Fluorinated organic substances

ELECTROCHEMISTRY APPLIED TO THE SYNTHESIS OF FLUORINATED ORGANIC SUBSTANCES... 

This chapter deals with recent advances in the application of electrochemical electron transfer reactions to the synthesis of fluorinated organic substances. The effect of fluorine atoms on the reduction and oxidation potentials of organic compounds is discussed first. Subsequently, recent applications of the electrochemistry to the conversion and functionalization of fluoro-organics (building-block approach) are described. Finally, methods for selective electrochemical fluorination of organic molecules (direct fluorination approach) are briefly considered. 

Fluorinated organic substances are classified into two groups, perfluoro compounds and partially fluorinated compounds. Substances in the former class are widely utilized as functional materials while those in the latter family find biological uses as pharmaceuticals and agrochemicals. 

Electrochemical fluorination was initially applied to produce per-fluorinated organic substances in processes which convert all C-H to... 

Fluorine is a special element within the periodic table, which results in unique and often valuable properties of fluorinated organic substances. When carrying out a biodegradation study with PFC, some of the characteristics of... 

CHLOROFLUOROCARBONS (cFcs) Organic substances containing chlorine and fluorine which were... 

The bones and teeth of humans and other vertebrate animals, for example, consist mainly of a composite material made up of an organic substance, collagen, and a biomineral, calcium carbonate phosphate (see Textboxes 32 and 61). The latter, which makes up about two-thirds of the total dry weight of bone, is composed of calcium phosphate containing between 4-6% calcite (composed of calcium carbonate) as well as small amounts of sodium, magnesium, fluorine, and other trace elements. The formula Ca HPChXPChMCChXOH) approximately represents its composition its crystal structure is akin to that... 

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. 

It has to be considered that titanium - at least without special protection layers - will be attacked by several chemicals for example, fluorides, fluorine-containing substances, such as tetrafluo-roborates BF4, or oxalates, and possibly by other organic acids, which may be formed during anodic oxidation reactions. An application of titanium in nonaqueous media is not suitable (instability of the passivating oxide layer). 

LC-MS/MS is recognized as the technique of choice for analysing many environmental pollutants, for example fluorinated alkyl substances (FASs). These organic compounds contain carbon and fluorine, and arise as a result of biological and geochemical processes, and may be produced synthetically for heat-, oil- and water-resistant products. FAS contaminants have been identihed in environmental and biological samples, and can bioaccumulate to toxic levels. LC-MS/MS has been widely used to study FAS contaminants in water, sediment and biological samples, and may confirm and extend more limited LC-MS studies. 

Organic substances with covalently bonded fluorine cannot be ashed in the usual way, but must be destroyed by special methods, e.g., by oxygen-flask combustion [3,4]. 

Toxic mechanism Fluorin derivative substances (indoclon etc.) in contact with the organism release hydrofluorin. Below are described the main damaging mechanisms ... 

Supercritical Carbon Dioxide - Refers to carbon dioxide that has been heated to above its critical temperature and pressure. Supercritical CO2 is a potent solvent for a great many organic substances. It is also a suitable medium for polymerization of fluorinated monomers. 

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