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Hydrogen fluoride does not boil until 20 °C in contrast to the heavier hydrogen halides, which boil between −85 °C (−120 °F) and −35 °C (−30 °F). [6] [7] [8] This hydrogen bonding between HF molecules gives rise to high viscosity in the liquid phase and lower than expected pressure in the gas phase.
Hydrogen bonding amongst HF molecules gives rise to high viscosity in the liquid phase and lower than expected pressure in the gas phase. Hydrogen fluoride does not boil until 20 °C in contrast to the heavier hydrogen halides which boil between −85 °C and −35 °C (−120 °F and –30 °F).
The Simons process, named after Joseph H. Simons entails electrolysis of a solution of an organic compound in a solution of hydrogen fluoride. An individual reaction can be described as: R 3 C–H + HF → R 3 C–F + H 2. In the course of a typical synthesis, this reaction occurs once for each C–H bond in the precursor.
CFC-112 can be made in a reaction with hydrogen fluoride with hexachloroethane or tetrachloroethane with extra chlorine. This reaction occurs with an aluminium fluoride catalyst with some extra iron, nickel and chromium at 400°C. With the extra metal in the catalyst yield of the isomer can be 98% compared with the unsymmetrical isomer. [2]
The acidity of fluoroboric acid is complicated by the fact that its name refers to a range of different compounds, e.g. [H(CH 3 CH 2) 2 O] + [BF 4] − (dimethyloxonium tetrafluoroborate), [H 3 O] + [BF 4] − (oxonium tetrafluoroborate), and HF·BF 3 (hydrogen fluoride-boron trifluoride 1:1 adduct) – each with a different acidity.
Fluoroantimonic acid is a mixture of hydrogen fluoride and antimony pentafluoride, containing various cations and anions (the simplest being H 2 F + and SbF − 6).This mixture is a superacid stronger than pure sulfuric acid, by many orders of magnitude, according to its Hammett acidity function.
Other acids, such as sulfuric acid, polyphosphoric acid, and hydrogen fluoride have all been used. Sulfuric acid is the most commonly used acid for commercial lactam production due to its formation of an ammonium sulfate by-product when neutralized with ammonia. Ammonium sulfate is a common agricultural fertilizer providing nitrogen and sulfur.
The wet etching of SiO 2 in buffered hydrogen fluoride solutions is a common and well understood process in micro fabrication. In 1966, Holmes and Snell found that SiO 2 can be etched in hydrogen fluoride vapor. [2]