Title of Invention

METHOD TO ELECTRODEPOSIT METALS USING IONIC LIQUIDS

Abstract The present invention relates to a method to electroplate or electropolish a metal on a substrate wherein an ionic liquid selected from the group of N+R1R2R3R4 X- or N+R5R6R7R8 Y- is employed as electrolyte, and a metal salt added to the ionic liquid is employed as the metal source or a metal anode is used as the metal source, wherein any one of R1 to R8 independently represents a hydrogen, alkyl, cycloalkyl, aryl, or aralkyl group that may be substituted with a group selected from OH, Cl, Br, F, I, phenyl, NH2, CN, NO2, COOR9, CHO, COR9, or OR9, at least one of R5 to R8 is a fatty alkyl chain, and one or more of R5 to R8 can be a (poly)oxyalkylene group wherein the alkylene is a C1 to C4 alkylene and the total number of oxyalkylene units can be from 1 to 50 oxyalkylene units, and at least one of R1 to R8 is a C1 to C4 alkyl chain, R9 is an alkyl or cycloalkyl group, X- is an anion having an N-acyl sulphonylimide anion (-CO-N -SO2-) functionality, Y is an anion compatible with the N+R5R6R7R8 ammonium cation, such as a halogenide anion, a carboxylate anion, a sulphate (both organic and inorganic sulphate), sulphonate, carbonate, nitrate, nitrite, thiocyanate, hydroxide, or sulphonylimide anion.
Full Text Method to electrodeposit metals using ionic liquids
The present invention relates to a method to electrodeposit a metal on a
substrate using an ionic liquid as the electrolyte.
Ionic liquids are non-volatile salts with a melting point below 100°C. Many are
liquid even at room temperature and they represent a relatively new class of
solvents.
It is known that, in general, ionic liquids may be used in many applications, e.g.
as reaction solvents, extraction solvents, electrolytes in batteries and
electrodeposition, catalysts, heat exchange fluids, as additives in coatings.
Until now, all commercially available ionic liquids suitable for use as electrolytes
in electrodeposition have been relatively high-priced, i.e. in the order of about
50 Euros up to about 1,000 Euros per kilogram. The term electrodeposition in
this application should be understood to include both electroplating and
electropolishing.
A number of examples of the use of ionic liquids are disclosed for example on
Merck's and lolitec's web pages: www.ionicliquids-merck.de and
www.iolitec.com (dated February 3, 2006).
Ionic liquids said to be useful in electrodeposition methods are specifically
trioctylmethylammonium trifluoromethane sulphonate, N-methyl,N-trioctyl-
ammonium bis(trifluoromethylsulphonyl)imide, trimethyl-N-hexylammonium
bis(trifluoromethylsulphonyl)imide, N-butyl, N-trimethylammonium bis(trifluoro-
methylsulphonyl)imide, 1 -butyl-1 -methyl-pyrrolidinium bis(trifluoromethyl-
sulphonyl)imide, 1 -hexyl-3-methylimidazolium tris(pentafluoroethyl)trifluoro-
phosphate, 1-butyl-3-methylimidazolium trifluoroacetate, which are all quite
expensive and carry the risk of very dangerous HF being formed as a
decomposition product of fluorine-containing ionic liquids.

The price of eutectic mixtures such as choline chloride/chromium chloride
hexahydrate or choline chloride/zinc chloride, also reported to be used in
electrodeposition, likewise is rather high. Furthermore, consumption of the
metal salt which is a building component of such ionic liquids during the
electrodeposition process may lead to decomposition of such ionic liquids.
WO 2002/026381 discloses ionic liquids (eutectic mixtures) of choline chloride
and a (hydrated) metal salt such as chromium(lll) chloride and the use thereof
in electrodeposition and electropolishing. The mixtures consist of choline
chloride and the (hydrated) metal salt in a ratio of ammonium to metal ion of
between 1:1 and 1:2.5 and are specifically said to be suitable for depositing
chromium, cobalt, zinc or silver on a metal substrate.
However, there is a desire for ionic liquids suitable for use in an electro-
deposition process which give a good quality of electrodeposited metal on a
substrate (i.e. an electrocoated substrate with a good appearance or with
adequate hardness) while at the same time they are economically attractive, or
in other words, available in high quality at a low price. Also, there is a need in
the industry for electrolytes suitable for use in an electrodeposition process
which are energy efficient, not based on the use of toxic chemicals, and which
enable large-scale plating. Moreover, there is a need for a method to deposit
metals on a substrate that requires only a low metal concentration in the
solvent, as this gives an improvement from an economic point of view and
makes the process more controllable.
Also, there is a desire for a method of electrodepositing metals on a substrate in
which ionic liquid is used as an electrolyte wherein the ionic liquid has good
electrical conductivity, a satisfying electrochemical stability range, and can
dissolve sufficient quantities of the salts of the metal to be satisfactorily
deposited on the substrate.

