CA2160669A1 - Bismuth dithiocarbamates and their use as additive for lubricants - Google Patents
Bismuth dithiocarbamates and their use as additive for lubricantsInfo
- Publication number
- CA2160669A1 CA2160669A1 CA002160669A CA2160669A CA2160669A1 CA 2160669 A1 CA2160669 A1 CA 2160669A1 CA 002160669 A CA002160669 A CA 002160669A CA 2160669 A CA2160669 A CA 2160669A CA 2160669 A1 CA2160669 A1 CA 2160669A1
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- CA
- Canada
- Prior art keywords
- alkyl
- optionally substituted
- bismuth
- compound
- oil
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Abandoned
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Classifications
-
- C—CHEMISTRY; METALLURGY
- C07—ORGANIC CHEMISTRY
- C07C—ACYCLIC OR CARBOCYCLIC COMPOUNDS
- C07C333/00—Derivatives of thiocarbamic acids, i.e. compounds containing any of the groups, the nitrogen atom not being part of nitro or nitroso groups
- C07C333/14—Dithiocarbamic acids; Derivatives thereof
- C07C333/16—Salts of dithiocarbamic acids
-
- C—CHEMISTRY; METALLURGY
- C10—PETROLEUM, GAS OR COKE INDUSTRIES; TECHNICAL GASES CONTAINING CARBON MONOXIDE; FUELS; LUBRICANTS; PEAT
- C10M—LUBRICATING COMPOSITIONS; USE OF CHEMICAL SUBSTANCES EITHER ALONE OR AS LUBRICATING INGREDIENTS IN A LUBRICATING COMPOSITION
- C10M2207/00—Organic non-macromolecular hydrocarbon compounds containing hydrogen, carbon and oxygen as ingredients in lubricant compositions
- C10M2207/10—Carboxylix acids; Neutral salts thereof
- C10M2207/12—Carboxylix acids; Neutral salts thereof having carboxyl groups bound to acyclic or cycloaliphatic carbon atoms
- C10M2207/125—Carboxylix acids; Neutral salts thereof having carboxyl groups bound to acyclic or cycloaliphatic carbon atoms having hydrocarbon chains of eight up to twenty-nine carbon atoms, i.e. fatty acids
-
- C—CHEMISTRY; METALLURGY
- C10—PETROLEUM, GAS OR COKE INDUSTRIES; TECHNICAL GASES CONTAINING CARBON MONOXIDE; FUELS; LUBRICANTS; PEAT
- C10M—LUBRICATING COMPOSITIONS; USE OF CHEMICAL SUBSTANCES EITHER ALONE OR AS LUBRICATING INGREDIENTS IN A LUBRICATING COMPOSITION
- C10M2219/00—Organic non-macromolecular compounds containing sulfur, selenium or tellurium as ingredients in lubricant compositions
- C10M2219/06—Thio-acids; Thiocyanates; Derivatives thereof
- C10M2219/062—Thio-acids; Thiocyanates; Derivatives thereof having carbon-to-sulfur double bonds
- C10M2219/066—Thiocarbamic type compounds
- C10M2219/068—Thiocarbamate metal salts
-
- C—CHEMISTRY; METALLURGY
- C10—PETROLEUM, GAS OR COKE INDUSTRIES; TECHNICAL GASES CONTAINING CARBON MONOXIDE; FUELS; LUBRICANTS; PEAT
- C10N—INDEXING SCHEME ASSOCIATED WITH SUBCLASS C10M RELATING TO LUBRICATING COMPOSITIONS
- C10N2010/00—Metal present as such or in compounds
- C10N2010/02—Groups 1 or 11
-
- C—CHEMISTRY; METALLURGY
- C10—PETROLEUM, GAS OR COKE INDUSTRIES; TECHNICAL GASES CONTAINING CARBON MONOXIDE; FUELS; LUBRICANTS; PEAT
- C10N—INDEXING SCHEME ASSOCIATED WITH SUBCLASS C10M RELATING TO LUBRICATING COMPOSITIONS
- C10N2010/00—Metal present as such or in compounds
- C10N2010/10—Groups 5 or 15
-
- C—CHEMISTRY; METALLURGY
- C10—PETROLEUM, GAS OR COKE INDUSTRIES; TECHNICAL GASES CONTAINING CARBON MONOXIDE; FUELS; LUBRICANTS; PEAT
- C10N—INDEXING SCHEME ASSOCIATED WITH SUBCLASS C10M RELATING TO LUBRICATING COMPOSITIONS
- C10N2040/00—Specified use or application for which the lubricating composition is intended
- C10N2040/02—Bearings
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- Chemical & Material Sciences (AREA)
- Organic Chemistry (AREA)
- Lubricants (AREA)
Abstract
Certain bismuth tris-(di-organic substituted dithiocarbamate) salts are useful as extreme pressure (EP) additives in oils and greases.
The bismuth compounds have EP properties which are as good as or better than those of the corresponding analogous antimony compounds which have previously been suggested and used as EP additives in lubricants. Some of the bismuth compounds, particularly where the substitution includes C6 alkyl or longer, or branched alkyl groups, are novel compounds.
The bismuth compounds have EP properties which are as good as or better than those of the corresponding analogous antimony compounds which have previously been suggested and used as EP additives in lubricants. Some of the bismuth compounds, particularly where the substitution includes C6 alkyl or longer, or branched alkyl groups, are novel compounds.
Description
Bismuth dithiocarbamates and their use as additive for lubricants This invention relates to organic bismuth compounds and their use as extreme pressure lubricant additives in oils and greases.
In some types of gears and particularly heavily loaded bearings where both high pressure and high rubbing velocities are present, it is difficult to maintain a thin film of lubricant between the gear or bearing surfaces. When this thin film breaks, the mating metal surfaces become susceptible to increased wear. This is particularly marked in bearings where the mating metal surfaces can weld together.
When the weld shears under the relative motion of the surfaces, particles of metal are removed which further damage the metal surfaces of the gears and bearings and can seriously impairing performance.
In order to overcome such problems, special compounds have been developed as extreme pressure (commonly referred to as EP) additives for lubricant oils and greases. Thus, US 3139405 discloses the use of antimony salts of dialkyldithiocarbamic acids as EP additives, especially antimony dipentyl- and dihexyl- dithiocarbamates. This patent states that these two compounds impart "amazingly high load-bearing capacity" to lubricants and this is stated to be surprising and unexpected since various other metallic salts of dialkyldithio-carbamic acids tested alongside the antimony compounds impart only moderate or low load bearing capacities to lubricants or are ineffective e.g. by being insoluble. These other compounds include two short chain linear alkyl, di-butyl and di-amyl (di-n-pentyl), bismuth tris-dialkyldithiocarbamates. The antimony compounds described in US 3139405 have been successfully used as EP additives for many years and are commercially available e.g. under the trade name Vanlube 73. However, none of the antimony dialkyldithio-carbamates is ideal; some exhibit low solubility and/or poor stability in typical lubricant systems and, furthermore, antimony salts are toxic and can cause health and environmental problems.
In contrast to the teaching of US 3139405 we have now found that certain bismuth salts of dialkyldithiocarbamic acids are useful as EP
additives for lubricants, such as oils and greases. Some of these bismuth compounds give superior results as EP additives and/or better WO 94i24100 '' ~ ~ 6 ~ 6 6 PCT/GB94/00830 compatibility and/or stability in the lubricant as compared with their antimony analogues.
Accordingly, the present invention provides a compound of the formula (I~:
[ Rl.R2 - N - C(S) - S - ]3 Bi (I) where each Rl and R2 is, independently, Cl_l2 alkyl, C7_lz aralkyl optionally substituted by Cl_l2 alkyl, cyclohexyl optionally substituted by Cl_l2 alkyl; or Rl and R2 together with the nitrogen atom to which they are attached form a heterocyclic ring optionally substituted by Cl_l2 alkyl, with the provlso that Rl and R2 sre not both ethyl, n-butyl or n-pentyl.
