Synthesis of perfluorinated carboxylic acid membrane monomers by utilizing liquid-phase direct fluorination

A new synthetic procedure for the preparation of perfluorinated carboxylic acid membrane monomers from non-fluorinated compounds has been developed. A key step in the synthetic route is liquid-phase direct fluorination reaction with elemental fluorine. Direct fluorination of a partially fluorinated diester, which was prepared from a hydrocarbon diol and a perfluorinated acyl fluoride, followed by thermal elimination, gave a perfluorinated diacyl fluoride, which is a precursor of a perfluorinated carboxylic acid membrane monomer.     

HPLC evaluation of mono-ol,butylphenyl and perfluorinated columns prepared via olefin hydrosilation on a silica hydride intermediate

Summary Three columns, mono-ol, butylphenyl and perfluorinated synthesized through the reaction of an olefin with a silica hydride intermediate, are evaluated for the separation of various model compounds. Two of the columns, mono-ol and perfluorinated, can operate in both the normal phase and reversed phase modes. Some effects of the hydride surface are detected, particularly for the perfluorinated phase. A four-component steroid mixture is tested on both the mono-ol and perfluorinated phases in the normal mode.     

Deprotection of 2-nitrobenzenesulfonamides using fluorous and solid phase reagents

The 2-nitrobenzenesulfonyl group was efficiently removed from primary and secondary amines as well as amides with a perfluorinated thiol under mild conditions. The resulting perfluorinated byproduct was removed via a solid phase extraction through perfluorinated silica gel making this a fast and simple procedure for parallel deprotection.     

无金属催化烯烃自由基环化合成多氟取代吲哚酮

一种无金属催化的活泼烯烃与全氟碘代丁烷自由基环化合成含氟吲哚酮的反应被发展。 在廉价易得的的偶氮二异丁腈(AIBN)介导下, 多种N-芳基丙烯酰胺类化合物与全氟碘代丁烷发生自由基串联环化反应,以53%~85%的产率合成了一系列的潜在生理活性的多氟取代吲哚酮。 此工作为潜在药用价值的多氟取代吲哚酮合成提供了一条高效、廉价、绿色的新途径。     

可见光诱导烯烃串联加成环化合成多氟烷基化异喹啉二酮

发展了一种可见光诱导的活泼烯烃与全氟碘代烷串联加成环化合成多氟异喹啉二酮的反应。 在可见光诱导下,多种N-丙烯酰基-N-丁基苯甲酰胺衍生物与全氟碘代烷发生自由基串联加成环化反应,以54%~80%的产率合成了一系列的多氟取代异喹啉二酮衍生物。 为具有潜在药用价值的多氟取代异喹啉二酮合成提供了一条高效、条件温和、绿色的新途径。     

Two-dimensional miscibility studies--the analysis of interaction between long-chain alcohols and semifluorinated alkanes

This work presents the results of phase behavior studies of two-dimensional (2D) binary systems involving semifluorinated alkanes (SFAs) and fatty alcohols. Four different SFAs were selected for investigations: (i) with a short and branched perfluorinated moiety (iF3H20), (ii) with a short and normal perfluorinated chain (F4H20), (iii) with a long and branched perfluorinated fragment (iF9H20), and (iv) with a long and normal perfluorinated group (F10H20). Two alcohols were selected to mix with the above-mentioned SFAs: tetradecanol and docosanol. The measurements were based on surface pressure/area isotherms in addition to Brewster angle microscope (BAM) imaging. Dependencies of the collapse surface pressure and the compression modulus vs the monolayer composition together with the excess free energy of mixing values, complemented with BAM images, enabled us to draw some general conclusions regarding the phase behavior of the investigated mixed systems. Generally, it has been noticed that the addition of docosanol into an SFA monolayer exerts a condensing effect, contrary to tetradecanol. Moreover, SFAs with a long perfluorinated segment mix to a larger extent with alcohols as compared to their analogues having a short perfluorinated moiety. The resultant phase diagrams for all the investigated eight mixtures are presented and discussed.     

