Fluorinert is the trademarked brand name for the line of electronics coolant liquids sold commercially by 3M. It is an electrically insulating, stable fluorocarbon-based fluid which is used in various cooling applications. It is mainly used for cooling electronics. Different molecular formulations are available with a variety of boiling points, allowing it to be used in "single phase" applications where it remains a liquid, or for "two-phase" applications where the liquid boils to remove additional heat via evaporative cooling. An example of one of the compounds 3M uses is FC-72, or perfluorohexane (C6F14). Perfluorohexane is used for low temperature heat transfer applications due to its 56°C /132.8°F boiling point. Another example is FC-75, perfluoro(2-butyl-tetrahydrofurane). There are 3M fluids that can handle up to 215°C / 419°F, like FC-70.
Fluorinert is used in situations where air will not carry away enough heat, or where airflow is so restricted that some sort of forced pumping is required.
Fluorinert may be harmful if inhaled and care should be taken to avoid contact with eyes and skin. No health effects are expected by ingestion of Fluorinert, however. Use should be constrained to closed systems and reduced volumes as fluorinated oils have a very high global warming potential and a long atmospheric lifetime.
Gases including oxygen have high solubility in Fluorinert, as fluorocarbons exhibit weak cohesive intermolecular forces. Experiments have been conducted on lab animals to determine animal survivability when submerged in highly oxygenated Fluorinert. Lab rats have survived for extended periods in such an environment, but invariably died due to lung trauma after removal.
The science fiction film The Abyss (1989) postulated an experimental liquid breathing system, in which the use of highly oxygenated Fluorinert would enable a diver to descend to great depths. While several rats were shown actually breathing Fluorinert (this scene was cut in the United Kingdom as it was seen as animal cruelty), scenes depicting actor Ed Harris using the fluid-breathing apparatus were simulated.
See also 
- "3M Manufacturing and Industry: 3M Fluorinert Electronic Liquids". 090519 products3.3m.com
- "Material safety data sheet FC-40 fluorinert brand electronic liquid 03/25/09". 090519 multimedia.3m.com
- "Fluorinert FC70 Product Information".
- Lemal, DM (2004). "Perspective on Fluorocarbon Chemistry". J. Org. Chem. 69 (1): 1–11. doi:10.1021/jo0302556. PMID 14703372