Fluorhydric acid

Fluorhydric Acid Fluoric Acid Fluorid Sodny Fluorine... 

The main reagents for nucleophilic fluorination are the metal and ammonium fluorides, the DAST reagent and its analogues, and the amine complexes of fluorhydric acid. 

HF—Amine Complexes Complexes of fluorhydric acid (HF) with pyridine or alkyl amines (Et3N, Et2NH) are often utilized as reagents in nucleophilic fluorination reactions such as the opening of oxiranes," the bromofluorination of double bonds in the presence of NBS, or the diazotation/fluorination of amines with sodium nitrite (the Balz-Schiemann-like reaction) (Figure 2.1). ... 

For decades, fluorine was a laboratory curiosity and it was studied mainly by mineral chemists. As is often the case, it was coincidence and not planned research that gave rise to fluorine chemistry. The development of the organic chemistry of fluorine is a direct consequence of the Manhattan Project in order to build nuclear weapons, the isotopic enrichment of natural uranium into its radioactive isotope was needed. For this purpose, the chosen process involved gas diffusion, which required the conversion of uranium into gas uranium hexafluoride (UFs) was thus selected. In order to produce UFe gas on a large scale, fluorhydric acid and elemental fluorine were needed in industrial quantities. This was the birth of the fluorine industry. 

Passivation — Passivation is mandatory. Use a 15 to 20% weight/weight nitric acid solution in water. Circulate at least 1 hour. Operate according to a written preapproved procedure. Do not use fluorhydric acid for passivation. Record and log passivation dates and steps. Drain the system completely. 

For other gases, such as hydrogen cyanide (HCN), fluorhydric acid (HF) or hydrogen suphide (H2S), the signal is generated by modification of the concentration of anions at the internal wall of the membrane. 

Recovery of Plutonium Traces from Nitric Acid-Fluorhydric Acid Solutions by Sorption onto Alumina... 

The aromatic compound and methylformate are diluted in anhydrous fluorhydric acid and a pressure of boron trifluoride is added to the mixture. Amounts of boron trifluoride can be changed to increase yields. Table 2 summarizes the obtained results. 

SYNONYMS anhydrous hydrofluoric acid, fluorhydric acid, HFA, hydrofluoric acid gas... 

There is only one positive root. This approximation is feasible only when the acid is sufficiently concentrated and strong for it to be dissociated. Then, in Eq. (5.12), [A ][OH ], For example, with acetic and fluorhydric acids, Eq. (5.15) is usable forC >5x10 mol/L. For hydrocyanic acid, which is far weaker than the previous ones, it is usable only for C > lO- mol/L. 

Tetrafluorethylene, ethylene, vinylidene fluoride, fluorhydric acid, 1,3,3,3-... 

Sometimes the association leads to the formation of chain-like or closed ring ag egates as in fluorhydric acid... 

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