre in order to
produce a fibrous material with enhanced properties. One example of
this embodiment is fatty acid functionalization of the surface
hydroxyl groups of the basically intact fibre to form a bio-based
plastic material.
[0040] The invention also relates to a process for recovery of the
fibrillated lignocellulosic material, components dissolved from the
lignocellulosic material and purified ionic liquid. Typically
separation of the solid material from the liquid material is done
at any stage of the process by filtration, centrifugation and other
common solid/liquid separation techniques. According to one
embodiment small amounts of molecular solvent are added to the
reaction mixture to increase the efficiency of separation, yet
still avoiding precipitation of the dissolved components.
Optionally dissolved compounds, such as pectins, are recovered by
addition of a further molecular solvent, allowing for solid/liquid
separation, or by membrane filtration. Typically the ionic liquid
is recovered after precipitation of dissolved components and/or
removal of solid material by evaporation of the solvent used for
precipitating. One or more of the components are optionally
recycled. According to a further option a range of molecular
solvents is used to remove traces of ionic liquid remaining on the
fibre by heating.
[0041] Another object of the invention is to provide a basically
intact fibre which is obtained by treating lignocellulosic material
with ionic liquid and recovering basically intact fibres of said
lignocellulosic material. Typically the ionic liquid treatment
increases the surface area of the fibres.
[0042] The basically intact fibre of the invention typically has an
average 2D aspect ratio of at least 5, more preferably at least 20
and most preferably at least 50. According to other preferred
embodiments the 2D aspect ratio values of the basically intact
fibre of the invention is at least 10, at least 15, at least 25, at
least 30, at least 35, at least 40, at least 45 or at least 55.
[0043] According to one embodiment of the invention the basically
intact fibre is activated during treatment of the lignocellulosic
material and/or thereafter modified either in the ionic liquid or
after the recovery of the basically intact fibres. Such a
modification of the basically intact fibre is preferably made by
chemical or physical modification.
[0044] According to still another embodiment of the invention the
basically intact fibre is dissolved in an ionic liquid after being
recovered from the ionic liquid used for treating the
lignocellulosic material.
[0045] A further object of the invention is the use of the
basically intact fibre of the process of the invention in the
production of bio-based materials, preferably bio-plastics, more
preferably conductive polymers, stimuli-responsive polymers,
bio-based polymer composites, ceramics, fabrics, or elastomers.
[0046] A still other object of the invention is to provide a
process for producing paper, board, pulp or the like from fibers of
lignocellulosic material which have been treated in ionic liquid
and recovered as basically intact fibres of said lignocellulosic
material.
[0047] The ionic liquid of the invention typically comprises at
least one anionic portion and at least one cationic portion. The
choice of one or more cationic portions and anionic portions
depends first of all on the lignocellulosic material and thereto on
the treatment and the conditions chosen.
[0048] The cationic portion of the ionic liquid according to the
invention can depending on the lignocellulosic material and the
treatment and conditions chosen comprise one or more organic
cations prepared by derivatizing one or more of imidazole,
pyrazole, thiazole, isothiazole, azathiazole, oxothiazole, oxazine,
oxazoline, oxazaborole, dithiazole, triazole, selenazole,
oxaphosphole, pyrrole, borole, furan, thiophene, phosphole,
pentazole, indole, induline, oxazole, isoxazole, isotetrazole,
tetrazole, benzofuran, dibenzofuran, benzothiophene,
dibenzothiophene, thiadiazole, pyridine, pyrimidine, pyrazine,
pyridazine, piperazine, piperdine, morpholone, pyran, annoline,
phthalazine, quinazoline, guanidinium, quinxaline, choline-based
analogues or combinations thereof with variable substituents such
as alkyl, alkenyl, alkynyl, alkoxy, alkenoxy, alkynoxy, vinyl,
allyl and propargyl groups. The substituents may also be aromatic
substituents, such as substituted or unsubstituted phenyl,
substituted or unsubstituted benzyl, or a variety of heterocycle
aromatics having one, two or three heteroatoms in the ring portion
thereof, said heterocyclics being substituted or unsubstituted.
Further the substituents may include additional terminal
functionalities such as disubstituted chalcogens (ethers,
thioethers etc.), carboxylic acids, carboxylic esters, thioacids,
thioesters, carbonates, carbamates, nitriles, imines, amides,
aldehydes, ketones or other heteroatom-containing functionalities.
The basic cation structure can be singly substituted, multiply
substituted, unsubstituted or covalently linked to one or more
cations to give dicationic, tricationic or polymeric cationic
species.
