Organometallic salt composition, a method for its preparation and a lubricant additive composition

Abstract

The purpose of the present invention is to provide organometallic salt compositions that are useful as lubricant additives and/or in lubricant additive compositions to reduce friction and wear, and also have improved solubility in all four types of hydrocarbon base oils (Groups I-IV) at a variety of concentrations and under a variety of conditions. The organometallic salt composition is derived from at least one long chain monocarboxylic acid and a single metal in combination with at least one short or medium branched-chain monocarboxylic acid. The compositions are particularly useful in combination with activated complexes comprising a first metal component, a second metal component and particles comprising the first metal component.

Claims

1. An organometallic salt composition comprising: salt of a single metal of at least one C.sub.13 to C.sub.22 monocarboxylic acid, and at least one C.sub.4-C.sub.12 branched-chain monocarboxylic acid, said organometallic salt composition having a solubility in hydrocarbon oils exceeding 0.1 w-% in all of hydrocarbon oil Groups I, II, III and IV.

2. The organometallic salt composition according to claim 1 having a solubility in Group I, II, III and IV hydrocarbon oils exceeding 0.5 w-%.

3. The organometallic salt composition according to claim 1, wherein the at least one saturated branched-chain contains at least one branched alkyl group that is methyl or ethyl.

4. The organometallic salt composition according to claim 3, wherein the at least one saturated short or medium branched chain monocarboxylic acid is 2-ethylhexanoic acid.

5. The organometallic salt composition according to claim 1, wherein the long chain carboxylic acid is oleic acid.

6. The organometallic salt composition according to claim 1, wherein the metal salt of the at least one long chain carboxylic acid is copper oleate.

7. The organometallic salt composition according to claim 1, wherein the organometallic salt is soluble in the hydrocarbon oil for at least one week at a temperature in the range 18 to 24? C.

8. The organometallic salt composition according to claim 1, wherein the organometallic salt is soluble in the hydrocarbon oil at a ratio of hydrocarbon oil to organometallic salt composition ranging from 100:1 to 200:1 in Group II, III and IV base oils.

9. A method for preparing an organometallic salt composition comprising the steps of: reacting a long chain carboxylic acid with a metal carbonate selected from the group consisting of silver, gold, palladium, copper, cobalt, lead, tin, bismuth, molybdenum, titanium, tungsten and nickel carbonate, and adding a short or medium branched-chain monocarboxylic acid in a weight amount in the range of 2 to 20 w-% of the total mass of the salt composition.

10. The method according to claim 9, wherein the metal carbonate comprises copper or cobalt carbonate.

11. The method according to claim 9, wherein the molar ratio of the carboxylic acid to the metal of the carbonate reactant is in the range 1:1 to 20:1.

12. The method according to claim 9, wherein the organometallic salt is heated to about 60? C. and the short or medium branched-chain monocarboxylic acid is added with vigorous mixing.

13. The method according to claim 9, wherein the weight ratio of organometallic salt and saturated short or medium branched chain monocarboxylic acid to make the organometallic salt composition is 5:1 to 50:1.

14. A lubricant additive composition comprising an organometallic salt composition optionally combined with further additive components, wherein the organometallic salt composition comprises: salt of a single metal of at least one C.sub.13 to C.sub.22 monocarboxylic acid, and at least C.sub.4-C.sub.12 branched-chain monocarboxylic acid, said organometallic salt composition having a solubility in hydrocarbon oils exceeding 0.1 w-% in all of hydrocarbon oil Groups, I, II, III and IV.

15. The lubricant additive composition according to claim 14, further comprising an activated complex containing: a first metal component and a second metal component, and particles comprising the first metal component and optionally the second metal component.

16. The lubricant additive composition according to claim 14 having a solubility in Group I, II, III or IV hydrocarbon oils exceeding 0.1 w-%.

17. (canceled)

Description

DETAILED DESCRIPTION OF THE INVENTION

[0031] The organometallic salt compositions derived from long chain monocarboxylic acids with short or medium branched-chain monocarboxylic acids useful in this invention may be characterized by way of both their generalized preparation route and certain common aspects of their structures.

