Fluorine history

In 1869 the English chemist G. Gore obtained a small amount of free fluorine which at once reacted explosively with hydrogen. There were about ten other researchers who hoped to obtain free fluorine. History, of course, has their names but we shall not mention them here. 

The discovery in 1954 that fluorination of the glucocorticoid hormone cortisol could bring about remarkable changes in the biological properties of the hormone was entirely unexpected and violated the then prevalent belief that synthetic variants could not surpass a naturally occurring hormone in its biological activity. Because of the impact that fluorination of steroids has had on subsequent developments in this area the history of the discovery of fluorocortisol will be briefly recounted. 

The synthesis and properties of PTFE have been well described by Sperati and Starkweather" and Sheratt Two books on fluorine-containing materials are also useful. The history of die discovery and development of PTFE has been documented by Plunkett and by Sperati. Polytetrafluoroethylene is a highly... 

Banks. R.E. in Fluorine - The First Hundred Years Banks, R. E. Sharp. D.W.A. Tatlow. J.C., Eds. Elsevier Sequoia Lausanne, 1986 p 3 the early history of inorganic fluorine chemistry is described here. 

Fur an mleresiing review of Ihcenrly history of fluorine chemistry, see Fluorimr The First Hutulretl Yean (I8S6-I986) Banks, R. E. Sharp. D. W. A.. Tallow. J. C. Eds Elsevier Sequoia. New York, 1986. 

Fluorinated radicals have played a significant role in the history and development of the field of free radical chemistry, and it was recognized quite early that they have natures which are quite different from those of their hydrocarbon counterparts. As a result, there has been much effort directed towards defining and understanding these differences with respect to their structure, reactivity and chemistry. 

This compound, fluorine perchlorate, does not possess a Cl—F bond and is not a true oxide fluoride. Details of its history, preparation, and chemical and physical properties can be found in Ref. (234). 

Most other simple compounds whose history has been examined have been those of obvious industrial interest. Thus, fluorinated compounds have been discussed, especially the now controversial chlorofluorocarbons (CFCs).80 Another aliphatic chemical that has received exhaustive historical treatment, chiefly in the context of its industrial use, is lactic acid.81 The development of urea as a fertilizer has been studied,82 and a history provided of the synthesis of methanol.83... 

Aromatic fluorination chemistry has a remarkably long history, and the first successful synthesis of aryl C-F bonds was reported in 1870 [22], Significant developments in the area in the early part of the 20th century included the discovery of Balz-Schiemann reaction [23,24] involving diazotization of an aromatic amine in the presence of tetrafluoroboric acid and the reaction scheme is shown in Fig. 4. The above reaction produces large quantities of waste (such as NaBF4,... 

The GC/MS procedures for methamphetamine are described in Table 4. The papers published in Japanese - have corresponding reports in English. - - Methamphetamine was detected and determined by mass fragmentography in rat hair after administration of the substance. Nine methods also detected the metabolite amphetamine or amphetamine alone. Suzuki et al. determined methamphetamine also in nail, sweat and saliva. The workup (EX after acid or alkaline hydrolysis) and derivatization technique (methanol-trifluoroacetic acid [TEA]) is rather uniform in most procedures. Nakahara et al. ° used methoxyphenamine excretion into beard hair to discuss several washing procedures. Alkaline or methanolic extraction are used with one exception. Derivatization is mainly made by fluorinated anhydrides. A review ° gives details on analytical procedures, incorporation rates of amphetamines from blood to hair, and relationship between drug history and drug distribution in hair. 

The concept of fluorine negative hyperconjugation (FNHC), which in its simplest form can be written as indicated in Figure 4.4, has had a controversial history although there can be little doubt about the firm theoretical requirement for such an effect [18-20]. Problems have arisen because there are few rate-constant measurements that require FNHC, in addition to inductive field effects, to account for the observations [21], although structural evidence for 4.5A and 4.5B (Figure 4.5) now illustrates the effect well [22, 23]. 

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