Alternative refrigerants such as HFC-125 (CF3CHF2) and HFC-134a (CF3CH2F) have been widely used as important replacements for CFC, HCFC, etc., which destroy the ozone layer. However, these alternative refrigerants are potent global warming substances, thus creating concern over the potential effects of their diffusion on global warming. To combat this, these refrigerants are collected after use; however, not all of them can be collected, and their diffusion due to, for example, leakage cannot be ignored. Although the use of CO2 or hydrocarbon-based substances as alternative refrigerants has also been studied, CO2 refrigerants have many difficulties in reducing comprehensive greenhouse gas emissions, including energy consumption, because of the requirement of large equipment due to the low efficiency of the CO2 refrigerants. Hydrocarbon-based substances also have safety problems due to their high flammability.
Fluorine-containing haloolefin compounds with a low warming potential are attracting attention as substances that can solve these problems. As an example of the fluorine-containing haloolefin compounds, 1233xf (2-chloro-3,3,3-trifluoropropene, CF3CCl═CH2) is known. 1233xf, used alone or in combination with other substances, such as hydrofluorocarbons (HFCs), hydrofluoroolefins (HFOs), and hydrochlorofluoroolefins (HCFOs), is expected to be useful as a refrigerant, and additionally as a blowing agent, propellant, extinguishing agent, or the like. 1233xf is also important as a starting material for producing other hydroolefin compounds such as HFO-1234yf, which is expected to be used for a refrigerant etc., or as a starting material for producing other hydrofluoroolefin precursors such as HCFC-244bb. Various 1233xf production methods are known. A method in which a pentachloropropane, such as 1,1,1,2,3-pentachloropropane (240db), is reacted with hydrogen fluoride (HF) in the presence of a catalyst is known. For example, Patent Literature 1 discloses a technique of producing 1233xf during the process of continuously producing 2,3,3,3-tetrafluoropropene (1234yf) by subjecting 240db to a gas-phase fluorination in the presence of a catalyst.
USPTO Backgrounds
USPTO Backgrounds