tetrafluoroethane

Tetrafluoroethane, commonly known by its refrigerant designation R-134a, is a colorless, synthetic fluorinated hydrocarbon with the chemical formula C2H2F4. Its systematic name is 1,1,1,2-tetrafluoroethane, and it is classified as a hydrofluorocarbon (HFC). It was developed as a replacement for ozone-depleting chlorofluorocarbons and has become a widely used refrigerant in vapor-compression systems, including automotive air conditioning and domestic refrigeration.

In typical applications, tetrafluoroethane is used as the working fluid in closed refrigeration cycles. At room temperature it is a gas that can be compressed and condensed into a liquid under pressure. It has a boiling point of about −26.3 °C at 1 atmosphere. It is generally considered non-flammable (ASHRAE safety class A1) and has low acute toxicity, but exposure at high concentrations can be harmful and proper handling and ventilation are advised.

Environmental and regulatory aspects are a major consideration. R-134a has zero ozone depletion potential (ODP) but a high global warming potential (GWP), conventionally around 1,430 over a 100-year horizon, and an atmospheric lifetime on the order of about a decade. Because of its high GWP, many regions are phasing down its use under international agreements and regional regulations. In new equipment, lower-GWP alternatives are increasingly adopted, such as R-1234yf, and some systems use carbon dioxide (R-744) or other options. R-134a is being gradually replaced in several applications, including automotive air conditioning and foam blowing, to reduce climate impact.

Safety considerations center on standard compressed-gas handling practices, including ventilation and avoidance of high concentrations, particularly in enclosed spaces.