Lubricating composition containing a detergent
The invention provides a lubricating composition containing an oil of lubricating viscosity and a detergent. The invention further relates to a process to prepare the detergent, and the use of the lubricating composition in a mechanical device such as an internal combustion engine, or a driveline device.
1. A process to prepare a detergent comprising:
(a) reacting in the presence of a solvent comprising (i) an oil medium or (ii) a hydrocarbon solvent, a mixture of
(i) an acidic detergent substrate, and
(iii) a basic metal compound, and optionally further in the presence of an alcohol;
(b) reacting the product of (a) with a hydroxy-carboxylic acid, or reactive equivalent thereof, and carbon dioxide to form an overbased detergent; and
(c) optionally, removing volatiles from the product of (a) or (b).
2. The process of claim 1 , the process preparing an overbased detergent, wherein the detergent has a TBN of 200 to 600mg KOH/g.
3. The process of claim 1 , wherein the basic metal compound is a hydroxide or oxide of the metal.
4. The process of claim 1 , wherein the basic metal compound comprises a metal that is monovalent, divalent, or trivalent.
5. The process of claim 4 , wherein the metal is an alkali metal or alkaline earth metal.
6. The process of claim 4 , wherein the metal is lithium, sodium, potassium, magnesium, calcium, barium, or mixtures thereof.
7. The process of any claim 5 , wherein the metal is calcium or magnesium.
8. The process of claim 1 , wherein the acidic detergent substrate is a hydrocarbyl-substituted sulphonic acid, a hydrocarbyl-substituted hydroxy-aromatic acid, or mixtures thereof.
9. The process of claim 8 , wherein the acidic detergent substrate is a hydrocarbyl-substituted sulphonic acid or mixtures thereof.
10. The process of claim 8 , wherein the acidic detergent substrate is a hydrocarbyl-substituted organic acid or a hydrocarbyl-substituted phenol.
11. The process of claim 1 , wherein the hydroxy-carboxylic acid is non-aromatic.
12. The process of claim 11 , wherein the hydroxy-carboxylic acid is represented by the formula:
wherein
n and m are independently integers of 1 to 5;
X is an aliphatic or alicyclic group, or an aliphatic or alicyclic group containing an oxygen atom in the carbon chain, or a substituted group of the foregoing types, said group containing up to 6 carbon atoms and having n+m available points of attachment;
each Y is independently —O—, >NH, or >NR 1 or two Ys together representing the nitrogen of an imide structure R-N<formed between two carbonyl groups; and
each R and R 1 is independently hydrogen or a hydrocarbyl group,
each R 2 is independently hydrogen, a hydrocarbyl group or an acyl group, further provided that at least one —OR 2 group is located on a carbon atom within X that is α or β to at least one of the —C(O)—Y—R groups, with the proviso that at least one of R and R 2 is hydrogen.
13. The process of claim 12 , wherein the hydroxy-carboxylic acid is tartaric acid, malic acid, citric acid, glycolic acid, or mixtures thereof.
14. The process of claim 13 , wherein the hydroxy-carboxylic acid is tartaric acid, citric acid, or mixtures thereof.
15. The process of claim 12 , wherein the hydroxy-carboxylic acid is lactic acid, malic acid, or mixtures thereof.
16. The process of claim 1 , wherein the acidic detergent substrate and the hydroxy-carboxylic acid are present as reactants with a mole ratio of the acidic detergent substrate to the hydroxy-carboxylic acid in the range of 20:1 to 1:2.
17. A product obtained/obtainable by the process of claim 1 .
18. A lubricating composition comprising an oil of lubricating viscosity and the product of claim 17 .
19. The lubricating composition of claim 18 , wherein the product is present in the range of 0.01 wt % to 8 wt of the lubricating composition.
20. A method of lubricating an internal combustion engine comprising supplying to the internal combustion engine a lubricating composition of claim 18 .
21. The method of claim 20 , wherein the internal combustion engine has a steel surface on a cylinder bore, cylinder block, or piston ring.
22. The method of claim 20 , wherein the internal combustion engine has a surface of steel, or an aluminium alloy, or an aluminium composite.
23. A method of lubricating a driveline device comprising supplying to the driveline device a lubricating composition of claim 18 .
24. The method of claim 23 , wherein the driveline device includes a manual transmission that may or may not contain a synchronizer system, or an axle.