Refrigerant blends having low global warming potential

A process of reducing the global warming potential of a refrigerant blend of R-449A, comprising:

• (a) selecting R-407A or R-410A recovered from one or more refrigeration systems;
• (b) purifying the R-407A or R-410A to form purified R-407A or R-410A, wherein the purifying of step (b) comprises removing solid impurities from the R-407A or R-410, and wherein the solid impurities are removed by one or more purification techniques selected from vacuum filtration, membrane centrifugal filtration, gravity filtration, depth filter filtration, granular bed filtration, cartridge filtration using carbon, fiber or metal filtration, and precoat filtration;
• (c) blending the purified R-407A or R-410 with 2,3,3,3-tetrafluoropropene (HFO-1234yf) to form a purified refrigerant blend;
• d) recovering the 2,3,3,3-tetrafluoropropene (HFO-1234yf) from one or more refrigeration, air conditioning or heat pump systems;
• (e) purifying the 2,3,3,3-tetrafluoropropene (HFO-1234yf) to form purified 2,3,3,3-tetrafluoropropene (HFO-1234yf);
• and
• (f) optionally adding one or more components of R-449A after step (c) to bring the refrigerant blend into specification;
• wherein steps (d) and (e) are each performed prior to the blending of step (c);
• wherein the purified R-449A refrigerant blend has a reduced global warming potential compared to a refrigerant blend comprising components which have not been recovered and purified according to steps (b)-(c);
• wherein the purifying of step (e) comprises removing liquid impurities, gaseous impurities, or a combination thereof, from the one or more hydrofluoroolefins, wherein the liquid impurities, gaseous impurities, or a combination thereof are removed by one or more purification techniques selected from distillation, decantation, contact with molecular sieves, and vapor space purging.