Abstract  Long-chain per- and polyfluoroalkyl substances (PFASs) are being replaced by short-chain PFASs and fluorinated alternatives. For ten legacy PFASs and seven recently discovered perfluoroalkyl ether carboxylic acids (PFECAs), we report (1) their occurrence in the Cape Fear River (CFR) watershed, (2) their fate in water treatment processes, and (3) their adsorbability on powdered activated carbon (PAC). In the headwater region of the CFR basin, PFECAs were not detected in raw water of a drinking water treatment plant (DWTP), but concentrations of legacy PFASs were high. The U.S. Environmental Protection Agency's lifetime health advisory level (70 ng/L) for perfluorooctanesulfonic acid and perfluorooctanoic acid (PFOA) was exceeded on 57 of 127 sampling days. In raw water of a DWTP downstream of a PFAS manufacturer, the mean concentration of perfluoro-2-propoxypropanoic acid (PFPrOPrA), a replacement for PFOA, was 631 ng/L (n = 37). Six other PFECAs were detected, with three exhibiting chromatographic peak areas up to 15 times that of PFPrOPrA. At this DWTP, PFECA removal by coagulation, ozonation, biofiltration, and disinfection was negligible. The adsorbability of PFASs on PAC increased with increasing chain length. Replacing one CF2 group with an ether oxygen decreased the affinity of PFASs for PAC, while replacing additional CF2 groups did not lead to further affinity changes.

Abstract  The fluoropolymer manufacturing industry is moving to alternative polymerization processing aid technologies with more favorable toxicological and environmental profiles as part of a commitment to curtail the use of long-chain perfluoroalkyl acids (PFAAs). To facilitate the environmental product stewardship assessment and premanufacture notification (PMN) process for a candidate replacement chemical, we conducted acute and chronic aquatic toxicity tests to evaluate the toxicity of ammonium 2,3,3,3-tetrafluoro-2-(heptafluoropropoxy)-propanoate (C6HF11O3.H3N) or the acid form of the substance to the cladoceran, Daphnia magna, the green alga, Pseudokirchneriella subcapitata, and a number of freshwater fish species including the rainbow trout, Oncorhynchus mykiss, In addition, testing with the common carp, Cyprinus carpio, was conducted to determine the bioconcentration potential of the acid form of the compound. Based on the relevant criteria in current regulatory frameworks, the results of the aquatic toxicity and bioconcentration studies indicate the substance is of low concern for aquatic hazard and bioconcentration in aquatic organisms. Evaluation of environmental monitoring data in conjunction with the predicted no effect concentration (PNEC) based on the available data suggest low risk to aquatic organisms.

Abstract  The production and use of long-chain perfluoroalkyl substances (PFASs) must comply with national and international regulations. Driven by increasingly stringent regulations, their production has been outsourced to less regulated countries in Asia. In addition, the fluoropolymer industry started to use fluorinated alternatives, such as 2,3,3,3-tetrafluoro-2-(1,1,2,2,3,3,3-heptafluoropropoxy)propanoic acid (HFPO-DA). Between August 2013 and September 2014, we investigated the occurrence and distribution of HFPO-DA and legacy PFASs in surface waters of the following river/estuary systems: the Elbe and Rhine Rivers in Germany, the Rhine-Meuse delta in The Netherlands, and the Xiaoqing River in China. Distinct differences were revealed among the study areas; notably, the Chinese samples were highly polluted by an industrial point source discharging mainly perfluorooctanoic acid (PFOA). This particular point source resulted in concentrations more than 6000 times higher than an industrial point source observed in the Scheur River, where HFPO-DA was the dominant compound with a concentration of 73.1 ng/L. Moreover, HFPO-DA was detected in all samples along the coastline of the North Sea, indicating that the compound may be transported from the Rhine-Meuse delta into the German Bight via the water current. To the best of our knowledge, the fluorinated alternative, HFPO-DA, was detected for the first time in surface waters of Germany and China.