Finally, there is a desire for a more suitable way of depositing certain metals
using an electrochemical method, such materials currently being deposited
using the methods known in the art, which pose significant health and
environmental risks. Aluminium and titanium are examples of metals that cannot
be deposited from aqueous solutions and are deposited from non-aqueous
organic electrolytes. As such organic baths present an explosion and fire
hazard, electrodeposition of such metals in more acceptable solvents would be
highly beneficial. Furthermore, the present industrial chromium deposition
processes still are based on chromic acid, which contains highly carcinogenic
chromium (VI) (see e.g. Modern Electroplating by F.A. Lowenheim, 1942 or
Electroplating Engineering Handbook by LJ. Durney, 1996). Also, conventional
chromium plating baths require the use of strong acids, which poses significant
disposal problems, while the use of the compounds of the invention enables
such disposal difficulties to be minimised or eliminated.
The present invention now provides a method to electroplate or electropolish a
metal on a substrate wherein an ionic liquid selected from the group of
N+R1R2R3R4 X- and N+R5R6R7R8 Y- is employed as electrolyte and a metal salt
added to the ionic liquid is employed as the metal source or a metal anode is
used as the metal source, wherein any one of R1 to R8 independently
represents a hydrogen, alkyl, cycloalkyl, aryl, or aralkyl group that may be
substituted with a group selected from OH, Cl, Br, F, I, phenyl, NH2, CN, NO2,
COOR9, CHO, CORg, or OR9, at least one of R5 to R8 is a fatty alkyl chain, and
one or more of R5 to R8 can be a (poly)oxyalkylene group wherein the alkylene
is a C1 to C4 alkylene and the total number of oxyalkylene units can be from 1 to
50 oxyalkylene units, and at least one of R1 to R8 is a C1 to C4 alkyl chain, R9 is
an alkyl or cycloalkyl group, X- is an anion having an N-acyl sulphonylimide
anion (-CO-N--SO2-) functionality, Y- is an anion compatible with the
N+R5R6R7R8 ammonium cation, such as a halogenide anion, a carboxylate
anion, a sulphate (both organic and inorganic sulphate), sulphonate, carbonate,

nitrate, nitrite, thiocyanate, hydroxide, or sulphonylimide anion; preferably it is
CI-, Br- or CH3SO4-.
In one embodiment, Y- is selected from the group of F, Cl-, Br-, I-; the group of
R10COO" anions wherein R10 may be hydrogen, a C1-C22 alkyl, alkenyl or
aromatic group; the group of R11SO4- anions wherein R11 may be absent, in
which case the cation is divalent, hydrogen, a C1-C22 alkyl, alkenyl or aromatic
group; the group of R12SO3- anions wherein R12 may be absent, in which case
the cation is divalent, hydrogen, a C1-C22 alkyl, alkenyl or aromatic group; the
group of R13CO3- anions wherein R13 may be absent, in which case the cation is
divalent, hydrogen, a C1-C22 alkyl, alkenyl or aromatic group; and the group of
R14-N--SO2-R15 anions wherein R14 and/or R15 independently may be hydrogen,
a C1-C22 alkyl, alkenyl or aromatic group, and R14 may be linked to the nitrogen
atom with a carbonyl group.
A fatty alkyl chain is meant to include saturated and/or unsaturated chains and
contains 8 to 22 carbon atoms; preferably, it contains 10 to 22 carbon atoms,
most preferably 12 to 20 carbon atoms.
In one embodiment, the N+R5R6R7R8 Y- ionic liquid has an iodine value of above
1, preferably above 2, more preferably above 3, and most preferably above 5 g
l2 per 100 gr of ionic liquid. The iodine value generally is below 210 g l2 per 100
gr of ionic liquid.
In a preferred embodiment, X- is based on a compound known as a sweetener.
In another preferred embodiment, N+R1R2R3R4 is an amine wherein the groups
R1 to R4 are hydrogen or an alkyl or cycloalkyl, optionally substituted with OH or
CI; more preferably, at least three thereof are an alkyl, more preferably a C1 to
C4 alkyl.

In a preferred embodiment, the ionic liquid is selected from any one of choline
saccharinate, choline acesulphamate, hexadecyltrimethyl ammonium chloride,
octadecyltrimethyl ammonium chloride, cocotrimethyl ammonium chloride,
tallowtrimethyl ammonium chloride, hydrogenated tallowtrimethyl ammonium
chloride, hydrogenated palmtrimethyl ammonium chloride, oleyltrimethyl
ammonium chloride, soyatrimethyl ammonium chloride, cocobenzyldimethyl
ammonium chloride, C12-16-alkylbenzyldimethyl ammonium chloride,
hydrogenated tallowbenzyldimethyl ammonium chloride, dioctyldi methyl
ammonium chloride, didecyldimethyl ammonium chloride, dicocodimethyl
ammonium nitrite, dicocodi methyl ammonium chloride, di(hydrogenated
tallow)dimethyl ammonium chloride, di(hydrogenated tallow)benzylmethyl
ammonium chloride, ditallowdimethyl ammonium chloride, dioctadecyldimethyl
ammonium chloride, hydrogenated tallow(2-ethylhexyl)dimethyl ammonium
chloride, hydrogenated tallow(2-ethylhexyl)dimethyl ammonium methylsulphate,
trihexadecylmethyl ammonium chloride, octadecylmethylbis(2-hydroxyethyl)
ammonium chloride, cocobis(2-hydroxyethyl)methyl ammonium nitrate,
cocobis(2-hydroxyethyl)methyl ammonium chloride, cocobis(2-hydroxyethyl)-
benzyl ammonium chloride, oleylbis(2-hydroxyethyl)methyl ammonium chloride,
coco[polyoxyethylene(15)]methyl ammonium chloride,
coco[polyoxyethylene(15)]methyl ammonium methylsulphate,
coco[polyoxyethylene(17)]methyl ammonium chloride,
octadecyl[polyoxyethylene(15)]methyl ammonium chloride, hydrogenated
tallow[polyoxyethylene(15)]methyl ammonium chloride, tris(2-
hydroxyethyl)tallow ammonium acetate, tallow- 1,3-propane pentamethyl
diammonium dichloride.
US 4,849,438 discloses choline saccharinate, a method to prepare choline
saccharinate, and the use of choline saccharinate to protect plants against fungi
and bacteria. The choline saccharinate reaction product of Preparation Example
1 first is an oily substance and later is in the crystal form because of the
presence of 0.3 mol H2O per mol of choline saccharinate. In Preparation

