Uses of Fluorine

The fluorine produced is either immediately used to prepare other final products or is first liquefied and delivered in steel cylinders where required. When fluorine is liquefied it is first led from the electrolyzer through a steel coil cooled to — 90 °C by dry ice. It then passes through a coil submerged in liquid oxygen, (— 183 °C) to separate the remaining traces of hydrogen fluoride, carbon dioxide and tetrafluoromethane. The product still contains a small 

In an oxidation reaction hydrogen peroxide is reduced according to equations  

From Nernst s equation related to individual equilibrium potentials we may deduce that the oxidizing power of hydrogen peroxide, which is higher with a more positive reduction potential of the system (lb), grows with increasing concentration of the hydrogen ions in the solution. On the other hand the 

Hydrogen peroxide reacts with some acids (sulphuric acid for instance) and forms peroxy-acida, and with some bases [such as Ca(OH2), Ba(OH)2, Mg(OH)2, Zn(OH)2] and forms peroxides. Oxides of the IV and VI group of the periodic system (i. e. oxides of Ce, Ti, V, Nb, Ta, Cr, Mo, W, U) also react with hydrogen peroxide to form peroxides, peroxy-acids and persalts. Many additive compounds of hydrogen peroxide are known such as with sodium metaborate, urea and hexamethylene-tetramine. 

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Fluorine was first produced commercially ca 50 years after its discovery. In the intervening period, fluorine chemistry was restricted to the development of various types of electrolytic cells on a laboratory scale. In World War 11, the demand for uranium hexafluoride [7783-81-5] UF, in the United States and United Kingdom, and chlorine trifluoride [7790-91 -2J, CIF, in Germany, led to the development of commercial fluorine-generating cells. The main use of fluorine in the 1990s is in the production of UF for the nuclear power industry (see Nuclearreactors). However, its use in the preparation of some specialty products and in the surface treatment of polymers is growing. 

Elemental fluorine is used captively by most manufacturers for the production of various inorganic fluorides (Table 5). The market for gaseous fluorine is small, but growing. The main use of fluorine is in the manufacture of uranium hexafluoride, UF, by... 

An important newer use of fluorine is in the preparation of a polymer surface for adhesives (qv) or coatings (qv). In this apphcation the surfaces of a variety of polymers, eg, EPDM mbber, polyethylene—vinyl acetate foams, and mbber tine scrap, that are difficult or impossible to prepare by other methods are easily and quickly treated. Fluorine surface preparation, unlike wet-chemical surface treatment, does not generate large amounts of hazardous wastes and has been demonstrated to be much more effective than plasma or corona surface treatments. Figure 5 details the commercially available equipment for surface treating plastic components. Equipment to continuously treat fabrics, films, sheet foams, and other web materials is also available. 

The high cost of SF and the incomplete use of fluorine justify its use only for inaccessible ben2otrifluorides. The related Hquid S—F reagent, (diethylarnino)sulfur trifluoride (DAST), (C2H )2NSF2, also effects similar transformations with aromatic carboxyhc acids (108). 

Fluorine. Fluorine is the most reactive product of all electrochemical processes (63). It was first prepared in 1886, but important quantities of fluorine were not produced until the early 1940s. Fluorine was required for the production of uranium hexafluoride [7783-81 -5] UF, necessary for the enrichment of U (see DIFFUSION SEPARATION METHODS). The Manhattan Project in the United States and the Tube Alloy project in England contained parallel developments of electrolytic cells for fluorine production (63). The principal use of fluorine continues to be the production of UF from UF. ... 

A. J. Rudge, The Manufacture and Use of Fluorine and Its Compounds, Oxford University Press, London, 1962. 

Some industrial uses of fluorine require molecular fluorine, F2, which is produced by electrolysis of HF. As Figure 21-16 shows, the cell uses liquid HF to which KF is added as an electrolyte. The redox chemistry is Anode 2 F" F2 + 2 e ... 

Londry KL, PM Fedorak (1993) Use of fluorinated compounds to detect aromatic metabolites from m-cresol in a methanogenic consortium evidence for a demethylation reaction. Appl Environ Microbiol 59 2229-2238. 