[0032] The first step in the preparation of the organometallic salts in the present invention generally involves the reaction of a metal carbonate, for example copper carbonate, with at least one long chain monocarboxylic, acid, for example oleic acid. A wide range in the proportions of the carboxylic acid may be employed, such that the molar ratio of the carboxylic acid to the metal of the carbonate reactant may range from 1:1 to 20:1.

[0033] The intermediate organometallic, salts used in the invention may, more specifically, be derived from the reaction of monocarboxylic acids in the range C.sub.13 to C.sub.22 and the selected metal carbonate. Examples of the acids include saturated monocarboxylic, acids such as lauric, myristic, palmitic or stearic. Preferably unsaturated acids should be used such as linolenic, linoleic and oleic acids. Saturated and unsaturated branched monocarboxylic acids can also be used, for example iso-stearic acid. Optionally naphthenic acids or synthetic carboxylic acids can be used.

[0034] The metal carbonate comprises one of silver, gold, palladium, copper, cobalt, lead, tin, bismuth, molybdenum, titanium, tungsten and nickel as metal element. More preferably, the metal carbonate comprises copper or cobalt, and most preferably copper.

[0035] In a second step, the organometallic salt compositions are prepared by reacting an organometallic salt derived from one or more long chain monocarboxylic acids, for example copper oleate, with at least one short or medium branched-chain monocarboxylic acid, for example 2-ethylhexanoic acid. Initially, the carboxylic acid salt is heated to about 60? C. until it is in liquid form. The short or medium branched-chain monocarboxylic acid is added with vigorous mixing. A wide range in the proportions of the short or medium branched-chain monocarboxylic acid may be employed, such that the weight ratio of the organometallic salt and the short or medium branched-chain monocarboxylic acid may range from 2:1 to 50:1. A ratio in the range of 5:1 to 20:1 is preferred, and the range 10:1 to 20:1 is most preferred.

[0036] Saturated short or medium branched chain monocarboxylic acids are preferred in the present invention. They should contain at least one branched alkyl group and 4 to 11 carbon atoms (C.sub.4 to C.sub.11), preferably 6 to 10 carbon atoms (C.sub.6 to C.sub.10) and most preferably 8 carbon atoms (C.sub.8). Examples include 2-ethylhexanoic acid, 2-methylbutyric acid, 2-ethylbutanoic acid, 2-methylpentanoic acid, 3-methylpentanoic acid, 4-methylpentanoic acid, 2-methylhexanoic acid, 5-methylhexanoic acid, 4-methyloctanoic acid, 4-methylnonanoic acid; more preferably 2-ethylbutyric acid and 2-ethylhexanoic acid; most preferably 2-ethylhexanoic acid.

[0037] Preferably, the lubricant additive is soluble in the hydrocarbon base oil both after initial mixing and for at least one week. Temperatures used for solubility testing herein include room temperature, which for the purpose of this specification is 18-24? C.

[0038] Conventional organometallic salts used as lubricant additives are typically not significantly soluble in Groups II, III or IV hydrocarbon oils. This means that the superior additives and lubricants according to the invention may be used in many applications where previously only lower performance conventional additives could be deployed.

[0039] It has been surprisingly and unexpectedly found that the organometallic salt compositions obtained by the process of the present invention, for example copper oleate reacted with 2-ethylhexanoic acid, are liquids at room temperature when the weight ratio of organometallic salt to short or medium branched chain monocarboxylic acid is in the range 5:1 to 50:1. This is especially surprising because for example, the individual compounds copper oleate and copper 2-ethylhexanoate are both solids at room temperature. The additives comprising the organometallic salt compositions according to the present invention have improved handling characteristics.