Preferably, Rl is Cl_l2 alkyl, C7_l2 aralkyl optionally substituted by Cl_l2 alkyl or cyclohexyl op~innnl1y substituted by Cl_l2 alkyl; and R2 is C6_l2 alkyl, C7_l2 aralkyl optionally substituted by Cl_l2 alkyl, cyclohe~yl opt~ nnn 1 ly substituted by Cl_lz alkyl, isopropyl, isobutyl, tertiary butyl or branched pentyl.
- When Rl or R2 represents or includes alkyl, the alkyl group may be linear or branched. Examples of alkyl are methyl, ethyl, isopropyl, butyl, pentyl, hexyl, heptyl, octyl, nonyl, decyl, dodecyl, l-methyl-pentyl, 2-ethylbutyl, 2-ethylhexyl and l-methylhexyl.
When Rl or R2 is aralkyl it is preferably benzyl or phenylethyl, optionally substituted in the phenyl ring by Cl_l2 alkyl. The phenyl ring msy contain more than one alkyl group, but preferably carries one alkyl group which is preferably present in the 4-position. An example of an alkyl substituted aralkyl group is 4-methylbenzyl.
When Rl or R2 is alkyl substituted cyclohexyl, the cyclohexyl ring may contain more than one alkyl substituent. However, when substituted by alkyl, it is preferably a singly alkyl substituent, which is preferably in the 4-position. Eramples of such substituted cyclohexyl groups are 4-methylcyclohexyl, 4-propylcyclohexyl, 4-butyl-cyclohexyl, 4-isopropylcyclohexyl, 4-tertiary butylcyclohexyl and 4-nonylcyclohexyl.
~ 0 94/24100 . PCTIGB94/00830 2I6066~
When Rl and R2 together with the nitrogen atom to which they are attached form a heterocyclic ring, the ring preferably contains 6 atoms as in morpholino, piperazino or piperidino. Where the ring is piperazino, both nitrogen atoms may carry a dithiocarbamyl radical whereby there is the possibility that the resulting bismuth salt is polymeric. However, it is preferred that one of the nitrogen atoms of the piperazino ring is substituted by Cl_l2 alkyl, especially Cl_g alkyl and more especially Cl_4 alkyl.
When Rl or R2 is alkyl substituted aralkyl or cyclohexyl or Rl and R2 together with the nitrogen atom to which they are attached form an N-alkyl piperazino ring, the alkyl group is preferably Cl_8 alkyl, and especially Cl_4 alkyl and may be linear or br~nrho~.
It is preferred that Rl and R2 are both linear or br~rhpd C1_l2 alkyl, and it i9 especially preferred that at least one of Rl and R2 is, or contains, branched alkyl since such compounds are easier to formulate and dissolve in oils and greases than when.Rl and R2 are both linear alkyl. Generally, we have obtained good results when Rl or R2 and desirably Rl and R2 are not both linear short chain (Cl_s) alkyl groups and this forms a particular aspect of the invention. Rl and R2 can be mixed groups, particularly of groups of the same carbon chain length e.g. mixed pentyl groups.
Although Rl and RZ may be different, they are preferably the same because of the greater av~ bil~ty of symmetrical secondary amines from which the dialkyldithiocarbamic acids are conveniently derivable.
In this context, 'symmetrical secondary amines' include amines made with mixed alkyl groups, especially of the same chain length as in secondary (mixed pentyl) amine.
The bismuth salts may be made from the single dialkyldithio-carbamic acid or may be made from a mixture of such acids. When the bismuth salt is made from a mixture of dialkyldithiocarbamic acids the three dialkyldithiocarbamic acid radicals in formula (I) are not the same. In certain circumstances it is beneficial to use a mixture of acids since compatibility of the EP additive in a lubricant system such as an oil or grease can be increased.
The dialkyldithiocarbamic acids can be made by methods known in the art. However, since some dialkyldithiocarbamic acids are -WO 94/24100 6 69 PCTtGB94tO0830 unstable, they are generally made as a salt which exhibits greater stability. The salt may be formed with an amine or an alkali metal.
In one preferred method, the salt is formed with an amine and is typically made by reacting an excess of a secondary amine of the formula RlR2NH with carbon disulphide in an appropriate organic solvent. The amount of amine used is preferably, 10 moles, more preferably S moles and especially 2 moles per mole of carbon disulphide. Such a method is described for example in Mém. services Chim état, (Paris), 34, 411-12 (1948). Preferred solvents are inert to the reactants and include ketones such as acetone. The reaction is facile and is generally carried out at temperatures below 60C, preferably below ZOC and especially below 10C. In another preferred method, stoi~hi~ -tric amounts of the amine and carbon disulphide are reacted together, and the dialkyldithiocarb~m;c acid then converted to a salt, e.g. an alkali metal salt, by addition of a base, e.g. an alkali metal hydroxide.
The bismuth salts of this invention are preferably made by reacting the appropriate dialkylti~hioc~rbamic acid with a suitable bil th halide such as bismuth trichloride in the presence of a suitable organic reaction ~ lm. Generally, 1 mole of bismuth halide i8 used with about three moles of the dithiocarbamic acid. The organic reaction medium is desirably chosen to be a solvent for the dialkyldithiocsrbamic acid and a non-solvent (or a poor solvent) for the bismuth salt to ease separation of the bismuth salt from the reaction mixture. However, if a volatile organic reaction ~ m is used differential solubility of the bismuth salt is less important as the solvent can be removed by evaporation and the bismuth salt purified in conventional manner, for example, by recrystallisation.
Suitable solvents for the reaction of the bismuth trih~ e with the dialkyldithiocarbamic acid are aliphatic hydrocarbons and chloro-hydrocarbons and, especially, ketones such as acetone. The reaction is typically carried out at temperatures below lZOC, preferably below 100C and especially below 60C. Where appropriate, the reaction may be carried out in a solvent at reflux.
The bismuth salts of this invention are typically pale yellow solids melting below 100C if derived from dialkyldithiocarbamic acids~
216066~9 PCrlGB94/00830 cont~;~i ng linear alkyl groups, but they can be oily liquids if derived from a dialkyldithiocarbamic acid con~;ning branched alkyl groups.
Particularly good EP properties in oils and greases have been obtained with bismuth tris-[bis-(2-ethylhexyl)dithiocarbamate], bismuth tris-(dihexyldithiocarbamate) and bismuth tris-[di(branched pentyl)dithiocarbamate].
As described above, the bismuth salts of this invention exhibit useful properties as EP additives in lubricating oils and gresses.
Some also exhibit useful antioxidant properties and superior stability to the antimony analogues, especially against light.
Thus, in a further aspect, the invention provides a composition comprising a bismuth salt of the formula I and a lubricant. The lubricant is preferably an oil or a gresse.
In a further aspect, the invention provides a composition comprising a grease and ce ,_ ~ of the formula (Ia):
[ Rl.R2 _ N - CtS) - S - ]3 Bi ~Ia) where each Rl and R2 is, indepPn~n~ly, Cl_lz alkyl, C7_12 aralkyl optionally substituted by C1_12 alkyl, cyclohexyl optionally substituted by C1_12 alkyl or Rl and R2 together with the nitrogen atom to which they are attached form a heterocyclic ring optionally substituted by C1_12 alkyl.
In a still further aspect, the invention provides a composition comprising an oil and a compound of the formula (Ib):
[ R1.R2 - N - C(S) - S - ]3 Bi (Ib) where each Rl and R2 is, independently, Cl-12 alkyl, C7-12 aralkyl optionally substituted by C1_12 alkyl, cyclohexyl optionally substituted by C1_12 alkyl; or Rl and R2 together with the nitrogen atom to which they are WO 94/Z4l00 2~6~66 PCT/CB94/U083 attached form a heterocyclic ring optionally substituted by Cl_lz alkyl, with the proviso that when Rl and R2 are either both n-pentyl or n-butyl the oil is not a SAE 90, high viscosity index, mineral oil having a viscosity of 87 seconds Saybolt viscosity at 210F
(equivalent to about 17 cSt at 100C) and 1030 seconds Saybolt viscosity at 100F (equivalent to about 190 cSt at 40C).
One preferred class of oils are gear or engines oils having a viscosity above about 200 cSt at 40C, more preferably above 300 and especially above 400 cSt at 40C. Such oils preferably have a viscosity below 1500 cSt at 40C and especially below 1000 cSt at 40C.