[0049] Preferably the ionic liquid of the invention comprises a
cationic portion, which comprises a cation of imidazolium type of
Formula I
##STR00001##
wherein R.sup.1, R.sup.2 and R.sup.3 independently of each other
are H or C.sub.1-C.sub.6, preferably H or C.sub.1-C.sub.2, and
R.sup.4 and R.sup.5 independently of each other are H or
C.sub.1-C.sub.8. Another preferred ionic liquid of the invention
comprises a cationic portion, which comprises a cation of
pyridinium type of Formula II
##STR00002##
wherein R.sup.1, R.sup.2, R.sup.3 and R.sup.4 independently of each
other are H or C.sub.1-C.sub.6, preferably H or C.sub.1-C.sub.2,
and R.sup.5 and R.sup.6 independently of each other are H or
C.sub.1-C.sub.8. The side chain functionalities of the compounds of
Formula I or II are cyclic or acyclic and the imidazolium is
preferably di- or tri-substituted. The pyridinium is prefereably
mono- or di-substituted. The cation structures are drawn as the
canonical resonance hybrid structures and are assumed to encompass
the contributing canonical resonance structures.
[0050] Imidazole based ionic liquids are one preferred type of
ionic liquids that can be used according to the present invention.
In another preferred type of ionic liquids the imidazole is
replaced with a pyridinium cation, as a low cost heterocycle.
[0051] Examples of ionic liquid cations according to the invention,
which depending on the lignocellulosic material and the treatment
and conditions used are preferred, comprise
1-butyl-3-methylimidazolium ([bmim].sup.+),
1-allyl-3-methylimidazolium ([amim].sup.+),
1-ethyl-3-methylimidazolium ([emim].sup.+), 1,3-dimethylimidazolium
([mmim].sup.+), 1-hydrogen-3-methylimidazolium ([hmim].sup.+),
1-benzyl-3-methylimidazolium ([bnmim].sup.+),
1-(2-hydroxyethyl)-3-methylimidazolium ([hemim].sup.+),
1-propyl-3-methylimidazolium ([prmim].sup.+),
1-isopropyl-3-methylimidazolium ([.sup.iprmim].sup.+),
1,2,3-trimethylimidazolium ([mmmim].sup.+),
1-ethyl-2,3-dimethylimidazolium ([emmim].sup.+),
2-ethyl-1,3-dimethylimidazolium ([memim].sup.+),
1-allyl-2,3-dimethylimidazolium ([ammim].sup.+), and
1-vinyl-3-methylimidazolium ([vmim].sup.+), 1-methylpyridinium
([mPyr].sup.+), 1-ethylpyridinium ([ePyr].sup.+),
1-propylpyridinium ([prPyr].sup.-), 1-isopropylpyridinium
([.sup.iprPyr].sup.+), 1-allylpyridinium ([aPyr].sup.+),
1-butylpyridinium ([bPyr].sup.-), 1-vinylpyridinium ([vPyr].sup.+),
1-benzylpyridinium ([bnPyr].sup.+), 1-hydrogenpyridinium
([HPyr].sup.+), 1-(2-hydroxyethyl)pyridinium ([hePyr].sup.+),
1,3-dimethylpyridinium ([mmPyr].sup.+), 1-ethyl-3-methylpyridinium
([emPyr].sup.+) or other homologues or regioisomers of imidazolium
or pyridinium cations.
[0052] A list of some structures of preferred examples of ionic
liquid cations, useful according to the invention is presented
below. The structures are shown as their canonical resonance
hybrids.
##STR00003##
[0053] The anionic portion of ionic liquids typically comprises one
or more inorganic moieties, one or more organic moieties, or
combinations thereof The anionic portion of the ionic liquid
according to the invention can depending on the lignocellulosic
material and the treatmentand conditions chosen comprise one or
more portions selected from halogens, phosphates, alkylphosphates,
arylphosphates, alkylphosphonates, arylphosphonates, partially
halogenated or perhalogenated alkylphosphates, such as
(CF.sub.3CF.sub.2O).sub.2PO.sub.2.sup.- or
(CF.sub.3CF.sub.2O)(CH.sub.3CH.sub.2O)PO.sub.2.sup.-, partially
halogenated or perhalogenated alkylphosphonates, such as
CF.sub.3CF.sub.2HPO.sub.3.sup.- or CF.sub.3CF.sub.2FPO.sub.3.sup.-,
partially halogenated or perhalogenated alkylsulfates, such as
CF.sub.3CF.sub.2SO.sub.4.sup.- or CF.sub.3SO.sub.4.sup.-, partially
halogenated or perhalogenated alkylsulfonates, such as
CF.sub.3CF.sub.2SO.sub.3.sup.- or CF.sub.3SO.sub.3.sup.-,
bis(trifluoromethylethylsulphonyl)imide, BF.sub.4.sup.-,
PF.sub.6.sup.-, AsF.sub.6.sup.-, NO.sub.3.sup.-, N(CN).sub.2.sup.-,
N(SO.sub.3CF.sub.3).sub.2.sup.-, amino acids, substituted or
unsubstituted carboranes, perchlorates, pseudohalogens such as
cyanides, thiocyanates, cyanates, fulminates, azides,
alkylsulfonates, tosylates, triflates alkylsulfates and
perfluorinated alkylsulfates, a combination of anions with metal
chloride-based Lewis acids (e.g. zinc dichloride, indium
trichloride or aluminium trichloride) or C.sub.1-8 carboxylatessuch
as formate, acetate, propionate, butyrate, valerate, pivalate,
hexanoate, heptanoate, octanoate, maleate, fumarate, oxalate,
lactate, pyruvate, tartarate and their isomers.