[0040] Importantly, it has been found that the organometallic salt compositions according to the current invention can be formulated with other suitable components leading to lubricant additive compositions that have improved solubility in Group I, II, III or IV hydrocarbon oils that also provide reduced friction and lower fuel and/or energy consumption as well as reduced emissions. The lubricant additive compositions according to the present invention enable the development of lubricants that do not comprise high amounts of phosphorus or sulphur based compounds. Moreover, the lubricant additive compositions enable increased wear protection, longer oil drain intervals and grease change intervals, and reduced maintenance as well as extended operational lifetime.

[0041] The organometallic salt composition according to the current invention can be combined with an activated complex containing a first metal component and a second metal component. Particles, preferably nanoparticles, are formed to provide a lubricant additive composition, and the particles include the first metal component in metallic form. The second metal component is able to reduce the metal element in the first metal component. The second metal component should be able to influence the redox potential of the metal element in the first metal component. The activated complex should contain a component that functions as a ligand. The ligand can be either a surfactant or a dispersant; examples are succinimide, poylethoxylated tallow amide and diethanol amine. The activated complex should comprise particles including the first metal component and optionally the second metal component. The activated complex should contain at least one compound improving the solubility of an oxidized form of the metal element in the first metal component, e.g. epoxy resin of diethylene glycol or epoxidized dipropylene glycol.

[0042] In addition, the activated complex also comprises at least one reducing agent, e.g. diphenyl amine or hexadecyl amine. Preferably, the difference of the standard electrode potentials of the metal element in the second metal component and the metal element in the first metal component is at least 0.2 V, based on the metallic form of each metal element and the first stable oxidized stage. Preferably, the first metal component comprises gold, silver, copper, palladium, tin, cobalt, zinc, bismuth, manganese and/or molybdenum, especially preferably copper and/or cobalt, more preferably copper. Preferably, the second metal component comprises tin, bismuth, zinc, and/or molybdenum, especially preferably, tin, bismuth and/or zinc, more preferably tin. Also preferably, the particles including a second metal component comprises the first metal component in metallic form.

[0043] The particles comprising the first and optionally the second metal component exhibit a diameter in the range of 1 to 10 000 nm, preferably in the range of 5 to 1000 nm, more preferably in the range of 10 to 500 nm, especially preferably in the range of 15 to 400 nm.

[0044] Preferably, the lubricant additive composition described above comprises a soluble metal compound derived from the first metal component. Preferably, this lubricant additive composition is able to form metal plating. This lubricant additive composition has a solubility in Group I, II, III or IV hydrocarbon oils exceeding 0.1 w-%, preferably 0.5 w-%, in all the hydrocarbon oil groups.

[0045] In the production of the activated complex, one or more alcohols are advantageously used as a reductant, solvent and/or cosolvent. Preferably, an alcohol comprising ether groups can be used, such as glycols alkylated with alkyl groups having 1 to 20 carbon atoms, e.g. diethylene glycol, Further, an alcohol having 1 to 20 carbon atoms, preferably 4 to 12 carbon atoms, such as octanol, is advantageously present.

[0046] Preferably, the weight ratio of the organometallic salt composition to the activated complex is in the range of 10000:1 to 1:1.

[0047] The preparation of the relevant activated complexes and their combination with organometallic salt compositions according to the present invention is illustrated further in example 12 below.

[0048] Processes for obtaining the activated complex referred to above are disclosed in further detail in international patent application No. PCT/EP2015/060811, hereby incorporated by reference.

EXAMPLES

Example 1

Preparation of a Modified Organometallic Salt According to the Present Invention

[0049] The modified organometallic salt of the present invention can be prepared by reacting a metal salt, preferably a metal carbonate where the metal is copper, with a fatty acid, preferably oleic acid, so that the metal content of the metal carboxylate provides a metal concentration in the final salt in the range of 8-9 w-%, after which a branched short- or medium-chained monocarboxylic acid is added to the metal carboxylate. The copper carbonate and the oleic acid are reacted in an oxygen-free environment for 16 h at 150? C. After the reaction, 2-ethylhexanoic acid is added to the copper oleate at a ratio of 7.5% of the total mass of the mixture. This will result in a copper-based organometallic salt composition that is liquid at room temperature and has a melting point of 10? C., whereas a copper oleate with a metal content in the range of 8-9% not containing the branched short- or medium-chain monocarboxylic acid has a melting point of 55? C. The melting temperature was determined visually. The metal content was verified by analysis with MP-AES.

