Catalytic antioxidants
View Patent ↗The present invention is directed to lubricating oils exhibiting improved resistance to oxidation and deposit/sludge formation comprising a lubricant base oil and catalytic antioxidants comprising an effective amount of a) one or more polymetal organometallic compound; and, b) effective amounts of one or more substituted N,N′-diaryl-o-phenylenediamine compounds or c) one or more hindered phenol compounds or both, to a method for improving the antioxidancy and the resistance to deposit/sludge formation of formulated lubricating oil compositions by the addition thereto of an effective amount of the aforementioned catalytic antioxidants, and to an additive concentrate containing the aforementioned catalytic antioxidants.
1. A lubricating oil exhibiting improved resistance to oxidation and deposit/sludge formation comprising a major amount of lubricant base oil and catalytic antioxidants comprising
(a) an effective amount of one or more oil soluble dimanganese compounds having the formula [Mn n (Ligand)] 2 , where n is the oxidation state and Ligand is an organic moiety complexing the manganese; and, effective amounts of
(b) one or more substituted N,N′-diaryl-o-phenylenediamine compounds having Formula I
where R 1 , R 2 , R 3 and R 4 are independently H or C 1 to C 12 alkyl; or,
(c) one or more hindered phenol compound having Formula II
where R 5 is OH and R 6 is C 1 to C 8 alkyl;
or a combination of both (b) and (c).
2. A method for improving the resistance of a lubricating oil to oxidation and deposit/sludge formation comprising adding to the lubricating oil catalytic antioxidants comprising
(a) an effective amount of one or more oil soluble dimanganese compounds having the formula [Mn n (Ligand)] 2 , where n is the oxidation state and Ligand is an organic moiety complexing the manganese; and, effective amounts of
(b) one or more substituted N,N′-diaryl-o-phenylenediamine compounds having Formula I
where R 1 , R 2 , R 3 and R 4 are independently H or C 1 to C 12 alkyl; or,
(c) one or more hindered phenol compound having Formula II
or a combination of both (b) and (c).
3. The lubricating oil of claim 1 wherein the one or more dimanganese compounds is present in an amount in the range of about 1 to 1000 ppm by weight of manganese based on the total amount of the lubricant base oil.
4. The lubricating oil of claim 3 where the one or more dimanganese compounds is present in an amount in the range of about 10 to 500 ppm by weight of manganese based on the total amount of lubricant base oils.
5. The lubricating oil of claim 1 wherein the substituted N,N′-diaryl-o-phenylenediamine compound is present in an amount in the range of about 10 to 5000 ppm based on the total amount of lubricant base oil.
6. The lubricating oil of claim 5 wherein the substituted N,N′-diaryl-o-phenylenediamine compound is present in an amount in the range of about 10 to 1000 ppm based on the total amount of lubricant base oil.
7. The lubricating oil of claim 1 wherein the hindered compound is present in an amount in the range of about 10 to 5000 ppm based on the total amount of lubricant base oil.
8. The lubricating oil of claim 7 wherein the hindered compound is present in an amount in the range of about 100 to 5000 ppm based on the total amount of lubricant base oil.
9. The lubricating oil of claim 1 wherein R 1 is methyl, and R 2 , R 3 and R 4 are H in Formula I.
10. The lubricating oil of claim 1 wherein R 5 is OH and R 6 is C 4 alkyl in Formula II.
11. The lubricating oil of claim 1 wherein the lubricant base oil is selected from the group consisting of natural oils, petroleum derived mineral oils, synthetic oils, unconventional oils and mixtures thereof.
12. The lubricating oil of claim 1 wherein the lubricant base oil is a GTL base oil, an isomerized wax base oil or mixture thereof.
13. The lubricating oil of claim 12 wherein the GTL base oil is derived from a hydroisomerized Fischer-Tropsch wax.
14. The lubricating oil of claim 1 wherein the Ligand comprises a polydentate Schiff base ligand.
15. The lubricating oil of claim 14 wherein the Schiff base ligand is a N,N′-disalicylidene-1,3-diaminopropane (H2Salpn) ligand or a N,N′-disalicylidene-1,4-diaminobutane (H2Salbn) ligand.
16. An additive concentrate for improving resistance to oxidation and deposit/sludge formation in lubricating oils comprising catalytic antioxidant comprising
an effective amount of one or more oil soluble dimanganese compounds having the formula [Mn n (Ligand)] 2 , where n is the oxidation state and Ligand is an organic moiety complexing the manganese; and, effective amounts of
(b) one or more substituted N,N′-diaryl-o-phenylenediamine compounds having Formula I
where R 1 , R 2 , R 3 and R 4 are independently H or C 1 to C 12 alkyl; or,
(c) one or more hindered phenol compound having Formula II
where R 5 is OH and R 6 is C 1 to C 8 alkyl;
or a combination of both (b) and (c).
17. Use of the lubricating oil of claim 1 for improving fuel economy in gasoline engine systems.
18. Use of the lubricating oil of claim 1 for improving exhaust emissions in a diesel fuel engine system, wherein the diesel fuel has a sulfur content ranging in the amount of about 5-1,000 ppm.
19. The method of claim 2 wherein the one or more dimanganese compounds is present in an amount in the range of about 1 to 1000 ppm by weight of metal based on the total amount of lubricant base oil.
20. The method of claim 19 wherein the one or more dimanganese compounds is present in an amount in the range of about 10 to 500 ppm by weight of metal based on the total amount of lubricant base oil.
21. The method of claim 2 wherein the substituted N,N′-diaryl-o-phenylenediamine compound is present in an amount in the range of about 10 to 5000 ppm based on the total amount of lubricant base oil.
22. The method of claim 21 wherein the substituted N,N′-diaryl-o-phenylenediamine compound is present in an amount in the range of about 10 to 1000 ppm based on the total amount of lubricant base oil.
23. The method of claim 2 wherein the hindered phenol compound is present in an amount in the range of about 10 to 5000 ppm based on the total amount of lubricant base oil.
24. The method of claim 23 wherein the hindered phenol compound is present in an amount in the range of about 100 to 5000 ppm based on the total amount of lubricant base oil.
25. The method of claim 2 wherein R 1 is methyl, and R 2 , R 3 and R 4 are H in Formula I.
26. The method of claim 2 wherein R 5 is OH and R 6 is C 4 alkyl in Formula II.
27. The method of claim 2 wherein the lubricant base oil is selected from the group consisting of natural oils, petroleum derived mineral oils, synthetic oils, unconventional oils and mixtures thereof.
28. The method of claim 27 wherein the lubricant base oil is a GTL base oil, an isomerized wax base oil or mixture thereof.
29. The method of claim 2 wherein the polymetal organometallic compound comprises a polydentate Schiff base ligand.
30. The method of claim 29 wherein the Schiff base ligand is a N,N′-disalicylidene-1,3-diaminopropane (H2Salpn) ligand or a N,N′-disalicylidene-1,4-diaminobutane (H2Salbn) ligand.