[0054] According to a preferred embodiment of the invention the
anionic portion of the invention is chosen from a list consisting
of phosphate, diphosphate, phosphonate, carboxylate, halides,
sulphonate, sulphate or perfluorinated alkylphosphate or
combinations thereof
[0055] Examples of ionic liquid anions, which depending on the
lignocellulosic material and the treatment and conditions used may
be used according to the invention, include chloride (Cl.sup.-),
bromide (Br), iodide (I), formate (HCOO.sup.-), acetate
(AcO.sup.-), propanoate (C.sub.2H.sub.5COO.sup.-), butyrate
(C.sub.3H.sub.7COO.sup.-), pivalate (Me.sub.3CCOO.sup.-), valerate
(C.sub.4H.sub.9COO.sup.-), hexanoate (C.sub.5H.sub.11COO.sup.-),
benzoate (PhCOO.sup.-), methylsulfate (MeSO.sub.4.sup.-),
ethylsulfate (EtSO.sub.4.sup.-), propylsulfate (PrSO.sub.4.sup.-),
isopropylsulfate (PrSO.sub.4.sup.-), butylsulfate
(BuSO.sub.4.sup.-), phenyl sulfate (PhSO.sub.4.sup.-),
p-tolylsulfate (p-TolSO.sub.4.sup.-), xylenesulfate
(MeSO.sub.4.sup.-), benzylsulfate (BnSO.sub.4.sup.-),
trifluoromethylsulfate (CF.sub.3SO.sub.4.sup.-), methylsulfonate
(MeSO.sub.3.sup.-), ethylsulfonate (EtSO.sub.3.sup.-),
propylsulfonate (PrSO.sub.3.sup.-), isopropylsulfonate
(PrSO.sub.3.sup.-), butylsulfonate (BuSO.sub.3.sup.-),
phenylsulfonate (PhSO.sub.3.sup.-), p-tolylsulfonate (TsO.sup.-),
xylenesulfonate (MeSO.sub.4.sup.-), benzylsulfonate
(BnSO.sub.3.sup.-), trifluoromethylsulfonate
(CF.sub.3SO.sub.3.sup.-), methylacetamide (MeAcN.sup.-),
ethylacetamide (EtAcN.sup.-), dimethylphosphate
(Me.sub.2PO.sub.4.sup.-), diethylphosphate (Et.sub.2PO.sub.4),
methylethylphosphate (EtMePO.sub.4.sup.-), dipropylphosphate
(Pr.sub.2PO.sub.4.sup.-), diisopropylphosphate
(Pr.sup.i.sub.2PO.sub.4.sup.-), catecholmonophosphate
(CatPO.sub.4.sup.-), diphenylphosphate (Ph.sub.2PO.sub.4.sup.-),
methylhydrogenphosphonate (MeHPO.sub.3.sup.-),
ethylhydrogenphosphonate (EtHPO.sub.3.sup.-),
propylhydrogenphosphonate (PrHPO.sub.3.sup.-),
isopropylhydrogenphosphonate (Pr'HPO.sub.3.sup.-),
dimethylphosphonate (Me.sub.2PO.sub.3.sup.-), diethylphosphonate
(Et.sub.2PO.sub.3.sup.-), dipropylphosphonate
(Pr.sub.2PO.sub.3.sup.-), diisopropylphosphonate
(Pr.sup.i.sub.2PO.sub.3.sup.-), O-ethyl-P-methylphosphonate
(MeEtPO.sub.3.sup.-), O-methyl-P-ethylphosphonate
(EtMePO.sub.3.sup.-), or related structures.
[0056] A list of some structures of preferred examples of ionic
liquid anions, according to the invention is presented below. The
structures are shown as their canonical resonance hybrids.
##STR00004##
[0057] The above lists of possible cations and anions according to
the invention is not intended to be an exhaustive listing of all
possible cationic and anionic portions. A variety of ionic liquids
can be prepared and used according to the present invention by
combining one or more cations with one or more anions to form ionic
liquid.
