Nanosized particles of molybdenum sulfide and derivatives, method for its preparation and uses thereof as lubricant additive
View Patent ↗A lubricant composition is disclosed that comprises: (a) a lubricant and (b) at least one molybdenum-containing compound in the form of surface-capped nanosized particles of the general formula: (Z) n (X—R) m wherein Z is an inorganic moiety comprising molybdenum and sulfur in the form of particles having dimensions in the range of from about 1 to about 100 nm; (X—R) is a surface-capping reagent wherein R is a C 4 to C 20 straight or branched-chain alkyl or alkylated cycloalkyl radical or radicals and X is a functional group capable of specific sorption and/or chemical interaction with molybdenum/sulfur moiety; n is the number of molecules of Z in the particles; m is an integer representing the amount of surface-capping reagents relative to a single particle; and the ratio of m to n is in the range of from about 1:1 to about 10:1.
1. A lubricant composition comprising:
A) a lubricant, and
B) at least one molybdenum-containing compound in the form of surface-capped nanosized particles of the general formula
(Z) n (X−R) m
wherein:
Z is selected from the group consisting of MoS 3 , MoS 2 O, Na 2 MoS 4 , Na 2 MoS 3 O, (NH 4 ) 2 MoS 4 , (NH 4 ) 2 MoS 3 O, and hydrates thereof in the form of particles having dimensions in the range of from about 1 to about 100 nm;
(X−R) is a surface-capping reagent selected from the group consisting of alkyl amines, dialkyl amines, trialkyl amines, carboxylic acids, dicarboxylic acids, carboxylic acid amides, dicarboxylic acid diamides, alicyclic imides, ammonium or alkali metal dialkyldithiocarbamates, divalent metal bis-dialkyldithiocarbamates, trivalent metal tris-dialkyldithiocarbamates, tetraalkyl thiuram disulfides, and derivatives thereof;
n is the number of molecules of Z in the particles;
m is an integer representing the amount of surface-capping reagents relative to a single particle; and
the ratio of m to n is in the range of from about 1:1 to about 10:1.
2. The lubricant composition of claim 1 wherein the alkyl amines, dialkyl amines, and trialkyl amines are of the formula
R 1 R 2 R 3 N
wherein: R 1 , R 2 , and R 3 are independently selected from the group consisting of hydrogen, straight or branched-chain C 1 -C 20 alkyl, C 6 -C 16 alkylaryl, and aryl.
3. The lubricant composition of claim 1 wherein the carboxylic and carboxylic acid amides are of the formula
wherein X is OH, NH 2 , NHR 3 or NR 4 R 4 and R 4 is an straight or branched-chain, saturated or partially unsaturated, alkyl moiety of from 1 to 40 carbon atoms.
4. The lubricant composition of claim 1 wherein the alicyclic imides are of the formula
wherein R 5 is hydrogen, (C═O)NHR 7 , or an alkylene amine wherein pairs of nitrogens are joined by alkylene groups, R 6 is hydrogen, straight or branched-chain (C 2 -C 400 )alkyl, and R 7 is H or (C 1 -C 20 )alkyl.
5. The lubricant composition of claim 1 wherein the ammonium or alkali metal dialkyldithiocarbamates are of the formula
wherein R 8 and R 9 are independently selected from the group consisting of (C 1 -C 24 )alkyl and M + is Na + , K + , or NH 4 + .
6. The lubricant composition of claim 2 wherein the divalent metal bis-dialkyldithiocarbamate is a compound of the formula
wherein R 8 and r 9 are selected from the group consisting of (C 1 -C 24 )alkyl and M +2 is Fe +2 , Zn −2 , Pb +2 , Cu +2 .
7. The lubricant composition of claim 1 wherein the trivalent metal tris-dialkyldithiocarbamates are of the formula
wherein R 8 and R 9 are selected from the group consisting of (C 1 -C 24 alkyl and M +3 is Sb +3 or Bi +3 .
8. The lubricant composition of claim 1 wherein the tetraalkyl thiuram disulfides are of the formula
wherein R 8 and R 9 are independently selected from the group consisting of (C 1 -C 24 )alkyl.
9. The lubricant composition of claim 1 wherein the molybdenum-containing compound in the form of surface-capped nanosized particles is employed in an amount of about 0.2 to about 5% by weight.
10. The lubricant composition of claim 9 further comprising at least one additional additive selected from the group consisting of dispersants, detergents, rust inhibitors, antioxidants, metal deactivators, anti-wear agents, antifoamants, friction modifiers, seal swell agents, demulsifiers, VI improvers, and pour point depressants.
