Fluorine, caution

A Caution Hydrogen fluoride and fluorine are dangerous materials. Exposure to them will cause severe, painful, and perhaps fatal injury. Exposure may not be evident for several hours. The procedures described here pose the risk of exposure to hydrogen fluoride and to elemental fluorine and should only be carried out by, or under the direct supervision of, qualified professionals. Qualified first aid treatment and professional medical resources must be established prior to working in the area. Prompt treatment is necessary to reduce the severity of damage from exposure and should be sought immediately following exposure or suspected exposure. Material safety data sheets are available from HF and fluorine suppliers. Their recommendations should be followed scrupulously. 

In the first half of the twentieth century much bone was dated using this method, and dates derived with it greatly contributed, for example, to unfolding the nature of the Piltdown bones (see Chapter 18). Experience has shown that bones buried in sand or gravel are suitable for dating with fluorine, while those buried in volcanic soils rarely yield useful dates dates derived from fluorine analysis results should, therefore, be used with caution (Schurr 1989 Oakley and Hoskins 1950). 

Schack. C. J., J. Fluorine Chem., 1981, 18, 584 Potentially hazardous, it must be handled with caution. 

Caution Phenylsulfur trifluoride and by-products (e.g., hydrogen fluoride from hydrolysis) are toxic, and all manipulations should be carried out in a good hood. Silva difluoride is a powerful oxidative fluorinating agent and reacts vigorously with many organic materials. These reagents should not be allowed to come in contact with the skin. 

CAUTION. Fluorine is a strong oxidizer and a very corrosive material. An appropriate vacuum line made from copper or Monel in a well-ventilated area should be constructed for working with this element. The reactions themselves were carried out in Teflon vessels. If elementary precautions are taken, work with fluorine is relatively simple. 

This example of the toxicity of fluoroacetate shows that interpreting a biological effect at the enzymological level requires long and complex studies. Thus, we must remember that explanations about the role of fluorine in the inhibition of enzymes should be considered with caution. In most cases, they must be considered as hypotheses. 

Caution. Metal hexafluorides are volatile, toxic, corrosive, and highly hygroscopic materials. They must be handled in a very dry, clean, fluorine-preconditioned metal vacuum system. The vacuum system should be constructed from stainless steel or Monel materials (glass is not acceptable if pure products are desired). Hydrogen fluoride also is quite toxic and volatile. If only one metal... 

Minnesota, caution should be exercised when dealing with some of the fluorine compounds. 

F2N.C( NF).NF.C(NF2)2F mw 265.04, N 26.42%, FB +7.2% FB is analogous with OB, being applied hereafter to fluorinated compds wherein the F is not already on C it is calculated in the same manner, the factor 1900/mw being used instead of 1600/mw) liq, bp ca 80° mp below —130° a 50/50 mixt of the cis and trans isomers, Prepd by fluorinating biguanide sulfate with nitrogen diluted fluorine and a sodium-magnesium fluoride mixt at 0° Proposed as an oxidizer for propints. Should be treated with extreme caution. May readily detonate into CF4 and N2. Do not let vapors contact mercury Refs 1) Beil, not found 2) J.J. Hockstra,... 

Diazonium Fluoroborates. Dr R.P. Johnson 8e J.P. Oswald of Abbot Laboratories, North Chicago, III urge caution regarding the stability of aromatic diazonium fluoroborate salts. These salts are intermediates in the Schie-mann-Balz reaction for replacing the aromatic primary amino group by fluorine... 

Trifluoromethyl hypofluorite is generally used at low temperatures with reactants dissolved in an inert solvent, but to increase the solubility of reactants a cosolvent (MeOH, acetone, THF) is often used however, it must be used with extra caution and appropriate safety precautions against explosions and fires, since trifluoromethyl hypofluorite is a powerful oxidizing agent. The toxicity of trifluoromethyl hypofluorite is expected to be high (as with fluorine). Fluori-nation reactions with trifluoromethyl hypofluorite have been discussed in the last twenty years in review papers6 11,65 and several monographs.12" 14... 

Reactions with bis(dialkylainino)difluoro-/l.4 -sulfanes can be performed in normal glassware under anhydrous conditions. Caution in the presence of moisture hydrolysis takes place liberating hydrogen fluoride. Bis(dialkylamino)difluoro-24 -sulfanes are less reactive fluorinating reagents than (dialkylamino)trifluoro-24 -sulfanes. This fact coupled with their lengthier syntheses and their noncommercial availability has limited their application. 

Ref 93). Extreme caution should be used in reducing any fluorinated compound with LiAlH4. Violent reactions have been observed with two different fluoro compounds (Refs 76 95). Excess trimethyl amine, NMes, reacts with an ethereal /solution of LiAlH4 in vacuo at -SO t to form a white addition compound which is slightly soluble in ether, insoluble in benzene, and spontaneously flammable in air (Ref 98a) Magnesium perchlorate may be used as a drying... 

Caution. Fluorine must be handled with great care and with special apparatus. See descriptions of apparatus and precautions for such handling in other contributions to this series.s... 

Caution Molecular fluorine is a very toxic and corrosive gas. The following reaction should be carried out in an efficient fume hood, and the experimenter should be familiar with the precautions necessary for safe handling of fluorine,s Since molecular fluorine diluted with an inert gas is much safer to handle than pure fluorine,... 

The selective oxidation of C—H bonds in alkanes under mild conditions continues to attract interest from researchers. A new procedure based upon mild generation of perfluoroalkyl radicals from their corresponding anhydrides with either H2O2, m-CPBA, AIBN, or PbEt4 has been described. Oxidation of ethane under the reported conditions furnishes propionic acid and other fluorinated products.79 While some previously reported methods have involved metal-mediated functionalization of alkanes using trifluoroacetic acid/anhydride as solvent, these latter results indicate that the solvent itself without metal catalysis can react as an oxidant. As a consequence, results of these metal-mediated reactions should be treated with caution. The absolute rate constants for H-abstraction from BU3 SnH by perfluorinated w-alkyl radicals have been measured and the trends were found to be qualitatively similar to that of their addition reactions to alkenes.80 a,a-Difluorinated radicals were found to have enhanced reactivities and this was explained as being due to their pyramidal nature while multifluorinated radicals were more reactive still, owing to their electrophilic nature.80... 

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