Semifluorinated alcohols in Langmuir monolayers--a comparative study

A series of semifluorinated alcohols differing in the proportion of the perfluorinated to hydrogenated chains length was synthesized and investigated in Langmuir monolayers using surface pressure and surface potential measurements. All the investigated semifluorinated alcohols were found to be capable of stable floating monolayer formation. The stability of monolayers was found to be higher upon increasing the length of the perfluorinated segment. A lower stability of the monolayers from alcohols having shorter perfluorinated fragment was attributed to the aggregation process, which was visualized with Brewster angle microscopy (BAM). Most condensed monolayers were formed by compounds with longer perfluorinated moiety, whereas monolayers composed by molecules with an iso-branched perfluorinated segment were found to be more expanded. The change of electric surface potential was negative along the whole compression. The maximum absolute values of DeltaV varies, depending on the number of CF(2) groups, from ca. -400 mV for F6H10OH to ca. -700 mV for F10H10OH. The dipole moments of free molecules were calculated with Hyperchem, and the obtained values were approximately the same (within the experimental error), i.e., 2.8D for all the investigated molecules, independently on the perfluorinated fragment length. The dipole moment vector was found to be virtually aligned to the main molecular axis for the studied compounds. Therefore, the observed differences in the measured values of DeltaV can result from a different dielectric permittivity of a particular monolayer.     

Syntheses and phase-transfer properties of dendritic nanocarriers that contain perfluorinated shell structures

Perfect dendrimers that contain perfluorinated shells have recently attracted attention because they have been shown to encapsulate polar molecules in supercritical CO(2) and catalytically active metal nanoparticles in perfluorinated solvents. Moreover, they can then be easily separated after reaction from the biphasic organic/fluorous system. In this paper several dendritic architectures that contain perfluorinated shells were derived by covalent modification of glycerol dendrimers ([G0.5]-[G3.5]), hyperbranched polyglycerol, and polyethyleneimine. These core-shell architectures show interesting physicochemical properties. For example, they are soluble in fluorinated solvents, they are able to transport different guest molecules, and they display thermomorphic behavior. The transport capacity of these molecular nanocarriers increases significantly when amino groups are present in the core. Certain functionalized polyethyleneimines that contain perfluorinated shells show high transport capacities (up to 3 dye molecules per nanocarrier) in perfluorinated solvents. Moreover, these perfluoro-functionalized dendritic polyethyleneimines can act as templates that stabilize nanoparticles; for example, encapsulation and subsequent chemical reduction of Ag(I) ions. Silver nanoparticles with a narrow size distribution (3.9+/-1 nm) have been prepared and characterized by transmission electron microscopy. Furthermore, it has been demonstrated that the encapsulated guest molecules remain accessible to small molecules after transport into the fluorous phase. Therefore, dendritic nanocarriers that contain perfluorinated shells are currently being investigated as polar environments in nonpolar reaction media such as fluorous phases and supercritical CO(2), in particular, for application in homogenous catalysis.     

The study of interaction between PFOA/PFOS and uracil by topology quality and spectroscopic analysis

It has been established that perfluorooctanoic acid (PFOA) and perfluorooctane sulfonate (PFOS) can be considered as emerging persistent organic pollutants. In recent years, there was increasing distribution of PFOA/PFOS in environmental systems, and accumulation and toxic effects of PFOA/PFOS in human body. In this paper, quantum chemistry methods were employed to study the interaction between perfluorinated organic pollutants and base (uracil). The results showed that there were four stable binding modes between the two perfluorinated compounds with uracil, especially the second mode which caused the most detrimental physiological functional response. NBO analysis showed that reactive hydrogen in the two perfluorinated compounds had the greatest effect on the hydrogen bond. The nature of the hydrogen bond formed between the two perfluorinated compounds and base was investigated using the AIM theory. The changes of spectroscopic properties in complexes were analyzed by IR and NMR spectra.     

