IONIC LIQUIDS
Field of the invention
The present invention relates to ionic liquids and uses thereof. The invention also
provides processes for the manufacture of ionic liquids.
Background to the invention
Ionic liquids are compounds which are composed exclusively or predominantly of ions
but are in liquid form, generally having a melting point below ambient temperature.
They arise from combinations of suitable ions, in which the lattice energy and melting
point are abnormally low. This may be achieved through the use of bulky,
asymmetrical, charge-delocalised ions, which associate relatively weakly and with a low
degree of structural order.
Ionic liquids can possess a number of remarkable properties, including negligible vapour
pressure, high solubilising power and a broad liquid temperature range, which have
rendered them interesting alternatives to conventional liquids in a variety of applications.
Ionic liquids may be made up of anions and cations or alternatively consist of
zwitterions which carry both a positive and a negative charge on the same molecule.
Most commonly an ionic liquid will comprise an anion and a cation.
Early ionic liquids comprised nitrogen- or phosphorous-based cations, generally
substituted with one or more alkyl groups. Examples were based on a nucleus selected
from quaternary ammonium cations, pyrrolidinium cations, imidazolium cations,
triazolium cations, pyridinium cations, pyridazinium cations, pyrimidinium cations,
pyrazinium cations and triazinium cations. These types of ionic liquids tend to be highly
viscous, potentially hazardous and strongly absorbent of UV and visible light.
Furthermore, the preparation of these ionic liquids can involve a number of chemical and
chromatographic steps that can make the process time consuming, expensive and
inefficient.

In WO-2004/063383, modified ionic liquids were disclosed in which one of the
component ions, typically the cation, included a functional group selected from alkenyl,
hydroxyl, amino, thio, carbonyl and carboxyl groups. By modifying the liquids in this
way, it was found possible to tailor them for use as solvents in various applications, in
particular for single-phase biocatalysis. The liquids could be made more biocompatible,
and could provide a more polar, protic, hydrogen bonding environment to mimic that
which would previously have been achieved using aqueous solvents. Thus, enzyme-
catalysed reactions that could not previously be carried out in non-aqueous environments
could now be performed in ionic liquids, with all their associated advantages.
Our co-pending PCT patent application no. PCT/GB2005/001364 discloses further ionic
liquids which comprise as the cation a primary, secondary or tertiary ammonium ion
containing a protonated nitrogen atom. The nitrogen atom can be substituted with one,
two or three hydrocarbyl groups, and the hydrocarbyl groups can themselves be
substituted, in order to tailor their functionality, with groups such as nitrogen-containing
functional groups (including nitrile, nitro or amino or another basic nitrogen-containing
functional group), thiol, alkylthio, sulphonyl, thiocyanate, isothiocyanate, azido,
hydrazino, halogen, alkyl optionally interrupted by one or more ether or thioether
linkages, alkoxy, alkenyl, hydroxy, carbonyl, carboxyl, boronate, silyl and substituted
amino. Such liquids have been found to demonstrate high solvation capabilities, low
viscosity and low toxicity, making them useful in a broader range of applications than
some of the previously available ionic liquids.
Anderson et al, J. Am. Chem. Soc. 124:14247-14254 (2002) also disclose ionic liquids
composed of a primary or tertiary ammonium based cation for use in certain chemical
applications.
Ionic liquids containing a hydroxyl group -OH on one of the hydrocarbyl side chains
have been used, as described in WO-2004/063383, as reaction media for biocatalytic
reactions. In some situations, however, for example when the enzyme used is a
hydrolase, such ionic liquids can suffer from the drawback that the hydroxyalkyl
function may interfere with or participate in the reaction being catalysed.

The present inventors have developed alternative ionic liquids, which can be used as
solvents and as reaction media in a wide range of situations, including those in which a
hydrogen bonding, protic environment is required, and including for biological solutes
such as enzymes. The invention can thus broaden the range of applications for ionic
liquids, in particular as solvents and/or reaction media and more particularly in
biocatalysis.
Statements of the invention
According to a first aspect of the present invention there is provided an ionic liquid
comprising a cation of the formula (I):
N+HR1R2R3 (I)
wherein R1 is a group -R4-O-R5;
R2 and R3 are each independently either hydrogen or hydrocarbyl, or R2 and R3 may be
joined together with the N to form a heterocyclic group;
R4 is a divalent hydrocarbyl radical; and
R5 is hydrocarbyl.
Ionic liquids according to this first aspect of the invention, which contain both a labile
proton (on the central nitrogen atom) and an ether group -R4-O-R5, have been found to
be capable of hydrogen bonding and hence of providing a fluid environment which is
similar in functional terms to that of an aqueous solvent. They can thus be used as
solvents and reaction media for relatively hydrophilic materials, in particular for
enzymes and enzyme-catalysed reactions.
A further advantage of such ionic liquids is their ability to provide a polar, hydrogen
bonding environment in the absence of hydroxyl groups. This can help to overcome the
drawbacks referred to above, where the presence of a hydroxyl moiety on an ionic liquid
solvent can in cases react with a solute such as an activated acid or a strong base, or
interfere with a reaction (in particular an enzyme-catalysed reaction such as one
involving a hydrolase or esterase) being carried out in the ionic liquid.

The cation (I) may be a primary ammonium ion, in which R2 and R3 are both hydrogen.
It may be a secondary ammonium ion, in which only one of R2 and R3 is hydrogen. It
may be a tertiary ammonium ion, in which neither of R2 and R3 is hydrogen. Preferably,
it is a secondary or a tertiary ammonium ion. Tertiary ions may be particularly
preferred, since they tend to be less reactive than their primary or secondary
counterparts, and can be less likely to form unwanted and potentially toxic byproducts
such as nitrosamines. The presence of at least one labile proton on the nitrogen atom is
however desirable as it tends to lower the viscosity of the ionic liquid and also helps to
provide the protic, hydrogen bonding environment which makes the ionic liquid suitable
for use as a solvent for hydrophilic materials.
In the context of the present invention, a hydrocarbyl group may be substituted with one
or more substituents selected from nitrogen-containing functional groups (including
nitrile, nitro or amino or another basic nitrogen-containing functional group), thiol,
alkythio, sulphonyl, thiocyanate, isothiocyanate, azido, hydrazino, halogen, alkyl, alkyl
interrupted by one or more ether or thioether linkages, alkoxy, alkenyl, hydroxy,
carbonyl (including aldehyde or ketone), carboxyl, boronate, silyl and substituted amino
(eg, mono- or di-alkylamino or alkyamido).
Preferred substituents for use in this context are selected from the group consisting of
alkenyl, hydroxyl, alkoxy, amino, thio, carbonyl and carboxyl groups. More preferably,
substituents are selected from hydroxyl and amino groups; yet more preferably a
substituent is a hydroxyl group.
Preferably, however, in the context of the present invention, a hydrocarbyl group is
unsubstituted.
Preferably R4 is -(CH2)n-, where n is an integer from 2 to 8, preferably from 2 to 6,
more preferably from 2 to 4, such as 2 or 3, suitably 2.
It may be preferred, in particular if R2 and R3 are both hydrogen and R5 is an
unsubstituted alkyl group, for R4 not to be CH2CH2. In other words, it may be preferred
for the cation (I) not to be an alkoxyethyl ammonium cation.

R1 may for example be a methoxyethyl group, in particular when R2 and R are not both
hydrogen.
Preferably R5 is alkyl or cycloalkyl, more preferably C1 to C6 alkyl or cycloalkyl, yet
more preferably C1 to C5 alkyl, such as in particular methyl, ethyl, propyl, iso-propyl,
butyl, iso-butyl or tert-butyl, more particularly methyl or ethyl, suitably methyl.
Preferably R5 is either unsubstituted or is substituted with a hydroxyl group, in particular
a terminal hydroxyl group.
Thus in some cases it may be preferred for R5 to be an unsubstituted alkyl group such as
CH3 or (CH2)nCH3, with n being an integer for example from 1 to 4, preferably either 1
or 2 and most preferably 1. In other cases it may be preferred for R5 to be (CH2)nOH,
with n being an integer suitably from 2 to 4, preferably either 2 or 3 and most preferably
2. This latter case, where R1 is a (hydroxyalkoxy)alkyl group, may be particularly
preferred when R2 and R3 are both alkyl groups, in particular selected from methyl and
ethyl groups, most particularly methyl groups; thus, the cation (I) may be a N,N-dialkyl-
N-[(hydroxyalkoxy)alkyl] ammonium ion such as a N,N-dimethyl-N-
[(hydroxyalkoxy)alkyl] ammonium ion, in particular a N,N-dimethyl-N-[(2-
hydroxyethoxy)ethyl] ammonium ion.
It may be preferred for R1 not to be a methoxyethyl group, in particular if both R2 and R3
are hydrogen.
It may be preferred for R1 not to be a methoxypropyl group, in particular if both R2 and
R3 are hydrogen.
hi some cases it may be preferred for R1 not to be an alkoxyethyl group, in particular if
both R2 and R3 are hydrogen.
Preferably R2 is alkyl or cycloalkyl, more preferably C1 to C6 alkyl or cycloalkyl, yet
more preferably C1 to C5 alkyl, such as in particular methyl, ethyl, propyl, iso-propyl,
butyl, iso-butyl or tert-butyl, more particularly methyl, ethyl, propyl or iso-propyl, yet
more particularly methyl or ethyl. Preferably R2 is unsubstituted.
R2 may be a group of formula -R4-O-R5, where R4 and R5 are as defined above; in this
case, R2 may be the same as or different to R1. In particular, R1 may be the same as R2,