Example 3 choline saccharinate is prepared by reacting choline chloride and
sodium saccharinate. It is not acknowledged that choline saccharinate is an
ionic liquid, but in Example 3 it is implicitly understood to be an ionic liquid.
E. B. Carter et al. in Chemical Communications 2004, (6), 630-631 disclose
ionic liquids of saccharinate and acesulphamate anions and a quaternary
ammonium cation such as a triethylmethyl ammonium or an imidazolium cation.
J. Tang et al in Polymer 46 (2005), pp. 12460-12467 disclose a dodecyltriethyl
ammonium based ionic liquid and the CO2 sorption thereof.
However, none of the above documents discloses or suggests the suitability of
N-acyl sulphonyl imide based or fatty alkyl based ionic liquids for use in a
method to electrodeposit metals on a substrate.
The above-indicated ionic liquids formed are safe - potentially food grade - and
can be applied as a solvent in an electrodeposition or electropolishing method,
since they contain a relatively low concentration of metal salt. On the other
hand, the metal salt concentration range is broad, or in other words, the method
to electrodeposit metals on a substrate according to the invention is controllable
over a wide range of a relatively low metal salt concentration. The plated
substrate resulting from the process according to the present invention has an
improved appearance compared to the methods of the state of the art using
other ionic liquids as the electrolyte. What is more, when using some of the
ionic liquids disclosed in the state of the art as electrolyte in a method to
electrodeposit, we were unable to get a layer of metal deposited on the
substrate at all, especially not when the metal was used in the preferred amount
as specified in this description.
The above-indicated ionic liquids for use in the method according to the
invention can be prepared by a simple reaction of salts, for example by a

metathesis reaction of choline chloride and sodium saccharinate
(acesulphamate) to form a choline saccharinate (acesulphamate) ionic liquid.
Also, it has been found that an ionic liquid made on the basis of commercially
available compounds, such as hydrogenated tallow methyl [polyoxy-
ethylene(15)] ammonium chloride, cocoalkylmethyl [polyoxyethylene(15)]
ammonium chloride, cocoalkylmethyl [polyoxyethylene(15)] ammonium
methylsulphate, octadecylmethyl [polyoxyethylene(15)] ammonium chloride,
and di(hydrogenated tallow) dimethyl ammonium chloride used as surfactants
and rheology modifiers, is suitable to be employed in the process according to
the invention.
In a preferred embodiment, the molar ratio of the ammonium cation of the ionic
liquid to the metal cation of the metal salt, which comes from the dissolved salt
or from the metal anode, is between 1,000:1 and 3:1. More preferred is a molar
ratio of the ammonium cation of the ionic liquid to the metal cation of the metal
salt of between 500:1 and 5:1, most preferred is a molar ratio between 100:1
and 7:1, this providing a high-quality metal layer, excellent dissolution of the
metal in the ionic liquid, and a good balance between the cost of the process
and the appearance of the plated substrate product.
In another preferred method to electrodeposit according to the present
invention, one of the metals chromium, aluminium, titanium, zinc or copper is
deposited; more preferably, chromium or aluminium is deposited, most
preferably chromium.
The electrodeposition is preferably performed at temperatures below 90 °C and
more preferably at room temperature, in open electrodeposition vessels, but
electrodeposition is not limited to these conditions. In the embodiment where a
metal anode is used, the anode may be in the form of metal pieces, chunks,
chips or any other suitable form known to the skilled person.

The ionic compounds according to the invention also find application in
electropolishing. For example, stainless steel can be polished using compounds
according to the invention. Stainless steels form the largest commercial
application for electropolishing and traditionally polishing baths contain mixtures
based on concentrated sulphuric and phosphoric acids. These are highly toxic
and corrosive and prone to form toxic and corrosive "mists" during
electropolishing as a result of prodigious gas evolution due to the high current
densities used. A major advantage of the preferred electropolishing processes
according to the invention is that they are generally more environmentally
friendly compared with the conventional methods. Additional advantages
offered are that they can be performed at room temperature and can operate
with lower power consumption, whilst providing bright reflective finishes
comparable to traditional techniques. An additional advantage of the materials
in accordance with the invention is that when they are used in electrolytic baths,
in particular plating or electropolishing baths, hydrogen evolution is significantly
reduced as compared with the acidic baths conventionally employed/This has a
number of important consequences. First, it results in a very high current
efficiency. Current efficiencies as high as 90% or more can be obtained in
favourable circumstances. Reduced hydrogen evolution is also advantageous
from the safety standpoint and significantly reduces the amount of hydrogen
embitterment that occurs in the substrate material during the electrochemical
process. It also results in plated materials having an improved surface finish,
with greatly diminished micro-cracking compared to electroplating produced by
conventional methods. This in turn can improve the corrosion resistance of the
coatings and/or allow the use of coatings which are thinner yet provide
comparable corrosion resistance to that of conventional coatings, which thus
are cheaper to produce, less consumptive of raw materials, and more
environmentally friendly.
Examples