[0058] Some preferred ionic liquids, according to the present
invention, are for example: 1-allyl-3-methylimidazolium
dimethylphosphate 1,3-dimethylimidazolium dimethylphosphate;
1-ethyl-3-methylimidazolium dimethylphosphate,
1-allyl-3-methylimidazolium methylhydrogenphosphonate
1,3-dimethylimidazolium methylhydrogenphosphonate;
1-ethyl-3-methylimidazolium methylhydrogenphosphonate,
1-allyl-3-methylimidazolium formate 1,3-dimethylimidazolium
formate; 1-ethyl-3-methylimidazolium formate,
1-allyl-3-methylimidazolium acetate 1,3-dimethylimidazolium
acetate; 1-ethyl-3-methylimidazolium acetate,
1-allyl-3-methylimidazolium propionate 1,3-dimethylimidazolium
propionate; 1-ethyl-3-methylimidazolium propionate,
1-allylpyridinium dimethylphosphate, 1-ethylpyridinium
dimethylphosphate, 1-methylpyridinium dimethylphosphate,
1-allylpyridinium methylhydrogenphosphonate, 1-ethylpyridinium
methylhydrogenphosphonate, 1-methylpyridinium
methylhydrogenphosphonate, 1-allylpyridinium formate,
1-ethylpyridinium formate, 1-methylpyridinium formate,
1-allylpyridinium acetate, 1-ethylpyridinium acetate,
1-methylpyridinium acetate, 1-allylpyridinium propionate,
1-ethylpyridinium propionate, 1-methylpyridinium propionate
[0059] According to preferred embodiments of the present invention
the ionic liquid(s) of the invention comprises the use of various
ionic liquids incorporating acetates, phosphates and phosphonates
as the anionic portion and dialkylimidazoliums as the cationic
portion. In other preferred embodiments, the ionic liquids useful
according to the invention encompass pyridinium halides, pyridinium
carboxylates, pyridinium phosphates or pyridinium phosphonates.
[0060] Examples of specific preferred examples of the present
invention are 1-ethyl-3-methylimidazolium dimethylphosphate
([emim]Me.sub.2PO.sub.4), 1-ethyl-3-methylimidazolium
methylphosphonate ([emim]MeHPO.sub.3) and
1-ethyl-3-methylimidazolium acetate ([emim]OAc).
##STR00005##
[0061] Based on the description it is clear how to arrive at still
further ionic liquids for the ionic liquid treatment according to
the invention by combining one or more cations with one or more
anions to form a ionic liquid. Multiple heterocyclic or acyclic
ionic liquids could be used as well. It is further known that
dicationic materials exhibit increased thermal stability and are
thus useful in embodiments, where it is desirable to carry out the
treatment of the lignocellulosic materials at increased
temperatures. Dicationic ionic liquids can be prepared using any
combination of cations and anions, such as those described above.
For example, imidazoles and pyridines could be used in preparing
dicationic ionic liquids in a similar manner as described for ionic
liquids having only a single cationic moiety. Ionic liquids are
typically relatively easy to prepare by known syntheses. For the
synthesis of a ionic liquid based on imidazolium phosphates or
phosphonates the
[0062] Menschutkin reaction (amine quaternization), where a
substituted imidazole is reacted with a trialkylphosphate or
dialkylhydrogenphosphonate (dialkylphosphite) or
trialkylphosphonate, is generally used. Related compounds can be
prepared by transesterification of phosphites, phosphates or
phosphonates starting with alcohols, such as, partially fluorinated
or perfluorinated alcohols, allyl alcohol, propargyl alcohol,
phenol or higher chain homologues with differing degrees of
unsaturation. In the synthesis of trialkylphosphonates, further
variation in substitution may be accessed, by employing the
Michaelis-Arbuzov reaction (shown below), by starting from easily
accessible trialkylphosphite esters:
##STR00006##
[0063] Phosphate and phosphonate based ionic liquids typically have
lower viscosities compared to halide-based ionic liquids, which
makes them particularly easy to use without the need for excessive
heating.
[0064] Other preferred methods of forming ionic liquids comprises
derivatization which involves functionalization of some existing
molecular heterocyclic or acyclic compound with a substituent or it
involves anion metathesis where an existing anion of an ionic
liquid is replaced or reacted with a reagent leaving another anion
in its place. This may give a completely new pure ionic liquid, or
an ionic liquid, which contains a mixture of anions and cations. A
further preferred method of ionic liquid preparation involves
direct mixing of two pure salts to give a molten salt or ionic
liquid mixture. Yet another method of ionic liquid preparation
involves direct mixing of a pure salt with a non-ionic (molecular)
compound, to afford an ionic liquid or eutectic mixture with high
ionic character. Such compounds are not typically thought of as
ionic liquids, but are herein referred to as ionic liquids.
