Refrigerants containing (E)-1,1,1,4,4,4-hexafluorobut-2-ene

1. A composition comprising (E)-1,1,1,4,4,4-hexafluorobut-2-ene and at least one compound having a boiling point less than or equal to −12° C. at a pressure of 101.325 KPa selected from the group consisting of an ether, a hydrofluoroether and a fluoroolefin, wherein the difference between the liquid saturation pressure and the vapor saturation pressure of the composition at a temperature of −5° C. is less than or equal to 10% of the liquid saturation pressure.

2. The composition as claimed in claim 1 , wherein the composition comprises a mixture selected from the group consisting of:

(E)-1,1,1,4,4,4-hexafluorobut-2-ene, 1,1,1,2-tetrafluoroethane and 1,3,3,3-tetrafluoropropene;

(E)-1,1,1,4,4,4-hexafluorobut-2-ene, 1,1,1,2-tetrafluoroethane and 2,3,3,3-tetrafluoropropene;

(E)-1,1,1,4,4,4-hexafluorobut-2-ene, 1,1,1,2-tetrafluoroethane and 3,3,3-trifluoropropene;

(E)-1,1,1,4,4,4-hexafluorobut-2-ene, isobutane and 1,3,3,3-tetrafluoropropene;

(E)-1,1,1,4,4,4-hexafluorobut-2-ene, isobutane and 2,3,3,3-tetrafluoropropene;

(E)-1,1,1,4,4,4-hexafluorobut-2-ene, isobutane and 1,1-difluoroethane;

(E)-1,1,1,4,4,4-hexafluorobut-2-ene, isobutane and propane;

(E)-1,1,1,4,4,4-hexafluorobut-2-ene, 3,3,3-trifluoropropene and 2,3,3,3-tetrafluoropropene;

(E)-1,1,1,4,4,4-hexafluorobut-2-ene, 3,3,3-trifluoropropene and 1,3,3,3-tetrafluoropropene;

(E)-1,1,1,4,4,4-hexafluorobut-2-ene, 3,3,3-trifluoropropene and isobutane;

(E)-1,1,1,4,4,4-hexafluorobut-2-ene, 3,3,3-trifluoropropene and 1,1-difluoroethane;

(E)-1,1,1,4,4,4-hexafluorobut-2-ene, 3,3,3-trifluoropropene and propane;

(E)-1,1,1,4,4,4-hexafluorobut-2-ene, 1,3,3,3-tetrafluoropropene and 2,3,3,3-tetrafluoropropene;

(E)-1,1,1,4,4,4-hexafluorobut-2-ene, 1,3,3,3-tetrafluoropropene and propane;

(E)-1,1,1,4,4,4-hexafluorobut-2-ene, 1,3,3,3-tetrafluoropropene and 1,1-difluoroethane;

(E)-1,1,1,4,4,4-hexafluorobut-2-ene, 2,3,3,3-tetrafluoropropene and propane;

(E)-1,1,1,4,4,4-hexafluorobut-2-ene, 2,3,3,3-tetrafluoropropene and 1,1-difluoroethane;

(E)-1,1,1,4,4,4-hexafluorobut-2-ene, pentafluoroethane and 1,3,3,3-tetrafluoropropene;

(E)-1,1,1,4,4,4-hexafluorobut-2-ene, pentafluoroethane and 2,3,3,3-tetrafluoropropene; and

(E)-1,1,1,4,4,4-hexafluorobut-2-ene, pentafluoroethane and 3,3,3-trifluoropropene.

3. The composition as claimed in claim 1 , wherein the composition comprises:

from 1% to 8% of (E)-1,1,1,4,4,4-hexafluorobut-2-ene and from 92% to 99% of 2,3,3,3-tetrafluoropropene; or

from 1% to 12% of (E)-1,1,1,4,4,4-hexafluorobut-2-ene and from 88% to 99% of 1,3,3,3-tetrafluoropropene; or

from 1% to 9% of (E)-1,1,1,4,4,4-hexafluorobut-2-ene and from 91% to 99% of 1,1,1,2-tetrafluoroethane; or

from 1% to 6% of (E)-1,1,1,4,4,4-hexafluorobut-2-ene and from 94% to 99% of difluoromethane; or

from 1% to 17% of (E)-1,1,1,4,4,4-hexafluorobut-2-ene and from 83% to 99% of 1,1-difluoroethane; or

from 1% to 26% of (E)-1,1,1,4,4,4-hexafluorobut-2-ene and from 74% to 99% of propane; or

from 1% to 10% of (E)-1,1,1,4,4,4-hexafluorobut-2-ene and from 90% to 99% of 3,3,3-trifluoropropene; or

from 1% to 10% of (E)-1,1,1,4,4,4-hexafluorobut-2-ene, from 1% to 98% of 1,1,1,2-tetrafluoroethane and from 1% to 98% of 1,3,3,3-tetrafluoropropene; or