and may for example be selected from methoxyalkyl and alkoxyethyl, in particular (so
long as R3 is not hydrogen) methoxyethyl.
In some cases it may be preferred for R2 to be hydrogen.
Preferably R3 is hydrogen. In some cases however it may be an alkyl or cycloalkyl
group, for instance as defined above in connection with R2.
In an embodiment of the invention, for example, R3 is an alkyl group and R1 and R2 are
both alkoxyalkyl groups of the formula -R4-O-R5. In this case R3 may be for instance a
C1 to C6 alkyl group, preferably a C1 to C5 alkyl group, such as in particular methyl,
ethyl, propyl, iso-propyl, butyl, iso-butyl or tert-butyl, more particularly methyl or ethyl,
suitably methyl; and R1 and R2 are preferably the same and may be of the types defined
above, in particular selected from methoxyalkyl and alkoxyethyl, more particularly
methoxyethyl.
In another embodiment, R2 and R3 may both be alkyl or cycloalkyl, for instance as
defined above in connection with R2. In this case R2 and R3 are preferably both alkyl,
more preferably C1 to C3 alkyl; they may be the same or different, preferably the same.
The presence of two alkyl groups, in particular lower alkyl groups such as ethyl or in
particular methyl, has been found to help lower the viscosity of the ionic liquid which
can be advantageous in the context of its use as a solvent or reaction medium.
Thus, the cation (I) may for instance be a dialkyl alkoxyalkyl ammonium ion, preferably
a dimethyl, diethyl or dipropyl alkoxyalkyl ammonium ion, a methyl ethyl alkoxyalkyl
ammonium ion, a methyl propyl alkoxyalkyl ammonium ion or an ethyl propyl
alkoxyalkyl ammonium ion. Most preferably (I) is selected from dimethyl alkoxyalkyl,
diethyl alkoxyalkyl and methyl ethyl alkoxyalkyl ammonium ions, in particular
dimethyl alkoxyalkyl ammonium. In such a case R1 could be for example a
methoxyethyl group.
Preferably R3 is not the same as R1.
In an embodiment of the invention, R3 may be an alkanolyl group, for example as
defined in connection with formula (II) below, in particular if R2 is an alkyl group such
as a C1 to C6 or C1 to C4 alkyl group.

R2 is preferably not the same as R1, in particular if R3 is hydrogen. It may be preferred,
again particularly if R3 is hydrogen, for R1 and R2 not both to be alkoxyalkyl groups, or
at least for R1 and R2 not to be the same alkoxyalkyl group. In some cases it may be
preferred, particularly if R3 is hydrogen, for R2 not to be an alkoxyalkyl group.
In particular if R3 is hydrogen, and more particularly if R3 is hydrogen and Rl is
methoxyethyl, R2 is preferably not methoxyethyl.
Particularly preferred ionic liquids according to the invention comprise a cation of the
formula (Ia):
N+HR1R2R3 (Ia)
wherein R1 is a group -R4-O-R5;
R2 and R3 are each independently either hydrogen, alkanolyl, alkyl or a group -R4-O-
R5, preferably either hydrogen, alkyl or -R4-O-R5, more preferably either hydrogen or
alkyl;
R4 is unsubstituted alkylene, more preferably -(CH2)n where n is as defined above; and
R5 is alkyl or a group (CH2)nOH (where n is an integer suitably from 2 to 4), preferably
alkyl.
Other preferred features of the substituents of the cation (Ia) may be as defined above for
the cation (I).
Preferably the cation (Ia) is not an alkoxyethyl ammonium ion or a di(alkoxyalkyl)
ammonium ion (in particular not a di(methoxyethyl) ammonium ion).
Preferably the cation (Ia) is a secondary or tertiary ammonium ion, more preferably
tertiary. Suitably each alkyl, alkylene and alkanoyl group is independently selected from
groups containing from 1 to 4, preferably from 1 to 3, carbon atoms.
Particularly preferred ionic liquids according to the first aspect of the invention comprise
a cation selected from alkoxypropyl (preferably methoxypropyl) ammonium ions,
methoxyalkyl ammonium ions (preferably other than methoxyethyl ammonium ions),

di(alkoxyalkyl) ammonium ions other than di(methoxyethyl) ammonium ions, alkyl
alkoxyalkyl ammonium ions (preferably methyl alkoxyalkyl or alkyl methoxyethyl
ammonium ions), dialkyl alkoxyalkyl ammonium ions (preferably dimethyl alkoxyalkyl
or dialkyl methoxyethyl ammonium ions), alkyl di(alkoxyalkyl) ammonium ions
(preferably methyl di(alkoxyalkyl) ammonium ions or alkyl di(methoxyethyl)
ammonium ions) and N,N-dialkyl-N-[(hydroxyalkoxy)alkyl] ammonium ions.
Yet more preferred ionic liquids according to the first aspect of the invention comprise a
cation selected from alkyl alkoxyalkyl ammonium ions, dialkyl alkoxyalkyl ammonium
ions, alkyl di(alkoxyalkyl) ammonium ions and N,N-dialkyl-N-[(hydroxyalkoxy)alkyl]
ammonium ions.
Most preferred ionic liquids according to the first aspect of the invention comprise a
cation selected from dialkyl alkoxyalkyl ammonium ions, alkyl di(alkoxyalkyl)
ammonium ions and N,N-dialkyl-N-[(hydroxyalkoxy)alkyl] ammonium ions.
It may be preferred for the ionic liquid of the first aspect of the present invention not to
be any of the following compounds:
N,N-Di(methoxyethyl)ammonium chloride
N,N-Di(methoxyethyl)ammonium bromide
N,N-Di(methoxyethyl)ammonium iodide
N,N-Di(methoxyethyl)ammonium formate
N,N-Di(methoxyethyl)ammonium acetate
N,N-Di(methoxyethyl)ammonium propanoate
N,N-Di(methoxyethyl)ammoniumpropanedioate
N,N-Di(methoxyethyl)ammonium butanoate
N,N-Di(methoxyethyl)ammonium butenoate
N,N-Di(methoxyethyl)ammonium butanedioate
N,N-Di(metb.oxyethyl)ammonium pentanoate
N,N-Di(methoxyethyl)ammoniumpentanedioate
N,N-Di(methoxyethyl)ammonium pentenoate
N,N-Di(methoxyethyl)ammonium hexanoate
N,N-Di(methoxyethyl)ammonium hexenoate

N,N-Di(methoxyethyl)ammonium heptanoate
N,N-Di(methoxyethyl)ammonium heptanedioate
N,N-Di(methoxyethyl)ammonium heptenoate
N,N-Di(methoxyethyl)ammonium octanoate
N,N-Di(methoxyethyl)ammonium octanedioate
N,N-Di(methoxyethyl)ammonium octenoate
N,N-Di(methoxyethyl)ammonium nonanoate
N,N-Di(methoxyethyl)ammonium nonanedioate
N,N-Di(methoxyethyl)ammonium nonenoate
N,N-Di(methoxyethyl)ammonium decanoate
N,N-Di(methoxyethyl)ammonium decanedioate
N,N-Di(methoxyethyl)ammonium decenoate
N,N-Di(methoxyethyl)ammonium undecanoate
N,N-Di(methoxyethyl)ammonium undecanedioate
N,N-Di(methoxyethyl)ammonium undecenoate
N,N-Di(methoxyethyl)ammonium dodecanoate
N,N-Di(methoxyethyl)ammonium dodecanedicarboxylate
N,N-Di(methoxyethy) ammonium dodecenecarboxylate
N,N-Di(methoxyethyl)ammonium dohexanecarboxylate
N,N-Di(methoxyethyl)ammonium dohexenecarboxylate
N,N-Di(metb.oxyethyl)ammonium phenoxide
N,N-Di(methoxyethyl) ammonium benzoate
N,N-Di(methoxyethyl) ammonium benezenedicarboxylate
N,N-Di(methoxyethyl)ammonium benzenetricarboxylate
N,N-Di(methoxyethyl)ammonium benzenetetracarboxylate
N,N-Di(methoxyethyl) ammoniium chlorobenzoate
N,N-Di(metb.oxyethyl)ammonium fluoroben2oate
N,N-Di(methoxyethyl)ammonium pentachlorobenzoate
N,N-Di(methoxyethyl)ammonium pentafluorobenzoate
N,N-Di(methoxyethyl)ammonium salicylate
N,N-Di(methoxyethyl)ammonium glycolate
N,N-Di(methoxyethyl)ammonium lactate

N,N-Di(methoxyethyl)ammonium pantothenate
N,N-Di(methoxyethyl)amtnonium tartrate
N,N-Di(methoxyethyl)ammoniiim hydrogen tartrate
N,N-Di(methoxyethyl)ammonium mandelate
N,N-Di(methoxyethyl)ammonium crotonate
N,N-Di(methoxyethyl)ammonium malate
N,N-Di(methoxyethyl)anunoniurn pyruvate
N,N-Di(methoxyethyl)ammonium succinate
N,N-Di(methoxyethyl)ammonium citrate
N,N-Di(methoxyethyl)ammonium fumarate
N,N-Di(methoxyethyl)ammonium phenylacetate
N,N-Di(methoxyethyl)ammonium oxalate
N,N-Di(methoxyelhyl)ammonium bis(trifluoromethylsulphonyl)imide
N,N-Di(methoxyethyl)ammonium carbonate
N,N-Di(methoxyethyl)ammonium hydrogen carbonate
N,N-Di(methoxyethyl)ammonium sulphate
N,N-Di(methoxyethyl)ammonium hydrogen sulphate
N,N-Di(methoxyethyl)ammonium phosphate
N,N-Di(methoxyethyl)ammonium hydrogen phosphate
N,N-Di(methoxyethyl)ammonium dihydrogen phosphate
N,N-Di(methoxyethyl)ammoniummethanesulphonate
N,N-Di(methoxyethyl)ammonium trifluoromethanesulphonate
N,N-Di(methoxyethyl)ammonium ethylenediaminetetraacetate
N,N-Di(methoxyethyl)ammonium hexafluorophosphate
N,N-Di(methoxyethyl)ammonium tetrafluoroborate
N,N-Di(methoxyethyl)ammonium trifluoroacetate
N,N-Di(methoxyethyl)ammonium pentafluoropropanoate
N,N-Di(methoxyethyl)ammonium heptafluorobutanoate
N,N-Di(methoxyethyl)ammonium phosphoenolpyruvate
N,N-Di(methoxyethyl)ammonium nicotinamide adenine dinucleotide phosphate
N,N-Di(methoxyethyl)ammonium adenosinephosphate
N,N-Di(methoxyethyl)ammonium adenosine diphosphate