Another preferred class of oils are lighter gear or engine oils having a viscosity below 180, more preferably below 150 and especially below 100 cSt at 40C. Such oils preferably have a viscosity above 10 and especially above 20 cSt at 40C.
The bismuth salt is typically used at a concentration of at least 0.01~, preferably at least 0.12, more preferably at least 0.5~, and especially at least 2Z by weight, based on the total weight of the lubricant. The bismuth salt may be present at a concentration up to 102, preferably up to 8Z, more preferably up to 6~ and especially up to 52 by weight, based on the total weight of the lubricant.
The term oil includes oils such as those described in standard texts on lubrication such as ~schmiermittel-Taschenhllch n by Schewe-Kobak, (~uethig Verlang, Heidelburg, 1974) and in ~Schmierstoffe and Verwandte Produkte~ by D Kl~ , (Verlage Chemie, Weinheim, 1982) and also those described in US 3139405.
The oil is preferably a mineral oil or a synthetic oil or a mixture of such oils. Examples of synthetic oils include polyalkylene glycols; poly(alpha-olefins); esters, especially phthalates;
perfluoroalkylethers and silicones.
Preferred lubricants are industrial oils especially gear and hydraulic oils.
The oil may contain other additives which are generally incorporated in fluid lubricant, such as metal passivating agents, viscosity index improvers, pour point depressants, dispersing agents.
~ O 94/21lOU ~ 66~
detergents, and other additives providing protection against wear, extreme pressure, corrosion, rusting and oxidation.
The grease is preferably a mineral or synthetic oil as described above which has been thickened by the addition of a gelling agent.
The gelling agents may be a soap, such as a lithium soap, a lithium complex soap, a non-soap gelling agent such as a clay, a carbon black, a silica or a polyurea which is preferably incorporated into the oil in finely divided form. The clay is preferably surface coated with an organic material to aid dispersion in the oil, such as a quaternary r i compound. Where the grease is based on a silicone oil, the non-soap gelling agent is preferably sillca, especially fused silica having an average particle diameter below one ~m.
Metals which benefit from protection by the bismuth salt include iron and copper and especially alloys such as steel and brass. As disclosed above, bismuth salts of the fo_ l~e (I), (Ia) and (Ib) has been found par~c-~lnrly effect as an EP additive in a lubricant where the metals are in frictional contsct and form part of a gear or bearing.
~ ccordingly in a further aspect, the invent$on provides the use of a compound of one of the formula (I), (Ia) and (Ib) as an EP additive for a lubricant, especially an oil or a grease.
In a yet further aspect, the invention provides a metal surface, particularly a gear and especially a bearing which is treated with a bismuth salt of one of the formula (I), (Ia) and (Ib) or a lubricant composition cont~ning a bismuth salt of one of the formula (I), (Ia) and (Ib).
The invention further includes a method of lubricating one or more surfaces, especially of mating metal surfaces, which comprises including in a lubricant, particularly a lubricating oil or grease, for the one or more surfaces a bismuth salt of one of the formula (I), (Ia) and (Ib), particularly in an amount of from O.l to lOZ by weight of the lubricant.
In some types of gears and particularly heavily loaded bearings where both high pressure and high rubbing velocities are present, it is difficult to maintain a thin film of lubricant between the gear or bearing surfaces. When this thin film breaks, the mating metal surfaces become susceptible to increased wear. This is particularly marked in bearings where the mating metal surfaces can weld together.
When the weld shears under the relative motion of the surfaces, particles of metal are removed which further damage the metal surfaces of the gears and bearings and can seriously impairing performance.
In order to overcome such problems, special compounds have been developed as extreme pressure (commonly referred to as EP) additives for lubricant oils and greases. Thus, US 3139405 discloses the use of antimony salts of dialkyldithiocarbamic acids as EP additives, especially antimony dipentyl- and dihexyl- dithiocarbamates. This patent states that these two compounds impart "amazingly high load-bearing capacity" to lubricants and this is stated to be surprising and unexpected since various other metallic salts of dialkyldithio-carbamic acids tested alongside the antimony compounds impart only moderate or low load bearing capacities to lubricants or are ineffective e.g. by being insoluble. These other compounds include two short chain linear alkyl, di-butyl and di-amyl (di-n-pentyl), bismuth tris-dialkyldithiocarbamates. The antimony compounds described in US 3139405 have been successfully used as EP additives for many years and are commercially available e.g. under the trade name Vanlube 73. However, none of the antimony dialkyldithio-carbamates is ideal; some exhibit low solubility and/or poor stability in typical lubricant systems and, furthermore, antimony salts are toxic and can cause health and environmental problems.
In contrast to the teaching of US 3139405 we have now found that certain bismuth salts of dialkyldithiocarbamic acids are useful as EP
additives for lubricants, such as oils and greases. Some of these bismuth compounds give superior results as EP additives and/or better WO 94i24100 '' ~ ~ 6 ~ 6 6 PCT/GB94/00830 compatibility and/or stability in the lubricant as compared with their antimony analogues.
Accordingly, the present invention provides a compound of the formula (I~:
[ Rl.R2 - N - C(S) - S - ]3 Bi (I) where each Rl and R2 is, independently, Cl_l2 alkyl, C7_lz aralkyl optionally substituted by Cl_l2 alkyl, cyclohexyl optionally substituted by Cl_l2 alkyl; or Rl and R2 together with the nitrogen atom to which they are attached form a heterocyclic ring optionally substituted by Cl_l2 alkyl, with the provlso that Rl and R2 sre not both ethyl, n-butyl or n-pentyl.
Preferably, Rl is Cl_l2 alkyl, C7_l2 aralkyl optionally substituted by Cl_l2 alkyl or cyclohexyl op~innnl1y substituted by Cl_l2 alkyl; and R2 is C6_l2 alkyl, C7_l2 aralkyl optionally substituted by Cl_l2 alkyl, cyclohe~yl opt~ nnn 1 ly substituted by Cl_lz alkyl, isopropyl, isobutyl, tertiary butyl or branched pentyl.
- When Rl or R2 represents or includes alkyl, the alkyl group may be linear or branched. Examples of alkyl are methyl, ethyl, isopropyl, butyl, pentyl, hexyl, heptyl, octyl, nonyl, decyl, dodecyl, l-methyl-pentyl, 2-ethylbutyl, 2-ethylhexyl and l-methylhexyl.
When Rl or R2 is aralkyl it is preferably benzyl or phenylethyl, optionally substituted in the phenyl ring by Cl_l2 alkyl. The phenyl ring msy contain more than one alkyl group, but preferably carries one alkyl group which is preferably present in the 4-position. An example of an alkyl substituted aralkyl group is 4-methylbenzyl.
When Rl or R2 is alkyl substituted cyclohexyl, the cyclohexyl ring may contain more than one alkyl substituent. However, when substituted by alkyl, it is preferably a singly alkyl substituent, which is preferably in the 4-position. Eramples of such substituted cyclohexyl groups are 4-methylcyclohexyl, 4-propylcyclohexyl, 4-butyl-cyclohexyl, 4-isopropylcyclohexyl, 4-tertiary butylcyclohexyl and 4-nonylcyclohexyl.
~ 0 94/24100 . PCTIGB94/00830 2I6066~
When Rl and R2 together with the nitrogen atom to which they are attached form a heterocyclic ring, the ring preferably contains 6 atoms as in morpholino, piperazino or piperidino. Where the ring is piperazino, both nitrogen atoms may carry a dithiocarbamyl radical whereby there is the possibility that the resulting bismuth salt is polymeric. However, it is preferred that one of the nitrogen atoms of the piperazino ring is substituted by Cl_l2 alkyl, especially Cl_g alkyl and more especially Cl_4 alkyl.
When Rl or R2 is alkyl substituted aralkyl or cyclohexyl or Rl and R2 together with the nitrogen atom to which they are attached form an N-alkyl piperazino ring, the alkyl group is preferably Cl_8 alkyl, and especially Cl_4 alkyl and may be linear or br~nrho~.