Preparation Example A - Preparation of semi-dry choline saccharinate
ionic liquid
1,080 g of sodium saccharinate hydrate (99%, ex Acros) were mixed with 732 g
of solid choiine chloride (99%, ex Acros), using 6 I of acetone as solvent. After 8
hours of agitating, allowing for ion exchange reaction to take place, the formed
suspension was filtered. The filtrate was subjected to evaporation in a Rotavap
at a temperature of about 60°C and minimal pressure of about 40 mbar until no
further evaporation of the solvent was observed. The remaining product was a
liquid and was confirmed to be choline saccharinate by elemental chemical
composition analysis (chloride, sodium, and sulphur concentration).
Preparation Example B - Preparation of dry choline saccharinate ionic
liquid
Sodium saccharinate hydrate (99%, ex Acros) was dried at a temperature of
120oC until no further decrease in mass was observed, in order to remove any
water present. After that the dry sodium saccharinate was mixed with choline
chloride (99%, ex Acros), in 1:1 molar ratio, using acetone as solvent. After 8
hours of agitating, allowing for ion exchange reaction to take place, the formed
suspension was filtered. The filtrate was subjected to evaporation in a Rotavap
at a temperature of about 85°C and minimal pressure of about 40 mbar until no
further evaporation of the solvent was observed. The remaining product was a
liquid and was confirmed to be dry choline saccharinate by elemental chemical
composition analysis (chloride, sodium, and sulphur concentration, and also
water concentration).

Example 1 - Electroplating of copper onto brass in a semi-dry choline
saccharinate
Into prepared choline saccharinate ionic liquid that contained around 2 wt% of
water, copper (II) chloride dihydrate salt was charged and the mixture was
stirred until the solid salt dissolved. In the prepared solution the concentration of
copper was around 11 g/kg, whereas the molar ratio of the amine salt to the
copper-hydrated salt was 21:1.
Around 250 ml of the solution was poured into a Hull cell equipped with an
electrical heating element which had a length of 65 mm on the anode side and
102 mm on the cathode side, a 48 mm shortest anode-cathode distance, a 127
mm longest anode-cathode distance, and a depth of 65 mm. The cell was
heated to a temperature between 70 and 80°C. The liquid was agitated using a
centrally positioned top-entering impeller.
Platinised titanium plate was applied as the anode and connected to the
positive terminal of a DC power source, whereas brass plate was used as the
cathode (substrate) and connected to the negative terminal. Prior to introduction
into the bath, the substrate plate was cleaned with a commercial scouring
powder, washed in demineralised water, in acetone and after that in ethanol,
and finally in a 4 M-HCI aqueous solution. When both plates were connected
and introduced into the cell, the voltage difference was set to 30 V. The current
flow was monitored on a meter connected in series.
After 1.5 hours of electroplating, the cathode was disconnected from the power
source and taken out of the cell. The plate was washed in water and acetone
and then dried. On the portion of the plate submerged in the ionic liquid during
electroplating, an orangy/brown copper-deposited layer was observed. The
thickness of the layer decreased from one side of the plate to the other due to
the differences in current density at different positions of the cathode.

Example 2 - Electroplating of chromium from Cr (III) salt onto carbon steel
in a wet choline saccharinate
Into a prepared choline saccharinate ionic liquid that contained around 7 wt% of
water chromium (III) chloride hexahydrate salt was charged and the mixture
was stirred until the solid salt dissolved. To increase the ratio of the amine salt
to the chromium salt and at the same time improve the solubility of chromium
salt, choline chloride was added. In the prepared solution the concentration of
chromium (III) was around 20 g/kg, whereas the molar ratio of the amine salt to
the chromium hydrated salt was 9:1.
Around 250 ml of the solution was poured into the Hull cell described in
Example 1. The cell was heated to a temperature between 70 and 80°C. The
liquid was agitated using a centrally positioned top-entering impeller.
Platinised titanium plate was applied as the anode and connected to the
positive terminal of a DC power source, whereas carbon steel was used as the
cathode (substrate) and connected to the negative terminal. Prior to introduction
into the bath, the substrate plate was cleaned with a commercial scouring
powder, washed in demineralised water, in acetone and after that in ethanol,
and finally in a 4 M-HCI aqueous solution. When both plates were connected
and introduced into the cell, the voltage difference was set to 30 V. The current
flow was monitored on a meter connected in series.
After 5 hours of electroplating, the cathode was disconnected from the power
source and taken out of the cell. The plate was washed in water and acetone
and then dried. On the portion of the plate submerged in the ionic liquid during
the electroplating, a light grey (metallic colour) deposited layer was observed.
The thickness of the layer decreased from one side of the plate to the other due
to the differences in current density at different positions of the cathode, having
no visible layer at one side. The chemical composition of the plate was
analysed by scanning electron microscopy combined with X-ray dispersion
(SEM/EDX).