N,N-Di(methoxyethyl)ammonium adenosine triphosphate
N,N-Di(methoxyethyl)ammonium oxyniacate
N,N-Di(methoxyethyl)ammonium nitrate
N,N-Di(methoxyethyl)ammonium nitrite.
However, generally speaking any of the anions referred to in this list may be used as the
counterion in an ionic liquid according to the invention.
In another embodiment of the invention, either or both of R2 and R3 may be substituted
with one or more hydroxyl groups, preferably one; it may for example be an alkanolyl
such as a C2 to C6, preferably a C2 to C5, alkanolyl, in particular ethanolyl, propanolyl or
butanolyl, more particularly ethanolyl or propanolyl. Such groups may be substituted
with two or more, such as two or three, hydroxyl groups; they may thus contain diol or
polyol moieties. Preferably such a group has a terminal hydroxyl group, such as in an
ethanolyl or 3-hydroxypropyl group. In this embodiment of the invention, R2 and R3
may again be the same or different, preferably the same.
Suitably R2 and R3 are not joined together with the N to form a heterocyclic group. If
they are, the heterocyclic group is preferably not a heteroaryl group; in particular the
cation (I) is preferably not a pyridinium, pyrrolidinium or imidazolium cation.
Preferably R2 and R3 are not both alkoxyalkyl. More preferably neither R2 nor R3 is
alkoxyalkyl. An alkoxyalkyl group typically means a group of the formula -R4-O-R5
where R4 and R5 are both unsubstituted alkyl groups.
The term "ionic liquid" herein includes, but is not limited to, a compound consisting of
ions and liquid at temperatures at which the compound is stable. An "ionic liquid" must
be a compound composed of ions, including a stable stoichiometric hydrate or other
solvate of such an ionic material. It need not necessarily be composed exclusively of
ions; it may for example exist as an equilibrium mixture of ions and molecules although
at least some of the liquid must be present in ionic form.
Ionic liquids typically have a freezing point below 100 °C. Suitably an ionic liquid
according to the invention will be capable of existing in liquid form at and below 50 °C,
preferably at and below 40 °C, more preferably at and below 30 °C and ideally at room

temperature, which for the present purposes may be defined as from 18 to 25 °C,
typically about 20 °C. Its boiling point may be at least 200 °C, in cases above 500 °C.
An ionic liquid according to the invention may thus consist substantially of ions, and is
preferably liquid at the above defined temperatures in the dry state. Such ionic liquids
will generally contain 5 % or less of water, by mass, preferably 1 % or less or 1000 ppm
or less and more preferably 100 ppm or less.
Preferably an ionic liquid according to the invention has a viscosity of less than 500
centipoise at 25 °C.
In the present context, "hydrocarbyl" may be defined as any group containing carbon
and hydrogen, which may also contain one or more heteroatoms such as oxygen,
nitrogen, sulphur, phosphorous or halogen. The term embraces saturated, partially
saturated and unsaturated groups, whether aromatic or aliphatic, whether straight chain,
branched chain, cyclic or any combination thereof. Hydrocarbyl thus includes, but is not
limited to, optionally substituted alkyl, alkenyl, alkynyl, cycloalkyl, cycloalkenyl,
cycloalkynyl, aryl, aralkyl, alkaryl, heterocyclyl, heteroaryl, alkoxy and moieties
containing a combination of two or more such groups.
In the present context, a hydrocarbyl group preferably does not contain heteroatoms. It
is preferably aliphatic.
As used herein, "alkyl" includes both straight and branched chain alkyl radicals, of any
chain length but typically of from 1 to 12 carbon atoms, more suitably from 1 to 10 or
from 1 to 8 carbon atoms, preferably from 1 to 6 carbon atoms. Suitable examples of
alkyl groups include methyl, ethyl, n-propyl, isopropyl, n-butyl, sec-butyl, isobutyl and
tert-butyl. The term "cycloalkyl" encompasses aliphatic saturated hydrocarbyl ring-
containing moieties such as for example cyclopropyl, cyclobutyl, cyclopentyl or
cyclohexyl.
The term "alkenyl" includes both straight and branched chain alkenyl radicals, which
contain one or more carbon-carbon double bonds. Again they may be of any chain
length, typically from 2 to 12 carbon atoms, more suitably from 2 to 10 or from 2 to 8

carbon atoms, yet more preferably from 2 to 6 carbon atoms. Examples include
ethylene, n-propyl-1-ene, n-propyl-2-ene and isopropylene.
"Cycloalkenyl" encompasses ring-containing groups where the ring structure
incorporates one or more carbon-carbon double bonds.
The term "alkynyl" includes both straight and branched chain alkynyl radicals, which
contain one or more carbon-carbon triple bonds. They may be of any chain length,
typically from 2 to 12 carbon atoms, more suitably from 2 to 10 or from 2 to 8 carbon
atoms, yet more preferably from 2 to 6 carbon atoms. "Cycloalkynyl" encompasses
ring-containing groups where the ring structure incorporates one or more carbon-carbon
triple bonds.
The term "aryl" includes aromatic (and thus at least partially unsaturated) hydrocarbyl
groups, which will typically incorporate one or more cyclic structures. Such groups may
contain for example from 3 to 12 carbon atoms, preferably from 3 to 10 or from 4 to 8
carbon atoms. They may be fused to one or more saturated or unsaturated rings. A
typical example is phenyl. It is to be noted that the term "hydrocarbyl" also embraces
radicals which combine both alkyl and aryl moieties, in particular aralkyl and alkaryl
groups such as for instance benzyl.
The term "heterocyclyl" includes a ring system containing one or more heteroatoms
selected for example from N, O and S. It may be saturated, unsaturated or partially
unsaturated. The ring containing the heteroatom may be fused to one or more other
rings, which in turn may be saturated, unsaturated or partially unsaturated and may
themselves contain heteroatom(s). Typically a heterocyclyl radical will be a 3 to 10-
membered ring system, preferably a 5 to 10-membered system, more preferably a 5- or
6-membered system. It may be or incorporate aromatic moieties.
Examples of cyclic groups such as cycloalkyl, aryl or heterocyclyl include but are not
limited to cyclohexyl, phenyl, acridine, benzimidazole, benzofuran, benzothiophene,
benzoxazole, benzothiazole, carbazole, cinnoline, dioxin, dioxane, dioxolane, dithiane,
dithiazine, dithiazole, dithiolane, furan, imidazole, imidazoline, imidazolidine, indole,
indoline, indolizine, indazole, isoindole, isoquinoline, isooxazole, isothiazole,
morpholine, napthyridine, oxazole, oxadiazole, oxathiazole, oxathiazolidine, oxazine,

oxadiazine, phenazine, phenothiazine, phenoxazine, phthalazine, piperazine, piperidine,
pteridine, purine, putrescine, pyran, pyrazine, pyrazole, pyrazoline, pyrazolidine,
pyridazine, pyridine, pyrimidine, pyrrolidine, pyrrole, pyrroline, quinoline, quinone,
quinoxaline, quinazoline, quinolizine, tetrahydrofuran, tetrazine, tetrazole, thiophene,
thiadiazine, thiadiazole, thiatriazole, thiazine, thiazole, thiomorpholine, thianaphthalene,
thiopyran, triazine, triazole, trithiane and tropine.
The tenn "alkoxy" includes both straight chain and branched alkyl radicals, for example
of 1 to 12 carbon atoms, preferably of 1 to 8 or 1 to 6 or 1 to 4 or 1 to 3 carbon atoms,
which contain one or more oxygen atoms, typically in the form of a hydrocarbyl group
linked to an oxygen atom via an ether linkage. Examples include methoxy and ethoxy
groups.
The term "halogen" means either F, Cl, Br or I, typically either F, Cl or Br, more
typically either F or Cl.
An ionic liquid according to the present invention preferably comprises an anion, for
example a counterion Xmwhere m is an integer such as in particular 1, 2 or 3,
preferably 1 or 2, most typically 1. This may be any suitable anion; the only theoretical
constraint upon the choice of anion is its ionic weight in order to keep the freezing point
of the ionic liquid below the desired temperature.
Examples of suitable anions include halogenated inorganic or organic anions, nitrates,
sulphates, phosphates, carbonates, sulphonates and carboxylates. The sulphonates and
carboxylates may be alkylsulphonates and alkylcarboxylates, in which the alkyl group is
a moiety, for example having 1 to 20 carbon atoms, selected from alkyl and alkyl
substituted at any position with alkenyl, alkoxy, alkeneoxy, aryl, arylalkyl, aryloxy,
amino, aminoalkyl, thio, thioalkyl, hydroxyl, hydroxyalkyl, carbonyl, oxoalkyl,
carboxyl, carboxyalkyl or halogen, including all salts, ethers, esters, pentavalent nitrogen
Or phosphorous derivatives or stereoisomers thereof.
For example, the anion may be selected from bis(trifluoromethylsulphonyl)imide,
carbonate, hydrogen carbonate, sulphate, hydrogen sulphate, sulphite, hydrogen sulphite,
silicate, phosphate, hydrogen phosphate, dihydrogen phosphate, hydrogen phosphite,
dihydrogen phosphite, metaphosphate, methanesulphonate, ethanesulphonate,

