Fluorotelomers from

PFOA emissions PFOA emissions arise from direct and indirect sources. The term direct sources refers to PFOA released to the environment during the manufacturing and use of PFCAs. Degradation from precursor substances, like fluorotelomer-... 

Under the agreement, companies will reduce emissions of these compounds from their facilities and consumer products by 95 per cent by 2010, and work towards eliminating the sources of PFOA by no later than 2015. Furthermore, PFOS and PFOA as well as other perfluorocarboxylic acids (PFCAs) are stable degradation products and/or metabolites of neutral PFCs such as fluorotelomer alcohols (PFTOHs), perfluorinated sulphonamides (PFASAs) and perfluorinated sulphonamide ethanols (PFASEs) [22]. Therefore, the largest global manufacturer and supplier of fluorotelomers such as Capstone, DuPont have adapted its entire product line to utilise short-chain chemistry because short-chain molecules cannot break down to PFOA in the environment. 

These types of reactions have been used extensively to prepare fluorotelomers For example, Zonyl products, manufactured by E I du Pont de Nemours Co, Inc, are based on materials prepared from perfluoroethyl iodide and tetrafluoroethylene [2] (equation 1)... 

Fig. 2 a Overall metabolic scheme for the perfluoroalkylsulfonamide alcohols based on rat and fish studies. Presumably the conversion of the alcohol to the corresponding acetates (e.g., N-EtFOSAA and FOSAA) proceed via the aldehyde intermediate though this has yet to be identified. Secondary metabolites for the alcohols (e.g., glucoronide and sulfate) and the carboxylic acids have been omitted, b Overall metabolic scheme for fluorotelomer alcohols (FTOH) derived from published work from microbial and rat studies [52-54,85]... 

Gumge, K. S., Taniyasu, S., Yamashita, N., Manage, P. M. Occurrence of perfluorinated acids and fluorotelomers in waters from Sri Lanka. Marine Pollution Bulletin, 54 1663-1672 (2007). Kannan, K., Koistinen, J., Beckmen, K., Evans, T., Jones, P. D., Eero, H., et al Accumulation of perfluorooctane sulfonate in marine mammals. Environmental Science and Technology, 35 1593-1598 (2001). 

In general, the synthesis of polyphosphazene polymers is unique in that, in theory, an infinite number of polymers with a variety of properties can be derived from the common polymeric intermediate, poly(dichlorophosphazene) (PNCI2), by replacing the chlorines with different nucleophiles. If the polydichlorophosphazene precursor is reacted with the sodium salts of trifluoroethanol and a mixed fluorotelomer alcohol, a poly(fluoroaIkoxyphosphazene) elastomer (FZ elastomer) is obtained. It contains a small amount of an unsaturated substituent as a curing site. The polymer is a soft gum, which can be compounded with carbon blacks and fillers and cured with sulfur or peroxides or by radiation. 

Sinclair, E., Kim, S. K., Akinleye, H. B., and Kannan, K. 2007. Quantitation of gas-phase perfluoroalkyl surfactants and fluorotelomer alcohols released from nonstick cookware and microwave popcorn bags. Environ. Sci. Technol. 41 1180-1185. 

The free-radical addition of TFE to pentafluoroethyl iodide yields a mixture of perfluoroalkyl iodides with even-numbered fluorinated carbon chains. This is the process used to commercially manufacture the initial raw material for the fluorotelomer -based family of fluorinated substances (Fig. 3) [2, 17]. Telomeri-zation may also be used to make terminal iso- or methyl branched and/or odd number fluorinated carbon perfluoroalkyl iodides as well [2]. The process of TFE telomerization can be manipulated by controlling the process variables, reactant ratios, catalysts, etc. to obtain the desired mixture of perfluoroalkyl iodides, which can be further purified by distillation. While perfluoroalkyl iodides can be directly hydrolyzed to perfluoroalkyl carboxylate salts [29, 30], the addition of ethylene gives a more versatile synthesis intermediate, fluorotelomer iodides. These primary alkyl iodides can be transformed to alcohols, sulfonyl chlorides, olefins, thiols, (meth)acrylates, and from these into many types of fluorinated surfactants [3] (Fig. 3). The fluorotelomer-based fluorinated surfactants range includes noiuonics, anionics, cationics, amphoterics, and polymeric amphophiles. 

The fact that elevated levels of PFC As have been detected in house dust in Japan, Canada and the United States strongly suggests the presence of indoor sources. It is well known that fluorotelomer and fluoropolymer products are sources of PFCAs and that PFCAs may exist in fluorotelomer products as unwanted by-products and in fluoropolymer products as residuals. Because a broad range of commercial products either contain or are treated with fluorotelomer and fluoropolymer products, they can be potential sources of PFCAs. Given that products are often used in close proximity to humans, it is hypothesized that they can contribute to human exposure to PFCAs either directly by dermal contact and hand-to-mouth transfer or indirectly through inhalation of suspended particles from treated carpet and other interior surfaces. 

Well-known advantages of GC(-MS) over LC(-MS) are an unbeaten chromatographic resolution, which may be of importance for structural isomer separation, for example, for PFOS isomers [34], and less susceptibility to matrix effects. However, only a small fraction of PFC can be directly analyzed by GC methods, owing to the polar or even ionic structure of most of the PFC and their metabolites. Typical PFC that can be directly analyzed by GC are FTOH, fluorotelomer olefins, and other fluorotelomer-based compounds and metabolites [16]. However, the typical PFC such as PFCA and perfiuorosulfonic acids (PFSA) are non-volatile and therefore not suited for GC analysis. This can be circumvented by derivatiza-tion, for example, to the butyl [34] or i-propyl esters [35] of sulfonates or preparation of the anilides [36] or methyl esters [37] from PFCA. 

Fig. 5 Product ion spectrum of 7 3-fluorotelomer acid (7 3-FTUA). Arrows represent loss of HF. Adopted from [17], structures of product ions have been added by the authors...

Selected organic contaminants covering a wide range of partitioning properties, including polycyclic aromatic hydrocarbons (PAHs), polychlorinated biphenyls (PCBs), hexachlorocyclohexanes (HCHs), fluorotelomer alcohols (FTOHs), chemicals from the BTEX group, light aldehydes (formaldehyde, acetaldehyde), and acetone... 

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