Hexafluoropropylene Trimer Research Articles

Oligoacrylates with perfluoroalkyl substituents based on hexafluoropropylene trimer as environment friendly hydrophobic coatings

The most effective classes of polymer water repellents include acrylic polymer with perfluoroalkyl additives. However, due to the prohibition of substances with a long perfluoroalkyl linear chain longer than 6 carbon atoms by the Stockholm Convention on Persistent Organic Pollutants, there is a significant necessity to replace them with approved analogues. This work considered substituted acrylates based on commercially available hexafluoropropylene trimer and their polymerization in a supercritical CO2 medium as the most convenient way and the hydrophobizing ability on various types of surfaces. The contact angles of the coatings obtained based on these oligomers are up to 111 ° on glass and aluminum, and 130 ° on cotton fabric, which is comparable to analogs with linear perfluoroalkyl substituents.

Biosafety assessments of hexafluoropropylene trimer derivative as a fluorinated cooling fluid for electronics.

The online version contains supplementary material available at 10.1007/s43188-024-00234-3.

Non-accumulative in the environment facile hydrophobic coatings based on branched siloxanes with perfluoroalkyl substituents

Based on triethoxy(3-(1,1,1,2,5,5,5-hepatfluoro3 - (perfluoropropan-2-yl) - 4-(trifluoromethyl)pent-3-en-2-yl) oxy)propylsilane, obtained from the commercially available trimer hexafluoropropylene, branched oligosiloxanes were synthesized by hydrolytic polycondensation in the active medium . The resulting polymers were studied by NMR and IR spectroscopy, and their molecular mass characteristics were investigated by GPC. In order to create stable hydrophobic coatings, the dependence of the hydrophobic properties of the resulting coatings on the surface of glass and aluminum on the conditions of polymer synthesis was studied. It has been shown that changes in the nature of the active medium (acetic or trifluoroacetic acid), the synthesis temperature, and the ratio of monomers:the active medium results in a polymer with similar molecular weights. For polymer coatings with the highest molecular weight Mw = 21.6 × 103, the average values of contact angles on glass and aluminum were 113 and 114°, respectively. In addition, condensation of the triethoxyl derivative of the hexafluoropropylene trimer with phenyltrimethoxysilane produced a modifier for hydrophobizing the surface of epoxy resins. When mixed into an epoxy resin up to 1.5% by weight of the resulting copolymer, resins with a contact angle of up to 113° were obtained.

Photochemistry of long-lived [(CF3)2CF]2C C2F5 radicals

Abstract The mechanism of the photodecomposition of the long lived radical [(CF3)2CF]2C C2F5 is explored by UV and ESR spectroscopy and quantum chemical calculations. The kinetics of the photodecomposition of [(CF3)2CF]2C C2F5 are investigated in a matrix of glassy and liquid hexafluoropropylene trimer at 77 and 300 K, respectively. The mechanism of [(CF3)2CF]2C C2F5 photodecomposition does not depend on the phase state of the matrix but differs from the thermal decomposition of the radical. Under UV light with λ CF3 bond of the perfluoro-ethyl group of [(CF3)2CF]2C C2F5 is broken. Thermal decomposition of the radical above 373 K occurs by breaking a CF CF3 bond in the perfluoro-isopropyl group. The experimental results are consistent with the calculated bond dissociation energies and UV–vis excitation spectra of the radical. Additional calculated C C BDEs for a number of fluorocarbon radicals show that radicals can be designed with very low C C BDEs for the generation of CF3 radicals.

Intermolecular-Interaction-Dominated Solvation Behaviors of Liquid Monomers and Polymers in Gaseous and Supercritical Carbon Dioxide

The strong desire for the extensive application of supercritical carbon dioxide (scCO2) as an environmentally benign solvent in polymers synthesis and processing has spurred numerous attempts to discern and improve its solvability toward monomers as well as polymers. The detailed solvation processes along with the phase behaviors of a fluorinated liquid monomer (LM) of 2,2,2-trifluoroethyl methacrylate (TFEMA), as well as another 13 non-fluorinated LMs in gaseous and supercritical CO2, were respectively investigated by using a newly built high-pressure ATR-FTIR in situ monitoring system as CO2 pressure stepwise increased from 0 to 38.0 MPa. Interestingly, an unexpected vibrational absorption variation, especially a distinct blue-shift in the in situ FTIR spectra of the functional groups in each LM + CO2 binary system, was generally observed during the solvation process as CO2 pressure increased. A similar variation trend of the vibrational absorption of the C–F bond in the TFEMA + CO2 system was also obtained by ab initio calculation (MP2). We believe that the special evolution of the vibrational absorption is directly rooted in and dynamically induced by the variation of the intermolecular interactions in the LM + CO2 binary systems as the pressure and/or the temperature varied and is closely related to the solvation behaviors of the LM in CO2. Based on this cognition, the solvation mechanism of the LMs in gaseous and supercritical CO2 was systematically demonstrated by introducing the concepts of transition pressure (PT) as well as the resultant forces/interactions of σ(A–B) and σ(B–B). Poly(vinyl acetate) (PVAc), poly(hexafluoropropylene oxide) (PHFPO), and PTFEMA oligomers were prepared and characterized. The proposed mechanism was evaluated by investigating the solvation behaviors of the prepared oligomers and hexafluoropropylene trimer ((HFP)3) in CO2 and was successfully employed to expound the special CO2-philicity of the carbonyl compounds and the fluorinated organics (FOs).

