Refrigerant compositions containing perfluoropolyethers

1. A composition for improving lubricant return in refrigeration and heat transfer apparatuses, comprising:

a) a refrigerant or heat transfer fluid selected from the group consisting of

HFC-32 and HFC-125;

HFC-125 and HFC-134a;

HFC-32, HFC-125, and HFC-134a;

HFC-32, HFC-125, HFC-134a, and n-butane;

HFC-32, HFC-125, HFC-134a, and 2-methylpropane;

HFC-32, HFC-125, HFC-134a, n-butane and 2-methylbutane;

HFC-32, HFC-125, HFC-134a, n-butane and n-pentane;

HFC-32, HFC-125, HFC-134a, 2-methylpropane and 2-methylbutane;

HFC-32, HFC-125, HFC-134a, 2-methylpropane and n-pentane;

HFC-125, HFC-134a, and n-butane;

HFC-125, HFC-134a, and 2-methylpropane;

HFC-125, HFC-134a, n-butane and 2-methylbutane;

HFC-125, HFC-134a, n-butane and n-pentane;

HFC-125, HFC-134a, 2-methylpropane and 2-methylbutane;

HFC-125, HFC-134a, 2-methylpropane and n-pentane;

HFC-125, HFC-134a, HFC-227ea, n-butane and 2-methylbutane;

HFC-125, HFC-134a, HFC-227ea, n-butane and n-pentane;

HFC-125, HFC-134a, HFC-227ea, 2-methylpropane and 2-methylbutane;

HFC-125, HFC-134a, HFC-227ea, 2-methylpropane and n-pentane;

R401A; R401B; R402A; R402B; R403A; R403B; R410B; R413A; R414A; R414B; R416A; R419A; R422B; R422c; R422D; R423A; R407A; R407B; R407D; R407E; R408A; R424A; R425A; R426A; R427A; R428A; and R508B; and

b) a lubricant and

c) at least one perfluoropolyether (PFPE),

wherein said lubricant is non-miscible in said refrigerant or heat transfer fluid, and

(i) at least one of the end groups of said perfluoropolyether is a functionalized group selected from the group consisting of esters, hydroxyls, amines, amides, cyanos, carboxylic acids and sulfonic acids; or

(ii) at least one of the two end groups of the perfluoropolyether is an unfunctionalized branched or straight chain perfluoroalkyl radical; and

wherein the amount of said perfluoropolyether is less than 1% by weight relative to said refrigerant or heat transfer fluid.

2. The composition of claim 1 , further comprising a lubricant oil which is mineral oil or synthetic oil selected from the group consisting of alkylbenzene, polyol ester, polyalkylene glycols, polyvinyl ethers, carbonates, polyalphaolefin and combinations thereof.

3. The composition of claim 1 , wherein at least one of the end groups of said perfluoropolyether is carboxylic acid.

4. The composition of claim 1 , wherein at least one of the end groups of said perfluoropolyether is sulfonic acid.

5. A composition comprising:

a. at least one saturated fluorocarbon,

b. up to 2 weight percent of at least one hydrocarbon, and

c. at least one perfluoropolyether, wherein said perfluoropolyether is non-miscible in said hydrocarbon,

(i) at least one of the end groups of said perfluoropolyether is a functionalized group selected from the group consisting of esters, hydroxyls, amines, amides, cyanos, carboxylic acids and sulfonic acids; or

(ii) at least one of the two end groups of the perfluoropolyether is an unfunctionalized branched or straight chain perfluoroalkyl radical; and

wherein the amount of said perfluoropolyether is less than 1% by weight relative to said saturated fluorocarbon.

6. A method of producing refrigeration, said method comprising: evaporating the refrigerant or heat transfer fluid composition of claim 1 , in the vicinity of a body to be cooled and thereafter condensing said composition.

7. A method of producing heat, said method comprising: condensing the refrigerant or heat transfer fluid composition of claim 1 , in the vicinity of the body to be heated and thereafter evaporation said composition.

8. A process for transferring heat, said process comprising transferring the compositions of claim 1 , from a heat source to a heat sink.

9. The method of claim 6 , wherein said composition further comprises a mineral oil.

10. A process for replacing refrigerant or heat transfer fluid, comprising: removing existing refrigerant or heat transfer fluid from the refrigeration or air conditioning system, introducing into said refrigeration or air conditioning system a composition comprising the composition according to claim 1 .

11. The process of claim 10 , wherein said amount of perfluoropolyether is less than 40% by weight relative to said substituting refrigerant or heat transfer fluid.

12. The process of claim 10 , wherein said amount of perfluoropolyether is less than 10% by weight relative to said substituting refrigerant or heat transfer fluid.

13. The process of claim 10 , wherein said amount of perfluoropolyether is less than 1% by weight relative to said substituting refrigerant or heat transfer fluid.

14. The process of claim 10 , wherein at least one of the end groups of said perfluoropolyether is a functionalized group selected from the group consisting of esters, hydroxyls, amines, amides, cyanos, carboxylic acids and sulfonic acids.

15. The process of claim 10 , wherein at least one of the end groups of said perfluoropolyether is carboxylic acid.

16. The process of claim 15 , wherein at least one of the end groups of said perfluoropolyether is sulfonic acid.