IONIC LIQUID, ADDUCT AND METHODS THEREOF
TECHNICAL FIELD
[001] The present disclosure relates to organic chemistry in general and reactions of organic
compounds in particular. The present disclosure provides a process for preparing liquid salt
including but not limiting to ionic liquid. More particularly, the present disclosure relates to a
process which involves reacting at least one electron-pair acceptor and at least one electronpair
donor to form an adduct. The adduct is in-turn reacted with at least one electron-pair
acceptor to prepare said liquid salt of the present disclosure. The process of the present
disclosure thus provides ionic liquid without subjecting the reactants to heating. The present
disclosure also relates to applications of the ionic liquid of the present disclosure across
varied organic reactions.
BACKGROUND
[002] Salts are ionic compounds that result from the neutralization reaction of an acid and
a base. They are composed of related numbers of cations (positively charged ions)
and anions (negative ions) so that the product is electrically neutral (without a net charge).
These component ions can be inorganic or organic, and salts as a whole can be monatomic, or
polyatomic. Salts may be in solid form or liquid form, and salts in liquid state are known as
ionic liquids.
[003] Ionic liquids are thus liquids that are composed entirely of ions or a combination of
cations and anions. The so-called "low temperature" Ionic liquids are generally organic salts
with melting points less than 100 degrees C, often even lower than room temperature. Ionic
liquids may be suitable, for example, for use as catalysts and solvents in alkylation and
polymerization reactions as well as in dimerization, oligomerization acetylation, metatheses
and copolymerization reactions.
[004] One class of ionic liquids is fused salt compositions, which are molten at low
temperature and are useful as catalysts, solvents and electrolytes. Such compositions are
mixtures of components which are liquids at temperatures below the individual melting
points of the components. The most common ionic liquids are those prepared from organicbased
cations and inorganic or organic anions. The most common organic cations are
ammonium cations. Ionic liquids of pyridinium and imidazolium are perhaps the most
commonly used cations. Anions include, but are not limited to BF4-, PF6-, haloaluminates
such as A12C17- and A12Br7- [(CF3S02)2N)]- alkyl sulphates (RS03-), carboxylates
(RC02-) and many others. The most catalytically interesting ionic liquids are those derived
from ammonium halides and Lewis acids (such as A1C13, TiC14, SnC14, FeC13 and the like).
Chloroaluminate ionic liquids are perhaps the most commonly used ionic liquid catalyst
systems.
[005] The Lewis acids, which are electron pair acceptors, and Lewis bases, which are
electron pair donors, react to form adducts in which a coordinate covalent bond is formed.
This type of bond is usually represented by an arrow. The strength of the interaction between
a Lewis acid and a Lewis base is controlled by at least two factors, electronic and steric.
Electron donating groups on an atom can increase the Lewis basicity of that atom, while
electron-withdrawing groups can increase the Lewis acidity.
[006] Often metal complexes expand their coordination number by interaction with a Lewis
base. This may take place by intermolecular association or by adduct formation with solvent
or available ligands of comparable ligating ability. The physical properties of the resulting
complex often are significantly different from those of the complex not having the expanded
coordination number. The ability to interact with bases seems to be related closely to the
electronic properties of the ligands as a whole, not just the atoms bonded to the metal.
[007] WO/2011/064556 discloses formation of a mixture having a freezing point up to
100°C formed by contacting 1 mole of A1X3, where X can be CL, Br, F with 1 or 2 moles of
R1-C(0)-N(R2)(R3) where Rl to R3 can be alkyl, Aryl or substituted alkyl and aryl. This
mixture can be used for electroreduction of the mixture to produce aluminium metal. It also
discloses the solid formation of A1X3 with 3 moles of Amide. However, this mixture requires
heating to form a good mixture, having freezing point up to 100°C.
[008] As per the methods of the prior art, addition of Lewis acid to weak Lewis base
requires heat to initiate the reaction to form ionic liquid. Thus, the methods of the prior art are
cumbersome and require excessive heating to obtain the ionic liquids. Further, the ionic
liquids so obtained by the method of the prior arts are highly viscous, thereby making them
difficult to handle, transfer, pump in reaction vessel and employ in industrial processes. The
present disclosure aims to overcome the drawbacks observed in the currently available
technology and provides for an easy and convenient method to prepare ionic liquids.
SUMMARY OF THE DISCLOSURE
[009] The present disclosure relates to a process of preparing salt such as liquid salt
preferably ionic liquid by reacting at least one electron-pair acceptor and at least one
electron-pair donor to form an adduct, and further reacting the adduct with at least one
electron-pair acceptor to prepare said salt.
[010] The present disclosure relates to a method of preparing ionic liquid, said method
comprising acts of contacting at least one electron-pair acceptor with at least one electronpair
donor to obtain an adduct and contacting the adduct with at least one electron-pair
acceptor to obtain the ionic liquid.
[011] In various embodiments, the present disclosure relates to a process of preparing liquid
salt preferably ionic liquid by reacting at least one electron-pair acceptor or Lewis acid and at
least one electron-pair donor or Lewis base to form an adduct. The adduct is thereafter further
reacted with at least one electron-pair acceptor or Lewis acid to prepare said liquid salt.
[012] The present disclosure also relates to ionic liquid prepared by the process of the
present disclosure, which comprises contacting at least one electron-pair acceptor with at
least one electron-pair donor to obtain an adduct; and contacting the adduct with at least one
electron-pair acceptor to obtain the ionic liquid. In a non-limiting embodiment, the process of
the present disclosure is carried out without subjecting the reactants to heating. In another
non-limiting embodiment of the present disclsoure, the electron-pair donor is not an amine.
[013] The present disclosure also relates to applications of the liquid salt including but not
limiting to ionic liquid prepared by the process of the present disclosure. In an embodiment,
the ionic liquid is suitable for applications involving organic reactions including but not
limiting to catalysis, alkylation, trans -alkylation, acylation, polymerization, dimerization,
oligomerization, acetylation, metatheses, pericyclic and copolymerization reactions.
[014] The present disclosure, also relates to a method of preparing an adduct of electronpair
acceptor and electron-pair donor, said method comprising act of contacting at least one
electron-pair acceptor with at least one electron-pair donor to obtain the adduct.
[015] The present disclosure also relates to adduct prepared according to the process of the
present disclosure, which comprises act of contacting at least one electron-pair acceptor with
at least one electron-pair donor to obtain the adduct. In an embodiment, the said adduct is
capable of forming ionic liquid on further reacting with electron-pair acceptor.
DETAILED DESCRIPTION
[016] The present disclosure relates to a method of preparing ionic liquid, said method
comprising acts of:
a) contacting at least one electron-pair acceptor with at least one electron-pair donor to
obtain an adduct; and
b) contacting the adduct with at least one electron-pair acceptor to obtain the ionic
liquid.
[017] The present disclosure also relates to an ionic liquid prepared according to the
aforesaid method.
[018] The present disclosure also relates to use of the aforesaid ionic liquid for application
in chemical reaction.
[019] The present disclosure also relates a method of preparing an adduct of electron-pair
acceptor and electron-pair donor, said method comprising act of contacting at least one
electron-pair acceptor with at least one electron-pair donor to obtain the adduct.
[020] The present disclosure also relates an adduct prepared accordingly to the above
method.
[021] In an embodiment of the present disclosure, the method of preparing the ionic liquid
comprises acts of:
a) contacting at least one electron-pair acceptor with at least one electron-pair donor , in
presence or absence of first solvent, to obtain a mixture;
b) optionally mixing and filtering the mixture of step (a) to obtain a filtrate and
optionally washing the filtrate or the mixture of step (a) with a second solvent,
followed by drying to obtain the adduct; and
c) contacting the adduct of step (b) with at least one electron-pair acceptor in presence
or absence of third solvent, followed by mixing to obtain the ionic liquid.
[022] In an embodiment of the present disclosure, the method of preparing the adduct
comprises acts of:
a) contacting at least one electron-pair acceptor with at least one electron-pair donor , in
presence or absence of first solvent, to obtain a mixture; and
b) optionally mixing and filtering the mixture of step (a) to obtain a filtrate and
optionally washing the filtrate or the mixture of step (a) with a second solvent,
followed by drying to obtain the adduct.
