Organo fluorination

Other solutions to dealing with interferences in the detection of H O have included the use of a copperfll) diethyldithiocarbamate precolumn to oxidize the sample before it reaches the immobilized enzyme, as well as the use of a palladium/gold sputtered electrode which catalyzes the oxidation of hydrogen peroxide In addition, peroxidase has been used to catalyze the reaction between hydrogen peroxide and iodide ferrocyanide and organo-fluorine compounds Am-... 

J. C. Tatlow (Eds.), Organo Fluorine Chemistry, Principles and Commercial Applications, Plenum Press, New York, 1994 pp. 501-541. 

J.T. Welch, Bond strengths and reactivity in organo-fluorine compounds, in B. Baasner (Ed.), Flouben Weyl Methoden der Organische Chemie, El Ob Part 2 Fluorine, Georg Thieme Verlag, Stuttgart, (1999), pp. 293-305. 

ATP 7 was converted to two, at that time unknown organo-fluorine compounds, 5 -fluoro-5 -deoxyadenosine (5 -FDA) 5 and 5 -fluoro-5 -deoxyinosine (5 -FDI) 6 as well as FAc 1 [6],... 

More recently, the possible contribution of organo-fluorine free radicals to ozone destruction has been considered with respect to the introduction of CFC transitional alternates and longer term replacements however, as discussed in Chapter 13.D, this also does not appear to be important in terms of ozone destruction. 

Anand M, Hobbs JP, Brass IJ (1994) In Banks RE, Smart BE, Tatlow JC (eds) Organo-fluorine Chemistry. Principles and Commercial Applications. Plenum, New York p 469... 

They could be trapped with a variety of electrophiles such as aldehydes, water, carbon dioxide, trimethylsilyl chloride, tributyltin chloride to give the corresponding difluorovinyl derivatives [132-138] (Scheme 52), which were demonstrated to be versatile and useful building blocks for the synthesis of organo-fluorine compounds. 

Sadly then, the first attempt to retain a C — F bond in an organic fluoride, whilst a functional group was replaced, failed. A reaction far more significant in organo-fluorine chemistry than the planned one had been hidden by the misinterpretation however. The first recorded nucleophilic displacement of fluorine from an aromatic C —F bond had occurred a process to become of vast importance. 

Swarts made a vast contribution to organo-fluorine chemistry. It is unlikely that its impact will ever be equaled hy that from any other individual s work, within their respective contexts. 

RufFs main work5 8 was on inorganic fluorides, but Bigelow. Simons and Miller all contributed9,41 much more to organo-fluorine chemistry. 

These and other chemical aspects of the Manhattan Project (code name for work on the atom bomb) have been described in full.37,42,43 Depending on fluorocarbons for its success, the project stimulated rapid developments in their background chemistry.41 Interest in all aspects of science involving organo-fluorine chemicals was engendered at that time, and has continued unabated until the present day. 

Clearly, Greek or Latin numeral roots in conjunction with numerical locants can be used to indicate the number and positions of fluorine substituents in any type of organo-fluorine compound or group, ranging from monofluorinated systems, e.g. 2-fluorobutane (1), to perfluorinated entities, e.g. l,l,l,2.2,3,4,4,4-nonafluoro-3-iodobutane(2). Fluorine locants may be omitted, and often are in non-indexing situations when naming simple and therefore easily visualized fully fluorinated aliphatic/cycloaliphatic or monocyclic aromatic compounds or groups, e.g. octafluoropropane (3), hexafluorocyclopropane (4), pentafluoropropanoic acid, (5). pentafluorophenyl (6). 

In organo-fluorine chemistry many reactions are known where more or less stable ionic or radical intermediates are formed, for example, carbocations, carbanions. and partially fluorinated and perfluorinated radicals and carbenes. While some of these species are short lived, others are surprisingly stable and isolable. In the latter case electronic and steric arrangements often kinetically stabilize the intermediate. 