11. A process for preparing, a molybdenum-containing compound in the form of surface-capped nanosized particles of the general formula
(Z) n (X−R) m
wherein:
Z is selected from the group consisting of MoS 3 , Mos 2 O, Na 2 MoS 4 , Na 2 MoS 3 O, (NH 4 ) 2 MoS 4 , (NH 4 ) 2 Mos 3 O, and hydrates thereof in the form of particles having dimensions in the range of from about 1 to about 100 nm;
(X−R) is a surface-capping reagent selected from the group consisting of alkyl amines, dialkyl amines, trialkyl amines, carboxylic acids, dicarboxylic acids, carboxylic acid amides, dicarboxylic acid diamides, alicyclic imides, ammonium or alkali metal dialkyldithiocarbamates, divalent metal bis-dialkyldithiocarbamates, trivalent metal tris-dialkyldithiocarbamates, tetraalkyl thiuram disulfides, and derivatives thereof;
n is the number of molecules of Z in the particles;
to is an integer representing the amount of surface-capping reagents relative to a single particle; and
the ratio of m to n is in the range of from about 1:1 to about 10:1;
wherein the process comprises the steps of:
A) creating a reversed microemulsion comprising a hydrocarbon-soluble surfactant solution in an organic solvent or solvent mixture and an aqueous solution of a water-soluble inorganic molybdenum (VI) compound;
B) if necessary to create a molybdenum/sulfur moiety, converting the water-soluble inorganic molybdenum (VI) compound into a thio-derivative by reaction with hydrogen sulfide;
C) adding a surfactant that chemically interacts with and/or adsorbs on the molybdenum/sulfur moiety;
D) removing water and the organic solvent(s) from the microemulsion and extracting the molybdenum/sulfur moiety-containing products thereof in the form of surface-capped nanosized particles with a suitable organic solvent; and
E) removing said suitable organic solvent.
12. The process of claim 11 wherein the hydrocarbon-soluble surfactant is a cationic, anionic, or non-ionic surfactant.
13. The process of claim wherein 12 the hydrocarbon-soluble surfactant is cationic.
14. The process of claim 13 wherein the surfactant is tetraalkylammonium halide.
15. The process of claim 14 wherein the surfactant is cetyltrimethylammonium halide.
16. The process of claim 15 wherein the cetyltrimethylammonium halide is dissolved in chloroform:n-alkane (1:1 v/v) in a concentration of 0.01 to 0.1 mol/L.
17. The process of claim 16 wherein the n-alkane is selected from the group consisting of pentane, hexane, heptane, octane and isomers and mixtures thereof.
18. The process of claim 11 wherein the aqueous solution of water-soluble inorganic molybdenum (VI) compounds has pH less than or equal to 8.
19. The process of claim 11 wherein the surfactant that chemically interacts with and/or adsorbs on the molybdenum/sulfur moiety is added to the microemulsion in step A) or step B).
20. The process of claim 11 wherein the surfactant that chemically interacts with and/or adsorbs on the molybdenum/sulfur moiety is selected from the group consisting of alkyl amines, dialkyl amines, trialkyl amines, carboxylic acids, dicarboxylic acids, carboxylic acid amides, dicarboxylic acid diamides, alicyclic imides, ammonium or alkali metal dialkyldithiocarbamates, divalent metal bis-dialkyldithiocarbamates, trivalent metal tris-dialkyldithiocarbamates, tetraalkyl thiuram disulfides, and derivatives thereof.
21. The process of claim 20 wherein the alkyl amines, dialkyl amines, trialkyl amines are of the formula
R 1 R 2 R 3 N
wherein R 1 , R 2 , and R 3 are independently selected from the group consisting of hydrogen, straight or branched-chain C 1 -C 28 alkyl, C 6 -C 34 alkylaryl, and aryl.
22. The process of claim 20 wherein the carboxylic acids; and carboxylic acid amides are of the formula
wherein X is OH, NH 2 , NHR 4 , or NR 4 R 4 and R 4 is an straight or branched-chain, saturated or partially unsaturated, alkyl moiety of from 1 to 40 carbon atoms.
23. The process of clam 20 wherein the alicyclic imides are of the formula
wherein R 5 is selected from the group consisting of hydrogen, (C═O)NKR 7 , and alkylene amines wherein pairs of nitrogens are joined by alkylene groups; R 6 is selected from the group consisting of hydrogen and straight and branched-chain (C 2 -C 400 )alkyl; and R 7 is hydrogen or (C 1 -C 20 ) alkyl.
24. The process of claim 20 wherein the alkali metal dialkyldithiocarbamates are of the formula
wherein R 8 and R 9 are independently selected from the group consisting of (C 1 -C 24 )alkyl and M + is Na + , K + , or NH 4 + .
25. The process of claim 20 wherein the divalent metal bis-dialkyldithiocarbamates are of the formula
wherein R 8 and R 8 are independently selected from the group consisting of (C 1 -C 24 )alkyl and M +2 is Fe +2 , Zn +2 , Pb +2 , or Cu −2 .
26. The process of claim 20 wherein the trivalent metal tris-dialkyldithiocarbamates are of the formula
wherein R 8 and R 9 are selected from the group consisting of (C 1 -C 24 )alkyl and M +3 is Sb +3 or Bi +3 .
27. The process of claim 20 wherein the thiuram disulfides are of the formula
wherein R 8 and R 9 are independently selected from the group consisting of (C 1 -C 24 )alkyl.