The analysis confirmed the presence of chromium at the submerged portion of
the substrate (Figure 1a), whereas no chromium was found at the non-
submerged surface (Figure 1b).
Example 3 - Electroplating of chromium from Cr (III) salt onto carbon steel
in a semi-dry choline saccharinate
Into a prepared choline saccharinate ionic liquid that contained around 2 wt% of
water chromium (III) chloride hexahydrate salt was charged and the mixture
was stirred until the solid salt dissolved. In the prepared solution the
concentration of chromium (III) was around 12 g/kg, whereas the molar ratio of
the amine salt to the chromium hydrated salt was 13:1.
Around 250 ml of the solution was poured into the Hull cell described in
Example 1. The cell was heated to a temperature between 70 and 80°C. The
liquid was agitated using a centrally positioned top-entering impeller.
Platinised titanium plate was applied as the anode and connected to the
positive terminal of a DC power source, whereas carbon steel was used as the
cathode (substrate) and connected to the negative terminal. Prior to introduction
into the bath, the substrate plate was cleaned with a commercial scouring
powder, washed in demineralised water, in acetone and after that in ethanol,
and finally in a 4 M-HCI aqueous solution. When both plates were connected
and introduced into the cell, the voltage difference was set to 30 V. The current
flow was monitored on a meter connected in series.
After 5 hours of electroplating, the cathode was disconnected from the power
source and taken out of the cell. The plate was washed in water and acetone
and then dried. The chemical analysis by scanning electron microscopy
combined with X-ray dispersion (SEM/EDX) indicated the presence of a very
thin deposited layer.

Comparative Example 4 - Electroplating of chromium from Cr (III) salt onto
carbon steel in a 2:1 molar ratio eutectic mixture of chromium (III) chloride
hexahvdrate and choline chloride
Chromium (III) chloride hexahydrate and choline chloride were mixed in a 2:1
molar ratio. The solid mixture was heated for several hours in an oven at a
temperature of around 120°C. The mixture was shaken from time to time, until
no more solids were observed. The dark green liquid product was cooled down
to room temperature.
Example 2 was repeated, but using the produced eutectic mixture of 2:1 molar
ratio of chromium (III) chloride hexahydrate and choline chloride instead of the
solution used in Example 2.
In Figure 2 the appearance of the substrates of Example 2 and Comparative
Example 4 is illustrated. It is clearly demonstrated that the method in
accordance with the present invention results in an improved visual appearance
of the plated substrate (shiny metallic instead of dark mat deposit).
Example 5 - Electroplating of chromium from CrCl3 hexahydrate salt onto
carbon steel in cocoalkylmethyl [polyoxyethylene(15)] ammonium
chloride
Chromium (III) chloride hexahydrate salt was added to cocoalkylmethyl
[polyoxyethylene(15)] ammonium chloride ionic liquid containing 0.2 wt% of
water and the mixture was agitated at a temperature of around 50°C until the
solid salt dissolved. In the prepared solution the concentration of chromium (III)
chloride hexahydrate was 75 g/kg.
Around 250 ml of that solution was poured into the Hull cell described in
Example 1. The cell was heated to a temperature between 70 and 80°C.
Platinised titanium plate was applied as the anode and connected to the
positive terminal of a DC power source, whereas carbon steel was used as the
cathode (substrate) and connected to the negative terminal. Prior to introduction

into the bath, the substrate plate was cleaned with a commercial scouring
powder, washed in demoralised water, in acetone and after that in ethanol,
and finally in a 4 M-HCI aqueous solution. When both plates were connected
and introduced into the ceil, the voltage difference was set to 30 V. The liquid
was agitated using a centrally positioned top-entering impeller. The current flow
between the electrodes was monitored on a meter connected in series.
After 18 hours of electroplating, the cathode was disconnected from the power
source and taken out of the cell. The plate was washed in water and acetone
and then dried. Chemical analysis by scanning electron microscopy combined
with X-ray dispersion (SEM/EDX) of the substrate was performed. Both the
submerged and the non-submerged part of the plate were analysed. On the
non-submerged part only iron, carbon, and oxygen were found, whereas the
submerged part contained chromium, iron, carbon, and oxygen, confirming the
deposition of the chromium onto the substrate. In addition to that, a coverage of
the submerged part of the plate by a metallic layer could be observed visually.
Example 6 - Electroplating of chromium using CrCI2 as a source of
chromium onto carbon steel in cocoalkylmethyl [polyoxyethylene(15)]
ammonium chloride
Dry chromium (ll) chloride was added to cocoalkylmethyl [polyoxyethylene(15)]
ammonium chloride ionic liquid containing 0.2 wt% of water and the mixture was
agitated at a temperature of around 50oC until the solid salt cculd be considered
dissolved. In the prepared solution the concentration of chromium (II) chloride
was 30 g/kg.
Around 250 ml gf that solution was poured into the Hull cell described in
Example 1. The cell was heated to a temperature between 70 and 80oC.
Platinised titanium plate was applied as the anode and connected to the
positive terminal of a DC power source, whereas carbon steel was used as the
cathode (substrate) and connected to the negative terminal. Prior to introduction
into the bath, the substrate plate was cleaned with a commercial scouring