from 1% to 8% of (E)-1,1,1,4,4,4-hexafluorobut-2-ene, from 1% to 98% of 1,1,1,2-tetrafluoroethane and from 1% to 98% of 2,3,3,3-tetrafluoropropene; or

from 1% to 8% of (E)-1,1,1,4,4,4-hexafluorobut-2-ene, from 1% to 98% of 2,3,3,3-tetrafluoropropene and from 1% to 98% of 3,3,3-trifluoropropene; or

from 1% to 8% of (E)-1,1,1,4,4,4-hexafluorobut-2-ene, from 1% to 98% of 1,1,1,2-tetrafluoroethane and from 1% to 98% of 3,3,3-trifluoropropene; or

from 1% to 8% of (E)-1,1,1,4,4,4-hexafluorobut-2-ene, from 1% to 98% of 2,3,3,3-tetrafluoropropene and from 1% to 98% of 1,3,3,3-tetrafluoropropene; or

from 1% to 20% of (E)-1,1,1,4,4,4-hexafluorobut-2-ene, from 1% to 98% of 2,3,3,3-tetrafluoropropene and from 1% to 98% of propane; or

from 1% to 13% of (E)-1,1,1,4,4,4-hexafluorobut-2-ene, from 1% to 98% of 2,3,3,3-tetrafluoropropene and from 1% to 98% of 1,1-difluoroethane; or

from 1% to 15% of (E)-1,1,1,4,4,4-hexafluorobut-2-ene, from 1% to 98% of 1,3,3,3-tetrafluoropropene and from 1% to 98% of 1,1-difluoroethane; or

from 1% to 20% of (E)-1,1,1,4,4,4-hexafluorobut-2-ene, from 1% to 98% of 1,3,3,3-tetrafluoropropene and from 1% to 98% of propane.

4. A heat-transfer composition comprising the composition as claimed in claim 1 and also one or more additives chosen from lubricants, stabilizers, surfactants, tracers, fluorescent agents, odorous agents and solubilizing agents, and mixtures thereof.

5. Heat-transfer equipment comprising a vapor compression circuit containing a composition as claimed in claim 1 .

6. The heat-transfer equipment as claimed in claim 5 , selected from mobile heat-pump heating or stationary heat-pump heating, air conditioning, refrigeration equipment and freezing equipment, and Rankine cycles.

7. A process for heating or cooling a fluid or a body by means of a vapor compression circuit containing a heat-transfer fluid, said process successively comprising evaporation of the heat-transfer fluid, compression of the heat-transfer fluid, condensation of the heat-transfer fluid and expansion of the heat-transfer fluid, wherein the heat-transfer fluid is a composition as claimed in claim 1 .

8. The process as claimed in claim 7 , comprising a process for cooling a fluid or a body, wherein the temperature of the fluid or of the body cooled is from −15° C. to 15° C.

9. A process for reducing the environmental impact of heat-transfer equipment comprising a vapor compression circuit containing an initial heat-transfer fluid, said process comprising a step replacing the initial heat-transfer fluid in the vapor compression circuit with a final heat-transfer fluid, the final heat-transfer fluid having a GWP which is lower than the initial heat-transfer fluid, wherein the final heat-transfer fluid is a composition as claimed in claim 1 .

10. The composition of claim 1 , wherein the difference between the liquid saturation pressure and the vapor saturation pressure at a temperature of −5° C. is less than or equal to 10% of the liquid saturation pressure.

11. The composition as claimed in claim 10 , wherein the difference between the liquid saturation pressure and the vapor saturation pressure at a temperature of −5° C. is less than or equal to 5% of the liquid saturation pressure.

12. The composition as claimed in claim 1 , wherein the at least one compound includes an ether.

13. The composition as claimed in claim 1 , wherein the at least one compound includes a hydrofluoroether.

14. The composition as claimed in claim 1 , wherein the at least one compound includes a fluoroolefin.

15. The process as claimed in claim 8 , comprising a process for cooling a fluid or a body, wherein the temperature of the fluid or of the body cooled is from −10° C. to 10° C.

16. The process as claimed in claim 15 , comprising a process for cooling a fluid or a body, wherein the temperature of the fluid or of the body cooled is from −5° C. to 5° C.

17. The process as claimed in claim 7 , comprising a process for heating a fluid or a body, wherein the temperature of the fluid or of the body heated is from 30° C. to 90° C.

18. The process as claimed in claim 17 , comprising a process for heating a fluid or a body, wherein the temperature of the fluid or of the body heated is from 35° C. to 60° C.

19. The process as claimed in claim 18 , comprising a process for heating a fluid or a body, wherein the temperature of the fluid or of the body heated is from 40° C. to 50° C.

20. The heat-transfer equipment as claimed in claim 5 , wherein the vapor-compression circuit comprises a centrifugal compressor.

21. Equipment comprising a vapor compression circuit containing a composition as claimed in claim 1 , wherein the vapor-compression circuit comprises a turbine.