Calcium fluoride as fluorinating

Calcium dithionate, 2 168 Calcium fluoride, as fluorinating agent, 4 137... 

Fluorine occurs widely in nature as insoluble fluorides. Calcium fluoride occurs as jluospar or fluorite, for example in Derbyshire where it is coloured blue and called bluejohn . Other important minerals are cryolite NajAlFg (p. 141) and Jluorapatite CaFjSCaj (P04)2. Bones and teeth contain fluorides and some natural water contains traces. 

Although stable at ambieat temperature, calcium fluoride is slowly hydrolyzed by moist air at about 1200°C, presumably to CaO and HF. Calcium fluoride is not attacked by alkahes or by reactive fluorine compounds, but is decomposed by hot, high boiling acids, as ia the reactioa with coaceatrated sulfuric acid which is the process used to produce hydrogea fluoride. Calcium fluoride is slightly soluble ia cold dilute acids, and somewhat more soluble ia solutioas of alumiaum hahdes. 

The large amount of fluorine values released from phosphate rock in the manufacture of fertilisers (qv) gives a strong impetus to develop fluorine chemicals production from this source (see Phosphoric acid and the phosphates). Additional incentive comes from the need to control the emission of fluorine-containing gases. Most of the fluorine values are scmbbed out as fluorosiUcic acid, H2SiPg, which has limited useflilness. A procedure to convert fluorosihcic acid to calcium fluoride is available (61). 

The most abundant fluorine mineral is fluorite—calcium fluoride (CaF )— which is often found with other minerals, such as quartz, barite, calcite, sphalerite, and galena. It is mined in... 

The highest yield of perchloryl fluoride (97%) was achieved with a mixture of fluorosulfonic acid and SbFj as fluorinating medium. Potassium, sodium, lithium, magnesium, barium, calcium, and silver perchlorates and perchloric acid itself undergo the reaction. Commercial reagents are used and their additional puriflcation is not necessary unlike all the previous methods the preparation of perchloryl fluoride by this method can be carried out at room temperature. At high temperature (100°-135°C) the reaction time is 1-10 min in all, which allows the process to be carried out continuously in a packed column. The purity of product obtained after the usual puriflcation reaches 98% and over air and carbon dioxide are present as trace impurities 23). 

Calcium fluoride occurs in nature as the mineral fluorspar or fluorite. It is used as a flux in ferrous metallurgy to enhance the fluidity of the slag. An important application of this compound is in the manufacture of fluorine and hydrofluoric acid, starting materials for producing many fluoroorganics. It also is used in glass and ceramics. Pure crystals are used in lasers, optics, and electronics. Other applications are in high temperature, dry-film lubricants ... 

Ruff and Giese passed fluorine over mixed silver(I) cyanide and calcium fluoride (a diluent). Pure products could not be isolated, but three were claimed as Aj/V-difluorotrifluoro-methylamine (CF3NF2), bis(trifluoromethyl)diazene (CF,N = NCF3), and trifluoroni-trosomethane (CF3NO) [silver(I) nitrate was present], a glimpse of progress to come. 

The fluorine in fluoride toothpaste is in the form of a fluorine compound. One such compound is sodium monofluoride phosphate. The fluorine in the sodium monofluoride phosphate bonds with calcium in tooth enamel and forms a calcium fluoride layer that acts as a bacterial barrier. 

The importance of fluorine lies largely in the use of several compounds of that element. Calcium fluoride, or fluorspar (CaF2), is used as a flux and, like sodium fluoride (NaF), as an insecticide. Ammonium fluoride (NH4F) is used as a disinfectant hydrofluoric acid is used in the etching of glass and organic compounds are used as commercial refrigerants. 

Fluorine, F2 (mp, -218°C bp, -187°C), is a pale yellow gas produced from calcium fluoride ore by first liberating hydrogen fluoride with sulfuric acid, then electrolyzing the HF in a 4 1 mixture with potassium fluoride, KF, as shown in the reaction... 

The starting material may be selected on the basis of the type of equipment available. A bromide might be used as a starting material in ordinary reactors, whereas a chloride might require pressure equipment. The fluorinating agent also may dictate the type of equipment to be used. Thus, calcium fluoride may be used in glass equipment, whereas hydrofluoric acid requires metal apparatus. 

Linear alkylbenzenes are made from linear terminal olefins and benzene and are important precursors of biodegradable anionic surfactants (LAS, linear alkylbenzenesulfonates). The conventional catalyst is HF, first to be replaced by a fluorinated silica-alumina in the DETAL process. The DETAL process is safer than the HF process and also more cost-effective because no special metallurgy is required and no calcium fluoride waste stream exists.52 Zeolites such as Beta may come to the fore here because they display a higher selectivity to the desired 2-phenyl isomers.55... 

Using electron dot notation, the production of sodium fluoride, calcium fluoride, and calcium oxide may be pictured as follows A sodium atom and a fluorine atom react in a 1 1 ratio, since sodium has one electron to lose from its outermost shell and fluorine requires one more electron to complete its outermost shell. 

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