Example 2

How Melting Point is Affected by the Amount of Added Short-Chain Branched Organic Acid

[0050] A modified organometallic salt was prepared according to the present invention by adding 2-ethylhexanoic acid at an amount of 11.25% of the total mass of the modified organometallic salt to copper oleate with a metal content in the range of 8-9%. The addition of 11.25% of 2-ethylhexanoic acid lowered the melting temperature of the modified organometallic salt to 4? C., whereas a modified organometallic salt of example 1 containing 7.5% 2-ethylhexanoic acid has a melting point of 10? C., and an organometallic salt consisting of only copper oleate has a melting point of 55? C. The melting temperature was determined visually.

Example 3

How Melting Point is Affected by the Amount of Added Short-Chain Branched Organic Acid

[0051] A modified organometallic salt was prepared according to the present invention by adding 2-ethylhexanoic acid at an amount of 15% of the total mass of the modified organometallic salt to copper oleate with a metal content in the range of 8-9%. The addition of 15% of 2-ethylhexanoic acid lowered the melting temperature of the modified organometallic salt to below 0? C., whereas a modified organometallic salt of example 2 containing 11.25% 2-ethylhexanoic acid has a melting point of 4? C., a modified organometallic salt of example 1 containing 7.5% 2-ethylhexanoic acid has a melting point of 10? C., and an organometallic salt consisting of only copper oleate has a melting point of 55? C. The melting temperature was determined visually.

Example 4

How Melting Point is Affected by Metal Content of the Metal Carboxylate and the Amount of Branched Short- or Medium-Chain Monocarboxylic Acid

[0052] To determine how the metal content and the content of branched short- or medium-chain monocarboxylic acid affect the melting temperatures of the modified organometallic salts, modified organometallic salts according to the present invention containing copper oleate with metal content in the range of 2-9% and 2-ethylhexanoic acid in the range of 1-10% were prepared. The melting temperatures were determined visually and are listed in Table 1. The metal content was verified by analysis with MP-AES.

TABLE-US-00001 TABLE 1 Melting temperatures of copper-based modified organic salts with metal content in the range of 2-9% with an addition of 2-ethylhexanoic acid in the range of 1-10% 0% 1% 2% 3% 4% 5% 6% 7% 8% 9% 10% % Cu 2-EHA 2-EHA 2-EHA 2-EHA 2-EHA 2-EHA 2-EHA 2-EHA 2-EHA 2-EHA 2-EHA 2.2% 16? C. 2? C. <0? C. <0? C. <0? C. <0? C. <0? C. <0? C. <0? C. <0? C. <0? C. 4.4% 35? C. 21? C. 13? C. 6? C. 5? C. 3? C. 2? C. <0? C. <0? C. <0? C. <0? C. 6.2% 40? C. >room >room >room >room 14? C. 7? C. 4? C. 2? C. <0? C. <0? C. temp temp temp temp 8.6% 50? C. >room >room >room >room >room >room 10? C. 8? C. 5? C. 2? C. temp temp temp temp temp temp

Example 5

Preparation of Other Organometallic Salts According to the Present Invention

[0053] Metal carboxylates were prepared by reacting metal carbonates with oleic acid under vacuum at 150? C. for 16 h. The metal carbonates used were bismuth subcarbonate and cobalt carbonate. The metal content by weight of the metal oleates were 5-10%. 2-ethylhexanoic acid was added at 5%, 10% and 15% of total mass of the organometallic salt until the melting temperature of the organometallic salt reached 0? C. or below 0? C. The melting temperatures are listed in Table 2.