Amorphous perfluorinated membrane materials: Structure,properties and application

The structure and properties of glassy amorphous perfluorinated polymers are considered with an emphasis of their use as membrane material. The results of the study of free volume in these polymers and simulation of their nanostructure are discussed. The perfluorinated polymers are featured by unusual thermodynamic properties, so the influence of these properties on the parameters of the membranes based on them is examined. In conclusion, various applications of the membranes based on the perfluorinated polymers (predominantly amorphous Teflon AF) in separation processes are described.     

Study of the selective retention of fluorinated compounds on perfluorinated stationary phases

Summary The basis of the selective retention of perfluorinated compounds on perfluorinated bonded phases is examined. It is shown that the selective retention increases dramatically by increasing chain length and strand multiplicity.     

Synthesis and Characterization of a Novel Perfluorinated Ionomer Polymer Containing Sulfonimide Functionality

The novel perfluorinated vinyl ether containing sulfonimide functionality CF2 = CFORfSO2NHSO2CF3 was synthesized by multiple reaction steps. It could be copolymerized with tetrafluoroethylene by radox initiator to give a novel perfluorinated ionomer polymer. Its physical and chemical properties were studied.     

First synthesis of perfluorinated corrole and its mn=o complex

A novel perfluorinated corrole, 2,3,7,8,12,13,17,18-octafluoro-5,10,15-tris(pentafluorophenyl)corrole, and its manganese(III) and oxomanganese(V) derivatives have been synthesized. The perfluorinated manganese corrolate exhibited excellent reactivity and stability in the catalytic oxidation of alkenes with iodosylbenzene.     

Novel photocurable multifunctional acrylate monomers containing perfluorinated aromatic units and their copolymers for photonic applications

We designed and synthesized novel UV‐curable multifunctional acrylate monomers with perfluorinated aromatic units and their copolymers. The UV‐curable multifunctional acrylate monomers with perfluorinated aromatic units were synthesized as follows. Perfluorinated aromatic methylmethane derivatives were prepared through the reaction of pentaerythritol with hexafluorobenzene and decafluorobiphenyl in the presence of sodium hydride. They were sequentially substituted with 2,2,3,3,4,4,5,5‐octafluoro‐6‐(tetrahydropyran‐2‐yloxy)‐hexan‐1‐ol, and this yielded hydroxy‐functional compounds after tetrahydropyran deprotection. Finally, the reaction of the resultant hydroxy compounds with acryloyl chloride generated the perfluorinated multifunctional acrylate monomers in high yields of greater than 85%. The novel photocrosslinked and perfluorinated copolyacrylates, obtained after the UV and thermal curing of these monomers, satisfied the material requirements for photonic devices. Most of these copolymers were thermally stable over 370 °C, and their glass‐transition temperatures were not detected because of their highly crosslinked nature. The refractive indices of the copolymers ranged from 1.410 to 1.441. The refractive indices of the photocrosslinked and perfluorinated copolyacrylates were easily tuned by the variation of the copolymer composition. Some of these copolymers exhibited a birefringence of less than 0.0003. This was much lower than the birefringence of fluorinated polyacrylate‐based materials. © 2004 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 42: 6375–6383, 2004     

Online background cleanup followed by high‐performance liquid chromatography with tandem mass spectrometry for the analysis of perfluorinated compounds in human blood

In this study, a novel method for the analysis of perfluorinated compounds in whole blood has been developed and validated. The method was developed by using a conventional reversed‐phase C₁₈ column as a trapping column for the elimination of background contamination and high‐performance liquid chromatography with tandem mass spectrometry for the target compounds analysis. The trapping column provided fast online separation of the background contamination of perfluorinated compounds. In this developed method, the limits of detection for different perfluorinated compounds ranged from 0.06 to 0.14 ng/mL. It is notable that the limit of detection (0.07 ng/mL) for perfluorooctanoic acid was improved significantly after the elimination of background contamination. The method was also validated in terms of sensitivity, accuracy, and precision. The recoveries ranged from 66.8 to 111.9%, with relative standard deviations from 2.1 to 15.3%. Our preliminary data suggest that the novel method based on trapping column cleanup followed by high‐performance liquid chromatography with tandem mass spectrometry could be applied in studies on the human exposure to perfluorinated compounds.     