Edwards PN (1994) Uses of fluorine in chemotherapy. In Organofluorine Chemistry Principles and Commercial Applications (Eds RE Banks, BE Smart, JC Tatlow), pp. 501-541. Plenum Press, New York. 

R. Berger, H. F. Fink, G. Koemer, J. Langner, and C. Weitemeyer. Use of fluorinated norbomylsiloxanes for defoaming freshly extracted degassing crude oil. Patent US 4626378, 1986. 

The use of plant extracts for insect control dates into antiquity the use of Paris green as an insecticide for control of the Colorado potato beetle in 1867 probably marks the beginning of the modern era of chemical control of injurious insects. The development of lead arsenate followed later in the nineteenth century for gypsy moth control. The commercial production of nicotine insecticides, the production of calcium arsenate at the time of the first world war, and the use of fluorine, arsenical, and cyanide compounds, as well as other inorganic chemicals for insect control, were important steps in pest control. These chemicals were applied largely by dilute high pressure sprays or dusts. 

Then, once the desired fluorine-containing compounds have been synthesized, the real fun begins as the world of fluorine NMR is entered. However, one s first encounter with fluorine NMR can also present a problem because although most synthetic organic chemists are thoroughly familiar with the use of proton and carbon NMR for compound characterization, few have much experience with the use of fluorine NMR for that purpose. Moreover, there is presently no single place where a person can turn to obtain a concise but thorough introduction to fluorine NMR itself and, just as importantly, to learn how the presence of fluorine substituents can enhance the efficacy of both proton and carbon NMR as tools for structure characterization. 

DesMarteau, D. D. et al., J. Amer. Chem. Soc., 1987, 109, 7194-7196 Fluorine is the most electronegative and reactive element known, reacting, often violently, with most of the other elements and their compounds (note the large MRH values quoted below). Handling hazards and disposal of fluorine on a laboratory scale are adequately described [1,2,3,4,5][6], and a more general review is also available [7], Safety practices associated with the use of laboratory- and industrial-scale fluorine cells and facilities have been reviewed [8], Equipment and procedures for the laboratory use of fluorine and volatile fluorides have been... 

Schmidt, 1967 Handling and Use of Fluorine and Fluorine-Oxygen Mixtures in Rocket Systems, SP-3037, Schmidt, H. W Harper, J. T Washington, NASA, 1967... 

CHEC-II(1996) comprehensively outlines the most commonly used synthetic approaches applied to these types of bicyclic compounds of phosphorus, arsenic, antimony, and bismuth <1996CHEC-II(8)863>. The six classes of compounds listed in this section have received considerable attention over the review period and as such the principal synthetic methods for these compounds are discussed. Schoth et al. <2000CCR101> have reviewed the use of fluorinated 1,3-diketones, 2-trifluoroacetylphenols, and their derivatives in the synthesis of phosphorus compounds. Included in this review is the use of these reagents for the synthesis of various [3.3.1] nonfused and [3.3.0] fused phosphorus bridgehead bicyclic systems. 

The use of fluorine to modulate properties including potency, selectivity, pharmacokinetics, and toxicity has have been highlighted. Fluorine has also been suggested as a potential bioisosteric replacement for a number of functional groups, examples of which are presented in the final section. 

There are two possible ways to introduce fluorinated groups into silanes and silicones through the use of fluorinated organometallic reactants (mainly orga-nomagnesians and organolithians) or by hydrosilylation of fluorinated alkenes. 

However, the fact that industrial applications of polymer surface fluorination employ a fluorine/nitrogen mixture as the fluorinating agent complicates matters because fluorine gas is toxic, may explode when brought into contact with organic substances, and causes severe bums on human tissue. Moreover, the use of fluorine requires highly qualified personnel and special safety systems. 

Industrial use of fluorine gas treatment started at the end of the 1980s. Surface modifications with fluorine offer improved reactivity for subsequent demands. One of the major advantages of fluorine gas treatment is the fact that modifications can be carried out under standard pressure and temperature (Figure 17.1), so that it can be used for on-line processes at low cost. Areas of application include, plastic fuel containers, gluing, dyeing or printing preparations on plastics.1-3... 

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