benzenesulphonate, trifluoromethanesulphonate, ethylenediaminetetraacetate, fluoride,
chloride, bromide, iodide, hexafluorophosphate, tetrafluoroborate, trifluoroacetate,
pentafluoropropanoate, heptafluorobutanoate, oxalate, formate, acetate, propanoate,
butanoate, pentanoate, hexanoate, heptanoate, octanoate, nonanoate, decanoate,
benzoate, benezenedicarboxylate, benzenetricarboxylate, benzenetetracarboxylate,
chlorobenzoate, fluorobenzoate, pentachlorobenzoate, pentafluorobenzoate salicylate,
glycolate lactate, pantothenate, tartrate, hydrogen tartrate, mandelate, acrylate,
methacrylate, crotonate, malate, pyruvate, oxaloacetate, succinate, citrate, fumarate,
phenylacetate, gluconate, glyoxylate, mercaptoacetate, oxamate, sulphamate,
methylphosphonate, ethylphosphonate, phenylphosphonate, phenylphosphinate,
thiocyanate, isothiocyanate, cyanate, isocyanate, thiosulphate, nitrate, nitrite,
thiophosphate or dicyanamide.
An ionic liquid according to the invention may contain cations which are all the same or
which are different. It may contain anions which are all the same or which are different.
Thus the invention encompasses ionic liquids including a mixture of different cations
and/or different anions.
In an ionic liquid according to the invention, the cation and anion should together be
chosen to ensure that the material is liquid at the requisite temperature. Freezing point
can be affected by factors such as the size of either or both of the ions, their degree of
delocalisation of charge and their degree of symmetry, as described above and in the
prior art literature relating to ionic liquids. The use of larger, and/or more charge-
delocalised ions can for instance help to reduce the ionic liquid's freezing point.
The invention encompasses an ionic liquid which is composed not of anions and cations
but of zwitterions which carry both a positive and a negative charge: in this situation, a
single ion will incorporate both the moieties N+HR1R2R3 and, for instance by
appropriate side-chain substitution, an anionic moiety such as Xm-.
In addition to demonstrating high solvation capability, the ionic liquids of the present
invention can have low viscosity, can be of relatively low toxicity and can be colourless.
These features can make the ionic liquids of the invention useful in a variety of
applications. In addition, ionic liquids of this composition can exhibit particular

advantages over the corresponding hydroxyalkyl species, being effective hydrogen bon<
acceptors but poor donors and functioning as significantly less polar, less protic solvent;
In an ionic liquid according to the invention, the cation (I) is preferably an alkoxypropyi
ammonium cation, a methyl alkoxyethyl ammonium cation, a methyl alkoxypropyi
ammonium cation, a dimethyl alkoxyethyl ammonium cation, a dimethyl alkoxypropyi
ammonium cation, an ethyl alkoxyethyl ammonium cation, an ethyl alkoxypropyi
ammonium cation, a diethyl alkoxyethyl ammonium cation, a diethyl alkoxypropyi
ammonium cation, a methyl ethyl alkoxyethyl ammonium cation, a methyl ethyl
alkoxypropyi ammonium cation, a propyl alkoxyethyl ammonium cation, a propyl
alkoxypropyi ammonium cation, a dipropyl alkoxyethyl ammonium cation, a dipropyl
alkoxypropyi ammonium cation, a methyl propyl alkoxyethyl ammonium cation, a
methyl propyl alkoxypropyi ammonium cation, an ethyl propyl alkoxyethyl ammoniun
cation or an ethyl propyl alkoxypropyi ammonium cation.
Of these, alkoxyethyl ammonium, alkoxypropyi ammonium, methyl alkoxyethyl
ammonium, methyl alkoxypropyi ammonium, dimethyl alkoxyethyl ammonium and
ethyl methyl alkoxyethyl ammonium ions may be preferred.
In all of these cations, the alkoxy group is preferably either methoxy or ethoxy.
According to a second aspect of the present invention there is provided an ionic liquid
comprising a cation of the formula (II):
N+HR6R7R8 (II)
wherein R6 is an alkanolyl group;
R7 is a hydrocarbyl group; and
R8 is either hydrogen or hydrocarbyl,
or R7 and R8 may be joined together with the N to form a heterocyclic group.
Again, such ionic liquids have been found to be useable as solvents for hydrophilic
materials, in particular for enzymes and their reactions, as they can provide a protic,
hydrogen bonding fluid environment.

R6 may contain more than one -OH group; in other words, it may comprise a diol or
polyol. It may be straight or branched chain. It preferably contains from 1 to 12 carbon
atoms, more preferably from 1 to 10, yet more preferably from 1 to 8, most preferably
from 1 to 6 or from 1 to 4 or from 1 to 3. Suitably R6 may be methanolyl, ethanolyl or
propanolyl, preferably ethanolyl or propanolyl (in particular 3-hydroxylpropyl). Most
suitably an alkanoyl group may be propanolyl such as 3-hydroxypropyl, 2-
hydroxypropyl or propan-2,3-diolyl, in particular 3-hydroxypropyl. Preferably it
contains a terminal -OH group.
R6 may be substituted with other groups such as those listed above as preferred
hydrocarbyl substituents. Preferably R6 is unsubstituted other than by one or more -OH
groups. In some cases, however, it may be preferred for R6 to contain an ether linkage -
for example, R6 may be a (hydroxyalkoxy)alkyl group of formula -(CH2)n-O-(CH2)m-
OH where n and m are independently selected integers suitably from 1 to 4, more
suitably from 2 to 4, most suitably either 2 or 3, such as 2.
R7 is preferably an alkyl or cycloalkyl group, suitably as defined above for R2. It is
preferably a C1 to C4 alkyl group, in particular a C1 to C3 alkyl group, such as methyl or
ethyl.
R7 may be an alkanolyl group, in particular as defined above for R6. In particular R6 and
R7 may both be alkanolyl; R6 and R7 may then be different alkanolyl groups or, more
preferably, the same. In one embodiment of the invention, R6 and R7 are both alkanolyl
(preferably the same) and R8 is alkyl or cycloalkyl, suitably as defined above for R2. In
another embodiment, R6 and R7 are both alkanolyl (preferably the same) and R8 is
hydrogen.
Generally, R8 is preferably hydrogen. Thus, the cation (II) may for instance be an
alkanolammonium ion, a dialkanolammonium ion or an alkyl alkanolammonium ion. Of
these, the alkyl alkanolammonium ions (excepting in some cases the methyl
ethanolammonium ions) may be preferred, in which case R7 may be for example a C1 to
C4 or C1 to C3 alkyl group and R6 may be for example a C2 to C4 or C2 to C3 alkanolyl
group such as ethanolyl.

However, in cases it may be preferred for R8 to be alkyl or cycloalkyl, suitably as
defined above for R2. In particular, R7 and R8 may both be alkyl or cycloalkyl, suitably
as defined above in connection with R2, In this case R7 and R8 are preferably both alkyl,
more preferably C1 to C3 alkyl, yet more preferably methyl or ethyl; they may be the
same or different, preferably the same. As described in connection with the first aspect
of the invention, the presence of two alkyl groups can help to lower the viscosity of the
ionic liquid.
Thus, the cation (II) may for instance be a dialkyl alkanolammonium ion (excepting in
some cases the dimethyl ethanolammonium ions), preferably a dimethyl, diethyl or
dipropyl alkanolammonium ion, a methyl ethyl alkanolammonium ion, a methyl propyl
alkanolammonium ion or an ethyl propyl alkanolammonium ion. It may be a dialkyl
ethanolammonium ion or a dialkyl propanolammonium ion, of which the dialkyl
ethanolammonium ions may be preferred. In the case of the dialkyl ethanolammonium
ions, preferably at least one of R7 and R8, and preferably both, are selected from methyl
and ethyl; more preferably both are ethyl. In the case of the dialkyl propanolammonium
ions, preferably at least one of R7 and R8, and preferably both, are selected from methyl
and ethyl; more preferably both are methyl.
Alternatively R8 may be an alkanolyl group, suitably as defined above for R6. Thus R6,
R7 and R8 may each independently be alkanolyl; they may be different or preferably at
least two of the groups, more preferably all three, are the same.
Either or both of R7 and R8 may be independently selected from groups of the formula -
R4-O-R5, for instance as defined above in connection with the first aspect of the
invention. Such groups have the advantage, as described above, of providing hydrogen
bonding capability but without the more reactive hydroxyl group. Suitably, R7 is a
group of formula -R4-O-R5 and R8 is an alkyl group, suitably as defined above for R2.
Thus, the cation (II) may be an alkyl(alkoxyalkyl) alkanolyl group, in which R6 is
preferably C2 to C4 alkanolyl such as ethanolyl or propanolyl, in particularl ethanolyl; R7
is preferably methoxy ethyl or ethoxy ethyl, more preferably the former; and R8 is
preferably C1 to C4 alkyl or C1 to C3 alkyl, for instance methyl or ethyl, suitably methyl.

Where R7 is methyl, and particularly when R8 is hydrogen, R6 is preferably not
ethanolyl. In other words, the cation (II) is preferably not a methyl ethanolammonium
cation.
It may be preferred for the cation (II) not to be an ethyl ethanolammonium ion.
Where R7 is an alkanolyl group, and particularly when R8 is hydrogen, preferably R6 and
R7 are not both ethanolyl. In other words, the cation (II) is preferably not a
diethanolammonium cation. This may also be the case when R8 is alkyl, for instance
butyl.
Where R7 and R8 are both methyl, R6 is preferably not ethanolyl. In other words, the
cation (II) is preferably not a dimethyl ethanolammonium cation.
In cases it may be preferred for the cation (II) not to be a diethyl ethanolammonium ion.
It may be preferred for the cation not to be a dialkyl ethanolammonium cation.
Where R6 and R7 are both ethanolyl, R8 is preferably not alkyl. In other words, the
cation (II) is preferably not an alkyl diethanolammonium cation. In particular it is
preferably not a butyl diethanolammonium cation.
It may be preferred for neither of R7 and R8 to be putrescinium, in particular where the
other is hydrogen. More particularly, where R7 is putrescinium, R6 is preferably not 3-
hydroxypropyl, especially if R8 is hydrogen. In other words, the cation (II) is preferably
not a 3-hydroxypropyl putrescinium cation.
Preferably R6, R7 and R8 are not all ethanolyl. In other words, the cation (II) is
preferably not a triethanolammonium cation.
Preferably the cation (II) is not an N-(3-hydroxypropyl)-N-methylcyclohexylammonium
cation.
Suitably R7 and R8 are not joined together with the N to form a heterocyclic group. If
they are, the heterocyclic group is preferably not a heteroaryl group; in particular the
cation (II) is preferably not a pyridinium, pyrrolidinium or imidazolium cation.

