Perfluorocarboxylic acid

Direct perfluoroalkylatwn of electron poor aromatic and heterocyclic systems with perfluorocarboxylic acids is mediated by xenon difluonde [165] (equation 142)... 

Hori H, A Yamamoto, E Hayakawa, S Taniyasu, S Kutsuna, H Kiatagawa, R Arakawa (2005a) Efficient decomposition of environmentally persistent perfluorocarboxylic acids by use of persulfate as a photochemical oxidant. Environ Sci Technol 39 2383-2388. 

Hori H, A Yamamoto, S Kutsuna (2005b) Efficient photochemical decomposition of long-chain perfluorocarboxylic acids by means of an aqueous/liquid COj biphasic system. Environ Sci Technol 39 7692-7697. 

Wallington TJ, Hurley MD, Xia J, Wuebbles DJ, Sillman S, Ito A, Penner JE, Ellis DA, Martin J, Mabury SA, Nielsen OJ, Andersen MPS (2006) Formation of C7F15COOH (PFOA) and other perfluorocarboxylic acids during the atmospheric oxidation of 8 2 Fluorotelomer Alcohol. Environ Sci Technol 40 924-930... 

The 3M company uses electrochemical fluorination (ECF) technology for the production of over lOOt/year perfluorocarboxylic acid, sulphonic acids, alkanes, trialkylamines, alkyl ethers [48]. 

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. 

The applications of commercially available perfluorinated compounds have been reported in a number of recent pub-Kcations [395-397]. In the presence of perfluorocarboxylic acids, the current efficiency increased, and surface morphology... 

Employment of Zn—Cu couple is representative of another approach. For example, reaction of perfluoroalkyl iodides with carbonates gives fluorocarboxylic esters (equation 107)132. Similarly, reaction of perfluoroalkyl iodides with Zn—Cu couple and C02 or S02 in DMSO affords the perfluorocarboxylic acids and sulfonyl chlorides, respectively133. A double methylene inserted product is formed when dibromomethane is used as a substrate (equation 108)134. 

The preparation of many long-chain perfluorocarboxylic acids and diacids is now carried out on the industrial scale using direct fluorination techniques (Fig. 36) [15,16,100]. 

Armitage, J.M., MacLeod, M. and Cousins, I.T. (2009) Comparative assessment of the global fate and transport pathways of long-chain perfluorocarboxylic acids (PFCAS) and perfluorocarboxylates (PFCS) emitted from direct sourcess. Environ Sci Technol, 43, 5830-5836. 

The products of the electrochemical perfluorination of aliphatic or cyclic ethers are the corresponding perfluorinated ethers. Byproducts are perfluorinated ethers with shorter carbon chains, perfluoroalkanes, perfluorocarboxylic acid fluorides and oxygen difluoride. Cyclic perfluorinated ethers can be produced by electrochemical fluorination of alcohols,32 aliphatic carboxylic acids33 or of their acid halides34 containing not less than four carbon atoms in the chain. 

If esters arc perfluorinated the main products are perfluoroalkanes or perfluoroacyl fluorides byproducts are carbon dioxide and oxygen difluoride. The acyl and the alkyl groups in the ester give perfluorocarboxylic acids.41 A comparison of the results obtained from butyl acetate and ethyl butyrate, and from butyl propionate and propyl butyrate, indicates that perfluoro-butanoic acid is obtained in better yield from ethyl and propyl butyrate than from butyl acetate and butyl propionate. Thus, perfluorocarboxylic acids are formed more readily from the acyl than from the alkyl group of the ester. 

The effluent gases from the cell were passed over NaF pellets and then bubbled through two consecutive bottles containing H20 (for collection of the perfluorocarboxylic acids which were formed as a result of the hydrolysis of the pcrfluoroalkanoyl fluorides). The gaseous products which did not react with H20 were led into an alkaline solution of K2S03, and finally collected in traps immersed in liquid N2. Products pcrfluoro(2.4-dimethyltetrahydrofuran) (20%), perfluoi o(2-methyltetrahydropyran) (5.5%), perfluoro(3-methyltetrahydropyran) (10%) and perfiuoro(2-methylpentanoyl fluoride) (7%). 

Photooadation -of dyes [CYANINE DYES] (Vol 7) -perfluorocarboxylic acids from [FLUORINE COMPOUNDS, ORGANIC - FLUORINATED HIGHERCARBOXYLIC ACIDS] (Vol 11) -in polyamides [POLYAMIDES - GENERAL] (Vol 19)... 

In dissociating solvents, perfluoroalkyl iodides react with a zinc-copper couple to give perfluoroalkylzmc compounds, R Znl, which react with alkyl carbonates or pyrocarbonates to give perfluorocarboxylic acids or esters, respectively [55] (equations 47 and 48)... 

Mochizuki, S., Wada, N., Smith, R. L., Inomata, H. (1999), Perfluorocarboxylic acid Counter ion Enhanced Extraction of Aqueous Alkali Metal Ions with Supercritical Carbon Dioxide, Analyst 124, 1507-1511. 

Scott, B.F., C.A. Moody, C. Spencer, et al. 2006. Analysis for perfluorocarboxylic acids/anions in surface waters and precipitation using GC-MS and analysis of PFOA from large-volume samples. Environ. Sci. Technol. 40 6405-6410. 

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