[023] In another embodiment of the present disclosure, the step a) or step b) or a
combination thereof is carried out in presence of solvent; the electron acceptor used in step b)
is same as or different than that used in step a); addition of the solvent is carried out along
with mixing; ratio of the electron-pair acceptor to the electron-pair donor in step a) is ranging
from about 1:1 to about 1:5; concentration of the adduct in step b) is ranging from about
0.001 mol to about 0.9 mol; and ratio of the adduct to the electron-pair acceptor in step b) is
ranging from about 1:1 to about 1:6.
[024] In yet another embodiment of the present disclosure, the method is carried out in
presence of solvent; wherein addition of the solvent is carried out along with mixing; and
wherein ratio of the electron-pair acceptor to the electron-pair donor is ranging from about
1:1 to about 1:5.
[025] In still another embodiment of the present disclosure, the method of preparing the
ionic liquid is carried out in absence of heating; the method is carried out under inert
atmosphere; and wherein the inert atmosphere is Nitrogen atmosphere.
[026] In still another embodiment of the present disclosure, the electron acceptor is a salt of
cation selected from group comprising aluminium, magnesium, calcium, chromium,
manganese, iron, cobalt, nickel, copper, zinc, gallium, germanium, zirconium, scandium,
vanadium, molybdenum, ruthenium, rhodium, indium, tin, titanium, lead, cadmium and
mercury or any combination thereof; the electron acceptor is a salt of cation selected from
group comprising acetate, carbonate, chloride, citrate, cyanide, fluoride, nitrate, nitrite,
phosphate and sulfate or any combination thereof; and the concentration of the electron
acceptor is ranging from about 0.001 mol to about 0.9 mol.
[027] The method as claimed in claim 1 or claim 4, wherein the electron donor is not an
amine; the electron donor is selected from group comprising phosphine, amide, alkyl
sulfoxide, ester and alcohol or any combination thereof; the phosphine is selected from group
comprising triphenylphosphine, triphenylphosphine oxide, trimethylphosphine and
tributylphosphine or any combination thereof; the amide is selected from group comprising
urea, dimethyl formamide, acetamide, N-methyl pyrrolidine, thiourea, phenylthiourea,
acetanilide, propanamide, 3-methylbutanamide, dimethylacetamide and butanamide or any
combination thereof; the alkyl sulfoxide is dimethyl sulfoxide; the ester is selected from
group comprising amyl acetate, ethyl acetate and propyl acetetate or any combination thereof;
the alcohol is cyclohexanol and isopropyl alcohol or any combination thereof; and the
concentration of the electron donor is ranging from about 0.001 mol to about 0.9 mol.
[028] In still another embodiment of the present disclosure, the first solvent, the second
solvent or the third solvent are same or different; wherein the solvent is selected from group
comprising Ethyl Acetate, Benzene, Toluene, Ethanol, Acetic Acid, Acetonitrile, Butanol,
Carbon Tetrachloride, Chlorobenzene, Chloroform, Cyclohexane, 1,2-Dichloroethane,
Heptane, Hexane, Methanol, Methylene Chloride, Nitromethane, Pentane, Propanol and
Xylene or any combination thereof; and wherein the amount of the solvent is ranging from
about 1% to about 80%.
[029] In still another embodiment of the present disclosure, the solvent in step a) is added to
either the electron-pair acceptor or the electron-pair donor, prior to the said contacting;
wherein the contacting is carried out along with mixing; wherein the mixing is carried out for
a time duration ranging from about 1 minute to about 12 hours, at a temperature ranging from
about 5°C to about 50°C; and wherein the mixing is carried out by technique selected from
group comprising stirring, milling, blending, static mixing, and grinding, or any combination
thereof.
[030] In still another embodiment of the present disclosure, wherein the chemical reaction is
selected from group comprising catalysis, alkylation reaction, trans-alkylation reaction,
acylation reaction, polymerization reaction, dimerization reaction, oligomerization reaction,
acetylation reaction, metatheses reaction, pericyclic reaction and copolymerization reaction
or any combination thereof.
[031] In an embodiment of the present disclosure, the terms 'catalyst', 'ionic liquid', 'ionic
liquid catalyst' and 'ionic catalyst' are used interchangeably.
[032] The present disclosure relates to a process of preparing salt by reacting at least one
electron-pair acceptor and at least one electron-pair donor to form an adduct, and further
reacting the adduct with at least one electron-pair acceptor to prepare said salt.
[033] In a non-limiting embodiment, the present disclosure relates to a process of preparing
salt preferably liquid salt including but not limiting to ionic liquid by reacting at least one
electron-pair acceptor and at least one electron-pair donor to form an adduct, and further
reacting the adduct with at least one electron-pair acceptor to prepare said liquid salt.
[034] In a preferred embodiment, the electron-pair acceptor employed in the process of
preparing liquid salt including but not limiting to ionic liquid is a Lewis acid and the electronpair
donor employed in said process is a Lewis base. Thus, the present disclosure provides a
process of preparing liquid salt including but not limiting to ionic liquid by reacting at least
one Lewis acid with at least one Lewis base to form an adduct, which is further reacted with
at least one Lewis acid to prepare said liquid salt.
[035] In a non-limiting embodiment, the process of the present disclosure for preparing
liquid salt including but not limiting to ionic liquid is carried out without subjecting the
reactants to heating.
[036] In an embodiment of the present disclosure, use of even a weak Lewis base, such as
but not limiting to urea, for formation of ionic liquid through an intermediary adduct, does
not require subjecting the reactants to heating.
[037] In a non-limiting embodiment of the present disclosure, the Lewis acid reacted with
the adduct in the process of the present disclosure is the same Lewis Acid which is reacted
initially with the Lewis base to form the adduct. In another non-limiting embodiment of the
present disclosure, the Lewis acid reacted with the adduct in the process of the present
disclosure is different from the Lewis Acid which is reacted initially with the Lewis base to
form the adduct.
[038] In an embodiment, addition of electron-pair acceptor (Lewis acid) to electron-pair
donor (Lewis base) reacts to form adducts in which a coordinate covalent bond is formed.
This type of bond is usually represented by an arrow. The strength of interaction between an
electron-pair acceptor and an electron-pair donor is controlled by at least two factors,
electronic and steric. Electron donating groups on an atom increases the Lewis basicity of
that atom, while electron-withdrawing groups increases the Lewis acidity. Metal complexes
expand their coordination number by interacting with a Lewis base. This takes place by
intermolecular association with solvent or by adduct formation with solvent or availability of
ligands of comparable ligating ability. The physical properties of the resulting complex often
are significantly different from those of the complex not having the expanded coordination
number. ML4 (M = metal; L = ligand) complexes vary substantially in their ability to interact
with Lewis bases. The ability to interact with bases is related closely to the electronic
properties of the ligands as a whole, not just the atoms bonded to the metal.
MlX m + nLB — >[Ml(LB) Xm]
Wherein Ml is metal, X is halide, LB is Lewis Base, n depends on the coordination
capability of Ml. Ml can be Cu, Zn, Fe, Al, Ga, In, Zr, Sc, Ti, V, Ca, Mg, Mn, Co, Ru, Rh,
Sn, Pb, Mb, Hg, etc
[039] In an embodiment, adduct formation depends on type of metal and the ligand attached
to it. For instance, CaCl 2 forms an adduct with 2 electron donors, whereas A1C13 forms an
adduct with 3 electron donors. The present disclosure is based on the theory of co-ordinate
bonds between filled orbitals of electron rich molecule overlapping the empty orbitals of the
electron deficient molecules electrons involving in such bonding, polarize the molecule
inheriting the acidic sites, favourable for chemical reactions such as alkylation.
[040] In an embodiment of the present disclosure, different types of Ionic Liquid are formed
by varying the Metal salt as well as Lewis Base employed. In an exemplary embodiment, the
Ionic liquid obtained is:
1) Acidic IL: such as AICI 3-UREA : + A1C13
2) Basic IL : such as MgCl 2-UREA + MnCl 2
3) Neural IL: such as ZnCl2-UREA + ZnCl2
[041] In an embodiment, the ionic liquid of the present disclosure is formed by reacting an
electron-pair acceptor with an electron-pair donor in a particular order.
