Synthetic refrigeration oil composition for HFC applications
Novel refrigeration compositions comprising at least one ester of a hydroxycarboxylic acid which can have a chain length in the range of from 8 to 22 carbon atoms. The composition can contain a carrier fluid or base oil selected from alkylbenzenes, alkylated naphthenics, polyalkylene glycols, polyvinylethers, polyalphaolefins, mineral oils, polyol esters, and combinations thereof, providing improved fluidity and heat transfer, and enhanced oil return. A method of making a refrigeration composition by preparing at least one ester by esterifying a first component comprising at least one hydroxycarboxylic acid with a second component comprising at least one alcohol and combining the at least one ester with a base oil selected from the group consisting of alkylbenzenes, alkylated naphthenics, polyalkylene glycols, polyvinylethers, polyalphaolefins, mineral oils, polyol esters, and combinations thereof.
1. A method of making a refrigeration composition, the method comprising:
preparing at least one ester by esterifying a first component comprising at least one hydroxycarboxylic acid with a second component comprising at least one alcohol; and
combining the at least one ester with a base oil selected from the group consisting of alkylbenzenes, alkylated naphthenics, polyalkylene glycols, polyvinylethers, polyalphaolefins, mineral oils, polyol esters, and combinations thereof.
2. The method of claim 1 wherein the at least one hydroxycarboxylic acid comprises from 8 to 22 carbons.
3. The method of claim 1 , further comprising incorporating a refrigerant selected from the group consisting of R134a, R125, R32, R23, R143a, R116, R152a, and combinations thereof.
4. The method of claim 3 further comprising incorporating a minority refrigerant component selected from the group consisting of isobutene, CO 2 , HCFC's, and combinations thereof.
5. The method of claim 1 wherein the at least one hydroxycarboxylic acid is selected from the group consisting of monohydroxy fatty acids and hydroxycarboxylic acids comprising more than one carboxylic acid group.
6. The method of claim 5 wherein the at least one hydroxycarboxylic acid is selected from the group consisting of hydroxycarboxylic acids comprising more than one carboxylic acid group, hydroxylinoleic acid, hydroxyerucic acid, hydroxyarachidonic acid, ricinoleic acid, and combinations thereof.
7. The method of claim 5 wherein the at least one hydroxycarboxylic acid comprises more than one carboxylic acid group.
8. The method of claim 7 wherein the at least one hydroxycarboxylic acid is selected from the group consisting of citric acid, tartaric acid, malic acid, and combinations thereof.
9. The method of claim 5 wherein the at least one hydroxycarboxylic acid is selected from the group consisting of hydroxystearic acid, hydroxylauric acid, hydroxydecanoic acid, hydroxyarachidic acid, hydroxypalmitic acid, hydroxylinoleic acid, hydroxyerucic acid, hydroxyarachidonic acid, ricinoleic acid, and combinations thereof.
10. The method of claim 9 wherein the at least one hydroxycarboxylic acid is selected from the group consisting of hydroxylinoleic acid, hydroxyerucic acid, hydroxyarachidonic acid, ricinoleic acid, and combinations thereof.
11. The method of claim 1 wherein the at least one hydroxycarboxylic acid comprises a ring system.
12. The method of claim 11 wherein the at least one hydroxycarboxylic acid is selected from the group consisting of salicylic acid, dihydroxybenzoic acid, and combinations thereof.
13. The method of claim 1 wherein the at least one alcohol is selected from the group consisting of alcohols that are linear, long chain, or both.
14. The method of claim 1 wherein the at least one alcohol is selected from the group consisting of monohydric alcohols.
15. The method of claim 14 wherein the at least one alcohol comprises isotridecanol.
16. The method of claim 1 wherein the at least one alcohol is selected from the group consisting of polyalkylene glycols.
17. The method of claim 16 wherein the at least one ester has an alkoxylate portion comprising one or more oxide monomers higher than ethylene oxide.
18. The method of claim 17 wherein the at least one hydroxycarboxylic acid comprises ricinoleic acid.
19. The method of claim 1 further comprising incorporating an ester of a fatty acid.
20. The method of claim 1 wherein the at least one ester comprises from about 1% by weight to about 60% by weight of the refrigeration composition.
21. The method of claim 1 wherein the at least one ester is a monoester.