TABLE-US-00002 TABLE 2 Melting temperatures of bismuth and cobalt- based organometallic salt compositions. 0% 5% 10% 15% Metal carboxylate 2-EHA 2-EHA 2-EHA 2-EHA Bismuth oleate 3? C. <0? C. (5% Bi) Cobalt oleate 65? C. 35? C. 15? C. <0? C. (10% Co)

Example 6

Solubility of the Organometallic Salt Composition of the Present Invention in a Group II Base Oil

[0054] Copper based modified organometallic salts of the present invention as prepared in examples 1, 2 and 3 were blended into a Group II base oil at concentrations in the range of 0.3-3.0%. Solubility was determined visually by following the samples for 14 weeks. The results are presented in Table 3. The modified organometallic salts were regarded as soluble if no phase separation or opacity of the sample was observed.

TABLE-US-00003 TABLE 3 Solubility in a Group II base oil. Organometallic salt of the 0% present 2-EHA 7.5% 11.25% 15% invention reference 2-EHA 2-EHA 2-EHA 0.3% slightly insoluble soluble soluble soluble 0.5% phase separation soluble soluble soluble .sup.1% phase separation soluble soluble soluble 1.5% phase separation slightly insoluble slightly insoluble slightly insoluble .sup.2% phase separation phase separation phase separation phase separation 2.5% phase separation phase separation phase separation phase separation .sup.3% phase separation phase separation phase separation phase separation

[0055] The solubility of copper oleate in a Group II base oil is below 0.3%. According to the present invention, the addition of 2-ethylhexanoic acid to copper oleate results in an organometallic salt composition with improved solubility in the said base stock.

Example 7

Solubility of the Present Invention in Group III Base Oils

[0056] Copper based modified organometallic salts of the present invention as prepared in examples 1, 2 and 3 were blended into a Group III base oil at concentrations in the range of 0.3%-3%. Solubility was determined visually by following the samples for 12 weeks. The results are presented in Table 4. The modified organometallic salts were regarded as soluble if no phase separation or opacity of the sample was observed.

TABLE-US-00004 TABLE 4 Solubility in a Group III base oil. Organometallic salt of the present 0% 7.5% 11.25% 15% invention 2-EHA 2-EHA 2-EHA 2-EHA 0.3% phase separation soluble soluble soluble 0.5% phase separation soluble soluble soluble .sup.1% phase separation soluble soluble soluble 1.5% phase separation soluble soluble soluble .sup.2% phase separation soluble soluble soluble 2.5% phase separation slightly insoluble soluble soluble .sup.3% phase separation slightly insoluble soluble soluble

[0057] Copper oleate is insoluble in a Group III base oil. According to the present invention the addition of 2-ethylhexanoic acid to copper oleate results in a modified organometallic salt with improved solubility in the said base stock.

Example 8

Solubility of the Present Invention in a Group IV Base Oil

[0058] Copper based modified organometallic salts of the present invention as prepared in example 1, 2 and 3 were blended into a Group II base oil at concentrations in the range of 0.3-3.0%. Solubility was determined visually by following the samples for 14 weeks. The results are presented in Table 4. The modified organometallic salts were regarded as soluble if no phase separation or opacity of the sample was observed.

TABLE-US-00005 TABLE 5 Solubility in a Group IV base oil (PAO). Organometallic salt of the 0% present 2-EHA 7.5% 11.25% 15% invention reference 2-EHA 2-EHA 2-EHA 0.3% clear phase soluble soluble soluble separation 0.5% clear phase soluble soluble soluble separation .sup.1% clear phase slightly slightly slightly separation insoluble insoluble insoluble 1.5% clear phase phase phase phase separation separation separation separation .sup.2% clear phase clear phase clear phase clear phase separation separation separation separation 2.5% clear phase clear phase clear phase clear phase separation separation separation separation .sup.3% clear phase clear phase clear phase clear phase separation separation separation separation

[0059] Copper oleate is insoluble in a Group IV base oil. According to the present invention the addition of 2-ethylhexanoic acid to copper oleate results in a modified organometallic salt with improved solubility in the said base stock.