[0065] The invention further relates to the use of various mixtures
of ionic liquids. In fact, ionic liquid mixtures can be useful for
providing mixtures having customized physiochemical properties,
such as viscosity or ability to process different materials,
according to the present invention. For example,
1-benzyl-3-methylimidazolium dimethylphosphate
([bnmim]Me.sub.2PO.sub.4) is a relatively viscous ionic liquid,
however, its viscosity can be significantly reduced by mixing it
with another ionic liquid such as [emim]MeHPO.sub.3. The viscosity
of the ionic liquid mixture can thus be adjusted by varying the
ratio between the more viscous component and the less viscous
component.
[0066] According to a further embodiment of the invention various
pure ionic liquids or ionic liquid mixtures are mixed with
additives, such as molecular solvents, preferably inorganic or
organic solvents and/or an organic acid or base. Typical solvents
are polar aprotic solvents such as dimethylsulfoxide (DMSO) in
small quantities (<20%). DMSO is a cheap and non-toxic solvent.
It can also be easily produced as a side stream from Kraft chemical
pulping of lignocelluloses. Pressurized CO.sub.2 and water may also
be added to moderate the process.
[0067] FIG. 1 shows one embodiment of the process according to the
invention. The lignocellulosic material is a typical pulpwood
feedstock, and the process involves chipping debarked wood (1) to
give wood chips (2) of the appropriate size. The chips may also be
extracted with a solvent, such as acetone, to further dry the
sample or remove extractives. The wood chips (2) are fibrillated in
ionic liquid media with heating and mechanical treatment to give
the fibres in ionic liquid media (3). This material is diluted with
the appropriate amount of solvent, such as methanol, and filtered
to give the "wet" fibres (4). The filtrate solution, which can be a
mixture of ionic liquid, polysaccharides (pectins and/or
hemicelluloses) and extractives (7), is retained. The "wet" fibres
may be further treated with a solvent at elevated temperatures to
remove any remaining traces of ionic liquid from the fibres. The
mixture is again filtered and dried to give dried fibres (5), the
yield of which will be typically 90-95%. The filtrate from the
second filtration step is combined with the solution of ionic
liquids, polysaccharides (pectins and/or hemicelluloses) and
extractives. Any polysaccharides or extractives (9) may be
recovered in 5-10% yield by a suitable method such as filtration
and/or membrane filtration. The remaining ionic liquid and solvent
(8) is treated by evaporation and/or pervaporation as a final step
in recycling the ionic liquid and molecular solvents.
[0068] The dried fibre (5) product of FIG. 1 may be treated further
(6). The further treatment, involves for example a sequence of
chemical modification steps, such as one or more of bleaching, mild
pulping, esterification, etherification or further extraction using
additional solvents such as supercritical-CO.sub.2 extraction
(sc-CO.sub.2), pressurized hot water extraction (PHWE), traditional
molecular solvent extraction or additional ionic liquid extraction.
The isolated polysaccharides and extractives (9) are optionally
further separated (10) using techniques such as solvent and
chemical extraction, membrane filtration (nanofiltration,
ultrafiltration) or selective precipitation.
[0069] The following examples are given to further illustrate the
invention. Based on the above description a person skilled in the
art will be able to modify the invention in many ways to provide
increased efficiency of fibrillation, pulping, fractionation or
novel materials based on chemical functionalization of the novel
fibrillated material.
EXAMPLE 1
Preparation of 1-methyl-3-methylimidazolium dimethylphosphate
([mmim]Me.sub.2PO.sub.4)
[0070] A mixture of 1-methylimidazole (50 ml, 0.519 mol) was added
over a space of 4 hrs to trimethylphosphate (60.7 ml, 0.519 mol) at
100.degree. C., with stirring. The solution was heated at
100.degree. C. for a further 18 hrs. The reaction of the mixture
was determined to be complete by analyzing a sample by .sup.1H NMR
from CDCl.sub.3. The mixture was rotary evaporated under high
vacuum for 18 hrs to give a pale yellow oily product (110 ml). The
purity of the product was determined to be >99% by .sup.1H NMR
analysis.
EXAMPLE 2
Preparation of 1-ethyl-3-methylimidazolium dimethylphosphate
([emim]Me.sub.2PO.sub.4)
[0071] A mixture of 1-ethylimidazole (50 ml, 0.519 mol) was added
over a space of 4 hrs to trimethylphosphate (60.7 ml, 0.519 mol) at
120.degree. C. with stirring. The solution was heated at
120.degree. C. for a further 18 hrs. The reaction of the mixture
was determined to be complete by analyzing a sample by .sup.1H NMR
from CDCl.sub.3. The mixture was rotary evaporated under high
vacuum for 18 hrs to give a pale yellow oily product (110 ml). The
purity of the product was determined to be >99% by .sup.1H NMR
analysis.