Fluorinated radicals play a significant role in synthetic organo-fluorine chemistry, for example, in electrophilic radical addition to alkenes, single-electron transfer reactions (SET), telomerization of fluoroalkenes with perfluoroalkyl iodides, polymerization to fluoropolymers and copolymers, and thermal, photochemical and radiation destruction of fluorocarbons. Furthermore, such free radicals are of interest for studying structures, reaction kinetics and ESR spectroscopic parameters.38... 

All of todays modern elemental analyzers will determine percentage amounts of carbon, hydrogen, and nitrogen successfully on the vast majority of organo-fluorine compounds without having to change the standard operating conditions of the instruments. 

The traditional peroxide or Parr bomb method2 is less popular these days as fluoride finishes up in a solution of high ionic strength, which may present problems in its determination. Most types of organo-fluorine compound can, however, be decomposed satisfactorily by this method including volatiles, polymers and BF compounds. 

Furthermore, toxic properties of organo-fluorine compounds are often published in medical, pharmacological, biochemical or other specialized journals which arc not read by experimental and industrial chemists and are written in an unfamiliar style with a specialized vocabulary. 

A good example of the difficulties involved in accessing toxicological data of organo-fluorine compounds can be seen by examining the work of Hodge, Smith and Chen,5 published in 1963. This included results many of which were mainly preliminary toxicity data, reported in the literature until 1961. Much data that was not comparable in depth of focus, meaningfulness, mode of application, animal material, doses, and quality of research was summarized in this article. Information contained within such an article is difficult for experimental chemists to assess. Further data on the toxicity of fluoroalkanes, fluoroalkenes and fluoropolymers has been published.6... 

This survey covers the most important information, published after 1960 in monographs, reviews, and papers of completely different nature in approach, experimental pathways and scientific weight and character. Therefore it is, as such, a cocktail of results, ranging from extensive, complete, statistically relevant toxic data of organo-fluorine compounds to the results of mere prescreening experiments. Some classes of compounds, considered to be nontoxic (see Section 5.1.) are, however, excluded. Bearing in mind the protection of scientists and their coworkers, this is the best approach, if conscious of adequate responsibility. This review is written for experimental chemists, rather than toxicologists. 

The Deutsche Forschungsgemeinschaft (DFG) publishes an annual report Maximale Arbeits-platzkonzentrationen (MAK) und Biologische Arbeitsstofftoleranzwerte (BAT) (maximum workplace concentrations and biological materials tolerance levels),20 to protect workers against well-defined and determined toxic or probably toxic materials in workroom air the organo-fluorine compounds included in the 1997 edition are listed in Table 3.20 These data also allow on a representative basis a comparison of acute toxic and safe concentrations of the same species (see also Section 5.2.7-)-... 

Fluorinated polymers are by nature inert and nontoxic materials. A certain toxicity may however be incorporated from additives added, e.g. perfluorooctanoic acid or traces of monomers. In addition, toxic organo-fluorine compounds may be generated from these polymers by high temperature decomposition.6-64- 16-118 Biological effects of fluorocarbon fibers have been described.119 Toxicities of polychlorotrifluoroethylenc oils (hydraulic fluids) have also been discussed.202... 

Additional and, occasionally, more detailed information on the toxic effects of organo-fluorine compounds can be found in general publications (see, for example, refs 157-172 and 210). Acknowledgements are presented in ref 209. 

Lc Blanc, M. Riess, J. G. in Preparation, Properties, and Industrial Applications of Organo-Fluorine Compounds, Banks, R.E., Ed. Ellis Horwood Chichester, 1982 p83. 

This section can provide only a glimpse of the remarkable diversity of the applications for organo-fluorine compounds which have been developed over the past fifty years and readers requiring more details are directed to the more comprehensive reviews which are cited. 

This is a time of transition in the organo-fluorine industry and to provide a proper perspective this article has looked backwards as much as forwards. A similar article in 20 years time is likely to present a very different picture. 

Nandakumar. S.R. Baker, B.E. in Organo-fluorine Chemistry. Principles and Commercial applications Banks, R.E. Smart B. E. Tatlow, J.C., Eds. Plenum New York, 1994 p321. 

The scope of selective fluorination should be broadened considerably on the basis of the present results. The 1-fluoropyridinium salt system should thus make possible the preparation of many useful organo-fluorine compounds. 

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