Example 9

Preparation of an Organometallic Salt Composition by Adding a Branched Long-Chain Monocarboxylic Acid to Copper Oleate

[0060] To investigate the possibility of obtaining a modified organometallic salt containing a branched long-chain monocarboxylic acid with a melting temperature below ambient temperature, modified organometallic salts were prepared by adding iso-stearic acid at an amount of 1-7%, 10% and 15% of the total mass of the modified organometallic salt to copper oleate with a metal content in the range of 8-9%. The iso-stearic acid was added to copper oleate heated to 60? C. under vigorous mixing. The samples were stirred for 15 minutes to ensure homogeneity. The samples solidified as the temperature of the samples reached ambient temperature.

Example 10

Tribological Effects of the Organometallic Salt Composition

[0061] The tribological effects of the organometallic salt composition was demonstrated in tribology tests on a ball-on-three-plates system. An organometallic salt composition of the present invention was prepared by mixing copper oleate with 8 w-% 2-ethylhexanoic acid under vigorous mixing at 60-70? C. The composition was added to Chevron Taro 30 DP 40 in concentrations of 0.3%, 1% and 3% and heated to 60-70? C. under stirring for 15 min. The homogeneous oil mixtures were allowed to cool at ambient conditions. The samples were tested by tribology measurements using an Anton Paar rotational rheometer.

[0062] The measurement starts with a running-in phase to ensure flattening of the sample and constant measuring conditions. This is done at 1200 rpm for 30 minutes. After running-in the friction behavior is measured in the Striebeck phase during the next 10 minutes. The measuring regime starts at 0 rpm and the speed increases during the 10 minutes to 3000 rpm. The normal force is 6 N and the temperature 100? C. throughout the measurement. Wear is measured by analyzing the wear scars on the plates with optical microscope and imaging software after friction analysis.

[0063] In Examples 11 and 12, the following parameters for friction and wear tests are used:

TABLE-US-00006 Normal force F.sub.N 6 N Temperature 100? C. Running-in phase 1200 rpm, 30 min Striebeck phase 0-3000 rpm, 10 min

[0064] The results of this testing are given in Table 5 and 6.

TABLE-US-00007 TABLE 6 Friction behavior of the samples. Sample Weight COF at COF at COF at COF at COF at description ratio 0.0001 m/s 0.001 m/s 0.01 m/s 0.1 m/s 1 m/s Reference oil/ 100/0 0.121 0.121 0.0976 0.109 0.0987 no additive Oil/organometallic 99.7/0.3 0.0578 0.0767 0.0846 0.1035 0.0780 salt composition Oil/organometallic 99/1 0.0538 0.0642 0.0782 0.0983 0.088 salt composition Oil/organometallic 97/3 0.0506 0.0588 0.0694 0.0886 0.0591 salt composition

TABLE-US-00008 TABLE 7 Wear behavior of the samples. Sample Weight Wear rate description ratio [nm/h] Reference oil/ 100/0 4192 no additive Oil/organometallic 99.7/0.3 2442 salt composition Oil/organometallic 99/1 2176 salt composition Oil/organometallic 97/3 3589 salt composition

[0065] From the tribology measurements it became apparent that the composition of the present invention has an advantageous impact on the friction and wear behavior.

Example 11

Tribological Effects of the Lubricant Additive Composition

[0066] An activated complex was added to a reducible adduct in order to demonstrate the tribological effects of the lubricant additive composition in tribology tests on a ball-on-three-plates system. A composition of the present invention was prepared by adding an activated complex as described in international patent application PCT/EP2015/060811 to the organometallic salt composition as prepared in Example 9 at a ratio of 2.35 w-% under vigorous mixing at 60-70? C. The composition of the present invention was added to Chevron Taro 30 DP 40 at concentrations of 0.3%, 1% and 3% and heated to 60-70? C. under stirring for 15 min. The homogeneous oil mixtures were allowed to cool at ambient conditions. The samples were tested by tribology measurements using an Anton Paar rotational rheometer according to the conditions described in example 9. The results are given in Table 7 and 8.