EXAMPLE 3
Preparation of 1-ethyl-3-methylimidazolium
methylhydrogenphosphonate ([emim]MeHPO.sub.3)
[0072] A mixture of 1-ethylimidazole (50 ml, 0.519 mol) was added
over a space of 4 hrs to diethylphosphite (47.6 ml, 0.519 mol) at
140.degree. C. with stirring. The solution was heated at
140.degree. C. for a further 18 hrs. The reaction of the mixture
was determined to be complete by analyzing a sample by .sup.1H NMR
from CDCl.sub.3. The mixture was rotary evaporated under high
vacuum for 18 hrs to give a pale yellow oily product (97 ml). The
purity of the product was determined to be >99% by .sup.1H NMR
analysis.
EXAMPLES 4-39
Fibrillation of Soft and Hardwood Chips in Different Ionic
Liquids
[0073] Fibrillation capability was assessed for a series of ionic
liquids and wood species. Some specific examples of ionic liquids,
capable of efficiently fibrillating lignocellulose, are chosen from
a series of ionic liquids that were screened in a methodical
manner. Screening involved varying both the cation and anion
structures of the ionic liquids. Screening was also assessed
against a selection of hardwoods, such as birch, aspen and oak, and
softwoods, such as such as pine and spruce. The results are
presented in Table 1.
[0074] The fibrillation experiments were performed in one of the
following ways:
[0075] Pine, spruce (softwood), birch or aspen (hardwood) chips
(ca. 2.5 cm.times.1 cm.times.0.2 mm) were soaked for 2 days at room
temperature in acetone, in order to remove extractives and
partially dry the material. The chips were then dried in an oven at
105.degree. C. Extracted and dried wood chips (2 g) in ionic liquid
(20 ml) were heated without agitation between 95-110.degree. C. for
18-66 hr in ionic liquid. Hardwoods required higher temperatures.
Methanol (40 ml) was added to the mixture and the fibres were
filtered. The fibres were thoroughly washed with further methanol
and dried in an oven at 105.degree. C. for 18 hrs to give pale
cream coloured fibres as product (1.9 g). The ability of different
ionic liquids to fibrillate different wood samples is presented in
Table 1.
TABLE-US-00001 TABLE 1 The efficiency of fibrillation for different
wood species with different ionic liquid structures, Examples 4-39.
Example Ionic Liquid Preparation Fibrillation Efficiency.sup.a 4
[mmim]Me.sub.2PO.sub.4 According to +++ (Softwood) Ex. 1 5 [amim]Cl
Synthesized ++ (gels) (Softwood) 6 [amim]Br Synthesized -
(Softwood) 7 [amim]Me.sub.2PO.sub.4 Synthesized +++ (Softwood) 8
[emim]Cl Merck - (Softwood) 9 [emim]Me.sub.2PO.sub.4 According to
+++++ (Softwood) Ex. 2 10 [emim]Et.sub.2PO.sub.4 Synthesized ++++
(Softwood) 11 [emim]SCN Merck - (Softwood) 12 [emim]MeHPO.sub.3
According to +++++ (Softwoods) Ex. 3 [No darkening of fibres] 13
[emim]EtHPO.sub.3 Synthesized +++ (Softwood) 14 [emim]HSO.sub.4
Merck - (Softwood) 15 [emim]MeSO.sub.4 Iolitec - (Softwood)
[Darkening of solution and fibres] 16 [emim]OTs Iolitec -
(Softwood) 17 [emim]OAc Iolitec ++++ (Hard and Softwoods) 18
[emim]Me.sub.2PO.sub.3 Synthesized - (Softwood) 19
[eeim]Et.sub.2PO.sub.4 Synthesized ++ (Softwood) 20
[mmmim]Me.sub.2PO.sub.4 Synthesized ++ (Softwood) 21 [emmim]Cl
Synthesized - (Softwood) 22 [emmim]Et.sub.2PO.sub.4 Synthesized +++
(Softwood) 23 [prmim]Me.sub.2PO.sub.4 Synthesized +++ (Softwood) 24
[.sup.iprmim]Pr.sup.i.sub.2PO.sub.4 Synthesized + (Softwood) 25
[bmim]Me.sub.2PO.sub.4 Synthesized ++ (Softwood) 26 [bmim]HSO.sub.4
Merck - (Softwood) 27 [omim]OctSO.sub.4 Merck - (Softwood) 28