Other preferred features of this second aspect of the invention may be as defined above
in connection with the first aspect. In particular, the cation (II) is preferably a secondary
ammonium ion.
Particularly preferred ionic liquids according to the second aspect of the invention
comprise a cation selected from alkyl alkanolammonium ions (preferably excluding
methyl ethanolammonium ions) and dialkyl alkanolammonium ions (preferably
excluding dimethyl ethanolammonium ions, and in cases excluding diethyl
ethanolammonium ions). Also preferred may be N,N-dialkyl-N-[(hydroxyalkoxy)alkyl]
ammonium ions, as described in connection with the first aspect of the invention.
It may be preferred for the ionic liquid of the present invention not to be any of the
following compounds:
Diethanolammonium bromide
Diethanolammonium iodide
Diethanolammonium formate
Diethanolammonium acetate
Diethanolammonium propanoate
Diethanolammonium propanedioate
Diethanolammonium butanoate
Diethanolammonium butenoate
Diethanolammonium butanedioate
Diethanolammonium pentanoate
Diethanolammonium pentanedioate
Diethanolammonium pentenoate
Diethanolammonium hexanoate
Diethanolammonium hexanedioate
Diethanolammonium hexenoate
Diethanolammonium heptanoate
Diethanolammonium heptanedioate
Diethanolammonium heptenoate
Diethanolammonium octanoate
Diethanolammonium octanedioate

Diethanolammonium octenoate
Diethanolammonium nonanoate
Diethanolammonium nonanedioate
Diethanolammonium nonenoate
Diethanolammonium decanoate
Diethanolammonium decanedioate
Diethanolammonium decenoate
Diethanolammonium undecanoate
Diethanolammonium undecanedioate
Diethanolammonium undecenoate
Diethanolammonium dodecanoate
Diethanolammonium dodecanedicarboxylate
Diethanolammonium dodecenecarboxylate
Diethanolammonium cyclohexanecarboxylate
Diethanolammonium cyclohexenecarboxylate
Diethanolammonium phenoxide
Diethanolammonium benzoate
Diethanolammonium benezenedicarboxylate
Diethanolammonium benzenetricarboxylate
Diethanolammonium benzenetetracarboxylate
Diethanolammonium chlorobenzoate
Diethanolammonium fluorobenzoate
Diethanolammonium pentachlorobenzoate
Diethanolammonium pentafluorobenzoate
Diethanolammonium salicylate
Diethanolammonium glycolate
Diethanolammonium lactate
Diethanolammonium pantothenate
Diethanolammonium tartrate
Diethanolammonium hydrogen tartrate
Diethanolammonium mandelate
Diethanolammonium crotonate

Diethanolammonium malate
Diethanolammonium pyruvate
Diethanolammonium succinate
Diethanolammonium citrate
Diethanolammonium fumarate
Diethanolammonium phenylacetate
Diethanolammonium oxalate
Diethanolammoniumbis(trifluoromethylsulphonyl)imide
Diethanolammonium carbonate
Diethanolammonium hydrogen carbonate
Diethanolammonium phosphate
Diethanolammonium hydrogen phosphate
Diethanolammonium dihydrogen phosphate
Diethanolammonium methanesulphonate
Diethanolammonium trifluoromethanesulphonate
Diethanolammonium ethylenediaminetetraacetate
Diethanolammonium hexafluorophosphate
Diethanolammonium tetrafluoroborate
Diethanolammonium trifluoroacetate
Diethanolammonium pentafluoropropanoate
Diethanolammonium heptafluorobutanoate
Diethanolammonium phosphoenolpyruvate
Diethanolammonium nicotinamide adenine dinucleotide phosphate
Diethanolammonium adenosinephosphate
Diethanolammonium adenosine diphosphate
Diethanolammonium adenosine triphosphate
Diethanolammonium oxyniacate
Diethanolammonium nitrate
Diethanolammonium nitrite
N-Butyldiethanolammonium chloride
N-Butyldiethanolammonium bromide
N-Butyldiethanolammonium iodide

N-Butyldiethanolanunonium formate
N-Butyldiethanolammonium acetate
N-Butyldiethanolammonium propanoate
N-Butyldiethanolammonium propanedioate
N-Butyldiethanolammonium butanoate
N-Butyldiethanolammonium butenoate
N-Butyldiethanolammonium butanedioate
N-Butyldiethanolammonium pentanoate
N-Butyldiethanolammonium pentanedioate
N-Butyldiethanolammonium pentenoate
N-Butyldiethanolammonium hexanoate
N-Butyldiethanolammonium hexenoate
N-Butyldiethanolammonium heptanoate
N-Butyldiethanolammonium heptanedioate
N-Butyldiethanolammonium heptenoate
N-Butyldiethanolammonium octanoate
N-Butyldiethanolammom'um octanedioate
N-Butyldiethanolammomum octenoate
N-Butyldiethanolammomum nonanoate
N-Butyldiethanolammonium nonanedioate
N-Butyldiethanolammonium nonenoate
N-Butyldiethanolammonium decanoate
N-Butyldiethanolammonium decanedioate
N-Butyldiethanolammonium decenoate
N-Butyldiethanolammonium undecanoate
N-Butyldiethanolammonium undecanedioate
N-Butyldiethanolammonium undecenoate
N-Butyldiethanolammonium dodecanoate
N-Butyldiethanolammonium dodecanedicarboxylate
N-Butyldiethanolammonium dodecenecarboxylate
N-Butyldiethanolammomum cyclohexanecarboxylate
N-Butyldiethanolammonium cyclohexenecarboxylate

N-Butyldiethanolammonium phenoxide
N-Butyldiethanolammonium benzoate
N-Butyldiethanolammonium benezenedicarboxylate
N-Butyldiethanolammonium benzenetricarboxylate
N-Butyldiethanolammonium benzenetetracarboxylate
N-Butyldiethanolammonium chlorobenzoate
N-Butyldiethanolammonium fluorobenzoate
N-Butyldiethanolammonium pentachlorobenzoate
N-Butyldiethanolammonium pentafluorobenzoate
N-Butyldiethanolammonium salicylate
N-Butyldiethanolammonium glycolate
N-Butyldiethanolammonium lactate
N-Butyldiethanolammonium pantothenate
N-Butyldiethanolammonium tartrate
N-Butyldiethanolammonium hydrogen tartrate
N-Butyldiethanolammonium mandelate
N-Butyldiethanolammonium crotonate
N-Butyldiethanolammom'um malate
N-Butyldiethanolammonium pyruvate
N-Butyldiethanolammonium succinate
N-Butyldiethanolammonium citrate
N-Butyldiethanolammonium fumarate
N-Butyldiethanolammonium phenylacetate
N-Butyldiethanolammonium oxalate
N-Butyldiethanolammonium bis(trifluoromethylsulphonyl)imide
N-Butyldiethanolammonium carbonate
N-Butyldiethanolammonium hydrogen carbonate
N-Butyldiethanolammonium sulphate
N-Butyldiethanolammonium hydrogen sulphate
N-Butyldiethanolammonium phosphate
N-Butyldiethanolammonium hydrogen phosphate
N-Butyldiethanolammonium dihydrogen phosphate

N-Butyldiethanolammoniummethanesulphonate
N-Butyldiethanolammoniumtrifluoromethanesulphonate
N-Butyldiethanolammoniumethylenediaminetetraacetate
N-Butyldiethanolammoniumhexafluorophosphate
N-Butyldiethanolammonium tetrafluoroborate
N-Butyldiethanolammonium trifluoroacetate
N-Butyldiethanolammoniumpentafluoropropanoate
N-Butyldiethanolammonium heptafluorobutanoate
N-Butyldiethanolammonium phosphoenolpyruvate
N-Butyldiethanolammonium nicotinamide adenine dinucleotide phosphate
N-Butyldiethanolammonium adenosinephosphate
N-Butyldiethanolammonium adenosine diphosphate
N-Butyldiethanolammonium adenosine triphosphate
N-Butyldiethanolammonium oxyniacate
N-Butyldiethanolammonium nitrate
N-Butyldiethanolammonium nitrite
N,N-Dimethylethanolammonium bromide
N,N-Dimethylethanolammonium iodide
N,N-Dimethylethanolammonium formate
N,N-Dimethylethanolammonium acetate
N,N-Dimethylethanolammonium propanoate
N,N-Dimethylethanolammonium propanedioate
N,N-Dimethylethanolammonium butanoate
N,N-Dimethylethanolammonium butenoate
N,N-Dimethylethanolammonium butanedioate
N,N-Dimethylethanolammonium pentanoate
N,N-Dimethylethanolammonium pentanedioate
N,N-Dimethylethanolammonium pentenoate
N,N-Dimethylethanolammonium hexanoate
N,N-Dimethylethanolammonium hexenoate
N,N-Dimethylethanolammonium heptanoate
N,N-Dimethylethanolammonium heptanedioate

