Among liquid fuels, the liquid hydrocarbon known as "tetrafluoroethylene" (C₂F₄) often burns with one of the highest flame temperatures. It is commonly used as a reference for comparing the combustion temperatures of different fuels. Tetrafluoroethylene can achieve flame temperatures around 3,200 to 3,600 degrees Celsius (5,800 to 6,500 degrees Fahrenheit).
It is important to note that the actual flame temperature achieved by a fuel depends on various factors, such as the availability of oxygen, combustion conditions, and the specific chemical properties of the fuel itself. Additionally, there may be other specialty or experimental fuels that can reach even higher temperatures, but tetrafluoroethylene is commonly recognized as one of the liquid fuels with high combustion temperatures.