[hemim]Cl Iolitec - (Softwood) 29 [Hmim]Cl BASF - (Softwood) 30
P.sub.4444Cl Iolitec - (Softwood) 31 P.sub.14444Cl Iolitec -
(Softwood) 32 P.sub.14666Cl Iolitec - (Softwood) 33
P.sub.4442Et.sub.2PO.sub.4 Iolitec - (Softwood) 34 P.sub.4441OTs
Iolitec - (Softwood) 35 [HTMG]OCOC.sub.2H.sub.5 Synthesized -
(Softwood) 36 [PMG]Me.sub.2PO.sub.4 Synthesized - (Softwood) 37
[PMG]MeHPO.sub.3 Synthesized - (Softwood) 38 [eTMG]EtHPO.sub.3
Synthesized - (Softwood) 39 [mPyr]MeHPO.sub.3 Synthesized ++
(Softwood) .sup.aefficiency of fibrillation: +++++ (strong
fibrillation), - (no fibrillation)
[0076] The chemical names of the ionic liquids of examples 4 to
39:
4. [mmim]Me.sub.2PO.sub.4--1,3-dimethylimidazolium
dimethylphosphate
5. [amim]Cl--1-allyl-3-methylimidazolium chloride
6. [amim]Br--1-allyl-3-methylimidazolium bromide
7. [amim]Me.sub.2PO.sub.4--1-allyl-3-methylimidazolium
dimethylphosphate
8. [emim]Cl--1-ethyl-3-methylimidazolium chloride
9. [emim]Me.sub.2PO.sub.4--1-ethyl-3-methylimidazolium
dimethylphosphate
10. [emim]Et.sub.2PO.sub.4--1-ethyl-3-methylimidazolium
diethylphosphate
11. [emim]SCN--1-ethyl-3-methylimidazolium thiocyanate
12. [emim]MeHPO.sub.3--1-ethyl-3-methylimidazolium
methylhydrogenphosphonate
13. [emim]EtHPO.sub.3--1-ethyl-3-methylimidazolium
ethylhydrogenphosphonate
14. [emim]HSO.sub.4--1-ethyl-3-methylimidazolium
hydrogensulfate
15. [emim]MeSO.sub.4--1-ethyl-3-methylimidazolium methylsulfate
16. [emim]OTs--1-ethyl-3-methylimidazolium tosylate
17. [emim]OAc--1-ethyl-3-methylimidazolium acetate
18. [eeim]Et.sub.2PO.sub.4--1,3-diethylimidazolium
diethylphosphate
19 [mmmim]Me.sub.2PO.sub.4--1,2,3-trimethylimidazolium
dimethylphosphate
20. [emmim]Cl--1-ethyl-2,3-dimethylimidazolium diethylphosphate
21. [emim]Me.sub.2PO.sub.3--1-ethyl-3-methylimidazolium
methylmethylphosphonate
22. [emmim]Et.sub.2PO.sub.4--1,2,3-trimethylimidazolium
diethylphosphate
23. [prmim]Me.sub.2PO.sub.4--1-propyl-3-methylimidazolium
dimethylphosphate
24.
[.sup.iprmim]Pr.sup.i.sub.2PO.sub.4--1-isopropyl-3-methylimidazolium
dimethylphosphate
25. [bmim]Me.sub.2PO.sub.4--1-butyl-3-methylimidazolium
dimethylphosphate
26. [bmim]HSO.sub.4--1-butyl-3-methylimidazolium
hydrogensulfate
27. [omim]OctSO.sub.4--1-octyl-3-methylimidazolium octylsulfate
28. [hemim]CI--1-(2-hydroxyethyl)-3-methylimidazolium chloride
29. [Hmim]Cl--1-methylimidazoliumhydrogen chloride
30. P.sub.4444Cl--tetrabutylphosphonium chloride
31. P.sub.14444Cl--tetradecyltributylphosphonium chloride
32. P.sub.14666Cl--tetradecyltrihexylphosphonium chloride
33. P.sub.4442Et.sub.2PO.sub.4--ethyltributylphosphonium
diethylphosphate
34. P.sub.4441OTs--methyltriisobutylphosphonium tosylate
35. [HTMG]OCOC.sub.2H.sub.5--tetramethylguanidiniumhydrogen
propionate
36. [PMG]Me.sub.2PO.sub.4--pentamethylguanidinium
dimethylphosphate
37. [PMG]MeHPO.sub.3--pentamethylguanidinium
methylhydrogenphosphonate
38. [eTMG]EtHPO.sub.3--ethyltetramethylguanidinium
ethylhydrogenphosphonate
39. [mPyr]MeHPO.sub.3--methylpyridinium
methylhydrogenphosphonate
[0077] It was determined that [emim]MeHPO.sub.3 was the most
preferred ionic liquid tested for fibrillating softwoods such as
pine and spruce, while [emim]OAc was also capable of fibrillating
hardwoods such as Birch, Aspen and Oak (at 95.degree. C. over 18
hr). The combination of [emim]MeHPO.sub.3 with softwoods under
milder conditions (110.degree. C. over 18 hr) was able to produce
fibres with no significant darkening, characteristic of dehydration
and lignin oxidation, in comparison to the starting wood material.