It is preferred that Rl and R2 are both linear or br~rhpd C1_l2 alkyl, and it i9 especially preferred that at least one of Rl and R2 is, or contains, branched alkyl since such compounds are easier to formulate and dissolve in oils and greases than when.Rl and R2 are both linear alkyl. Generally, we have obtained good results when Rl or R2 and desirably Rl and R2 are not both linear short chain (Cl_s) alkyl groups and this forms a particular aspect of the invention. Rl and R2 can be mixed groups, particularly of groups of the same carbon chain length e.g. mixed pentyl groups.
Although Rl and RZ may be different, they are preferably the same because of the greater av~ bil~ty of symmetrical secondary amines from which the dialkyldithiocarbamic acids are conveniently derivable.
In this context, 'symmetrical secondary amines' include amines made with mixed alkyl groups, especially of the same chain length as in secondary (mixed pentyl) amine.
The bismuth salts may be made from the single dialkyldithio-carbamic acid or may be made from a mixture of such acids. When the bismuth salt is made from a mixture of dialkyldithiocarbamic acids the three dialkyldithiocarbamic acid radicals in formula (I) are not the same. In certain circumstances it is beneficial to use a mixture of acids since compatibility of the EP additive in a lubricant system such as an oil or grease can be increased.
The dialkyldithiocarbamic acids can be made by methods known in the art. However, since some dialkyldithiocarbamic acids are -WO 94/24100 6 69 PCTtGB94tO0830 unstable, they are generally made as a salt which exhibits greater stability. The salt may be formed with an amine or an alkali metal.
In one preferred method, the salt is formed with an amine and is typically made by reacting an excess of a secondary amine of the formula RlR2NH with carbon disulphide in an appropriate organic solvent. The amount of amine used is preferably, 10 moles, more preferably S moles and especially 2 moles per mole of carbon disulphide. Such a method is described for example in Mém. services Chim état, (Paris), 34, 411-12 (1948). Preferred solvents are inert to the reactants and include ketones such as acetone. The reaction is facile and is generally carried out at temperatures below 60C, preferably below ZOC and especially below 10C. In another preferred method, stoi~hi~ -tric amounts of the amine and carbon disulphide are reacted together, and the dialkyldithiocarb~m;c acid then converted to a salt, e.g. an alkali metal salt, by addition of a base, e.g. an alkali metal hydroxide.
The bismuth salts of this invention are preferably made by reacting the appropriate dialkylti~hioc~rbamic acid with a suitable bil th halide such as bismuth trichloride in the presence of a suitable organic reaction ~ lm. Generally, 1 mole of bismuth halide i8 used with about three moles of the dithiocarbamic acid. The organic reaction medium is desirably chosen to be a solvent for the dialkyldithiocsrbamic acid and a non-solvent (or a poor solvent) for the bismuth salt to ease separation of the bismuth salt from the reaction mixture. However, if a volatile organic reaction ~ m is used differential solubility of the bismuth salt is less important as the solvent can be removed by evaporation and the bismuth salt purified in conventional manner, for example, by recrystallisation.
Suitable solvents for the reaction of the bismuth trih~ e with the dialkyldithiocarbamic acid are aliphatic hydrocarbons and chloro-hydrocarbons and, especially, ketones such as acetone. The reaction is typically carried out at temperatures below lZOC, preferably below 100C and especially below 60C. Where appropriate, the reaction may be carried out in a solvent at reflux.
The bismuth salts of this invention are typically pale yellow solids melting below 100C if derived from dialkyldithiocarbamic acids~
216066~9 PCrlGB94/00830 cont~;~i ng linear alkyl groups, but they can be oily liquids if derived from a dialkyldithiocarbamic acid con~;ning branched alkyl groups.
Particularly good EP properties in oils and greases have been obtained with bismuth tris-[bis-(2-ethylhexyl)dithiocarbamate], bismuth tris-(dihexyldithiocarbamate) and bismuth tris-[di(branched pentyl)dithiocarbamate].
As described above, the bismuth salts of this invention exhibit useful properties as EP additives in lubricating oils and gresses.
Some also exhibit useful antioxidant properties and superior stability to the antimony analogues, especially against light.
Thus, in a further aspect, the invention provides a composition comprising a bismuth salt of the formula I and a lubricant. The lubricant is preferably an oil or a gresse.
In a further aspect, the invention provides a composition comprising a grease and ce ,_ ~ of the formula (Ia):
[ Rl.R2 _ N - CtS) - S - ]3 Bi ~Ia) where each Rl and R2 is, indepPn~n~ly, Cl_lz alkyl, C7_12 aralkyl optionally substituted by C1_12 alkyl, cyclohexyl optionally substituted by C1_12 alkyl or Rl and R2 together with the nitrogen atom to which they are attached form a heterocyclic ring optionally substituted by C1_12 alkyl.
In a still further aspect, the invention provides a composition comprising an oil and a compound of the formula (Ib):
[ R1.R2 - N - C(S) - S - ]3 Bi (Ib) where each Rl and R2 is, independently, Cl-12 alkyl, C7-12 aralkyl optionally substituted by C1_12 alkyl, cyclohexyl optionally substituted by C1_12 alkyl; or Rl and R2 together with the nitrogen atom to which they are WO 94/Z4l00 2~6~66 PCT/CB94/U083 attached form a heterocyclic ring optionally substituted by Cl_lz alkyl, with the proviso that when Rl and R2 are either both n-pentyl or n-butyl the oil is not a SAE 90, high viscosity index, mineral oil having a viscosity of 87 seconds Saybolt viscosity at 210F
(equivalent to about 17 cSt at 100C) and 1030 seconds Saybolt viscosity at 100F (equivalent to about 190 cSt at 40C).
One preferred class of oils are gear or engines oils having a viscosity above about 200 cSt at 40C, more preferably above 300 and especially above 400 cSt at 40C. Such oils preferably have a viscosity below 1500 cSt at 40C and especially below 1000 cSt at 40C.
Another preferred class of oils are lighter gear or engine oils having a viscosity below 180, more preferably below 150 and especially below 100 cSt at 40C. Such oils preferably have a viscosity above 10 and especially above 20 cSt at 40C.
The bismuth salt is typically used at a concentration of at least 0.01~, preferably at least 0.12, more preferably at least 0.5~, and especially at least 2Z by weight, based on the total weight of the lubricant. The bismuth salt may be present at a concentration up to 102, preferably up to 8Z, more preferably up to 6~ and especially up to 52 by weight, based on the total weight of the lubricant.
The term oil includes oils such as those described in standard texts on lubrication such as ~schmiermittel-Taschenhllch n by Schewe-Kobak, (~uethig Verlang, Heidelburg, 1974) and in ~Schmierstoffe and Verwandte Produkte~ by D Kl~ , (Verlage Chemie, Weinheim, 1982) and also those described in US 3139405.
The oil is preferably a mineral oil or a synthetic oil or a mixture of such oils. Examples of synthetic oils include polyalkylene glycols; poly(alpha-olefins); esters, especially phthalates;
perfluoroalkylethers and silicones.
Preferred lubricants are industrial oils especially gear and hydraulic oils.
The oil may contain other additives which are generally incorporated in fluid lubricant, such as metal passivating agents, viscosity index improvers, pour point depressants, dispersing agents.
~ O 94/21lOU ~ 66~
detergents, and other additives providing protection against wear, extreme pressure, corrosion, rusting and oxidation.
The grease is preferably a mineral or synthetic oil as described above which has been thickened by the addition of a gelling agent.
The gelling agents may be a soap, such as a lithium soap, a lithium complex soap, a non-soap gelling agent such as a clay, a carbon black, a silica or a polyurea which is preferably incorporated into the oil in finely divided form. The clay is preferably surface coated with an organic material to aid dispersion in the oil, such as a quaternary r i compound. Where the grease is based on a silicone oil, the non-soap gelling agent is preferably sillca, especially fused silica having an average particle diameter below one ~m.
Metals which benefit from protection by the bismuth salt include iron and copper and especially alloys such as steel and brass. As disclosed above, bismuth salts of the fo_ l~e (I), (Ia) and (Ib) has been found par~c-~lnrly effect as an EP additive in a lubricant where the metals are in frictional contsct and form part of a gear or bearing.