[042] In an embodiment, the adduct of electron-pair acceptor and electron-pair donor is
stabile and leads to the formation of ionic liquid. In an embodiment, the stability is directly
proportional to the ratio between the Lewis base and Lewis acid. The adduct stability is also
dependent on the type of electron pair donor as well as electron pair acceptor.
[043] In an embodiment of the present disclosure, the ionic liquid is formed by reacting the
adduct of Lewis base and Lewis acid with Lewis acid, and not by reacting a salt of Lewis
Base and Bronsted acid with Lewis Acid. A Bronsted acid forms a salt and not an adduct with
a Lewis base.
[044] For formation of ionic liquid from a salt of Lewis base and Bronsted acid, such as 1-
Butyl-3-methylimidazolium Chloride ([BMIM][C1]), the salt is reacted with a metal halide,
such as AICI 3, in a salt: AICI 3 ratio of 1:1 and up to 1:3. If said ratio is greater than 1:3, the
AICI 3 starts precipitating out from the ionic liquid formed and hence concentration of the
AICI 3 in the ionic liquid formed should not be beyond three times the concentration of the
salt. However, as is the case in the present disclosure, when Ionic Liquid is formed from the
adduct, which in-turn is formed from electron pair acceptor (metal halide such as AICI 3) and
electron pair donor, will require about 3 moles of AICI 3 and once the ionic liquid is formed it
can further take about 3 more moles of AICI 3 making the ratio of adduct:AICI 3 to about 1:6.
Thus, higher concentration of AICI 3 per mole of adduct is dissolved in the ionic liquid formed
through an adduct than when formed through a salt.
[045] In an embodiment, the adduct based ionic liquids of the present disclosure, can
dissolve more metal halide. Due to this property the adduct-based ionic liquid are also useful
in applications for metal deposition. Further, the adduct based ionic liquid have higher
activity as a catalyst due to presence of high active catalyst.
[046] In an embodiment of the present disclosure, formation of the adduct is done by
reacting one Lewis acid with one Lewis Base, one Lewis acid with two Lewis Base, one
Lewis acid with three Lewis bases, one Lewis acid with four Lewis bases, and so on,
depending on the vacant orbitals on the central metal atom of the Lewis Acid. In an
embodiment of the present disclosure, an adduct is formed between the electron-pair acceptor
(Lewis acid) and electron-pair donor (Lewis base) when ratio of the electron-pair acceptor to
the electron-pair donor is ranging from about 1:1 to about 1:5
[047] In an embodiment, addition of more Lewis acid to the adduct formed results in
collapse in the structure of the adduct which leads to formation of the Ionic Liquid.
[048] In an embodiment of the present disclosure, an ionic liquid is formed between the
aforesaid adduct and the electron-pair acceptor (Lewis acid) when ratio of the adduct to the
electron-pair acceptor is ranging from about 1:1 to about 1:6.
[049] In an embodiment, the ionic liquid of the present disclosure is stable, has good
thermal conductivity, biocompatibility and increased active surface area. It has several
applications industrially and in other areas. In an embodiment, the ionic liquids of the present
disclosure can be regenerated and recycled.
[050] In a non-limiting embodiment, the Lewis acid employed in the present disclosure is a
salt of cation including but not limiting to Aluminium (Al), Magnesium (Mg), Calcium (Ca),
Chromium (Cr), Manganese (Mn), Iron (Fe), Cobalt (Co), Nickel (Ni), Copper (Cu),
Zinc(Zn), Gallium (Ga), Germanium (Ge), Indium (In), Zirconium (Zr), Scandium (Sc),
Vanadium (V), Molybdenum (Mb) , Ruthenium (Ru), Rhodium (Rh), Tin (Sn), Titanium
(Ti), Lead (Pb), Cadmium (Cd) and Mercury (Hg).
[051] In a non-limiting embodiment, the Lewis acid employed in the present disclosure is a
salt of cation, wherein the anionic moiety of the salt includes but is not limited to inorganic,
organic, monatomic and polyatomic moiety. In an exemplary embodiment, the anion moiety
in the salt includes but is not limited to Acetate, Carbonate, Chloride, Citrate, Cyanide,
Fluoride, Nitrate, Nitrite, Phosphate and Sulfate.
[052] In a non-limiting embodiment, the Lewis base employed in the present disclosure
includes but is not limited to ,In a non-limiting embodiment, the Lewis base employed in the
present disclosure is selected from a group comprising phosphine class of compound, amide
class of compound, alkyl sulfoxide class of compound, ester class of compound and alcohol
class of compound or any combination thereof. In an exemplary embodiment of the present
disclosure, the phosphine class of compound is selected from a group comprising
triphenylphosphine, triphenylphosphine oxide and tributylphosphine or trimethylphosphine
(PMe3)or any combination thereof; the amide class of compound is selected from a group
comprising urea, dimethyl formamide (DMF), acetamide, N-methyl pyrrolidine (NMP),
thiourea, phenylthiourea, acetanilide, propanamide, 3-methylbutanamide and butanamide,
Dimethylacetamide (DMA) or any combination thereof; alkyl sulfoxide class of compound is
dimethyl sulfoxide (DMSO); ester class of compound is selected from a group comprising
amyl acetate and propyl acetetate and ethyl acetate (EtOAc) or any combination thereof; the
alcohol is selected from a group comprising cyclohexanol and isopropyl alcohol (IPA) or
combination thereof.
[053] In a preferred embodiment, the process of the present disclosure is carried out without
employing amine as the Lewis base.
[054] Amine is toxic and has slow biodegradability when compared to other Lewis bases
such as amides, alcohols, esters, etc. Hence, use of amine for formation of ionic liquid is
avoided to make the ionic liquids of the present disclosure more user and environment
friendly.
[055] In an exemplary embodiment, the process of preparing liquid salt including but not
limiting to ionic liquid in the present disclosure comprises acts of:
a) contacting at least one electron-pair acceptor with at least one electron-pair donor in
presence or absence of a solvent to obtain an adduct; and
b) Contacting the adduct with at least one electron-pair acceptor in presence or absence
of a solvent to prepare the liquid salt of the present disclosure.
[056] In a preferred embodiment, the at least one electron-pair acceptor is contacted with
the at least one electron-pair donor in presence of a solvent under nitrogen atmosphere to
obtain a slurry. The slurry is stirred and thereafter subjected to filtration, followed by washing
with a solvent to obtain an adduct.
[057] The adduct is contacted with the at least one electron-pair acceptor in presence of a
solvent under nitrogen atmosphere to obtain a mass. The mass is further stirred to obtain the
liquid salt of the present disclosure.
[058] In an exemplary embodiment, the process of preparing liquid salt including but not
limiting to ionic liquid in the present disclosure comprises acts of:
a) contacting at least one electron-pair acceptor with a first solvent under nitrogen
atmosphere to obtain a mixture;
b) adding at least one electron-pair donor to the mixture of step (a) to obtain a slurry;
c) stirring and filtering the slurry of step (b) and washing with a second solvent
followed by drying to obtain an adduct;
d) contacting the adduct of step (c) with a third solvent under nitrogen atmosphere,
followed by stirring, to obtain a mixture; and
e) adding at least one electron-pair acceptor to the mixture of step (d) , followed by
stirring to prepare the liquid salt.
[059] In a preferred embodiment, the at least one electron-pair donor is added to the mixture
under stirring to obtain a slurry. In another preferred embodiment, the adduct is contacted
with a solvent under stirring to obtain a mixture, and thereafter, the mixture is subjected to
water bath before addition of the at least one electron-pair acceptor.
[060] In another preferred embodiment, the electron-pair acceptor employed in the process
of preparing liquid salt including but not limiting to ionic liquid is a Lewis acid and the
electron-pair donor employed in said process is a Lewis base. In a non-limiting embodiment
of the present disclosure, the Lewis acid reacted with the adduct in the process of the present
disclosure is the same Lewis Acid which is reacted initially with the Lewis base to form the
adduct. In another non-limiting embodiment of the present disclosure, the Lewis acid reacted
with the adduct in the process of the present disclosure is different from the Lewis Acid
which is reacted initially with the Lewis base to form the adduct.