Ionic liquids such as [emim]Me.sub.2PO.sub.4 and
[mmim]Me.sub.2PO.sub.4 fibrillated softwood under harsher
conditions (110.degree. C. up to 3 days) and yielded fibres that
were more colourized than the [emim]MeHPO.sub.3 fibrillated
samples. Although all of the above combinations in these particular
examples of on one hand lignocellulosic material (the specific
softwood or hardwood species) and on the other hand ionic liquid
and treatment conditions did not lead to fibrillation, also these
ionic liquids are believed to fibrillate other lignocellulosic
materials according to the process of the invention.
EXAMPLE 40
Total Sugar Analysis of Fibrillated Pine Wood Chips, After
Treatment With [mmim]Me.sub.2PO.sub.4
[0078] Pine was treated with [mmim]Me.sub.2PO.sub.4 (according to
Examples 1 and 4) and analysed by total sugar analysis (Table
2).
TABLE-US-00002 TABLE 2 Total sugar analysis, according to methods
detailed in DOI10.1007/s00226-005-0039-4, of fibrillated pine wood
chips, after treatment with [mmim]Me.sub.2PO.sub.4. Values are
relative against internal standards. Average Wood Fibrillated
Fibrillated Fibrillated Late Monomer Chips Sample 1 Sample 2 Sample
Wood Arabinose 11 9 9 9 10 Xylose 51 52 59 56 62 Rhamnose 2.1 1.1
0.8 1.0 0.8 Glucuronic 0.0 0.4 0.6 0.5 0.3 Acid Galacturonic 10.2
1.7 2.1 1.9 2.6 Acid Mannose 106 87 97 92 112 Galactose 15 23 12 17
14 Glucose 37 47 56 52 65 1,4-bis-O- 3.6 2.8 2.6 2.7 2.4 MeGlcA
Unknown 1.4 1.1 1.0 1.1 0.9 Unknown 0.7 0.6 0.8 0.7 0.8 Total 239
225 242 234 270
[0079] It was determined that a large portion of galacturonic acid
residues were missing, indicating extraction of pectins. This
indicates that pectins, which are present in the lumen of woody
material, acts as a binder for adjacent tracheids. The ionic liquid
residue was evaporated to dryness by rotary evaporation to be
submitted for .sup.31P NMR analysis. This involved
functionalization of the remaining hydroxyl groups as phosphite
esters and observing the resulting .sup.31P resonances according to
FIG. 2, wherein (1) shows the internal standard, (2) the methyl
(methanol) phosphite ester resonance, (3) the aliphatic (alcohol)
phosphite ester resonance region, (4) the guiacyl (phenol)
phosphite ester resonance region and (5) a carboxylate phosphite
mixed anhydride (carboxylic acid) resonance region.
[0080] Using this technique it was possible to determine that there
was a very low lignin content in the material that was extracted.
This is evident from the lack of lignin guiacyl phenolic resonances
(5) against both internal standard (1) and aliphatic resonances
(3). The small (5%) weight loss of the fibres also indicated that
lignin was not being extracted to any significant degree. Moreover,
due to the mild nature of the treatment, the extracted pectins are
thought not to be covalently linked to lignin. Lignin is also
present in its highest concentration in the lumen.
EXAMPLE 41
Fatty Acid (Oleic Acid) Surface Modification of Fibrillated
Pine
[0081] Pyridine (1 ml) and oleoyl chloride (1 ml) were added to a
solution of ionic liquid fibrillated pine (360 mg) in dioxane (12
ml). The mixture was heated in an oil bath with stirring at
90.degree. C. for 18 hrs. The resulting fibers were filtered,
washed with toluene and hot methanol. The fibres were dried at
105.degree. C. for 18 hrs to obtain pale cream coloured fibres as
product (900 mg). The product was hydrophobic to the extent that it
floated on water, even after agitation. The ATR-IR spectra showed a
high ratio of C.dbd.O to OH stretch indicating a high degree of
substitution as fatty acid ester.
[0082] The present invention has been described herein with
reference to specific embodiments. It is however clear to those
skilled in the art that the process(es) may be varied within the
bounds of the claims.
* * * * *