Stability of Hydrogen Fluoride Under Water-Gas-Reaction Conditions

Abstract

The prime objective of the investigation was to prove the stability of hydrogen fluoride under water-gas-reaction conditions. Calculations of the thermodynamically equilibrium composition of substances in the system of elements C–H–F–O were conducted, and it has been shown that with excess carbon and at a temperature of 1000 to 2000 K, the basic components of the mixture are carbon mono- and dioxide, hydrogen, methane, and hydrogen fluoride, and carbon fluorides and oxyfluorides are absent. At a temperature above 1300 K, the thermodynamically equilibrium mixture consists of carbon monoxide, hydrogen, and hydrogen fluoride. Calculation results have been confirmed by laboratory experiments in which the only fluorine-containing substance, i.e., hydrogen fluoride, was found as part of the products of interaction of water and carbon in the presence of hydrogen fluoride at a temperature of the order of 1500 K. The obtained results can become a basis for the technology of obtaining anhydrous hydrogen fluoride from its aqueous solutions, including the azeotropic one, by high-temperature interaction of the steam and carbon at