[061] In a non-limiting embodiment, the adduct of the method of the present disclosure is
directly exposed to nitrogen atmosphere without the third solvent.
[062] In a non-limiting embodiment, the electron-pair acceptor or the Lewis acid employed
in the process of preparing liquid salt including but not limiting to ionic liquid is present at an
amount ranging from about 0.001 mol to about 0.9 mol, preferably about 0.3 mol to about 0.8
mol.
[063] In a non-limiting embodiment, the electron-pair donor or the Lewis base employed in
the process of preparing liquid salt including but not limiting to ionic liquid is present at an
amount ranging from about 0.001 mol to about 0.9 mol, preferably about 0.3 mol to about 0.8
mol.
[064] In a non-limiting embodiment, the adduct employed for reaction with at least one
electron-pair acceptor to prepare liquid salt of the present disclosure is present at an amount
ranging from about 0.01 mol to about 0.9 mol, preferably from about 0.1 mol to about 0.7
mol.
[065] In a non-limiting embodiment, the process of preparing liquid salt including but not
limiting to ionic liquid in the present disclosure comprises acts of:
a) contacting at least one electron-pair acceptor at an amount ranging from about 0.001
mol to about 0.9 mol with a first solvent under nitrogen atmosphere to obtain a
mixture;
b) adding at least one electron-pair donor at an amount ranging from about 0.001 mol to
about 0.9 mol to the mixture of step (a) under stirring to obtain a slurry;
c) stirring and filtering the slurry of step (b) and washing with a second solvent
followed by drying to obtain an adduct;
d) contacting the adduct of step (c) at an amount ranging from about 0.001 mol to about
0.9 mol with a third solvent under nitrogen atmosphere, followed by stirring, to
obtain a mixture; and
e) adding at least one electron-pair acceptor at an amount ranging from about 0.001 mol
to about 0.9 mol to the mixture of step (d) under stirring, followed by further stirring
to prepare the liquid salt.
[066] In a non-limiting embodiment, the at least one electron-pair donor is added to the
mixture of step (a) of the process of the present disclosure for a time period ranging from
about 1 minute to 60 minutes at a temperature ranging from about 10°C to about 50°C.
[067] In a non-limiting embodiment, the stirring of the slurry of the process of the present
disclosure is carried out for a time period ranging from about 1 hour to about 10 hours.
[068] In another non-limiting embodiment, the adduct is contacted with a solvent under
stirring to obtain a mixture, and thereafter, the mixture is subjected to water bath having
temperature ranging from about 30°C to about 50°C, before addition of the at least one
electron-pair acceptor.
[069] In another non-limiting embodiment, the at least one electron-pair acceptor is added
to the mixture of step (d) of the process of the present disclosure under stirring for a time
period ranging from about 1 minute to 60 minutes. In another non-limiting embodiment, the
further stirring of the mixture to prepare the liquid salt is carried out for a time period ranging
from about 1 hour to about 10 hours.
[070] In another non-limiting embodiment of the present disclosure, the solvent initially
contacted with the at least one electron-pair acceptor (first solvent), the solvent employed for
washing the slurry of the present disclosure (second solvent) and the solvent contacted with
the at least one electron-pair acceptor to obtain the liquid salt of the present disclosure (third
solvent) are either all same, or all different or a combination thereof.
[071] In a non-limiting embodiment, the process of preparing liquid salt of the present
disclosure is carried out in presence of a solvent, preferably organic solvent including but not
limiting to polar and non-polar solvent. In an exemplary embodiment, the solvent includes
but is not limited to ethyl acetate, methyl acetate, benzene, toluene, ethanol, acetic acid,
acetonitrile, butanol, carbon tetrachloride, chlorobenzene, chloroform, cyclohexane, 1,2-
dichloroethane, heptane, hexane, methanol, methylene chloride, nitromethane, pentane,
propanol, and xylene. Alternatively, the process of preparing liquid salt of the present
disclosure is carried out in absence of any solvent.
[072] In an exemplary embodiment, the process of preparing adduct comprises act of
contacting at least one electron-pair acceptor with at least one electron-pair donor in presence
or absence of a solvent to obtain an adduct.
[073] In an exemplary embodiment, the at least one electron-pair acceptor is contacted with
the at least one electron-pair donor in presence or absence of a solvent under nitrogen
atmosphere to obtain a slurry. The slurry is stirred and thereafter subjected to filtration,
followed by washing with a solvent to obtain an adduct.
[074] In an exemplary embodiment, the process of preparing adduct comprises acts of:
a) contacting at least one electron-pair acceptor with a first solvent under nitrogen
atmosphere to obtain a mixture;
b) adding at least one electron-pair donor to the mixture of step (a) to obtain a slurry;
and
c) stirring and filtering the slurry of step (b) and washing with a second solvent
followed by drying to obtain an adduct.
[075] In a non-limiting embodiment, the electron-pair acceptor or the Lewis acid employed
in the process of preparing including but not limiting to adduct is present at an amount
ranging from about 0.001 mol to about 0.9 mol, preferably about 0.3 mol to about 0.8 mol.
[076] In a non-limiting embodiment, the electron-pair donor or the Lewis base employed in
the process of preparing liquid salt including but not limiting to adduct is present at an
amount ranging from about 0.001 mol to about 0.9 mol, preferably about 0.3 mol to about 0.8
mol.
[077] In a non-limiting embodiment, the process of preparing the adduct comprises acts of:
a) contacting at least one electron-pair acceptor at an amount ranging from about 0.001
mol to about 0.9 mol with a first solvent under nitrogen atmosphere to obtain a
mixture;
b) adding at least one electron-pair donor at an amount ranging from about 0.001 mol to
about 0.9 mol to the mixture of step (a) under stirring to obtain a slurry; and
c) stirring and filtering the slurry of step (b) and washing with a second solvent
followed by drying to obtain the adduct.
[078] In an embodiment of the present disclosure, the first solvent is preferably ethyl
acetate, methyl acetate, ethanol and methanol or any combination thereof. In an embodiment
of the present disclosure, amount of the first solvent is ranging from about 1 w/w% to about
80 w/w , preferably about 30 w/w% to about 50 w/w%.
[079] In an embodiment of the present disclosure, the second solvent is preferably ethyl
acetate, methyl acetate, ethanol, methanol and hexane or any combination thereof. In an
embodiment of the present disclosure, amount of the second solvent is ranging from about 1
w/w% to about 80 w/w , preferably about 5 w/w% to about 30 w/w%.
[080] In an embodiment of the present disclosure, the third solvent is selected from group
comprising benzene, toluene and xylene or any combination thereof. In an embodiment of the
present disclosure, amount of the third solvent is ranging from about 1 w/w% to about 80
w/w , preferably about 30 w/w% to about 70 w/w%.
[081] In a non-limiting embodiment, the adduct of the method of the present disclosure is
directly exposed to nitrogen atmosphere without the third solvent. Thus, in one embodiment,
the electron-pair acceptor is added to the adduct in absence of any solvent.
[082] In an embodiment of the present disclosure, liquid clathrate compounds are formed by
interactions between aromatic solvent molecules and Ionic Liquid (ionic solid) ions, which
separate cation-anion packing interactions to a sufficient degree such that localized cage-like
structures are formed. If the interaction is very less, the ionic liquid is completely miscible/or
immiscible with the aromatics compound. If the ion-ion interactions are very high, then
crystallization of the salt/ ionic liquid occurs. Thus, the liquid clathrate formation depends on
the physical properties of the organic salts.
[083] The present disclosure also relates to a salt prepared by the process of the present
disclosure which involves reacting at least one electron-pair acceptor and at least one
electron-pair donor to form an adduct, and further reacting the adduct with at least one
electron-pair acceptor.
[084] In a non-limiting embodiment, the present disclosure relates to a salt preferably liquid
salt including but not limiting to ionic liquid prepared by the process of the present disclosure
which involves reacting at least one electron-pair acceptor and at least one electron-pair
donor to form an adduct, and further reacting the adduct with at least one electron-pair
acceptor to prepare said liquid salt.
[085] In an embodiment of the present disclosure, density of ionic liquid is measured by
specific gravity method. In another embodiment of the present disclosure, viscosity of ionic
liquid is measured by Oswald viscometer.
