Trifluoroiodomethane, synonyms is iodotrifluoromethane, molecular formula is CF3I, is a colorless, odorless and non-flammable gas under normal temperature and pressure. CF3I has good environmental properties (ODP=0, GWP<5, atmospheric lifetime is 1.2 days), good safety properties, non-toxic, nonflammable, good oil solubility and material compatibility. CF3I is an ideal replacement for Halon 1301 and CFCs, HCFCs, and HFCs refrigerants. CF3I is also an important fluorine-containing intermediate for introducing trifluoromethyl in organic synthesis, it is widely used in organic synthesis, biochemistry, pesticides, medicine, surfactants and dyes. In addition, CF3I also has a wide range of applications in the fields of semiconductor etching, electrical equipment insulation, magnesium alloys melting protective gas, foaming agents and aerosol propellants.
CF3I, as a replacement for traditional freon refrigerants, the US company Ikon Corporation (non-existing) began to apply for patents on it as a component in mixed refrigerant since the 1990s. But so far, Honeywell has applied for nearly one third of the global patents on CF3I as a refrigerants component.
Many global regulations, including F-Gas, the Montreal Protocol and the Kigali Amendment, require reductions in the use of high GWP products. Therefore, the HVAC industry has been looking for a solution with low GWP, energy saving, nonflammable and comparable or better performance to replace the R-410A refrigerant currently widely used in this industry. Currently, Honeywell has disclosed two products: Solstice® N41 (R-466A) and HDR 147, which are the most potential R-410A refrigerant replacements.
On June 26th 2018, Honeywell unveiled R-410A refrigerant replacement Solstice® N41, or R-466A, which is a blend of R-32, R-125 and CF3I (makes up 49%, 11.5% and 39.5%, respectively). Solstice® N41 possess a GWP of 733, which is 65% that of R-410A, is the first R-410A (R-32 and R-125 makes up this blend 50% and 50%, respectively) replacement refrigerant that meets all the above requirements and is a new generation refrigerant that can replace R-410A in stationary air conditioning systems. Its safety is the same as R-410A, which can meet the most stringentr regulatory requirements and safety standards currently faced by the HVAC industry. The test results show that moving to Solstice® N41 requires only minor changes to the equipment, and the cost is comparable to or more economical than those required for conversion to a flammable refrigerant. Once on the market, Solstice® N41 will be the first A1 ASHRAE classification, nonflammable, and lowest GWP R-410A replacement refrigerant available worldwide.
At the 18th European Conference on Refrigeration and Air Conditioning Technologies, Honeywell revealed the results of performance tests (show in table 1) using a new Honeywell development refrigerant, HDR-147, in a reversible heat pump system. It is said that HDR-147 have a GWP value of around 400 with A1 (non-flammable, non-toxic) ASHRAE classification. HDR-147 is still under assessing by ASHRAE, and may be a long-term replacement for R410A. Like Solstice® N41, HDR-147 includes CF3I but the other components have not been revealed. We believe that the key component and the main reason for non-flammability of these two blends, is trifluoroiodomethane (CF3I), a relatively new gas which has not previously been used in refrigerant blends. Significantly, CF3I is also a major contributor to these two blends’ low GWP.
Table 1. Performance of R-410A Replacements