~ ccordingly in a further aspect, the invent$on provides the use of a compound of one of the formula (I), (Ia) and (Ib) as an EP additive for a lubricant, especially an oil or a grease.
In a yet further aspect, the invention provides a metal surface, particularly a gear and especially a bearing which is treated with a bismuth salt of one of the formula (I), (Ia) and (Ib) or a lubricant composition cont~ning a bismuth salt of one of the formula (I), (Ia) and (Ib).
The invention further includes a method of lubricating one or more surfaces, especially of mating metal surfaces, which comprises including in a lubricant, particularly a lubricating oil or grease, for the one or more surfaces a bismuth salt of one of the formula (I), (Ia) and (Ib), particularly in an amount of from O.l to lOZ by weight of the lubricant.
2 1 6 ~ 6 ~ 9 PCT/GB94/00830 ~
The invention is further illustrated in the following examples in which all parts are by weight unless stated to the contrary.
Materials BDAC bismuth tris-(di-n-pentyldithiocarbamate) made in Comparative Synthesis Example C.
BDAC (mixed) is bismuth tris-~di-(mixed pentyl isomers)dithio-carbamate] made in Synthesis Example 3.
BDHC is bismuth tris-(dihexyldithiocarbamate) made in synthesis Esample 1 BDHC is bismuth tris-(dihexyldi~hioc~rbamate) BDEHC is bismuth tris-[di-(2-ethylhexyl)dithiocarbamate]
ADHC is antimony tris-(dihexyldithiocarbamate) made in Comparative Synthesis Example A.
ADAC is antimony tris-(dipentyldithiocarbamate) made in Comparative Synthesis Example B
ADAC (mixed) is antimony tris-[di-(mixed pentyl isomers) dithiocarbamate] made in Comparative Synthesis Example D
Vanlube 73 is a commercially avsilable nnt~ y tris-(dialkyldithio-carbamate) EP additive from Vanderbilt C~ . ~, New York USA.
Synthesis Example 1 Bismuth tris-(dihexyldithiocarbamate) a) dihexyldithiocarbamic acid dihexylamine salt Carbon disulphide (13 g; 0.17 mol) dissolved in acetone (75 ml) was slowly added over 20 minutes. with stirring to a solution of dihexylamine ~63.02 g; 0.34 mol) in acetone (75 ml) keeping the temperature below 5C. The acetone solution (193.8 g) was stirred for a further 30 minutes and was used directly in the preparation of the bismuth salt described below without isolation of ~he scid.
b) bismuth tris-(dihexyldithiocarbamate) (BDHC) The solution of dihexyldithiocarbamic acid salt in acetone (96.9 g) was stirred with anhydrous bismuth trichloride (7.89 g;
0 94/24100 ~6g PCT/GB94/00830 0.025 mol), and then heated to reflux at 56C for about 30 minutes.
The product separated as a yellow solid. Most of the acetone was removed by distillation to leave the product as a yellow slurry.
Water (250 ml) was added and the solid filtered off, washed with water(200 ml) followed by methanol (100 ml). The product was finally recrystallised from ethanol.
Yield: 20.76 g (74~ of theory); mp 79.8 - 80.4C.
Elemental analysis:- Theory 47.3~C; 7.9ZH; 4.22N, 19.4~S; 21.1ZBi Found 47.32C; 7.9~H; 4.2~N; 18.8~S; Z0.5~Bi Comparative Synthesis ExamPle A
Antimony tris-(dlhexyldithiocarbamate) tADHC) The preparation of Synthesis Example l(b) was repeated, but substituting ~nti y trichloride (5.63 g; 0.025 mol) for the bismuth trichloride. The antimony salt was obtained as a pale yellow crys~nlli n~ solid.
Yield: 15.84 g (622 theory); mp 69.6 - 71.2C.
Elemental analysis:- Theory 51.9ZC; 8.72H; 4.71N; 21.3ZS; 13.52Sb Found 52.02C; 8.3ZH; 4.7~N; 20.4ZS; 13.5~Sb Synthesis Example 2 Bismuth tris-[di-(mixed pentyl isomers) dithiocarbamate~ (BDAC mixed) Synthesis Example 1 was repeated. but substituting dipentylamine based on mixed pentyl isomers cont~;nin~ about 80~ branched pentyl groups (53.5 g; 0.34 mol; from Aldrich Chemicals) for the dihexylamine used in Synthesis Example 1. The bismuth tris-[di(mixed pentyl isomers) dithiocarbamate] was obtained as yellow solution in acetone. The product was recovered by distilling off the acetone and washing with methanol (4 x 200 ml) to remove excess amine. The methanol, which formed an upper layer, was decanted and the residual oily product dissolved in methylene chloride. This was washed with a waterlmethanol mixture (80:~0) (4 x 40 ml). The methylene chloride WO 94/24100 ~ ~ PCT/GB94/00830 '6 ~ --solution was then dried over anhydrous sodium sulphate. screened and the methylene chloride evaporated to give the title product as a yellow oily liquid which slowly solidified on st~n~ing to yield a waxy solid.
Yield: 12.5 g (55.3Z of theory).
Elemental analysis:- Theory 43.7ZC; 7.3~H; 4.6ZN; Zl.2ZS;
Found 43.6~C; 7.1X~; 4.5~N; 19.3ZS
Synthesis Exam~le 3 Bismuth tris-[di-(2-ethylhexyl)dithiocarbamate] (BDE~C) Synthesis Example 2 was repeated, but substituting di-2-ethylhexylamine (25 g; 0.34 mol) for the mixed isomer dipentylPmine used in Synthesis Example 2. The bismuth tris-(di-2-ethylhexyldithiocarbama~e) was obtained as a yellow solution in acetone. The product was recovered by dis~ n~ off the acetone.
Methanol (200 ml) was added and the mi~ture cooled to 0C. The upper solution was decanted off and the product washed further with methanol (3 x 100 ml). A check of the decanted solution on the last wnshing indicated the absence of further amine. The residual oily product dissolved in methylene chloride, washed three times with water/
methanol mixture (80:20) (total volume 100 ml), dried over anhydrous sodium sulphate, filtered and the methylene chloride evaporated to give the title product as an orange oily liquid.
Yield: 20.2 g (70Z of theory).
Com~arative Synthesis Example B
Antimony tris-(di-n-pentyldithiocarbamate) (ADAC) Di-n-pentyldithiocarbamic acid salt was prepared as described in Example l(a), but substituting di-n-pentylamine (53.5 g; 0.34 mol;
from Aldrich Chemicals) for the dihexylamine.
The antimony salt was prepared by the method described in comparative Example A, but substituting di-n-pentyldithiocarbamic acid for the dihexyldithiocarbamic acid. The title product was obtained as a pale yellow solid.
0 9412~100 ~ ~ 6 0 PCTIGB94/~0830 Yield: 13.7 g (67Z of theory); mp 70.2 - 71.0C.
Elemental Analysis:- Theory 48.4ZC; 8.lZH; 5.lZN; 23.5ZS; 14.9ZSb Found 48.7ZC; 8.3ZH; 5.lZN; 23.1ZS; 14.4ZSb Comparative Synthesis Example C
Bismuth tris-(di-n-pentyldithiocarbamate) (BDAC) - The title compound was made by the method described in Example l(a) and (b), but substituting di-n-pentylamine (53.5 g; 0.34 mol;
from Aldrich Chemicals) for the dihexylamine. The product was obtained as a yellow solid.
Yield: 16.2 g (71Z of theory); mp 69 - 70C.
Elemental Analysis:- Theory 43.7ZC; 7.3ZH; 4.6ZN; 21.22S; 23.1ZBi Found 44.ZZC; 7.5ZH; 4.6ZN: 21.3ZS; 22.7ZBi Comparative Synthesis Example D
Antimony tris-ldi-(m$xed pentyl isomers) dithiocarbamate] (ADAC mixed) Es~mple 3 was repeated, but substituting ant$mony trichloride for bismuth trichloride as described in Comparative E~ample A. The product was isolated as a yellow oily liquid.
Yield: 12.96 g (63.3Z of theory).