powder, washed in demineralised water, in acetone and after that in ethanol,
and finally in a 4 M-HCI aqueous solution. When both plates were connected
and introduced into the cell, the voltage difference was set to 30 V. The liquid
was agitated using a centrally positioned top-entering impeller. The current flow
between the electrodes was monitored on a meter connected in series.
After 18 hours of electroplating, the cathode was disconnected from the power
source and taken out of the cell. The plate was washed in water and acetone
and then dried. On the portion of the plate submerged in the ionic liquid during
the electroplating, a light bluish-grey metallic deposited layer was observed to
cover more than 95% of the area. Chemical analysis by scanning electron
microscopy combined with X-ray dispersion (SEM/EDX) of the substrate was
performed. Both the submerged and the non-submerged part of the plate were
analysed. On the non-submerged part iron, carbon, and oxygen were found,
whereas the submerged part contained chromium, iron, and carbon, confirming
the deposition of the chromium onto the substrate
Example 7 - Electroplating of chromium using CrCI3 hexahydrate as a
source of chromium onto carbon steel in wet cocoalkylmethyl [polyoxy-
ethylene(15)] ammonium methylsulphate
Chromium (III) chloride hexahydrate was charged to cocoalkylmethyl [polyoxy-
ethylene(15)] ammonium methylsulphate ionic liquid into which 10 wt% of water
was introduced prior to the addition of chromium salt. The mixture was agitated
at a temperature of around 50°C until the solid salt dissolved. In the prepared
solution the concentration of chromium (III) chloride hexahydrate was 74 g/kg.
Around 250 ml of that solution was poured into the Hull cell described in
Example 1. The cell was heated to a temperature between 70 and 80 °C.
Platinised titanium plate was applied as the anode and connected to the
positive terminal of a DC power source, whereas carbon steel was used as the
cathode (substrate) and connected to the negative terminal. Prior to introduction
into the bath, the substrate plate was cleaned with a commercial scouring

and introduced into the cell, the voltage difference was set to 30 V. The liquid
was agitated using a centrally positioned top-entering impeller. The current flow
between the electrodes was monitored on a meter connected in series.
After 5 hours of electroplating, the cathode was disconnected from the power
source and taken out of the cell. The plate was washed in water and acetone
and then dried. Chemical analysis by scanning electron microscopy combined
with X-ray dispersion (SEM/EDX) of the substrate was performed. Both the
submerged and the non-submerged part of the plate were analysed. On the
non-submerged part iron, carbon, and oxygen were found. whereas the
submerged part contained chromium, iron, carbon, and oxygen, confirming the
deposition of the chromium onto the substrate.
Example 9 - Electroplating of chromium using chromium anode
(chromium metal chips) as a source of chromium onto carbon steel in
cocoalkyl methyl [polyoxyethylene(15)] ammonium chloride
Around 250 ml of cocoalkylmethyl [polyoxyethylene(15)] ammonium chloride
ionic liquid containing 0.2 wt% of water was poured into the Hull cell described
the Example 1. The cell was heated to a temperature between 70 and 80oC
Chromium metal chips, 2 mm thick, were charged into a titanium basket. This
basket was applied as the anode and connected to the positive terminal of a DC
power source, whereas carbon steel was used as the cathode (substrate) and
connected to the negative terminal. Prior to introduction into the bath, the
substrate plate was cleaned with a commercial scouring powder, washed in
demineralised water, in acetone and after that in ethanol, and finally in a 4 M-
HCl aqueous solution. When both plates were connected and introduced into
the cell, the voltage difference was set to 30 V. The liquid was agitated using a
centrally positioned tap-entering impeller. The current flow between the
electrodes was monitored on a meter connected in series.
After 5 hours of electroplating, the cathode was disconnected from the power
source and taken out of the cell. The plate was washd in water and acetone

and then dried. Chemical analysis by scanning electron microscopy combined
with X-ray dispersion (SEM/EDX) of the substrate was performed. Both the
submerged and the non-submerged part of the plate were analysed. On the
non-submerged part iron, carbon, and oxygen were found, whereas the
submerged part contained chromium, iron, carbon, and oxygen, confirming the
deposition of the chromium onto the substrate.
Comparative Example 10 - Electroplating of chromium from CrCI3
hexahydrate salt onto carbon steel in N-methyl-N-trioctylammonium
bis(trifiuoromethylsulphonyi)imide
Example 5 was repeated, but using N-methyl-N-trioctylammonium
bis(trifluoromethyisulphony!)imide ionic liquid (98%, ex Solvent Innovation)
instead of cocoalkylmethyl [polyoxyethylene(15)] ammonium chloride ionic liquid
as used in Example 5.
After 18 hours of electroplating, the cathode was disconnected from the power
source and taken out of the cell. The plate was washed in water and acetone
and then dried. Chemical analysis by scanning electron microscopy combined
with X-ray dispersion (SEM/EDX) of the substrate was performed. Both the
submerged and the non-submerged part of the plate were analysed. No
chromium was found on any part of the plate. Hence, no detectable chromium
deposition occurred. As under the same conditions and with the same
chromium source applied (Example 5) a chromium deposit was formed when
using cocoalkylmethyl [polyoxyethylene(15)] ammonium chloride ionic liquid,
which is covered in the present patent, the advantage of the method in
accordance with the present invention is clearly demonstrated.
Comparative Example 11-- of chromium from CrCl2 onto carbon steel in N-
methyl-N-trioctylammonium bis(trifluoromethylsulphonyl)imide

Example 6 was repeated, but using N-methyl-N-trioctylammonium
bis(trifluoromethylsulphonyl)innide ionic liquid (98%, ex Solvent Innovation)
instead of cocoalkylmethyl [polyoxyethylene(15)] ammonium chloride ionic liquid
as used in Example 6.
After 5 hours of electroplating, the cathode was disconnected from the power
source and taken out of the cell. The plate was washed in water and acetone
and then dried. Chemical analysis by scanning electron microscopy combined
with X-ray dispersion (SEM/EDX) of the substrate was performed. Both the
submerged and the non-submerged part of the plate were analysed. No
chromium was found on any part of the plate. Hence, no detectable chromium
deposition occurred. As under the same conditions and with the same
chromium source applied (Example 6) a chromium deposit was formed when
using cocoalkylmethyl [polyoxyethylene(15)] ammonium chloride ionic liquid,
which is covered in the present patent, the advantage of the method in
accordance with the present invention is clearly demonstrated.