[086] In an embodiment of the present disclosure, the ionic liquid is suitable for applications
involving chemical reaction. In an embodiment of the present disclosure, the chemical
reaction is an organic reaction.
[087] In an exemplary embodiment, the liquid salt including but not limiting to ionic liquid
is suitable for applications involving organic reactions including but not limiting to catalysis,
alkylation, trans-alkylation, acylation, polymerization, dimerization, oligomerization,
acetylation, metatheses, pericyclic and copolymerization reactions. In an exemplary
embodiment, the liquid salt including but not limiting to ionic liquid is suitable for organic
reaction including but not limiting to Diels-Alder reaction.
[088] Additional embodiments and features of the present disclosure will be apparent to one
of ordinary skill in art based upon description provided herein. The embodiments herein
provide various features and advantageous details thereof in the description. Descriptions of
well-known/conventional methods and techniques are omitted so as to not unnecessarily
obscure the embodiments herein. The examples provided herein are intended merely to
facilitate an understanding of ways in which the embodiments herein may be practiced and to
further enable those of skill in the art to practice the embodiments herein. Accordingly, the
following examples should not be construed as limiting the scope of the embodiments herein.
EXAMPLES
Example 1; Preparation of Ionic Liquid from DMSO-Aluminium chloride adduct
(a) Preparation of DMSO-Aluminium chloride adduct
[089] About 2.7 g (0.020 mol) of A1C13 and about 20 ml of ethyl acetate are charged into a
250 ml RB flask under N2 atmosphere. Slowly under stirring, about 5 g (0.064 mol) of
DMSO is added for about 10 minutes at a temperature ranging from about 15°C to about
20°C to obtain a slurry. The whole mass is further stirred for about 4 hours. The resultant
mixture is then separated by filtration. The solids obtained are washed with about 25 ml of
fresh ethyl acetate followed by drying to get about 6.8 g of DMSO-Aluminium chloride
adduct.
(b) Preparation of Ionic liquid with Aluminium chloride as the electron-pair acceptor
(without solvent)
[090] About 15 g (0.040mol) of DMSO-Aluminium chloride adduct obtained above is
charged into a 100 ml single neck RB flask kept on a magnetic stirrer. N2 flow is ensured
inside the flask. The flask is kept in a water bath at a temperature ranging from about 30°C to
about 35°C. A magnetic needle is kept inside the flask for stirring. Slowly, about 32.7 g
(0.245 mol) of AICI 3 is added to the flask under stirring for about 30 minutes. The obtained
mass is stirred for a time period ranging from about 3 hours to about 4 hours. The resultant
ionic liquid is kept under nitrogen in closed conditions. Density of the IL is measured by
specific gravity method and is found to be about 1.62 and its viscosity is measured by Oswald
viscometer and is found to be about 220 cp.
Preparation of Ionic liquid with Aluminium chloride as the electron-pair acceptor in
presence of solvent
[091] About 15 g (0.040mol) of DMSO -Aluminium chloride adduct obtained above and
about 20 ml benzene are charged into a 100 ml single neck RB flask kept on a magnetic
stirrer. N2 flow is ensured inside the flask. The flask is kept in a water bath at a temperature
ranging from about 30°C to about 35°C. A magnetic needle is kept inside the flask for
stirring. Slowly, about 32.7 g (0.245 mol) of A1C13 is added to the flask under stirring for
about 30 minutes. The obtained mass is stirred for a time period ranging from about 3 hours
to about 4 hours. The resultant ionic liquid is kept under nitrogen in closed conditions.
Density of the IL obtained is about 1.40 and its viscosity is about 25 cp.
Example 2 : Preparation of Ionic Liquid from DMF-Aluminium chloride adduct
(a) Preparation of DMF-Aluminium chloride adduct
[092] About 2.7 g (0.020mol) of AICI 3 and about 20 ml of ethyl acetate are charged into a
250 ml RB flask under N2 atmosphere. Slowly under stirring, about 4.5 g (0.063 mol) of
DMF is added for about 10 minutes at a temperature ranging from about 15°C to about 20°C
to obtain a mass. The whole mass is further stirred for about 4 hours. The resultant mixture is
then separated by filtration. The solids obtained are washed with about 25 ml fresh ethyl
acetate followed by drying to get about 6.5 g of DMF-Aluminium chloride adduct.
b _ Preparation of Ionic liquid with Aluminium chloride as the electron-pair acceptor
(without solvent)
[093] About 14.1 g (0.040 mol) of DMF-Aluminium chloride adduct obtained above is
charged into a 100 ml single neck RB flask kept on a magnetic stirrer. N2 flow is ensured
inside the flask. The flask is kept in a water bath at a temperature ranging from about 30°C to
about 35°C. A magnetic needle is kept inside the flask for stirring. Slowly, about 32.7 g
(0.245 mol) of AICI 3 is added to the flask under stirring for about 30 minutes. The obtained
mass is stirred for a time period ranging from about 3 hours to about 4 hours. The resultant
ionic liquid is kept under nitrogen in closed conditions.
(c) Preparation of Ionic liquid with Aluminium chloride as the electron-pair acceptor in
presence of solvent
[094] About 14.1 g (0.040 mol) of DMF- Aluminium chloride adduct obtained above and
about 20 ml benzene are charged into a 100 ml single neck RB flask kept on a magnetic
stirrer. N2 flow is ensured inside the flask. The flask is kept in a water bath at a temperature
ranging from about 30°C to about 35°C. A magnetic needle is kept inside the flask for
stirring. Slowly, about 32.7 g (0.245 mol) of A1C13 is added to the flask under stirring for
about 30 minutes. The obtained mass is stirred for a time period ranging from about 3 hours
to about 4 hours. The resultant ionic liquid is kept under nitrogen in closed conditions.
Density of the IL obtained is about 1.45 and its viscocity is about 32 Cp.
Example 3 : Preparation of Ionic Liquid from IPA-Aluminium chloride adduct
(a) Preparation of Isopropyl alcohol-Aluminium chloride adduct
[095] About 2.7 g (0.020 mol) of AICI 3 and about 20 ml of ethyl acetate are charged into a
250 ml RB flask under N2 atmosphere. Slowly under stirring, about 3.8 g (0.063 mol) of IPA
is added for about 10 minutes at a temperature ranging from 15°C to about 20°C to obtain a
mass. The whole mass is then stirred for about 4 hours. The resultant mixture is then
separated by filtration. The solids obtained are washed with about 25 ml of fresh ethyl acetate
followed by drying to get about 5.04 g of IPA-Aluminium chloride adduct.
(b) Preparation of Ionic liquid with Aluminium chloride as the electron-pair acceptor
[096] About 12.53 g (0.040 mol) of IPA-Aluminium chloride adduct obtained above and
about 20 ml benzene are charged into a 100 ml single neck RB flask kept on a magnetic
stirrer. N2 flow is ensured inside the flask. The flask is kept in a water bath at a temperature
ranging from about 30 C to about 35 C. A magnetic needle is kept inside the flask for stirring.
Slowly, about 32.7 g (0.245 mol) of AICI 3 is added to the flask under stirring for about 30
minutes. The obtained mass is stirred for a time period ranging from about 3 hours to about 4
hours. The resultant ionic liquid is kept under nitrogen in closed conditions.
Example 4 : Preparation of Ionic Liquid from DMSO-Aluminium chloride adduct and
Zinc chloride as the electron-pair acceptor
(a) Preparation of DMSO-Aluminium chloride adduct
[097] The DMSO-Aluminium chloride adduct is prepared on the basis of the process
described in the present disclosure and protocols of examples including but not limiting to
Example 1 and Example 3 above.
(b) Preparation of Ionic liquid with Zinc chloride as the electron-pair acceptor
[098] About 14.7 g (0.04 mol) of DMSO-Aluminium chloride adduct is charged into a 100
ml glass reactor kept under an overhead stirrer, placed in a water bath at 30-35 °C. Then,
about 32.7 g (0.24 mol) of Zinc Chloride (ZnCl 2) is slowly added in to it with constant
stirring. N2 flow is ensured inside the reactor. The mixture is stirred for about 3 hours to get
ionic liquid.