N,N-Dimethylethanolammonium heptenoate
N,N-Dimethylethanolammonium octanoate
N,N-Dimethylethanolammonium octanedioate
N,N-Dimethylethanolammonium octenoate
N,N-Dimethylethanolammonium nonanoate
N,N-Dimethylethanolammonium nonanedioate
N,N-Dimethylethanolammonium nonenoate
N,N-Dimethylethanolammonium decanoate
N,N-Dimethylethanolammonium decanedioate
N,N-Dimethylethanolammonium decenoate
N,N-Dimethylethanolammonium undecanoate
N,N-Dimethylethanolammonium undecanedioate
N,N-Dimethylethanolammonium undecenoate
N,N-Dimethylethanolammonium dodecanoate
N,N-Dimethylethanolaminoniumdodecanedicarboxylate
N,N-Dimethylethanolammoniumdodecenecarboxylate
NjN-Dimethylethanolammoniximcyclohexanecarboxylate
NjN-Dimethylethanolammoniumcyclohexenecarboxylate
N5N-Dimethylethanolammonium phenoxide
N5N-Dimethylethanolammonium benzoate
N,N-Dimethylethanolammonium benezenedicarboxylate
N,N-Dimethylethanolammonium benzenetricarboxylate
NSN-Dimetb.ylethanolammonium benzenetetracarboxylate
N,N-Dimethylethanolanunonium chlorobenzoate
N,N-Dimethylethanolammonium fluorobenzoate
N,N-Dimethylethanolammonium pentachlorobenzoate
N,N-Dimethylethanolanunonium pentafluorobenzoate
N,N-Dimethylethanolammonium salicylate
N,N-Dimethylethanolammonium glycolate
N,N-Dimethylethanolammonium lactate
N5N-Dimethylethanolammonium pantothenate
N,N-Dimethylethanolammonium tartrate

N,N-Dimethylethanolammonium hydrogen tartrate
N,N-Dimethylethanolammonium mandelate
N,N-Dimethylethanolammonium crotonate
N,N-Dimethylethanolammonium malate
N,N-Dimethylethanolammonium pyruvate
N,N-Dimethylethanolammonium succinate
N,N-Dimethylethanolammonium citrate
N,N-Dimethylethanolammonium fumarate
N,N-Dimethylethanolammonium phenylacetate
N,N-Dimethylethanolammonium oxalate
N,N-Dimethylethanolammonium bis(trifluoromethylsulphonyl)imide
N,N-Dimethylethanolammonium carbonate
N,N-Dimethylethanolammonium hydrogen carbonate
N,N-Dimethylethanolarnmonium sulphate
N,N-Dimethylethanolammonium hydrogen sulphate
N,N-Dimethylethanolammonium phosphate
N,N-Dimethyiethanolammonium hydrogen phosphate
N,N-Dimethylethanolammonium dihydrogen phosphate
N,N-Dimethylethanolammoniummethanesulphonate
N,N-Dhnethylethanolammoniumtrifluoromethanesulphonate
N,N-Dimethylethanolarnmoniumethylenediaminetetraacetate
N,N-Dimethylethanolammonium hexafluorophosphate
N,N-Dimethylethanolammonium tetrafluoroborate
N,N-Dimethylethanolammonium trifluoroacetate
N,N-Dimethylethanolammonium pentafluoropropanoate
N,N-Dimethylethanolammonium heptafluorobutanoate
N,N-Dimethylethanolammonium phosphoenolpyruvate
N,N-Dimethylethanolammonium nicotinamide adenine dinucleotide phosphate
N5N-Dimethylethanolammonium adenoshinephosphate
N5N-Dimethylethanolammonium adenosine diphosphate
N,N-Dimethylethanolammonium adenosine triphosphate
N,N-Dimethylethanolammonium oxyniacate

N,N-Dimethylethanolammonium nitrate
N,N-Dimethylethanolammonium nitrite
N-Methylethanolammonium bromide
N-Methylethanolammonium iodide
N-Methylethanolammonium formate
N-Methylethanolammonium acetate
N-Methylethanolammonium propanoate
N-Methyiethanolammonium propanedioate
N-Methylethanolammonium butanoate
N-Methylethanolammonium butenoate
N-Methylethanolammonium butanedioate
N-Methylethanolammonium pentanoate
N-Methylethanolammonium pentanedioate
N-Methylethanolammonium pentenoate
N-Methylethanolammonium hexanoate
N-Methylethanolammonium hexenoate
N-Methylethanolammonium heptanoate
N-Methylethanolammonium heptanedioate
N-Methylethanolammonium heptenoate
N-Methylethanolammonium octanoate
N-Methylethanolammonium octanedioate
N-Methylethanolammonium octenoate
N-Methylethanolammonium nonanoate
N-Methylethanolammonium nonanedioate
N-Methylethanolammonium nonenoate
N-Methylethanolammonium decanoate
N-Methylethanolammonium decanedioate
N-Methylethanolammonium decenoate
N-Methylethanolammonium undecanoate
N-Methylethanolammonium undecanedioate
N-Methylethanolammonium undecenoate
N-Methylethanolammonium dodecanoate

N-Methylethanolammoniumdodecanedicarboxylate
N-Methylethanolanunoniumdodecenecarboxylate
N-Methylethanolammoniumcyclohexanecarboxylate
N-Methylethanolammoniumcyclohexenecarboxylate
N-Methylethanolammonivun phenoxide
N-Memylethanolammonium benzoate
N-Methylethanolammonixunbenezenedicarboxylate
N-Methylethanolammonium benzenetricarboxylate
N-Methylethanolammonium benzenetetracarboxylate
N-Methylethanolammonium chlorobenzoate
N-Methylethanolammonium fluorobenzoate
N-Methylethanolammonium pentachlorobenzoate
N-Methylethanolammonium pentafluorobenzoate
N-Methylethanolammonium salicylate
N-Methylethanolammonium glycolate
N-Methylethanolammonium lactate
N-Methylethanolammonium pantothenate
N-Methylethanolammonium tartrate
N-Methylethanolammonium hydrogen tartrate
N-Methylethanolammonium mandelate
N-Methylemanolammonium crotonate
N-Methylethanolammonium malate
N-Methylethanolammonium pyruvate
N-Methylethanolammonium succinate
N-Methylethanolammonium citrate
N-Methylethanolammonium fumarate
N-Methylethanolammonium phenylacetate
N-Methylethanolammonium oxalate
N-Methylemanolammoniumbis(trifluorornethylsulphonyl)imide
N-Methylethanolammonium carbonate
N-Methylethanolammonium hydrogen carbonate
N-Methylethanolammonium sulphate

N-Methylethanolammonium hydrogen sulphate
N-Methylethanolammonium phosphate
N-Methylethanolanunonium hydrogen phosphate
N-Methylethanolammonium dihydrogen phosphate
N-Methylethanolammonium methanesulphonate
N-Methylethanolammonium trifluoromethanesulphonate
N-Methylethanolammonium ethylenediaminetetraacetate
N-Methylethanolammonium hexafluorophosphate
N-Methylethanolammonium tetrafluoroborate
N-Methylethanolammonium trifluoroacetate
N-Methylethanolammonium pentafluoropropanoate
N-Methylethanolammonium heptafluorobutanoate
N-Methylethanolammonium phosphoenolpyruvate
N-Methylethanolammonium nicotinamide adenine dinucleotide phosphate
N-Methylethanolammonium adenosinephosphate
N-Methylethanolammonium adenosine diphosphate
N-Methylethanolammonium adenosine triphosphate
N-Methylethanolammonium oxyniacate
N-Methylethanolammonium nitrate
N-Methylethanolammonium nitrite
1-(3-Hydroxypropyl)putrescinium chloride
1-(3-Hydroxypropyl)putrescinium bromide
1-(3-Hydroxypropyl)putrescinium iodide
1-(3-Hydroxypropyl)putrescinium formate
1-(3-Hydroxypropyl)putrescinium acetate
1-(3-Hydroxypropyl)putresciniumpropanoate
1-(3-Hydroxypropyl)putrescinium propanedioate
1-(3-Hydroxypropyl)putrescinium butanoate
1-(3-Hydroxypropyl)putrescinium butenoate
1-(3 -Hydroxypropyl)putrescinium butanedioate
1-(3 -Hydroxypropyl)putrescinium pentanoate
1-(3-Hydroxypropyl)putrescinium pentanedioate

1-(3-Hydroxypropyl)putresciniumpentenoate
1-(3-Hydroxypropyl)putrescinium hexanoate
1-(3-Hydroxypropyl)putrescinium hexenoate
1-(3-Hydroxypropyl)putrescinium heptanoate
1-(3-Hydroxypropyl)putrescinium heptanedioate
1-(3-Hydroxypropyl)putrescinium heptenoate
1-(3-Hydroxypropyl)putrescinium octanoate
1-(3-Hydroxypropyl)putrescinium octanedioate
1-(3-Hydroxypropyl)putrescinium octenoate
1-(3-Hydroxypropyl)putrescinium nonanoate
1-(3-Hydroxypropyl)putresciniumnonanedioate
1-(3-Hydroxypropyl)putrescinium nonenoate
1-(3-Hydroxypropyl)putrescinium decanoate
1-(3-Hydroxypropyl)putrescinium decanedioate
1-(3 -Hydroxypropyl)putrescinium decenoate
1-(3-Hydroxypropyl)putresciniumundecanoate
1-(3-Hydroxypropyl)putrescinium undecanedioate
1-(3-Hydroxypropyl)putrescinium undecenoate
1-(3-Hydroxypropyl)putrescinium dodecanoate
1-(3-Hydroxypropyl)putrescinium dodecanedicarboxylate
1-(3 -Hydroxypropyl)putrescinium dodecenecarboxylate
1-(3 -Hydroxypropyl)putrescinium cyclohexanecarboxylate
1-(3 -Hydroxypropyl)putrescinium cyclohexenecarboxylate
1-(3 -Hydroxypropyl)putrescinium phenoxide
1-(3-Hydroxypropyl)putrescinium benzoate
1-(3-Hydroxypropyl)putrescinium benezenedicarboxylate
1-(3-Hydroxypropyl)putrescinium benzenetricarboxylate
1-(3-Hydroxypropyl)putrescinium benzenetetracarboxylate
1-(3 -Hydroxypropyl)putrescinium chlorobenzoate
1-(3-Hydroxypropyl)putrescinium fluorobenzoate
1-(3-Hydroxypropyl)putrescinium pentachlorobenzoate
1-(3-Hydroxypropyl)putresciniumpentafluorobenzoate