Amended set of CLAIMS
1. Method to electroplate or electropolish a metal on a substrate wherein an
ionic liquid selected from the group of
N+R1R2R3R4 X- or
N+R5R6R7R8 Y-
is employed as electrolyte, and a metal salt added to the ionic liquid is
employed as the metal source or a metal anode is used as the metal
source, wherein any one of R1 to R8 independently represents a hydrogen,
alkyl, cycloalkyl, aryl, or aralkyl group that may be substituted with a group
selected from OH, CI, Br, F, I, phenyf, NH2, CN, NO2, COOR9, CHO,
COR9, or OR9, at least one of R5 to R8 is a saturated or unsaturated alkyl
chain having 8 to 22 carbon atoms, and one or more of R5 to R8 can be an
oxyalkylene group wherein the alkylene is a C1 to C4 alkylene and the total
number of oxyalkylene units can be from 1 to 50 oxyalkylene units, and at
least one of R1 to R8 is a C1 to C4 alkyl chain, R9 is an alkyl or cycloalkyl
group, X- is an anion having an N-acyl sulphonylimide anion functionality,
Y is an anion compatible with the N+R5R6R7R8 ammonium cation, such as
a halogenide anion, a carboxylate anion, a sulphate (both organic and
inorganic sulphate), sulphonate, carbonate, nitrate, nitrite, thiocyanate,
hydroxide, or sulphonylimide anion.
2. Method to electrodeposit according to claim 1 wherein Y- is selected from
the group of F-, Cl-, Br-, I-, SO42-, SO32-, CO32-; the group of R10COO-
anions wherein R10 may be hydrogen, a C1-C22 alkyl, alkenyl or aromatic
group; the group of R11SO4- anions wherein R11 may be hydrogen, a C1-C22
alkyl, alkenyl or aromatic group; the group of R12SO3- anions wherein R12
may be hydrogen, a C1-C22 alkyl, alkenyl or aromatic group; the group of
R13CO3- anions wherein R13 may be hydrogen, a C1-C22 alkyl, alkenyl or
aromatic group; and the group of R14-N-SO2-R15 anions wherein R14
and/or R15 independently may be hydrogen, a C1-C22 alkyl, alkenyl or

aromatic group, and R14 may be linked to the nitrogen atom with a
carbonyl group.
3. Method to electrodeposit according to claim 2 wherein Y- is CI- , Br- or
CH3SO4-.
4. Method to electrodeposit according to any one of claims 1 to 3 wherein the
ionic liquid of the formula N+R5R6R7R8 Y- has an iodine value of above 1 g
I2 per 100 g of ionic liquid.
5. A method to electrodeposit according to any one of claims 1 to 4 wherein
the molar ratio of the ammonium cation of the ionic liquid to the metal
cation of the metal salt or derived from the metal anode is between 1,000:1
and 3:1.
6. A method to electrodeposit according to claim 5 wherein the molar ratio is
between 100:1 and 7:1.
7. A method to electrodeposit according to any one of claims 1 to 6 wherein
one of the metals chromium, aluminium, or copper is deposited.
8. A method to electrodeposit according to any one of claims 1 to 7 wherein
the ionic liquid is selected from the group of choline saccharinate, choline
acesulphamate, hexadecyltrimethyl ammonium chloride, octadecyltrimethyl
ammonium chloride, cocotrimethyl ammonium chloride, tallowtrimethyl
ammonium chloride, hydrogenated tallowtrimethyl ammonium chloride,
hydrogenated palmtrimethyl ammonium chloride, oleyltrimethyl ammonium
chloride, soyatrimethyl ammonium chloride, cocobenzyldimethyl
ammonium chloride, C12-16-alkylbenzyldimethyl ammonium chloride,
hydrogenated tallowbenzyldimethyl ammonium chloride, dioctyldimethyl
ammonium chloride, didecyldimethyl ammonium chloride, dicocodimethyl

ammonium nitrite, dicocodimethyl ammonium chloride, di(hydrogenated
tallow)dimethyl ammonium chloride, di(hydrogenated tallow)benzylmethyl
ammonium chloride, ditallowdimethyl ammonium chloride,
dioctadecyldimethyl ammonium chloride, hydrogenated tallow(2-
ethylhexyl)dimethyl ammonium chloride, hydrogenated tallow(2-
ethylhexyl)dimethy) ammonium methylsulphate, trihexadecylmethyl
ammonium chloride, octadecylmethylbis(2-hydroxyethyl) ammonium
chloride, cocobis(2-hydroxyethyl)methyl ammonium nitrate, cocobis(2-
hydroxyethyl)methyl ammonium chloride, cocobis(2-hydroxyethylbenzyl
ammonium chloride, oleylbis(2-hydroxyethyl)methyl ammonium chloride,
coco[polyoxyethylene(15)]methyl ammonium chloride,
coco[polyoxyethylene(15)] methyl ammonium methylsulphate,
coco[polyoxyethylene(17)]methyl ammonium chloride,
octadecyl[polyoxyethylene(15)]methyl ammonium chloride, hydrogenated
talllow[polyoxyethylene(15)]methyl ammonium chloride, tris(2-
hydroxyethyl)tallow ammonium acetate, tallow-1,3-propane pentamethyl
diammonium dichloride.