Elemental Analysis:- Theory 48.3ZC; 8.lZH; 5.lZN; 23.4ZS
Found 48.8ZC; 7.9ZH; 5.1ZN; 22.6ZS
APplication ExamPle 1 Various bismuth tris-(dithiocarbamates), and certain antimony tris-(dithiocarbamates) as controls, were added to samples of a highly refined neutral petroleum based base oil having a viscosity of approximately lOOcSt at 40C to give an additive concentration of 0.0035 mol.(100 g oil)~l. These samples were subjected to a four ball test according to British Institute of Petroleum test IP 239 and the load at which welding occurred was measured. A control contn;n;ng no 21~
EP additive was included. The sdditives, concentrations and welding loads are set out in Table 1 below.
The results show that the bismuth tris-tdialkyldithiocarbamates) are effective EP additives in the petroleum based oil.
APPlication Example 2 Various antimony and bismuth tris-(dithiocarbamates) were evaluated as EP additives at a concentration of 0.0035 mol.(100 g oil)~l as described in Application Example 1 and the loading deter~inP~ at which welding occurred. The results show that the bismuth tris-(dialkyldith~ocnrbamates) are effective EP additives in the petroleum based oil. It i8 particularly notable that antimony tris-(dipentyldithiocarbamate) made from linear dipentylamine (ADAC) and from mixed isomers of dipentylamine (ADAC mixed) behave very similarly as EP additives in the petroleum based oil. These antimony salts behave very similarly as EP additives to Yanlube 73.
Remarkably, the bi th salts BDAC, BDAC (mised) and BDHC all eshibit superior p ope-Lles as EP additives in the oil. th~s is contrary to the tesrh~ngs of US 3139405 which demonstrates that both bismuth tris-(dipentyldithiocarbamate) and bi_ th tri8-(dibutyldi~h;oc~rbamate) ' are significantly inferior to the antimony analogues.
-AP~lication Example 3 Various antimony and bismuth tris-(dithiocarbamates) were evaluated as EP additives in a lithium hydroxystearate soap thic~pnpd grease. The base grease had a total soap content of 9.4Z by weight, lithium 0.22Z and glycerol 0.6Z, which was dispersed in a refined mineral oil derived from North West European crude having a specific gravity of 0.88, a viscosity of 576 seconds Saybolt at 100F (about 120 cSt at 40C) and 67 seconds Saybolt at Z10F (about 12 cSt at 100C), a viscosity index of 95, closed flash point of 480F (250C) and pour point of -15F (-26C). The compounds listed in Table 3 below were mixed into the grease, with heating as necessary, to distribute the compound uniformly throughout the grease, to give a concentration of 0.0035 mol.(100 g grease)~1. The results of four ball testing as described in application Example 1 is included in ~ O 94i~4100 - 13 _ 60~ PcT/GB94~on83o Table 3. These results indicate that the bismuth salts exhibit similar performance in this grease to the antimony analogues. This is unexpected from the teachings of US 3139405.
Applicstion Example 4 Application Example 1 was repeated using a lighter mineral oil, Vitrea 22 (from Shell) having a viscosity of about 24 cSt at 40C.
The results are set out in Table 4 below. These show that the bismuth salt exhibits a similar relative advantage over the antimony analogue as established for the oil described in Application Example 1.
W O 94/24100~ ~ 6 ~ 6 ~ PCT/GB94/00830 Table 1 AdditiveconcentrationWeld load (Zw/w) (kgf) BDHC 3.42 S10 BDE~C 4.0 380 ADHC 3.12 310 ADAC 2.83 370 Control - 150 Table 2 AdditiveconcentrationWeld load (~w/w) (kgf) ADAC 2.83 3?0 ADAC (mixed) 2.83 370 Vanlube 736.40 330 BDAC 3.13 560 BDAC (mixed) 3.13 610 BD~C 3.42 S10 Control - 150 Table 3 AdditiveconcentrationWeld load (~w/w) (kgf) ADAC 2.83 330 ADAC (mixed) 2.83 350 Vanlube 73 6.4 340 BDAC 3.13 360 BDAC (mixed) 3.13 300 BDHC 3.42 380 Control - 130 Table 4 AdditiveconcentrationWeld load (~w/w) (kgf) ADAC mixed2.83 240 BDAC mixed3.13 370
The invention is further illustrated in the following examples in which all parts are by weight unless stated to the contrary.
Materials BDAC bismuth tris-(di-n-pentyldithiocarbamate) made in Comparative Synthesis Example C.
BDAC (mixed) is bismuth tris-~di-(mixed pentyl isomers)dithio-carbamate] made in Synthesis Example 3.
BDHC is bismuth tris-(dihexyldithiocarbamate) made in synthesis Esample 1 BDHC is bismuth tris-(dihexyldi~hioc~rbamate) BDEHC is bismuth tris-[di-(2-ethylhexyl)dithiocarbamate]
ADHC is antimony tris-(dihexyldithiocarbamate) made in Comparative Synthesis Example A.
ADAC is antimony tris-(dipentyldithiocarbamate) made in Comparative Synthesis Example B
ADAC (mixed) is antimony tris-[di-(mixed pentyl isomers) dithiocarbamate] made in Comparative Synthesis Example D
Vanlube 73 is a commercially avsilable nnt~ y tris-(dialkyldithio-carbamate) EP additive from Vanderbilt C~ . ~, New York USA.
Synthesis Example 1 Bismuth tris-(dihexyldithiocarbamate) a) dihexyldithiocarbamic acid dihexylamine salt Carbon disulphide (13 g; 0.17 mol) dissolved in acetone (75 ml) was slowly added over 20 minutes. with stirring to a solution of dihexylamine ~63.02 g; 0.34 mol) in acetone (75 ml) keeping the temperature below 5C. The acetone solution (193.8 g) was stirred for a further 30 minutes and was used directly in the preparation of the bismuth salt described below without isolation of ~he scid.
b) bismuth tris-(dihexyldithiocarbamate) (BDHC) The solution of dihexyldithiocarbamic acid salt in acetone (96.9 g) was stirred with anhydrous bismuth trichloride (7.89 g;
0 94/24100 ~6g PCT/GB94/00830 0.025 mol), and then heated to reflux at 56C for about 30 minutes.
The product separated as a yellow solid. Most of the acetone was removed by distillation to leave the product as a yellow slurry.
Water (250 ml) was added and the solid filtered off, washed with water(200 ml) followed by methanol (100 ml). The product was finally recrystallised from ethanol.
Yield: 20.76 g (74~ of theory); mp 79.8 - 80.4C.
Elemental analysis:- Theory 47.3~C; 7.9ZH; 4.22N, 19.4~S; 21.1ZBi Found 47.32C; 7.9~H; 4.2~N; 18.8~S; Z0.5~Bi Comparative Synthesis ExamPle A
Antimony tris-(dlhexyldithiocarbamate) tADHC) The preparation of Synthesis Example l(b) was repeated, but substituting ~nti y trichloride (5.63 g; 0.025 mol) for the bismuth trichloride. The antimony salt was obtained as a pale yellow crys~nlli n~ solid.
Yield: 15.84 g (622 theory); mp 69.6 - 71.2C.
Elemental analysis:- Theory 51.9ZC; 8.72H; 4.71N; 21.3ZS; 13.52Sb Found 52.02C; 8.3ZH; 4.7~N; 20.4ZS; 13.5~Sb Synthesis Example 2 Bismuth tris-[di-(mixed pentyl isomers) dithiocarbamate~ (BDAC mixed) Synthesis Example 1 was repeated. but substituting dipentylamine based on mixed pentyl isomers cont~;nin~ about 80~ branched pentyl groups (53.5 g; 0.34 mol; from Aldrich Chemicals) for the dihexylamine used in Synthesis Example 1. The bismuth tris-[di(mixed pentyl isomers) dithiocarbamate] was obtained as yellow solution in acetone. The product was recovered by distilling off the acetone and washing with methanol (4 x 200 ml) to remove excess amine. The methanol, which formed an upper layer, was decanted and the residual oily product dissolved in methylene chloride. This was washed with a waterlmethanol mixture (80:~0) (4 x 40 ml). The methylene chloride WO 94/24100 ~ ~ PCT/GB94/00830 '6 ~ --solution was then dried over anhydrous sodium sulphate. screened and the methylene chloride evaporated to give the title product as a yellow oily liquid which slowly solidified on st~n~ing to yield a waxy solid.