1-(3-Hydroxypropyl)putrescinium salicylate
1-(3 -Hydroxypropyl)putrescininm glycolate
1-(3-Hydroxypropyl)putrescinium lactate
1-(3-Hydroxypropyl)putrescinimn pantothenate
1-(3-Hydroxypropyl)putrescinium tartrate
1-(3-Hydroxypropyl)putrescinium hydrogen tartrate
1-(3-Hydroxypropyl)putrescinivimmandelate
1-(3 -Hydroxypropyl)putrescinium crotonate
1-(3-Hydroxypropyl)putrescinium malate
1-(3-Hydroxypropyl)putrescinium pyruvate
1-(3-Hydroxypropyl)putrescinium succinate
1-(3-Hydroxypropyl)putrescininm citrate
1-(3-Hydroxypropyl)putrescinium fumarate
1-(3 -Hydroxypropyl)putrescinium phenylacetate
1-(3-Hydroxypropyl)putrescinium oxalate
1-(3-Hydroxypropyl)putrescinivun bis(trifluoromethylsulphonyl)imide
1-(3-Hydroxypropyl)putrescinium methanesulphonate
1-(3-Hydroxypropyl)putrescinium trifluoromethanesulphonate
1-(3-Hydroxypropyl)putrescinium hexafluorophosphate
1-(3-Hydroxypropyl)putresciniumtetrafluoroborate
1-(3-Hydroxypropyl)putrescinium trifluoroacetate
1-(3-Hydroxypropyl)putrescinium pentafluoropropanoate
1-(3-Hydroxypropyl)putrescinium heptafluorobutanoate
1-(3-Hydroxypropyl)putresciniumphosphoenolpyruvate
1-(3-Hydroxypropyl)putrescinium nicotinamide adenine dinucleotide phosphate
1-(3-Hydroxypropyl)putrescinium adenosinephosphate
1-(3-Hydroxypropyl)putrescinium adenosine diphosphate
1-(3-Hydroxypropyl)putrescinium adenosine triphosphate
1-(3-Hydroxypropyl)putrescinium carbonate
1-(3-Hydroxypropyl)putrescinium hydrogen carbonate
1-(3-Hydroxypropyl)putrescinium sulphate
1-(3-Hydroxypropyl)putrescinium hydrogen sulphate

1-(3-Hydroxypropyl)putrescinium phosphate
1-(3-Hydroxypropyl)putrescinium hydrogen phosphate
1-(3-Hydroxypropyl)putrescinium dihydrogen phosphate
1-(3-Hydroxypropyl)putrescirdiun nitrate
1-(3-Hydroxypropyl)putrescinium nitrite.
Again, however, generally speaking any of the anions referred to in this list may be used
as the counterion in an ionic liquid according to the invention.
According to a further aspect, the present invention provides a process for the
preparation of an ionic liquid according to the invention, the process comprising the
steps of:
a) providing a nitrogen-containing compound of the formula (III):
NR1R2R3 (III)
or a nitrogen-containing compound of the formula (IV):
NR6R7R8 (IV)
in which R1 to R8 are as defined above; and
b) neutralising the compound (HI) or (IV) with an acid, preferably an acid of the
formula HmX where X and m are as defined above.
The process of the present invention can provide an economical route to the manufacture
of ionic liquids since the process often involves only a single step and can use starting
materials that are generally readily available.
During the process of the invention, the nitrogen atom of the amine (IE) or (TV) is
protonated to provide a protonated ammonium ion.
Preferably, the acid includes an anion as defined herein.

Preferably the acid anion comprises a halide, halogenated inorganic anion, nitrate,
sulphate, carbonate, sulphonate, carboxylate or halogenated organic anion (eg,
halogenated carboxylate).
The invention also encompasses compounds of formula (III) or (IV) and their use in the
preparation of one or more ionic liquids.
The invention further provides the use of a cation (I) or (II) as defined above in a solvent
for an enzyme-catalysed reaction. Further provided is the use of an ionic liquid
according to the present invention as a solvent for an enzyme-catalysed reaction.
The use of ionic liquids in certain biological and/or chemical reactions can have several
advantages over traditional aqueous solutions. Ionic liquids have an ability to dissolve a
wide range of inorganic, organic, polymeric and biological materials, often to a very
high concentration. They have a wide liquid range, allowing both high and low
temperature processes to be carried out in the same solvent. They do not elicit solvolysis
phenomena and most stabilise short-lived reactive intermediates. There are no pH
effects in the solvents and there is practically zero vapour pressure over much of the
liquid range. Ionic liquids also exhibit excellent electrical and thermal conductivity
whilst being non-flammable, recyclable and generally of low toxicity.
The invention further provides the use of an ionic liquid according to the present
invention in or as a solvent for organic synthesis, a matrix in matrix-assisted laser
desorption/ionisation (MALDI) mass spectrometry, a solvent for a solvent extraction
process (eg, to remove desired components from an immiscible liquid or solid), a vehicle
in chromatography (eg, gas chromatography), a lubricant, a hydraulic fluid or a biocide.
Also provided is the use of an ionic liquid according to the invention (for instance as a
solvent) in catalysis, liquefaction, nuclear fuel reprocessing, fuel cells, electrochemical
applications, optical (including optoelectronic) systems, pervaporation, drug delivery,
adhesives or sensors.
Preferably an ionic liquid according to the invention is used as a reaction medium -
preferably a solvent - for a chemical or biochemical reaction, in particular a catalysed
reaction, such as an enzyme-catalysed reaction. It may be particularly suited as a solvent

for materials which would otherwise require an aqueous, or at least polar and/or
hydrogen bonding, solvent environment.
The invention thus further provides a method for carrying out an enzyme-catalysed
reaction comprising:
a) providing a liquid reaction medium which comprises an ionic liquid according to
the present invention;
b) providing in the liquid reaction medium an enzyme and a substrate for the
enzyme; and
c) allowing reaction of the substrate to occur.
Further provided is a method for the synthesis of one or more organic compounds, the
method comprising carrying out an organic synthesis reaction in an ionic liquid
according to the present invention.
Throughout the description and claims of this specification, the words "comprise" and
"contain" and variations of the words, for example "comprising" and "comprises", mean
"including but not limited to", and are not intended to (and do not) exclude other
moieties, additives, components, integers or steps.
Throughout the description and claims of this specification, the singular encompasses
the plural unless the context otherwise requires. In particular, where the indefinite
article is used, the specification is to be understood as contemplating plurality as well as
singularity, unless the context requires otherwise.
Features, integers, characteristics, compounds, chemical moieties or groups described in
conjunction with a particular aspect, embodiment or example of the invention are to be
understood to be applicable to any other aspect, embodiment or example described
herein unless incompatible therewith.
Preferred features of each aspect of the invention may be as described in connection with
any of the other aspects.

Other features of the present invention will become apparent from the following
examples. Generally speaking the invention extends to any novel one, or any novel
combination, of the features disclosed in this specification (including any accompanying
claims and drawings). Moreover unless stated otherwise, any feature disclosed herein
may be replaced by an alternative feature serving the same or a similar purpose.
The present invention will now be further described with reference to the following non-
limiting examples.
Example 1 - Preparation of N-(methoxvpropyl)ammonium elvcolate
Glycolic acid (76.05 g) and 3-methoxypropylamine (89.14 g, 1 equiv.) were
independently dissolved in 200 mL volumes of absolute ethanol. The acid solution was
added dropwise to the amine over a period of 1 hour, with magnetic stirring and external
cooling being continued throughout. At the conclusion of the reaction the solvent was
removed in vacuo and the product was dried by lyophilization to yield a yellow liquid,
N-(methoxypropyl)ammonium glycolate.
Example 2 - Preparation of further ionic liquids
Using an analogous method to that of Example 1, further ionic liquids in accordance
with the invention were prepared and their viscosities, densities and/or refractive indices
measured. Where the starting materials were both liquids, no solvent was used for the
synthesis.
Viscosities were measured using an AND™ SV10 vibrational viscometer. Refractive
indices were obtained using a Mettler Toledo Refracto™ 30 portable refractometer.
Densities were measured simply by determining the mass of a measured volume of the
liquid.
All products were dried prior to characterisation, to a water content of between about 0.2
and 1 % w/w.

All products were liquid at room temperature, apart from 2-methoxyethylammonium
acetate and N-butylethanolammonium propionate which were solid at room temperature
but meltable at 51 °C and 25 °C respectively.
The starting materials used are shown in Table 1 below, and the properties in Table 2.



Most of the starting materials were readily available as off-the-shelf products. N,N-
dimethyl-2-methoxyethylamine and N-methyl-bis(2-methoxyethyl)amine were sourced
from CSS Chemicals, Belfast, Northern Ireland.