The present invention relates to a method to electroplate or electropolish a metal on a substrate wherein an ionic liquid selected from the group of N+R1R2R3R4 X- or N+R5R6R7R8 Y- is employed as electrolyte, and a metal salt added to the ionic liquid is employed as the metal source or a metal anode is used as the metal source, wherein any one of R1 to R8 independently
represents a hydrogen, alkyl, cycloalkyl, aryl, or aralkyl group that may be substituted with a group selected from OH, Cl, Br, F, I,
phenyl, NH2, CN, NO2, COOR9, CHO, COR9, or OR9, at least one of R5 to R8 is a fatty alkyl chain, and one or more of R5 to R8 can be a (poly)oxyalkylene group wherein the alkylene is a C1 to C4 alkylene and the total number of oxyalkylene units can be from 1 to 50 oxyalkylene units, and at least one of R1 to R8 is a C1 to C4 alkyl chain, R9 is an alkyl or cycloalkyl group, X- is an anion having an
N-acyl sulphonylimide anion (-CO-N -SO2-) functionality, Y is an anion compatible with the N+R5R6R7R8 ammonium cation, such as a halogenide anion, a carboxylate anion, a sulphate (both organic and inorganic sulphate), sulphonate, carbonate, nitrate, nitrite, thiocyanate, hydroxide, or sulphonylimide anion.

Documents:

3701-KOLNP-2008-(04-07-2013)-CORRESPONDENCE.pdf

3701-KOLNP-2008-(04-07-2013)-FORM-3.pdf

3701-KOLNP-2008-(04-07-2013)-OTHERS.pdf

3701-KOLNP-2008-(14-02-2013)-CORRESPONDENCE.pdf

3701-KOLNP-2008-(14-02-2013)-OTHERS.pdf

3701-KOLNP-2008-(19-09-2013)-CLAIMS.pdf

3701-KOLNP-2008-(19-09-2013)-CORRESPONDENCE.pdf

3701-KOLNP-2008-(19-09-2013)-FORM-2.pdf

3701-KOLNP-2008-(19-09-2013)-FORM-3.pdf

3701-KOLNP-2008-(19-09-2013)-OTHERS.pdf

3701-KOLNP-2008-(19-09-2013)-PETITION UNDER RULE 137.pdf

3701-KOLNP-2008-(20-06-2012)-CORRESPONDENCE.pdf

3701-KOLNP-2008-(20-06-2012)-FORM-1.pdf

3701-KOLNP-2008-(20-06-2012)-OTHERS.pdf

3701-KOLNP-2008-(20-06-2012)-PA.pdf

3701-kolnp-2008-abstract.pdf

3701-KOLNP-2008-ASSIGNMENT.pdf

3701-kolnp-2008-claims.pdf

3701-KOLNP-2008-CORRESPONDENCE-1.1.pdf

3701-kolnp-2008-correspondence.pdf

3701-kolnp-2008-description (complete).pdf

3701-kolnp-2008-drawings.pdf

3701-kolnp-2008-form 1.pdf

3701-KOLNP-2008-FORM 13.pdf

3701-KOLNP-2008-FORM 18.pdf

3701-KOLNP-2008-FORM 3-1.1.pdf

3701-kolnp-2008-form 3.pdf

3701-kolnp-2008-form 5.pdf

3701-kolnp-2008-gpa.pdf

3701-kolnp-2008-international preliminary examination report.pdf

3701-kolnp-2008-international publication.pdf

3701-kolnp-2008-international search report.pdf

3701-kolnp-2008-others.pdf

3701-KOLNP-2008-PA.pdf

3701-kolnp-2008-pct priority document notification.pdf

3701-kolnp-2008-pct request form.pdf

3701-kolnp-2008-specification.pdf


Patent Number 260529
Indian Patent Application Number 3701/KOLNP/2008
PG Journal Number 19/2014
Publication Date 09-May-2014
Grant Date 06-May-2014
Date of Filing 10-Sep-2008
Name of Patentee AKZO NOBEL N.V.
Applicant Address VELPERWEG 76, NL-6824 BM, ARNHEM
Inventors:
# Inventor's Name Inventor's Address
1 VAN STRIEN, CORNELIS, JOHANNES, GOVARDUS KRAAIEKAMP 61, NL-6662 SJ ELST
2 BARTEL, COLIN, ERIC ORANJESTRAAT 40, NL-7331 BW APELDOORN
3 ZEITLER, MICHAEL IM WIESENGRUND 18,, 53347 ALFTER
4 SPEELMAN, JOHANNA, CHRISTINA NENGERMANHOF 9, NL-7231 BP WARNSVELD
5 KUZMANOVIC, BORIS FRANCOIS MAURIACWEG 137, NL-3731 BC DE BILT
PCT International Classification Number C25D 3/66
PCT International Application Number PCT/EP2007/051329
PCT International Filing date 2007-02-12
PCT Conventions:
# PCT Application Number Date of Convention Priority Country
1 60/778971 2006-03-06 EUROPEAN UNION
2 06101714.1 2006-02-15 EUROPEAN UNION