Refrigeration oil from gas-to-liquid-derived and bio-derived triesters
The present invention is directed to a refrigerator oil composition comprising (a) a triester species having the following structure: wherein R 1 , R 2 , R 3 , and R 4 are the same or independently selected from hydrocarbon groups having from 2 to 20 carbon atoms and wherein “n” is an integer from 2 to 20; and (b) a refrigerant, wherein the refrigerant is a halohydrocarbon.
1. A refrigerator oil composition comprising
(a) a triester species having the following structure:
wherein R 1 , R 2 , R 3 , and R 4 are the same or independently selected from hydrocarbon groups having from 2 to 20 carbon atoms and wherein “n” is an integer from 2 to 20; and
(b) a refrigerant, wherein the refrigerant is a halocarbon.
2. The refrigerator oil composition of claim 1 wherein the halocarbon comprises a chlorine-free type halocarbon, a chlorine-containing type halocarbon, or mixtures thereof.
3. The refrigerator oil composition of claim 2 wherein halocarbon is selected from the group consisting of: difluoromethane (HFC-32), trifluoromethane (HFC-23), pentafluoroethane (HFC-125), 1,1,2,2-tetrafluoroethane (HFC-134), 1,1,1,2-tetrafluoroethane (HFC-134a), 1,1,1-trifluoroethane (HFC-143a), 1,1-difluoroethane (HFC-152a), monochlorodifluoromethane (HCFC-22), 1-chloro-1,1-difluoroethane (HCFC-142b), dichlorotrifluoroethane (HCFC-123) and monochlorotetrafluoroethane (HCFC-124); and mixtures thereof.
4. The refrigerator oil composition of claim 1 wherein the triester species is derived from a process comprising:
(a) esterifying a mono-unsaturated fatty acid having from 10 to 22 carbon atoms with an alcohol thereby forming an unsaturated ester;
(b) epoxidizing the unsaturated ester in step (a) thereby forming an epoxy-ester species comprising an epoxide ring;
(c) opening the ring of the epoxy-ester species in step (b) thereby forming a dihydroxy ester; and
(d) esterifying the dihydroxy ester in step (c) with an esterifying species to form a triester species, wherein the esterifying species is selected from the group consisting of carboxylic acids, acyl halides, acyl anhydrides, and combinations thereof, and wherein the esterifying species has a carbon number of from 2 to 18.
5. The refrigerator oil composition of claim 1 wherein the pour point is less than −25° C.
6. The refrigerator oil composition of claim 1 wherein the cloud point is less than 0° C.
7. The refrigerator oil composition of claim 4 wherein the esterifying species is a carboxylic acid.
8. The refrigerator oil composition of claim 7 wherein the carboxylic acid is derived from a bio-derived fatty acid.
9. The refrigerator oil composition of claim 7 wherein the carboxylic acid is derived from alcohols generated by a Fischer-Tropsch process.