Fluorine gaseous sources

Many different processes using HF as a reactant or source of fluorine are employed in the manufacture of fluorinated chemical derivatives. In many cases the chemistry employed is complex and in some cases proprietary. Electrochemical fluorination techniques and gaseous fluorine derived from HF are used in some of these appHcations. 

The addition of a gas to a reaction mixture (commonly the hydrogen halides, fluorine, chlorine, phosgene, boron trifluoride, carbon dioxide, ammonia, gaseous unsaturated hydrocarbons, ethylene oxide) requires the provision of safety precautions which may not be immediately apparent. Some of these gases may be generated in situ (e.g. diborane in hydroboration reactions), some may be commercially available in cylinders, and some may be generated by chemical or other means (e.g. carbon dioxide, ozone). An individual description of the convenient sources of these gases will be found under Section 4.2. 

Laser-induced breakdown spectrometry was used for the analysis of gaseous samples containing elements such as F, Cl, S, P, As and Hg in air, and hydrides of column 111 and V elements (e.g. B,H, PH,) [184-189]. The aim was to measure trace amounts of analytes in hostile environments and gas impurities for hydride work. Mercury was detected at the parts-per-billion level in air using a photodiode array detector that recorded single-shot spectra over a range of 20 nm [186]. Cremers el al. [189] reported limits of detection of 8 and 38 pg/ml for chlorine and fluorine, respectively, the source of both... 

The presence of halogens in reaction systems has been found to lead to an increased activation of the deposition surface, especially at low temperatures. " The rate coefficient of the abstraction reaction of surface H atoms by gaseous F atoms is more than two orders of magmtude greater than that of the abstraction reaction by H at 900°C or lower. " The deposition of diamond films at substrate temperatures as low as 250°C and relatively mild gas activation has been achieved in which fluorine was added to the gas mixture. " In addition, the sp carbon components may be preferentially etched by F atoms. " The use of chlorine-permuted methane as a carbon source also fevors high-purity diamond deposition at low temperatures and high methane concentrations. ... 

The determination of fluorine in various liquid and gaseous hydrocarbons is vital at many points in the refining process primarily in any blend component that has been sourced fiom the hydrogen fluoride (HF) Alkylation Unit. Fluorinated compounds poison process catalysts therefore, it is essential that process feeds be as free of fluorine as possible. As an example, butane is used to produce methyl tertiary-butyl ether (MTBE). The butane must be fluorine free prior to butane isomerization to prevent the poisoning of the process catalyst, fri addition, any HF acid or its combustion products may be extremely destructive in any environment. Therefore, any finished hydrocarbon product or synthesized material that is utilized in the presence of sufficient heat (i.e., car engine), such as frel and lubricating oils, must be free of fluoride. 

Gaseous SF3 is a gentle and effective electrophilic monofluorinating reagent for flve-membered heterocyclic compounds. The reaction of thiophenes 1,7 with gaseous SF3, generated by electron ionization of sulfur hexafluoride and acting as a source of fluorine cation (F ), is one more example of a direct fluorination process [12],... 

---