Example 5 : Preparation of Ionic Liquid from DMSO-Aluminium chloride adduct and
Ferric chloride as the electron-pair acceptor
(a) Preparation of DMSO-Aluminium chloride adduct
[099] About 22.8 g (0.17 mol) of A1C13 and about 100 ml of ethanol are charged into a 250
ml glass reactor kept under an overhead stirrer, placed in a water bath. Then, about 40.9 g
(0.17 mol) of DMSO is slowly added in to it with constant stirring. N2 flow is ensured inside
the reactor. The mixture is stirred for about 4 h to get white coloured solid. The reaction mass
is allowed to settle for about 10 minutes. The solid is then separated and dried at about 100 C
to obtain DMSO-Aluminium chloride adduct.
b _ Preparation of Ionic liquid with Ferric chloride as the electron-pair acceptor
[100] About 14.7 g (0.04 mol) of DMSO-Aluminium chloride adduct is charged into a 100
ml glass reactor kept under an overhead stirrer, placed in a water bath at 30-35 °C. Then,
about 39 g (0.24 mol) of Ferric Chloride (FeCl 3) is slowly added in to it with constant
stirring. N2 flow is ensured inside the reactor. The mixture is stirred for about 3 hours to get
ionic liquid.
Example 6 : Preparation of Ionic Liquid from Urea-Aluminium chloride adduct and
Aluminium chloride as the electron-pair acceptor
(a) Preparation of urea- Aluminum chloride Adduct
[101] 13.84 g (0.22 mol) of urea and about 60 ml of ethanol are charged into a 250 ml RB
flask under N2 atmosphere for 1-2 hrs. Slowly under stirring, about 9.62 g (0.072 mol) of
AICI 3 is added for about 30 minutes at about 15-20°C to obtain a mass. The whole mass is
then stirred for about 4 hours. The resultant mixture is then separated by filtration. The solids
are washed with about 50 ml fresh ethanol followed by drying to get about 22.3 g of urea-
Aluminum chloride salt.
(b) Preparation of Ionic liquid with Aluminium chloride as the electron-pair acceptor (with
solvent)
[102] About 10 g (0.030 mol) of total solid powder obtained in the Example 6-a and about
20 ml benzene are charged into a 100 ml single neck RB flask kept on a magnetic stirrer. N2
flow is ensured inside the flask. The flask is kept in a water bath at about 30-35 °C. A
magnetic needle is kept inside the flask for stirring. Slowly, about 24.4 g (0.18 mol) of AICI 3
is added to the flask under stirring for about 30 minutes. The obtained mass is stirred for
about 3-4 hours at room temperature. Ionic Liquid formed is stored in inert atmosphere. The
density of the IL is 1.25 and the viscosity is 9 Cp.
(c) Preparation of Ionic liquid with Aluminium chloride as the electron-pair acceptor
(without solvent)
[103] About 10 g (0.030 mol) of total solid powder obtained in the Example 6-a is charged
into a 100 ml single neck RB flask kept on a magnetic stirrer. N2 flow is ensured inside the
flask. The flask is kept in a water bath at about 30-35 °C. A magnetic needle is kept inside the
flask for stirring. Slowly, about 24.4 g (0.18 mol) of AICI 3 is added to the flask under stirring
for about 30 minutes. The obtained mass is stirred for about 3-4 h. The Ionic Liquid formed is
stored in inert atmosphere. The density of the IL is 1.61.
Example 7 : Preparation of Ionic Liquid from DMF-Aluminium chloride adduct and
Ferric chloride as the electron-pair acceptor
(a) Preparation of DMF-Aluminium chloride adduct
[104] About 2.7 g (0.020 mol) of A1C13 and about 20 ml of ethyl acetate are charged into a
250 ml RB flask under N2 atmosphere. Slowly under stirring, about 4.65 g (0.063 mol) of
DMF is added for about 10 minutes at a temperature ranging from about 15-20 C to obtain a
mass. The whole mass is then stirred for about 4 hrs. The resultant mixture is separated by
filtration and the solid obtained is washed with about 25 ml fresh ethyl acetate followed by
drying at about 100 C to get about 6.5 g of DMF- Aluminium chloride adduct.
(b) Preparation of Ionic liquid with Ferric chloride as the electron-pair acceptor
[105] About 14.2 g (0.04 mol) of DMF- Aluminium chloride adduct is charged into a 100 ml
glass reactor kept under an overhead stirrer, placed in a water bath kept at 30-35 °C. Then,
about 38.9 g (0.24 mol) of Ferric Chloride (FeCl 3) is slowly added in to it with constant
stirring. N2 flow is ensured inside the reactor. The mixture is stirred for about 3 hours to get
ionic liquid.
Example 8 : Preparation of Ionic Liquid from N-methylpyrolidone -Aluminium chloride
adduct and Aluminium chloride as the electron-pair acceptor
a Preparation of N-methylpyrolidone -Aluminium chloride adduct
[106] About 13.36 g (O.lmol) of anhydrous A1C13 is added under slow stirring to about 10 g
(O.lmol) of N-methylpyrolidone in a round bottom flask and the mixture is kept in water bath
at room temperature for about 240 minutes. The two reactants are mixed, and an exothermic
reaction is observed wherein they fuse to form a white solid adduct of N-methylpyrolidone -
Aluminium chloride (1:1 adduct) .
(b) Preparation of Ionic liquid with Aluminium chloride as the electron-pair acceptor
[107] About 5 (0.021 mol) g of solid adduct of N-methylpyrolidone- Aluminium chloride is
mixed with about 2.86 (0.021 mol) g of Aluminium chloride in RB Flask with nitrogen purge
at room temperature. The above mixture is stirred for about 3.5 h and the resulting
homogenous eutectic liquid formed is an ionic liquid compound.
Example 9 : Preparation of Ionic Liquid from NMP-Aluminium chloride adduct
(a) Preparation of NMP-Aluminium chloride adduct
[108] About 13.36 g (0.1 mol) of A1C13 and about 20 ml of ethyl acetate are charged into a
250 ml RB flask under N2 atmosphere. Slowly under stirring, about 10 g (0.1 mol) of NMP is
added for about 10 minutes at a temperature ranging from about 15°C to about 20°C to obtain
a slurry. The whole mass is further stirred for about 4 hours. The resultant mixture is then
separated by filtration. The solids obtained are washed with about 25 ml of fresh ethyl acetate
followed by drying to get about 20 g of NMP- Aluminium chloride adduct (1:1 adduct).
b Preparation of Ionic liquid with Aluminium chloride as the electron-pair acceptor
(without solvent)
[109] About 5 g (0.021 mol) of NMP- Aluminium chloride adduct obtained above is
charged into a 100 ml single neck RB flask kept on a magne tic stirrer. N2 flow is ensured
inside the flask. The flask is kept in a water bath at a temperature ranging from about 30°C to
about 35°C. A magnetic needle is kept inside the flask for stirring. Slowly, about 2.86 g
(0.021 mol) of AICI 3 is added to the flask under stirring for about 30 minutes. The obtained
mass is stirred for a time period ranging from about 3 hour to about 4 hours. The resultant
ionic liquid is kept under nitrogen in closed conditions.
Preparation of Ionic liquid with Aluminium chloride as the electron-pair acceptor in
presence of solvent
[110] About 5 g (0.021 mol) of NMP-Aluminium chloride adduct obtained above and about
5 ml benzene are charged into a 100 ml single neck RB flask kept on a magnetic stirrer. N2
flow is ensured inside the flask. The flask is kept in a water bath at a temperature ranging
from about 30°C to about 35°C. A magnetic needle is kept inside the flask for stirring.
Slowly, about 2.86 g (0.021 mol) of AICI 3 is added to the flask under stirring for about 30
minutes. The obtained mass is stirred for a time period ranging from about 3 hour to about 4
hours. The resultant ionic liquid is kept under nitrogen in closed conditions.
Example 10:
(a) Preparation of electron-pair acceptor- electron-pair donor adduct
[111] About 13.35 g (0.1 mol) of A1C13 and about 20 ml of ethyl acetate are charged into a
250 ml RB flask under N2 atmosphere. Slowly under stirring, about 22.2 g (0.3 mol) of
diethyl ether is added for about 10 minutes at a temperature ranging from about 15°C to
about 20°C to obtain a slurry. The whole mass is further stirred for about 4 hours. The
resultant mixture is then separated by filtration. The solids obtained are washed with about 25
ml of fresh ethyl acetate followed by drying to get about 20 g of diethyl ether- aluminium
chloride adduct the adduct formed here is (1:1 adduct).