Yield: 12.5 g (55.3Z of theory).
Elemental analysis:- Theory 43.7ZC; 7.3~H; 4.6ZN; Zl.2ZS;
Found 43.6~C; 7.1X~; 4.5~N; 19.3ZS
Synthesis Exam~le 3 Bismuth tris-[di-(2-ethylhexyl)dithiocarbamate] (BDE~C) Synthesis Example 2 was repeated, but substituting di-2-ethylhexylamine (25 g; 0.34 mol) for the mixed isomer dipentylPmine used in Synthesis Example 2. The bismuth tris-(di-2-ethylhexyldithiocarbama~e) was obtained as a yellow solution in acetone. The product was recovered by dis~ n~ off the acetone.
Methanol (200 ml) was added and the mi~ture cooled to 0C. The upper solution was decanted off and the product washed further with methanol (3 x 100 ml). A check of the decanted solution on the last wnshing indicated the absence of further amine. The residual oily product dissolved in methylene chloride, washed three times with water/
methanol mixture (80:20) (total volume 100 ml), dried over anhydrous sodium sulphate, filtered and the methylene chloride evaporated to give the title product as an orange oily liquid.
Yield: 20.2 g (70Z of theory).
Com~arative Synthesis Example B
Antimony tris-(di-n-pentyldithiocarbamate) (ADAC) Di-n-pentyldithiocarbamic acid salt was prepared as described in Example l(a), but substituting di-n-pentylamine (53.5 g; 0.34 mol;
from Aldrich Chemicals) for the dihexylamine.
The antimony salt was prepared by the method described in comparative Example A, but substituting di-n-pentyldithiocarbamic acid for the dihexyldithiocarbamic acid. The title product was obtained as a pale yellow solid.
0 9412~100 ~ ~ 6 0 PCTIGB94/~0830 Yield: 13.7 g (67Z of theory); mp 70.2 - 71.0C.
Elemental Analysis:- Theory 48.4ZC; 8.lZH; 5.lZN; 23.5ZS; 14.9ZSb Found 48.7ZC; 8.3ZH; 5.lZN; 23.1ZS; 14.4ZSb Comparative Synthesis Example C
Bismuth tris-(di-n-pentyldithiocarbamate) (BDAC) - The title compound was made by the method described in Example l(a) and (b), but substituting di-n-pentylamine (53.5 g; 0.34 mol;
from Aldrich Chemicals) for the dihexylamine. The product was obtained as a yellow solid.
Yield: 16.2 g (71Z of theory); mp 69 - 70C.
Elemental Analysis:- Theory 43.7ZC; 7.3ZH; 4.6ZN; 21.22S; 23.1ZBi Found 44.ZZC; 7.5ZH; 4.6ZN: 21.3ZS; 22.7ZBi Comparative Synthesis Example D
Antimony tris-ldi-(m$xed pentyl isomers) dithiocarbamate] (ADAC mixed) Es~mple 3 was repeated, but substituting ant$mony trichloride for bismuth trichloride as described in Comparative E~ample A. The product was isolated as a yellow oily liquid.
Yield: 12.96 g (63.3Z of theory).
Elemental Analysis:- Theory 48.3ZC; 8.lZH; 5.lZN; 23.4ZS
Found 48.8ZC; 7.9ZH; 5.1ZN; 22.6ZS
APplication ExamPle 1 Various bismuth tris-(dithiocarbamates), and certain antimony tris-(dithiocarbamates) as controls, were added to samples of a highly refined neutral petroleum based base oil having a viscosity of approximately lOOcSt at 40C to give an additive concentration of 0.0035 mol.(100 g oil)~l. These samples were subjected to a four ball test according to British Institute of Petroleum test IP 239 and the load at which welding occurred was measured. A control contn;n;ng no 21~
EP additive was included. The sdditives, concentrations and welding loads are set out in Table 1 below.
The results show that the bismuth tris-tdialkyldithiocarbamates) are effective EP additives in the petroleum based oil.
APPlication Example 2 Various antimony and bismuth tris-(dithiocarbamates) were evaluated as EP additives at a concentration of 0.0035 mol.(100 g oil)~l as described in Application Example 1 and the loading deter~inP~ at which welding occurred. The results show that the bismuth tris-(dialkyldith~ocnrbamates) are effective EP additives in the petroleum based oil. It i8 particularly notable that antimony tris-(dipentyldithiocarbamate) made from linear dipentylamine (ADAC) and from mixed isomers of dipentylamine (ADAC mixed) behave very similarly as EP additives in the petroleum based oil. These antimony salts behave very similarly as EP additives to Yanlube 73.
Remarkably, the bi th salts BDAC, BDAC (mised) and BDHC all eshibit superior p ope-Lles as EP additives in the oil. th~s is contrary to the tesrh~ngs of US 3139405 which demonstrates that both bismuth tris-(dipentyldithiocarbamate) and bi_ th tri8-(dibutyldi~h;oc~rbamate) ' are significantly inferior to the antimony analogues.
-AP~lication Example 3 Various antimony and bismuth tris-(dithiocarbamates) were evaluated as EP additives in a lithium hydroxystearate soap thic~pnpd grease. The base grease had a total soap content of 9.4Z by weight, lithium 0.22Z and glycerol 0.6Z, which was dispersed in a refined mineral oil derived from North West European crude having a specific gravity of 0.88, a viscosity of 576 seconds Saybolt at 100F (about 120 cSt at 40C) and 67 seconds Saybolt at Z10F (about 12 cSt at 100C), a viscosity index of 95, closed flash point of 480F (250C) and pour point of -15F (-26C). The compounds listed in Table 3 below were mixed into the grease, with heating as necessary, to distribute the compound uniformly throughout the grease, to give a concentration of 0.0035 mol.(100 g grease)~1. The results of four ball testing as described in application Example 1 is included in ~ O 94i~4100 - 13 _ 60~ PcT/GB94~on83o Table 3. These results indicate that the bismuth salts exhibit similar performance in this grease to the antimony analogues. This is unexpected from the teachings of US 3139405.
Applicstion Example 4 Application Example 1 was repeated using a lighter mineral oil, Vitrea 22 (from Shell) having a viscosity of about 24 cSt at 40C.
The results are set out in Table 4 below. These show that the bismuth salt exhibits a similar relative advantage over the antimony analogue as established for the oil described in Application Example 1.
W O 94/24100~ ~ 6 ~ 6 ~ PCT/GB94/00830 Table 1 AdditiveconcentrationWeld load (Zw/w) (kgf) BDHC 3.42 S10 BDE~C 4.0 380 ADHC 3.12 310 ADAC 2.83 370 Control - 150 Table 2 AdditiveconcentrationWeld load (~w/w) (kgf) ADAC 2.83 3?0 ADAC (mixed) 2.83 370 Vanlube 736.40 330 BDAC 3.13 560 BDAC (mixed) 3.13 610 BD~C 3.42 S10 Control - 150 Table 3 AdditiveconcentrationWeld load (~w/w) (kgf) ADAC 2.83 330 ADAC (mixed) 2.83 350 Vanlube 73 6.4 340 BDAC 3.13 360 BDAC (mixed) 3.13 300 BDHC 3.42 380 Control - 130 Table 4 AdditiveconcentrationWeld load (~w/w) (kgf) ADAC mixed2.83 240 BDAC mixed3.13 370
Claims (13)
1 A compound of the formula (I):
[ R1.R2 - N - C(S) - S - ]3 Bi (I) where each R1 and R2 is, independently, C1-12 alkyl, C7-12 aralkyl optionally substituted by C1-12 alkyl, cyclohexyl optionally substituted by C1-12 alkyl; or R1 and R2 together with the nitrogen atom to which they are attached from a heterocyclic ring optionally substituted by C1-12 alkyl, with the proviso that R1 and R2 are not both ethyl, n-butyl or n-pentyl.
