Process for reducing the total acidity of refrigerating compositions

1. A process for limiting or controlling the increase in the total acid number in a refrigerating composition comprising at least one refrigerant and at least one lubricant, said process comprising a stage of bringing said refrigerating composition into contact with at least one zeolitic adsorbent, wherein the at least one zeolitic adsorbent is free of metal impregnation and the at least one zeolitic adsorbent is based on zeolite(s) A exchanged with potassium, the degree of exchange of which is between 50% and 70% (reported as molar equivalents) of all of the exchangeable cationic sites, wherein the at least one zeolitic adsorbent is present in an effective amount to limit or reduce the total acid number of the lubricant and the effective amount is about 40 mg to about 1000 mg per 5 g of lubricant.

2. The process as claimed in claim 1 , wherein the at least one zeolitic adsorbent is chosen from a mixture of zeolite A type and one or both of zeolites of faujasite type and zeolites Y.

3. The process as claimed in claim 1 , wherein the at least one zeolitic adsorbent is chosen from a mixture of zeolites of zeolite A type and zeolites of faujasite type.

4. A process for limiting or controlling the increase in the total acid number in a refrigerating composition comprising at least one refrigerant and at least one lubricant, said process comprising a stage of bringing said refrigerating composition into contact with at least one zeolitic adsorbent, in the form of a powder formed of zeolite(s) or of agglomerate(s) formed of zeolite(s), wherein the at least one zeolitic adsorbent is free of metal impregnation and the at least one zeolitic adsorbent is based on zeolite(s) A exchanged with potassium, the degree of exchange of which is between 50% and 70% (reported as molar equivalents) of all of the exchangeable cationic sites, wherein the at least one zeolitic adsorbent is present in an effective amount to limit or reduce the total acid number of the lubricant and the effective amount is about 40 mg to about 1000 mg per 5 g of lubricant.

5. The process of claim 2 , wherein the at least one zeolitic adsorbent is present in the effective amount to limit or reduce the total acid number (“TAN-14 day”) of the lubricant such that the total acid number is maintained at or below 2.7 mg KOH/g.

6. The process as claimed in claim 1 , wherein the at least one lubricant is chosen from the lubricants employed in the fields of refrigeration and air conditioning for air or gas compressors and for refrigerating machine compressors and more generally for all dynamic or static refrigeration systems.

7. The process as claimed in claim 1 , wherein the at least one refrigerant comprises fluorinated compounds.

8. The process as claimed in claim 1 , wherein the at least one lubricant is selected from the group consisting of polyalkylene glycols (PAGs), polyol esters (POEs), polyvinyl ethers (PVEs), and combinations thereof.

9. The process as claimed in claim 1 , wherein the at least one lubricant is a lubricant used in refrigeration systems and comprises at least one refrigerant chosen from hydrofluoroolefins (HFOs) and hydrofluorocarbons (HFCs).

10. The process as claimed in claim 1 , wherein the at least one lubricant is a mixture of a lubricant and of a refrigerant, said mixture being chosen from PAG lubricant and 1,1,1,2-tetrafluoroethane, PAG lubricant and 2,3,3,3-tetrafluoropropene, POE lubricant and 1,1,1,2-tetrafluoroethane, POE lubricant and 2,3,3,3-tetrafluoropropene, PVE lubricant and 1,1,2-tetrafluoroethane, and PVE lubricant and 2,3,3,3-tetrafluoropropene, preferably comprising PAG and 1,1,1,2-tetrafluoroethane, PAG and 2,3,3,3-tetrafluoropropene, PVE and 1,1,1,2-tetrafluoroethane and PVE and 2,3,3,3-tetrafluoropropene.

11. The process as claimed in claim 1 , wherein the lubricating composition is employed in refrigeration systems, motor vehicle or domestic air conditioning systems, heat pumps, electric transformers or metal cutting and milling instruments.

12. The process of claim 1 , wherein the at least one zeolitic adsorbent is selected from the group consisting of zeolite 3A powder and agglomerates based on zeolite A powder, wherein the potassium exchange is carried out on the powder, the agglomerate, or both.

13. A process for limiting or controlling the increase in the total acid number in a refrigerating composition comprising at least one refrigerant and at least one lubricant, said process comprising a stage of bringing said refrigerating composition into contact with at least one zeolitic adsorbent, wherein the at least one zeolitic adsorbent is free of metal impregnation and the at least one zeolitic adsorbent is based on zeolite(s) A exchanged with potassium, the degree of exchange of which is between 50% and 70% (reported as molar equivalents) of all of the exchangeable cationic sites, and at least one other alkali or alkaline earth metal, the degree of exchange of which is between 30% and 50% (reported as molar equivalents) of all of the exchangeable cationic sites.

14. The process of claim 13 , wherein the at least one other alkali or alkaline earth metal is sodium.

15. The process of claim 13 , wherein the at least one zeolitic adsorbent is present in an effective amount to limit or reduce the total acid number of the lubricant such that the total acid number (“TAN-14 day”) is maintained at or below 2.7 mg KOH/g.

16. The process of claim 7 , wherein the at least one refrigerant is selected from the group consisting of hydrofluoroolefins (HFOs), hydrofluorocarbons (HFCs), and combinations thereof.

17. The process of claim 16 , wherein the at least one refrigerant is selected from the group consisting of tetrafluoroethanes, tetrafluoropropenes, and combinations thereof in all proportions.

18. The process of claim 17 , wherein the at least one refrigerant is selected from the group consisting of 1,1,1,2-tetrafluoroethane (R-134a), 2,3,3,3-tetrafluoropropene (HFO-1234yf), and combinations thereof.

19. The process of claim 8 , wherein the at least one lubricant is selected from the group consisting of PAGs, PVEs, and combinations thereof.

20. The process of claim 9 , wherein the at least one refrigerant is selected from the group consisting of tetrafluoroethanes, tetrafluoropropenes, and combinations thereof.

21. The process of claim 20 , wherein the at least one refrigerant is selected from the group consisting of 1,1,1,2-tetrafluoroethane, 2,3,3,3-tetrafluoropropene, and combinations thereof.

22. The process of claim wherein the at least one zeolitic adsorbent is present in an effective amount to limit or reduce the total acid number of the lubricant and the effective amount is about 40 mg to about 1000 mg per 5 g of lubricant.

23. The process of claim 1 , wherein the at least one zeolitic adsorbent is based on zeolite(s) 3A.

24. The process of claim 1 , wherein the at least one zeolitic adsorbent is based on zeolite(s) 4A.

25. The process of claim 1 , wherein the at least one zeolitic adsorbent is based on zeolite(s) 5A.

26. The process of claim 1 , wherein the at least one zeolitic adsorbent provides for a total acid number (“TAN-14 day”) in the refrigerating composition of 2.7 or less (mg KOH/g).

27. The process of claim 26 , wherein the TAN-14 day value is 0.4 to 2.7 (mg KOH/g).

28. A process for limiting or controlling the increase in the total acid number in a refrigerating composition comprising at least one refrigerant and at least one lubricant, said process comprising a stage of bringing said refrigerating composition into contact with at least one zeolitic adsorbent, wherein the at least one zeolitic adsorbent is free of metal impregnation and the at least one zeolitic adsorbent is based on zeolite(s) A exchanged with potassium, the degree of exchange of which is between 50% and 70% (reported as molar equivalents) of all of the exchangeable cationic sites, wherein the at least one zeolitic adsorbent is present in an effective amount to limit or reduce the total acid number (“TAN-14 day”) of the lubricant such that the total acid number is maintained at or below 2.7 mg KOH/g.