ω-(2-benzimidazolyl)perfluorinated carboxylic acids and their derivatives

A convenient method is proposed for the preparation of -(2-benzimidazolyl) perfluorinated carboxylic acids and their amides by condensation of o-phenylenediamine with imides of perfluorinated dicarboxylic acids. The transformations of the o-aminoanilides of the amides of the perfluorinated dicarboxylic acids were studied by thermal analysis and mass spectroscopy.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 9, pp. 1262–1265, September, 1976.     

Structural and electrokinetic characteristics of track-etched initial membranes and membranes modified with perfluorinated sulfocationic ionomer

Structural and electrokinetic characteristics of track-etched microfilters with pore radii of 1 μm and microfilters modified with perfluorinated sulfocationic ionomer are studied as functions of pH and concentration of KCl solutions. Colloidochemical properties of modified microfilters and perfluorinated sulfocationic MF-4SK membrane are compared.     

Mechanism of selectivity in ion-pair high-performance liquid chromatography of aminoglycoside antibiotics using perfluorinated pairing ions

The behaviour of perfluorinated carboxylic acids as pairing ions for the chromatography of the aminoglycoside antibiotics was studied. As with perhydrogenated pairing ions, the capacity factor can be modified according to the percentage of organic modifier and the nature and concentration of perfluorinated pairing ion in the mobile phase. The special selectivity effect observed with trifluoroacetic acid was investigated and interpreted as a concerted mechanism involving ionic and hydrophobic interactions.     

Fast ultrasound‐assisted extraction combined with LC–MS/MS of perfluorinated compounds in manure

A fast analytical method for the determination of perfluorinated compounds in poultry manure by LC–MS/MS was developed. The extraction was carried out by ultrasound‐assisted extraction of 1 g of sample, during 2 × 15 min using low volume (5.5 mL) of a mixture of methanol and acetonitrile. An efficient extraction of perfluoroalkyl carboxylates, perfluoroalkyl sulfonates, and perfluoroalkyl sulfonamides from poultry manure was obtained with recoveries higher than 81%. The cleanup of extracts was carried out by dispersive SPE. The validation of the proposed method showed the suitability of this procedure to determine perfluorinated compounds in poultry manure with detection limits in the range of 0.44–2.12 ng/g, depending on the target compound. In comparison with previously published methods, the miniaturization of the sample preparation method with ultrasound‐assisted extraction together with the use of a core‐shell column permit a lower consumption of organic solvents and a fast analysis of perfluorinated compounds. Manure samples obtained from Spanish commercial farms were analyzed and low perfluorinated compounds levels were found, which may be originated by dietary or environmental exposure. The highest concentrations measured corresponded to the perfluoroalkyl sulfonates, which varied from 8.2 to 35.9 ng/g.     

Enhanced thermal response of the SAd1 layer thickness in highly fluorinated thermotropic liquid crystals

X-ray studies of a homologous series of rod-shaped liquid crystal molecules with one tail perfluorinated and the other protonated, reveal large decreases in the smectic A layer spacing with increasing temperature. These materials form unique dimer phases in which the smectic layer spacing is dependent on the length of the perfluorinated tail and independent of the length of the protonated tail. The chain statistics of the perfluorinated tail significantly influence the thermal expansion coefficient since the length of the fluorinated tail defines the smectic layer spacing. Thermal expansion coefficients for the layer spacing observed here are negative and nearly an order of magnitude greater than for typical protonated rod-shaped thermotropic liquid crystals in the SA phase.