[ R1.R2 - N - C(S) - S - ]3 Bi (I) where each R1 and R2 is, independently, C1-12 alkyl, C7-12 aralkyl optionally substituted by C1-12 alkyl, cyclohexyl optionally substituted by C1-12 alkyl; or R1 and R2 together with the nitrogen atom to which they are attached from a heterocyclic ring optionally substituted by C1-12 alkyl, with the proviso that R1 and R2 are not both ethyl, n-butyl or n-pentyl.
2 A compound as claimed in claim 1 wherein R2 is C6-12 alkyl, C7-12 aralkyl optionally substituted by C1-12 alkyl, cyclohexyl optionally substituted by C1-12 alkyl, isopropyl, isobutyl, tertiary butyl or branched pentyl.
3 A compound as claimed in either claim 1 or claim 2 wherein R1 and R2 are the same.
4 A compound as claimed in any one of claims 1 to 3 wherein at least one of R1 and R2 is, or contains, branched alkyl.
The compounds bismuth tris-(dihexyldithiocarbamate), bismuth tris-[bis-(2-ethylhexyl)dithiocarbamate], bismuth tris-[di-(mixed pentyl isomers) dithiocarbamate].
6 A composition comprising a grease and a compound of the formula (Ia):
[ R1.R2 - N - C(S) - S - ]3 Bi (Ia) where each R1 and R2 is, independently, C1-12 alkyl. C7-12 aralkyl optionally substituted by C1-12 alkyl, cyclohexyl optionally substituted by C1-12 alkyl; or R1 and R2 together with the nitrogen atom to which they are attached form a heterocyclic ring optionally substituted by C1-12 alkyl.
[ R1.R2 - N - C(S) - S - ]3 Bi (Ia) where each R1 and R2 is, independently, C1-12 alkyl. C7-12 aralkyl optionally substituted by C1-12 alkyl, cyclohexyl optionally substituted by C1-12 alkyl; or R1 and R2 together with the nitrogen atom to which they are attached form a heterocyclic ring optionally substituted by C1-12 alkyl.
7 A composition comprising an oil and a compound of the formula (Ib):
[ R1.R2 - N - C (S) - S - ]3 Bi (Ib) where each R1 and R2 is, independently, C1-12 alkyl, C7-12 aralkyl optionally substituted by C1-12 alkyl, cyclohexyl optionally substituted by C1-12 alkyl; or R1 and R2 together with the nitrogen atom to which they are attached form a heterocyclic ring optionally substituted by C1-12 alkyl, with the proviso that when R1 and R2 are both n-pentyl or n-butyl the oil is not an SAE 90 high viscosity index mineral oil having a viscosity of 17 cSt at 100°C and 190 cSt at 40°C.
[ R1.R2 - N - C (S) - S - ]3 Bi (Ib) where each R1 and R2 is, independently, C1-12 alkyl, C7-12 aralkyl optionally substituted by C1-12 alkyl, cyclohexyl optionally substituted by C1-12 alkyl; or R1 and R2 together with the nitrogen atom to which they are attached form a heterocyclic ring optionally substituted by C1-12 alkyl, with the proviso that when R1 and R2 are both n-pentyl or n-butyl the oil is not an SAE 90 high viscosity index mineral oil having a viscosity of 17 cSt at 100°C and 190 cSt at 40°C.
8 A composition as claimed in claim 7 wherein the oil has a viscosity above 200 cSt at 40°C.
9 A composition as claimed in either claim 7 wherein the oil has a viscosity below 180 cSt at 40°C.
A composition as claimed in any one of claims 7 to 9 wherein at least one of R1 and R2 is, or contains, branched alkyl.
11 The use of a compound as claimed in any one of claims 1 to 5 as an extreme pressure additive for a lubricant for protecting metals.
12 A metal surface which is treated with a compound as claimed in any one of claims 1 to 5 or a composition as claimed in any one of claims 7 to 10.
13 A metal surface as claimed in claim 12 which is a gear or bearing.
Applications Claiming Priority (4)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| GB939308091A GB9308091D0 (en) | 1993-04-20 | 1993-04-20 | Compounds and use |
| GB9311223.3 | 1993-06-01 | ||
| GB939311223A GB9311223D0 (en) | 1993-06-01 | 1993-06-01 | Compounds and use |
| GB9308091.9 | 1993-06-01 |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA2160669A1 true CA2160669A1 (en) | 1994-10-27 |
Family
ID=26302776
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA002160669A Abandoned CA2160669A1 (en) | 1993-04-20 | 1994-04-20 | Bismuth dithiocarbamates and their use as additive for lubricants |
Country Status (5)
| Country | Link |
|---|---|
| EP (1) | EP0695291A1 (en) |
| JP (1) | JPH08508993A (en) |
| AU (1) | AU6541994A (en) |
| CA (1) | CA2160669A1 (en) |
| WO (1) | WO1994024100A1 (en) |
Families Citing this family (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US6090755A (en) * | 1994-03-28 | 2000-07-18 | Skf Industrial Trading & Development Company, B.V. | Use of bismuth compounds in extreme pressure grease lubricant compositions for rolling bearing applications with extended service life |
| NL9400493A (en) * | 1994-03-28 | 1995-11-01 | Skf Ind Trading & Dev | Use of bismuth joints in high pressure grease lubricant compositions for long life rolling bearing applications. |
| US5576273A (en) * | 1995-11-20 | 1996-11-19 | R.T. Vanderbilt Company, Inc. | Lubricating compositions containing bismuth compounds |
| GB2355466A (en) * | 1999-10-19 | 2001-04-25 | Exxon Research Engineering Co | Lubricant Composition for Diesel Engines |
| JP2005042102A (en) * | 2003-07-04 | 2005-02-17 | Koyo Seiko Co Ltd | Rolling bearing grease composition and rolling bearing |
| US7491683B2 (en) | 2003-07-04 | 2009-02-17 | Jtekt Corporation | Grease composition for rolling bearing and rolling bearing using the same |
| WO2014031181A1 (en) * | 2012-04-25 | 2014-02-27 | Dow Global Technologies Llc | Polyurethanes made using bismuth thiocarbamate or thiocarbonate salts as catalysts |
Family Cites Families (9)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US2716089A (en) | 1952-07-10 | 1955-08-23 | Exxon Research Engineering Co | Motor oil inhibitor |
| BE542726A (en) * | 1954-11-11 | |||
| US3139405A (en) * | 1961-05-29 | 1964-06-30 | Vanderbilt Co R T | Extreme pressure lubricants |
| US3234129A (en) * | 1962-08-01 | 1966-02-08 | Ethyl Corp | Lubricating compositions |
| US3630897A (en) * | 1969-10-06 | 1971-12-28 | Phillips Petroleum Co | Color stabilization of lubricating compositions |
| US3772197A (en) * | 1970-12-04 | 1973-11-13 | Cities Service Oil Co | Lubricating oil composition |
| GB1284512A (en) * | 1971-03-22 | 1972-08-09 | Optimol Olwerke G M B H | Liquid lubricants |
| US4524185A (en) * | 1983-03-07 | 1985-06-18 | Federal-Mogul Corporation | Halogen-containing elastomer composition, and vulcanizing process using dimercaptothiodiazole and dithiocarbamate curing system |
| JPH0539495A (en) * | 1991-08-05 | 1993-02-19 | Tonen Corp | Lubricant oil composition |
-
1994
- 1994-04-20 EP EP94913165A patent/EP0695291A1/en not_active Withdrawn
- 1994-04-20 JP JP6522929A patent/JPH08508993A/en active Pending
- 1994-04-20 CA CA002160669A patent/CA2160669A1/en not_active Abandoned
- 1994-04-20 AU AU65419/94A patent/AU6541994A/en not_active Abandoned
- 1994-04-20 WO PCT/GB1994/000830 patent/WO1994024100A1/en not_active Application Discontinuation
Also Published As
| Publication number | Publication date |
|---|---|
| WO1994024100A1 (en) | 1994-10-27 |
| JPH08508993A (en) | 1996-09-24 |
| EP0695291A1 (en) | 1996-02-07 |
| AU6541994A (en) | 1994-11-08 |
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| Date | Code | Title | Description |
|---|---|---|---|
| FZDE | Dead |