TABLE-US-00009 TABLE 8 Friction behavior of the samples. Sample Weight COF at COF at COF at COF at COF at description ratio 0.0001 m/s 0.001 m/s 0.01 m/s 0.1 m/s 1 m/s Reference oil/ 100/0 0.121 0.121 0.0976 0.109 0.0987 no additive Oil/additive 99.7/0.3 0.0706 0.0692 0.07745 0.0955 0.0755 composition Oil/additive 99/1 0.06875 0.06475 0.07435 0.0928 0.0755 composition Oil/additive 97/3 0.0539 0.05545 0.06805 0.0876 0.0825 composition

TABLE-US-00010 TABLE 9 Wear behavior of the samples. Sample Weight Wear rate description ratio [nm/h] Reference oil/ 100/0 4192 no additive Oil/additive 99.7/0.3 3059 composition Oil/additive 99/1 1924 composition Oil/additive 97/3 1870 composition

[0067] From the tribology measurements it became apparent that the composition of the present invention has an advantageous impact on the friction and wear behavior.

Example 12

Preparation of Combinations of an Activated Complex and an Organometallic Salt Composition According to the Invention

[0068] a) Organometallic Salt Composition Based on Copper

[0069] The preparation of the activated complex involves a three-step process.

[0070] The first step is preparation of copper (II) chloride solution. Diethylene glycol (about 3.5 kg) was placed in a glass-lined vessel fitted with a stirrer and heating capability. This was heated to about 40? C. and copper chloride (0.357 kg) was slowly added with stirring to ensure the material is totally dissolved. C-5A succinimide (2.1 kg) was then slowly added with stirring but no heating. Diphenylamine (1.72 kg) was next added in small portions and the mixture was stirred to ensure it was homogenous. Finally DEG-1 epoxy resin (1.86 kg) was added and thoroughly stirred.

[0071] The second step is preparation of tin (IV) chloride solution. In a separate glass-lined vessel fitted with a stirrer and heating capability, Tin (IV) chloride pentahydrate (4.2 kg) was dissolved in octanol (about 9.8 kg) by stirring the mixture at about 40? C.

[0072] The third step is making of the activated complex. In a separate glass-lined vessel fitted with a stirrer and cooling capability, the tin (IV) chloride solution prepared above was added to the copper (II) chloride solution also prepared above under stirring. The tin (IV) chloride solution was added in small portions and the temperature must be maintained below 50? C. After the addition was complete the mixture was stirred for a further period to ensure it was homogenous.

[0073] The activated complex (3 grams) is added to a solution of copper-based organometallic salt composition (125 grams) prepared according to Example 1 in a glass-lined vessel fitted with a stirrer and heating capability. The temperature of the mixture was maintained at about 60? C. and stirred for a further period to ensure it was homogenous.

[0074] b) Organometallic Salt Composition Based on Cobalt

[0075] A modified organometallic salt according to the present invention is prepared by reacting cobalt carbonate with oleic acid, so that the metal content of the metal carboxylate provides a metal concentration in the final salt in the range of 8-9 w-%, after which 2-ethylhexanoic acid is added to the metal carboxylate. Cobalt carbonate hexahydrate and oleic acid are reacted in an oxygen-free environment for 16 h at 150? C. After the reaction, 2-ethylhexanoic acid is added to the cobalt oleate at a ratio of 10% of the total mass of the mixture. This will result in a cobalt-based organometallic salt composition that is liquid at room temperature and has a melting point of 15? C. The melting point was determined visually. The metal content was verified by analysis with MP-AES.

[0076] Preparation of the activated complex is carried out as described above.

[0077] The activated complex (3 grams) made above is added to the cobalt-based organometallic salt composition (125 grams) in a glass-lined vessel fitted with a stirrer and heating capability. The temperature of the mixture was maintained at about 60? C. and stirred for a further period to ensure it was homogenous.