5 [112] Similarly, about 19 g of tetrahydrofuan -aluminium chloride adduct is formed by
using about 13.35 g (0.1 mol) of A1C13 and 21.6 g (0.3 mol) of tetrahydrofuran as the
electron-pair donor instead of diethyl ether. The adduct formed in this case is also 1:1 adduct.
[113] Similarly, about 18 g of ethylene glycol-aluminium chloride adduct is formed by
using about 13.35 g (0.1 mol) of A1C13 and 6.2 g (0.1 mol) of ethylene glycol as the electron
ic) pair donor instead of diethyl ether. The adduct formed in this case is also 1:1 adduct.
[114] Similarly, about 22 g of glycerol- aluminium chloride adduct is formed by using about
13.35 g (0.1 mol) of A1C13 and 9.2g (O.lmol) of glycerol as the electron-pair donor instead of
diethyl ether. The adduct formed in this case is also 1:1 adduct.
[115] Similarly, about 20 g of propylene glycol-aluminium chloride adduct is formed by
15 using about 13.35 g (0.1 mol) of A1C13 and 7.6 g (0.1 mol) of propylene glycol as the
electron-pair donor instead of diethyl ether. The adduct formed in this case is also 1:1 adduct.
[116] Similarly, about 2 1 g of cyclopentanone-aluminium chloride adduct is formed by
using about 13.35 g (0.1 mol) of A1C13 and 8.4 g (O.lmol) of cyclopentanone as the electronpair
donor instead of diethyl ether. The adduct formed in this case is also 1:1 adduct.
20 [117] Similarly, about 22.5 g of cyclohexanone-aluminium chloride adduct is formed by
using about 13.35 g (O.lmol) of A1C13 and 9.8g (0.1 mol) of cyclohexanone as the electronpair
donor instead of diethyl ether. The adduct formed in this case is also 1:1 adduct.
(b) Preparation of Ionic liquid with addition of electron-pair acceptor
25 [118] About 10 g (0.048 mol) of the adducts obtained above are charged individually into
100 ml single neck RB flask kept on a magnetic stirrer. N2 flow is ensured inside the flask.
The flask is kept in a water bath at a temperature ranging from about 30°C to about 35°C. A
magnetic needle is kept inside the flask for stirring. Slowly, about 33.7 g (0.29 mol) of A1C13
is added to the flask under stirring for about 30 minutes. The obtained mass is stirred for a
30 time period ranging from about 3 hour to about 4 hours. However, no ionic liquid is formed
and the mixture remained as a solid. All the above compounds are found to form a stable
adduct with AICI3 in a 1:1 ratio in first step (step a) and do not form ionic liquid in second
step (step b). Addition of extra reagent in step a) or step b) does not make any difference.
Example 11; Alkylation reaction by Ionic Liquid from DMSO-Aluminium chloride
adduct (prepared in Example 1)
[119] About 52.02 litres of hydrocarbon stream containing about 10% to about 13% of C10-
C14 olefins and about 87% to about 90% paraffins and about 20.02 litres of benzene are
charged into a 250 L glass reactor kept under an overhead stirrer, placed in a heating mantle.
N2 flow is ensured inside the reactor. The reactor is then heated to a temperature ranging
from about 38°C to about 39°C. Once the temperature is achieved, about 0.7 kg of the ionic
liquid catalyst prepared as per Example 1 is added to the reactor and stirred for about 5
minutes. After about 5 minutes, the reaction mass is allowed to settle for about 10 minutes.
The layers are then separated.
[120] The upper hydrocarbon layer is then analysed using titration. The conversion of
olefins is found to be 98% to form linear alkyl benzene.
[121] The lower layer is recycled with fresh hydrocarbon stream and benzene as per the
procedure above. The conversion of olefins present in the paraffin stream to linear alkyl
benzene is analysed and is found to be about 98 %.
Examplel2; Alkylation reaction by Ionic Liquid from DMSO-Aluminium chloride
adduct (prepared in Example 1)
[122] About 141.5 ml (124.3 gm) of benzene is added to a 250 ml RB flask kept under an
overhead stirrer under N2 atm. About 7.5 g of ionic liquid catalyst prepared as per Example 1
is added to the flask. About 23.4 ml benzyl chloride is added to the flask at a temperature
ranging from about 45°C to about 46°C and stirred for about 15 minutes. After completion of
reaction, catalyst and hydrocarbon layers are separated. The upper hydrocarbon layer is then
analysed by gas chromatography for benzyl chloride conversion. The conversion of benzyl
chloride to biphenyl methane is analysed by gas chromatography and is found to be about
92%.
Example 13; Oligomerization reaction by Ionic Liquid from DMSO-Aluminium
chloride adduct (prepared in Example lb)
[123] About 100 ml of hydrocarbon stream containing about 10% to about 13% of Cio-Ci4
olefins and about 87% to about 90% of paraffins are charged into a 250 ml glass reactor kept
under an overhead stirrer, placed in a heating mantle. N2 flow is ensured inside the reactor.
The reactor is then heated to about 45 C. Once the temperature is achieved, about 0.1 g of the
ionic liquid catalyst prepared as per Example 1 is added to the reactor and stirred for about 10
minutes. After about 10 minutes the reaction mass is allowed to settle for about 10 minutes.
The layers are then separated. The upper hydrocarbon layer is then analysed. The conversion
of olefins is analysed using titration and is found to be about 97%.
Example 14: Alkylation reaction by Ionic Liquid from DMSO-Aluminium chloride
adduct (prepared in Example lb)
[124] About 23.5 g of Phenol and about 2.2 g of Methyl tert-butyl ether (MTBE) are
charged into a 100 ml glass reactor kept under an overhead stirrer, placed in a heating mantle.
N2 flow is ensured inside the reactor. The reactor is then heated to a temperature of about
60 C. Once the temperature is achieved, about 0.25 g of the ionic liquid catalyst prepared as
per Example 1 is added to the reactor and stirred for about 3 hours. After about 3 hrs the
reaction is worked-up with 25 ml distilled water. The conversion of MTBE is analysed and is
found to be about 95%.
Example 15: Diels-Alder reaction by Ionic Liquid from DMSO-Aluminium chloride
adduct (prepared in Example lb)
[125] About 2.76 g of Isoprene and about 1.02 g Vinyl Acetate are charged into a 100 ml
glass reactor kept under an overhead stirrer, placed in a heating mantle. N2 flow is ensured
inside the reactor. The reactor is then heated to a temperature of about 60 C. Once the
temperature is achieved, about 0.03 g of the ionic liquid catalyst prepared as per Example 1 is
added to the reactor and stirred for about 4 hours. After about 4 hours the reaction is workedup
with 10 ml ethyl acetate. The conversion of reactants is analysed and is found to be about
96%.
Example 16: Acylation reaction by Ionic Liquid from DMSO-Aluminium chloride
adduct (prepared in Example 1)
[126] About 19.5 g of Benzene and about 3.5 g Acetyl Chloride are charged into a 100 ml
glass reactor kept under an overhead stirrer, placed in a heating mantle. N2 flow is ensured
inside the reactor. The reactor is then heated to a temperature of about 60 C. Once the
temperature is achieved, about 0.21 g of the ionic liquid catalyst prepared as per Example 1 is
added to the reactor and stirred for about 2 hrs. After about 2 hours, the reaction is worked-up
with about 25 ml distilled water. The conversion of Acetyl Chloride is analysed and is found
to be about 96%.
Example 17: Acylation reaction by Ionic Liquid from DMSO-Aluminium chloride
adduct (prepared in Example 1)
[127] About 19.5 g of Benzene and about 1.95 g Benzoyl Chloride are charged into a 100
ml glass reactor kept under an overhead stirrer, placed in a heating mantle. N2 flow is ensured
inside the reactor. The reactor is then heated to a temperature of about 60 C. Once the
temperature is achieved, about 0.21 g of the ionic liquid catalyst prepared as per Example 1 is
added to the reactor and stirred for about 3 hours. The reaction is worked-up with about 15 ml
distilled water and 15 ml of ethyl acetate. The conversion of Benzoyl Chloride is analysed
and is found to be 91%.