Abstract  The perfluoro. carboxylic acid fluorides prepared by electrochemical perfluorination (ECPF) method were analyzed by gas chromatography/mass spectrometry. Methanol was used to convert the perfluoro. carboxylic acid fluorides into the methyl esters at 60 degrees C. The effects of column length, polarity and film thickness on the separation efficiency were investigated. The KB-1MS capillary column (90 m x 0. 25 mm x 1. 0 mu m) was employed in the GC/MS analysis. The fragmentation patterns and mass spectrometric characteristics of perfluorinated alicyclic acid methyl esters, aliphatic carboxylic acid methyl esters and mono. unsaturated perfluorinated aliphatic carboxylic acid methyl esters were analyzed and deduced from known patterns of perfluoro-organic mass spectrometry. In this work, five perfluoro. carboxylic acid fluorides including two isomers were identified and the perfluorocyclohexylcarboxylic acid fluoride accounted for about 65% of the total perfluoro-carboxylic acid fluorides in the product.

Abstract  The composition of the products of the additive Kolbe electrosynthesis involving perfluorovaleric and perfluoro-2-propoxypropionic acids and conducted in the presence of butadiene and their current efficiencies are determined by competitive adsorption of the corresponding carboxylates and butadiene at the anode. The perfluoro-2-propoxypropionate anion was the most effective adsorbate in this series. The perfluorovalerate anion was largely displaced by butadiene from the anode. This drastically decreased the current efficiency and led to an anomalously high content of higher telomer homologs among the products of additive electrosynthesis.

Abstract  Fluoroalkyl end-capped vinyltrimethoxysilane oligomer [R(F)-(CH2-CHSi(OMe)3)n-R(F); n = 2, 3; R(F) = CF(CF3)OC3F7 (R(F)-VM oligomer)] can undergo the sol-gel reaction in the presence of talc particles under alkaline conditions at room temperature to provide the corresponding fluorinated oligomeric silica/talc nanocomposites (RF-VM-SiO2/Talc). A variety of guest molecules such as 2-hydroxy-4-methoxybenzophenone (HMB), bisphenol A (BPA), bisphenol AF, 3-(hydroxysilyl)-1-propanesulfonic acid (THSP), and perfluoro-2-methyl-3-oxahexanoic acid (R(F)-COOH) are effectively encapsulated into the R(F)-VM-SiO2/Talc composite cores to afford the corresponding fluorinated nanocomposites-encapsulated these guest molecules. The R(F)-VM-SiO2/Talc composites encapsulated low molecular weight aromatic compounds such as HMB and BPA can exhibit a superoleophilic-superhydrophobic characteristic on the surfaces; however, the R(F)-VM-SiO2/Talc composite-encapsulated THSP and R(F)-COOH exhibit a superoleophobic-superhydrophilic characteristic on the modified surfaces. In these nanocomposites, the R(F)-VM-SiO2/Talc/THSP composites are applicable to the surface modification of polyester fabric, and the modified polyester fabric possessing a superoleophobic-superhydrophilic characteristic on the surface can be used for the membrane for oil (dodecane)/water separation. In addition, the R(F)-VM-SiO2/Talc composites-encapsulated micrometer-size controlled cross-linked polystyrene particles can be also prepared under similar conditions, and the obtained composite white-colored particle powders are applied to the packing material for the column chromatography to separate water-in-oil (W/O) emulsion.