38

Ionic liquids according to the present invention, such as those described in Examples 1
and 2, may be used as reaction media for enzyme-catalysed reactions. For example, an
ionic liquid such as an alkyl alkoxyalkyl ammonium salt, a dialkyl alkoxyalkyl
ammonium salt or an alkyl di(alkoxyalkyl) ammonium salt may be used as a solvent for
a reaction catalysed by a hydrolase or an esterase. Generally speaking, it will be
possible to use such an ionic liquid as the sole solvent, without the need for an aqueous
cosolvent in order to preserve enzyme activity.
Similarly, ionic liquids such as alkyl alkanolammonium salts and dialkyl
alkanolammoniutn salts may be used as solvents in biocatalysis.
Example 4-further uses of the ionic liquids
Ionic liquids according to the invention may be used as solvents in a wide range of
situations, including as reaction media for both chemical and biochemical (including
enzyme-catalysed) reactions, or as extracting solvents for target solutes. By varying the
nature of the substituents on the central nitrogen atom, the solvating properties,
viscosity, melting point and other relevant properties of the ionic liquid can be varied
according to requirements, thus offering the opportunity to "tailor" the ionic liquid as a
solvent for a specific solute or solutes.
For example, if the ionic liquid is to be used as a solvent in an environment containing
an activated acid or a strong base, then it may be preferred not to include hydroxyl
groups on the cation - in such a situation, cations substituted with only alkyl and
alkoxyalkyl groups may then be appropriate. The same may apply when the ionic liquid
is to be used as a medium for a hydrolase- or esterase-catalysed reaction.
If the ionic liquid is to be used as a solvent for a metal-containing species, then it may be
preferred for the cation to be substituted with two alkoxyalkyl groups, as it can then act
as a chelating agent and help to solubilise the metal-containing species.
If the ionic liquid is to be used to dissolve a cellulosic material, then a cation substituted
with a group of formula -(CH2)n-O-(CH2)m-OH (where n and m are independently
selected integers, suitably from 2 to 4) may be preferred, for instance an N,N-dialkyl-N-

[(2-hydroxyethoxy)ethyl] ammonium ion, in particular an N,N-dimethyl-N-[(2-
hydroxyethoxy)ethyl] ammonium ion.

Claims
1. An ionic liquid comprising a cation of the formula (I):
N+HR1R2R3 (I)
wherein R1 is a group -R4-O-R5;
R2 and R3 are each independently either hydrogen or hydrocarbyl, or R2 and R3
may be joined together with the N to form a heterocyclic group;
R4 is a divalent hydrocarbyl radical; and
R5 is hydrocarbyl.
2. An ionic liquid according to claim 1, which is a secondary or tertiary ammonium
ion.
3. An ionic liquid according to claim 1 or claim 2, wherein R4 is -(CH2)n-, where n
is an integer from 2 to 4.
4. An ionic liquid according to claim 3, wherein n is 2.
5. An ionic liquid according to any one of the preceding claims, wherein R5 is C1 to
C4 alkyl.
6. An ionic liquid according to claim 5, wherein R5 is methyl.
7. An ionic liquid according to any one of claims 1 to 4, wherein R5 is (CH2)nOH,
where n is an integer from 1 to 4.
8. An ionic liquid according to any one of the preceding claims, wherein R2 is C1 to
C4 alkyl.
9. An ionic liquid according to claim 8, wherein R2 is methyl.

10. An ionic liquid according to any one of claims 1 to 7, wherein R2 is a group of
formula -R4-O-R5, where R4 and R5 are as defined in any one of the preceding
claims, and wherein R2 is either the same as or different to R1.
11. An ionic liquid according to any one of the preceding claims, wherein R3 is
hydrogen.
12. An ionic liquid according to any one of claims 1 to 9, wherein R2 and R3 are each
independently selected from C1 to C3 alkyl groups.
13. An ionic liquid according to claim 12, wherein R2 and R3 are both methyl.
14. An ionic liquid according to any one of the preceding claims, wherein either or
both of R2 and R3 is an alkanolyl group.
15. An ionic liquid according to claim 14, wherein R2 is an alkanolyl group and R3 is
an alkyl group.
16. An ionic liquid according to claim 14 or claim 15, wherein the alkanolyl group is
a C2 to C5 alkanolyl group.
17. An ionic liquid according to claim 16, wherein the alkanolyl group is ethanolyl.
18. An ionic liquid according to any one of the preceding claims, wherein the cation
(I) is an alkoxypropyl ammonium cation, a methoxyalkyl ammonium cation, a
di(alkoxyalkyl) ammonium cation other than a di(methoxyethyl) ammonium
cation, an alkyl alkoxyalkyl ammonium cation, a dialkyl alkoxyalkyl ammonium
cation, an alkyl di(alkoxyalkyl) ammonium cation or a N,N-dialkyl-N-
[(hydroxyalkoxy)alkyl] ammonium cation.
19. An ionic liquid according to claim 18, wherein the cation (I) is an alkyl
alkoxyalkyl ammonium cation, a dialkyl alkoxyalkyl ammonium cation, an alkyl
di(alkoxyalkyl) ammonium cation or a N,N-dialkyl-N-[(hydroxyalkoxy)alkyl]
ammonium cation.

20. An ionic liquid according to claim 19, wherein the cation (I) is a dialkyl
alkoxyalkyl ammonium cation, an alkyl di(alkoxyalkyl) ammonium cation or a
N,N-dialkyl-N-[(hydroxyalkoxy)alkyl] ammonium cation.
21. An ionic liquid according to claim 20, wherein the cation (I) is a dimethyl 2-
methoxyethyl ammonium cation or a methyl-bis(2-methoxyethyl) ammonium
cation.
22. An ionic liquid according to any one of the preceding claims, wherein the cation
(I) is selected from methyl alkoxyethyl ammonium cations, methyl alkoxypropyl
ammonium cations, dimethyl alkoxyethyl ammonium cations, dimethyl
alkoxypropyl ammonium cations, ethyl alkoxyethyl ammonium cations, ethyl
alkoxypropyl ammonium cations, diethyl alkoxyethyl ammonium cations, diethyl
alkoxypropyl ammonium cations, methyl ethyl alkoxyethyl ammonium cations,
methyl ethyl alkoxypropyl ammonium cations, propyl alkoxyethyl ammonium
cations, propyl alkoxypropyl ammonium cations, dipropyl alkoxyethyl
ammonium cations, dipropyl alkoxypropyl ammonium cations, methyl propyl
alkoxyethyl ammonium cations, methyl propyl alkoxypropyl ammonium cations,
ethyl propyl alkoxyethyl ammonium cations and ethyl propyl alkoxypropyl
ammonium cations.
23. An ionic liquid according to claim 22, wherein the cation (I) is selected from
alkoxypropyl ammonium, methyl alkoxyethyl ammonium, methyl alkoxypropyl
ammonium, dimethyl alkoxyethyl ammonium and ethyl methyl alkoxyethyl
ammonium ions.
24. An ionic liquid according to claim 22 or claim 23, wherein the alkoxy group is
either methoxy or ethoxy.
25. An ionic liquid comprising a cation of the formula (II):
N+HR6R7R8 (II)
wherein R6 is an alkanolyl group;
R7 is a hydrocarbyl group; and

R8 is either hydrogen or hydrocarbyl,
or R7 and R8 may be joined together with the N to form a heterocyclic group.
26. An ionic liquid according to claim 25, wherein R6 is selected from methanolyl,
ethanolyl and propanolyl.
27. An ionic liquid according to claim 26, wherein R6 is ethanolyl or propanolyl.
28. An ionic liquid according to claim 25, wherein R6 is a group of formula -(CH2)n-
O-(CH2)m-OH where n and m are independently selected integers from 1 to 4.
29. An ionic liquid according to any one of claims 25 to 28, wherein R6 contains a
terminal -OH group.
30. An ionic liquid according to any one of claims 25 to 29, wherein R6 and R7 are
each independently selected from alkanolyl groups.
31. An ionic liquid according to any one of claims 25 to 29, wherein R7 is C1 to C4
alkyl.
32. An ionic liquid according to any one of claims 25 to 31, wherein R8 is C1 to C4
alkyl.
33. An ionic liquid according to claim 31 or claim 32, wherein R7 and R8 are each
independently selected from methyl and ethyl.
34. An ionic liquid according to any one of claims 25 to 31, wherein R8 is hydrogen.
35. An ionic liquid according to any one of claims 25 to 34, wherein the cation (II) is
selected from alkyl alkanolammonium ions, dialkyl alkanolammonium ions and
N,N-dialkyl-N-[(hydroxyalkoxy)alkyl] ammonium ions.
36. An ionic liquid according to claim 35, wherein the cation (II) is selected from
propyl ethanolammonium, butyl ethanolammonium, dimethyl
propanolammonium and diethyl propanolammonium ions.

37. An ionic liquid according to any one of the preceding claims, which is capable of
existing in liquid form at and below 40 °C.
38. An ionic liquid according to claim 37, which is capable of existing in liquid form
at room temperature.
39. An ionic liquid according to any one of the preceding claims, which contains 5 %
or less of water, by mass.
40. An ionic liquid according to any one of the preceding claims, which has a
viscosity of less than 500 centipoise at 25 °C.
41. An ionic liquid according to any one of the preceding claims, which comprises a
counterion Xm- where m is an integer from 1 to 3.
42. An ionic liquid substantially as herein described.
43. A process for the preparation of an ionic liquid according to any one of the
preceding claims, the process comprising the steps of:
a) providing a nitrogen-containing compound of the formula (III):
NR1R2R3 (TO)
or a nitrogen-containing compound of the formula (IV):
NR6R7R8 (IV)
in which R1 to R8 are as defined in any one of the preceding claims; and
b) neutralising the compound (III) or (TV) with an acid.
44. A process according to claim 43, wherein the acid used in step (b) has the
formula HmX where m is an integer from 1 to 3 and the anion X comprises a
halide, halogenated inorganic anion, nitrate, sulphate, carbonate, sulphonate,
carboxylate or halogenated organic anion.
45. Use of an ionic liquid according to any one of claims 1 to 42 as a solvent for a
chemical or biochemical reaction

46. Use according to claim 45, wherein the reaction is an enzyme-catalysed reaction.
47. Use according to claim 45, wherein the reaction is an organic synthesis reaction.

The invention provides ionic liquids and processes for
their preparation. The liquids may either comprise a
cation of the formula (I); N+HR1R2R3 (I) wherein Rl is a
group-R4-0-R5; R2 and R3 are each independently either
hydrogen or hydrocarbyl, or R2 and R3 may be joined
together with the N to form a heterocyclic group; R4 is
divalent hydrocarbyl radical; and R5 is hydrocarbyl; or
a cation of the formula (II); N+HR6R7R8 (II) wherein R6
is an alkanolyl group; R7 is a hydrocarbyl group; and
R8 is either hydrogen or hydrocarbyl, or R7 and R8 may
be joined together with the N to form a heterocyclic
group