[128] The present disclosure in view of the above described illustrations and various
embodiments, is thus able to successfully overcome the various deficiencies of prior art and
provide for an improved process for preparing liquid salt including but not limiting to ionic
liquid.
[129] Additional embodiments and features of the present disclosure will be apparent to one
of ordinary skill in art based on the description provided herein. The embodiments herein
provide various features and advantageous details thereof in the description. Descriptions of
well-known/conventional methods and techniques are omitted so as to not unnecessarily
obscure the embodiments herein.
[130] The foregoing description of the specific embodiments will so fully reveal the general
nature of the embodiments herein that others can, by applying current knowledge, readily
modify and/or adapt for various applications such specific embodiments without departing
from the generic concept, and, therefore, such adaptations and modifications should and are
intended to be comprehended within the meaning and range of equivalents of the disclosed
embodiments. It is to be understood that the phraseology or terminology employed herein is
for the purpose of description and not of limitation. Therefore, while the embodiments in this
disclosure have been described in terms of preferred embodiments, those skilled in the art
will recognize that the embodiments herein can be practiced with modification within the
spirit and scope of the embodiments as described herein.
[131] Throughout this specification, the word "comprise", or variations such as "comprises"
or "comprising" wherever used, will be understood to imply the inclusion of a stated element,
integer or step, or group of elements, integers or steps, but not the exclusion of any other
element, integer or step, or group of elements, integers or steps.
[132] The use of the expression "at least" or "at least one" suggests the use of one or more
elements or ingredients or quantities, as the use may be in the embodiment of the disclosure
to achieve one or more of the desired objects or results.
[133] Any discussion of documents, acts, materials, devices, articles and the like that has
been included in this specification is solely for the purpose of providing a context for the
disclosure. It is not to be taken as an admission that any or all of these matters form a part of
the prior art base or were common general knowledge in the field relevant to the disclosure as
it existed anywhere before the priority date of this application.
[134] While considerable emphasis has been placed herein on the particular features of this
disclosure, it will be appreciated that various modifications can be made, and that many
changes can be made in the preferred embodiments without departing from the principles of
the disclosure. These and other modifications in the nature of the disclosure or the preferred
embodiments will be apparent to those skilled in the art from the disclosure herein, whereby
it is to be distinctly understood that the foregoing descriptive matter is to be interpreted
merely as illustrative of the disclosure and not as a limitation.
We claim:
1) A method of preparing ionic liquid, said method comprising acts of:
a) contacting at least one electron-pair acceptor with at least one electron-pair donor to
obtain an adduct; and
b) contacting the adduct with at least one electron-pair acceptor to obtain the ionic
liquid.
2) An ionic liquid prepared according to the method of claim 1.
3) Use of the ionic liquid as claimed in claim 2 for application in chemical reaction.
4) A method of preparing an adduct of electron-pair acceptor and electron-pair donor, said
method comprising act of contacting at least one electron-pair acceptor with at least one
electron-pair donor to obtain the adduct.
5) An adduct prepared accordingly to the method of claim 4.
6) The method as claimed in claim 1, wherein the method of preparing the ionic liquid
comprises acts of:
a) contacting at least one electron-pair acceptor with at least one electron-pair donor, in
presence or absence of first solvent, to obtain a mixture;
b) optionally mixing and filtering the mixture of step (a) to obtain a filtrate and
optionally washing the filtrate or the mixture of step (a) with a second solvent,
followed by drying to obtain the adduct; and
c) contacting the adduct of step (b) with at least one electron-pair acceptor in presence or
absence of third solvent, followed by mixing to obtain the ionic liquid.
7) The method as claimed in claim 4, wherein the method of preparing the adduct comprises
acts of:
a) contacting at least one electron-pair acceptor with at least one electron-pair donor , in
presence or absence of first solvent, to obtain a mixture; and
b) optionally mixing and filtering the mixture of step (a) to obtain a filtrate and
optionally washing the filtrate or the mixture of step (a) with a second solvent,
followed by drying to obtain the adduct.
8) The method as claimed in claim 1, wherein the step a) or step b) or a combination thereof
is carried out in presence of solvent; the electron acceptor used in step b) is same as or
different than that used in step a); addition of the solvent is carried out along with mixing;
ratio of the electron-pair acceptor to the electron-pair donor in step a) is ranging from
about 1:1 to about 1:5; concentration of the adduct in step b) is ranging from about 0.001
mol to about 0.9 mol; and ratio of the adduct to the electron-pair acceptor in step b) is
ranging from about 1:1 to about 1:6.
9) The method as claimed in claim 4, wherein the method is carried out in presence of
solvent; addition of the solvent is carried out along with mixing; and ratio of the electronpair
acceptor to the electron-pair donor is ranging from about 1:1 to about 1:5.
10) The method as claimed in claim 1 or claim 4, wherein the method of preparing the ionic
liquid is carried out in absence of heating; the method is carried out under inert
atmosphere; and wherein the inert atmosphere is Nitrogen atmosphere.
11) The method as claimed in claim 1 or claim 4, wherein the electron acceptor is a salt of
cation selected from group comprising aluminium, magnesium, calcium, chromium,
manganese, iron, cobalt, nickel, copper, zinc, gallium, germanium, zirconium, scandium,
vanadium, molybdenum, ruthenium, rhodium, indium, tin, titanium, lead, cadmium and
mercury or any combination thereof; the electron acceptor is a salt of cation selected from
group comprising acetate, carbonate, chloride, citrate, cyanide, fluoride, nitrate, nitrite,
phosphate and sulfate or any combination thereof; and the concentration of the electron
acceptor is ranging from about 0.001 mol to about 0.9 mol.
12) The method as claimed in claim 1 or claim 4, wherein the electron donor is not an amine;
the electron donor is selected from group comprising phosphine, amide, alkyl sulfoxide,
ester and alcohol or any combination thereof; the phosphine is selected from group
comprising triphenylphosphine, triphenylphosphine oxide, trimethylphosphine and
tributylphosphine or any combination thereof; the amide is selected from group
comprising urea, dimethyl formamide, acetamide, N-methyl pyrrolidine, thiourea,
phenylthiourea, acetanilide, propanamide, 3-methylbutanamide, dimethylacetamide and
butanamide or any combination thereof; the alkyl sulfoxide is dimethyl sulfoxide; the
ester is selected from group comprising amyl acetate, ethyl acetate and propyl acetetate or
any combination thereof; the alcohol is cyclohexanol and isopropyl alcohol or any
combination thereof; and the concentration of the electron donor is ranging from about
0.001 mol to about 0.9 mol.
13) The method as claimed in claim 1 or claim 4 or claim 6, wherein the first solvent, the
second solvent or the third solvent are same or different; the solvent is selected from
group comprising Ethyl Acetate, Methyl Acetate, Benzene, Toluene, Ethanol, Acetic
Acid, Acetonitrile, Butanol, Carbon Tetrachloride, Chlorobenzene, Chloroform,
Cyclohexane, 1,2-Dichloroethane, Heptane, Hexane, Methanol, Methylene Chloride,
Nitromethane, Pentane, Propanol and Xylene or any combination thereof; and the amount
of the solvent is ranging from about 1% to about 80%.
14) The method as claimed in claim 6 or claim 7, wherein the solvent in step a) is added to
either the electron-pair acceptor or the electron-pair donor, prior to the said contacting;
the contacting is carried out along with mixing; the mixing is carried out for a time
duration ranging from about 1 minute to about 12 hours, at a temperature ranging from
about 5°C to about 50°C; and the mixing is carried out by technique selected from group
comprising stirring, milling, blending, static mixing, and grinding, or any combination
thereof.
15) The use as claimed in claim 3, wherein the chemical reaction is selected from group
comprising catalysis, alkylation reaction, trans-alkylation reaction, acylation reaction,
polymerization reaction, dimerization reaction, oligomerization reaction, acetylation
reaction, metatheses reaction, pericyclic reaction and copolymerization reaction or any
combination thereof.