Abstract  Perfluoro-2-methyl-3-oxahexanoic acid/silica nanocomposites [R-F-CO2H/SiO2] were prepared by the sol-gel reaction of tetraethoxysilane in the presence of silica nanoparticles and the corresponding fluorinated carboxylic acid under alkaline conditions. R-F-CO2H/SiO2 nanocomposites were found to exhibit no weight loss in proportion to the contents of fluorinated carboxylic acid in the composites even after calcination at 800 A degrees C. The modified glass surface treated with the R-F-CO2H/SiO2 nanocomposites was shown to give a good oleophobicity with superhydrophilicity imparted by fluorinated carboxylic acid in the composites. R-F-CO2H/SiO2 nanocomposites were also applied to the encapsulation of a variety of low molecular weight aromatic and aliphatic compounds such as bisphenol AF [BPAF], bisphenol A [BPA], 4,4'-biphenol [BPOH], octafluoro-4,4'-biphenol [FBPOH], 4,4'-bis(triethoxysilyl)-1,1'-biphenyl [BTSBP], 3-(trihydroxysilyl)propane-1-sulfonic acid [THSP], alpha-cyclodextrin (alpha-CD), beta-cyclodextrin (beta-CD), and gamma-cyclodextrin (gamma-CD). Encapsulated aromatic compounds possessing acidic hydroxyl groups such as BPAF, BPA, and FBPOH in the R-F-COOH/SiO2 nanocomposites were found to exhibit no weight loss corresponding to the contents of aromatic compounds in the composites even after calcination at 800 A degrees C. On the other hand, encapsulated aromatic compounds possessing no acidic hydroxyl groups such as BTSBP and aliphatic compounds (THSP, alpha-, beta-, and gamma-CD) gave a clear weight loss corresponding to the contents of these compounds in the composites after calcination. In addition, the fluorinated silica nanocomposite-encapsulated these compounds were applied to the surface modification of glass to exhibit a good oleophobicity with superhydrophilicity imparted by fluorinated carboxylic acid on the surface.

Abstract  Silver salts of racemic 2H-perfluoro(3-oxahexanoic) (3a), perfluoro(2-methyl-3-oxahexanoic) (3b) and 2,3,3,3-tetrafluoro-2-methoxypropanoic acid (3c) gave with Hoveyda-Grubbs 2nd generation catalyst 4 or its bis(polyfiuoroalkylated) analogue 5 the corresponding bis(polyfluoroacylated) ruthenium complexes 1a-1c or 2a, 2b as mixtures of three diastereoisomers. Their catalytic activity in model ring-closing metathesis (RCM) reactions decreased in the order 1b-2b > 1a-2a > 1c due to increased steric hindrance around the catalytic centre in complexes 1a, 1c and 2a, as well as due to lower acidity of acid 3c resulting in lower electrophilicity of the complex 1c. Thus, the complexes 1b and 2b displayed high activity in RCM of bis-unsaturated malonates forming disubstituted (RCM2) or trisubstituted (RCM3) double bond and were even significantly active in the formation of tetrasubstituted bond (RCM4), while complexes 1a, 1c were active in RCM2 but inactive in RCM3. Moreover, the yield of RCM2 catalyzed with complex is was rather low. (C) 2016 Elsevier B.V. All rights reserved.

Abstract  Perfluoro-2-propoxypropionic acid, which was prepared by the anionic dimerization of hexafluoro-1,2-epoxypropane, was optically resolved via diastereomeric salt formation with chiral amines. The optically pure (+) and (−) perfluoro-2-propoxypropionic acids thus obtained were found to be a convenient chiral reagent for determining enantiomeric compositions of α-amino acids by means of 19F nmr analysis.

Abstract  Supplementary materials

Abstract  Ammonium, 2,3,3,3-tetrafluoro-2-(heptafluoropropoxy)-propanoate has been developed as a processing aid used in the manufacture of fluoropolymers. The absorption, distribution, elimination, and distribution (ADME) and kinetic behavior of this substance has been evaluated in rats, mice, and cynomolgus monkeys by oral and intravenous routes of exposure and studied in both plasma and urine. The test substance is rapidly and completely absorbed in both rats and mice and both in vivo and in vitro experiments indicate that it is not metabolized. The test substance is rapidly eliminated exclusively in the urine in both rats and mice, with rats eliminating it more quickly than mice (approximately 5h elimination half-life in rats, 20 h half-life in mice). Pharmacokinetic analysis in monkeys, rats, and mice indicate rapid, biphasic elimination characterized by a very fast alpha phase and a slower beta phase. The beta phase does not contribute to potential accumulation after multiple dosing in rats or monkeys. Comparative pharmacokinetics in rats, mice, and monkeys indicates that the rat is more similar to the monkey and is therefore a more appropriate rodent model for pharmacokinetics in primates.