Photochemistry of Long-Lived [(CF 3 ) 2 CF] 2 C · C 2 F 5 Radicals in a Hexafluoropropylene Trimer Matrix

The kinetics of photodecomposition of long-lived [(CF3)2CF]2C·C2F5 radicals (I) in glassy and liquid hexafluoropropylene trimer was studied at 77 and 300 K, respectively. It was found that the phase state of the hexafluoropropylene trimer matrix did not affect the photodecomposition mechanism. In both cases, I eliminates ·CF3 radical from the perfluoroethyl fragment. The molar absorption coefficient of I was determined: e250 = 49 m2 mol–1. It was shown that the photodecomposition of I in a liquid matrix at 300 K led to the formation of other long-lived radicals. One of these species is [(CF3)2CF]3C· radical, which results from addition of ·CF3 radical to the double bond of a hexafluoropropylene trimer molecule.

ESR Spectra of Trifluoromethyl Radical Obtained by Radiolysis and Photolysis in Solid Matrices

The ESR spectrum of ⋅CF3 radicals trapped at 77 K in glassy matrices of a hexafluoropropylene trimer was examined. All the anisotropic components of the spectrum were assigned. The signals from parallel and perpendicular components resulting from hyperfine coupling to fluorine nuclei in the axially symmetrical ⋅CF3 radical were identified. The values of magnetic parameters were found to be A|| = 25.15 mT, A⊥ = 9.1 mT, g|| = 1.9996, and g⊥ = 2.0056. The computer simulated ESR spectrum of ⋅CF3 radical obtained in a glassy hexafluoropropylene trimer matrix can be used to interpret the spectrum of this radical in other solid matrices. Available literature data on the ESR spectra of ⋅CF3 radicals trapped in solid matrices are summarized.

Formation and decay of trifluoromethyl radicals during photodecomposition of the long-lived perfluoro-2,4-dimethyl-3-ethylpent-3-yl radical

UV irradiation of the long-lived radical [(CF3)2CF]2C·C2F5 (1) in a hexafluoropropylene trimer (HFPT) glassy matrix at 77 K and in a HFPT solution at 300 K leads to its decomposition to the ·CF3 radical and perfluoroolefin molecule. About 90% of the ·CF3 radicals formed recombine at 300 K. The remaining radicals add to the HFPT molecules generating the long-lived radicals [(CF3)2CF]3C·. Unlike the ·CF3 radicals produced by the photodecomposition of radicals 1, the ·CF3 radicals formed during radiolysis of HFPT are not stabilized in the glassy HFPT matrix at 77 K.

ESR spectra of trifluoromethyl radical formed during the solid-phase photodecomposition of long-lived perfluoro-2,4-dimethyl-3-ethylpentyl-3 radicals

The products of photolysis of the long-lived radical [(CF3)2CF]2C·C2F5 at 77 K were studied by ESR. The mechanism of photodecomposition to form ·CF3 radicals was proposed. The ESR spectra of the trifluoromethyl radicals stabilized at 77 K in a glassy hexafluoropropylene trimer matrix were simulated, and the parameters A∥ = 25.15 mT, A⊥ = 9.1 mT, and g∥ = l.9996, g⊥ = 2.0056 were determined.

Low-temperature addition of molecular fluorine to unsaturated perfluorohydrocarbons

Calorimetry and ESR Spectroscopy were used to study the low-temperature fluorination (77–300 K) of unsaturated perfluorohydrocarbons. In the solid phase at 77–100 K (glassy or crystalline state) fluorination does not occur. On transition from glassy systems to the overcooled liquid state formation of molecular complexes in which fluorine is attached to the >C=C< bond becomes possible. These complexes are stabilized on crystallization of the system; with a further increase in temperature, efficient addition of molecular fluorine takes place in the crystal phase. However, the addition of fluorine by some chain or carbene mechanism must not be ruled out for such systems. Thus, in the case of hexafluoropropylene trimer, the addition proceeds as a chain reaction producing long-living free radicals at the initial stage.

Role of radicals, long-lived in a liquid, in the polymerization of fluoroolefins

Using the polymerization of tetrafluoroethylene in a branched perfluoroolefin medium as an example (hexafluoropropylene, and its dimer and trimer), it is shown that hexafluoroethylene and its dimer are effective traps for growing polymer radicals. As a result of this interaction inactive, long-lived radicals not capable of mutual recombination are formed, which results in chain termination and prevents homo- and copolymerization of hexafluoropropylene. The hexafluoropropylene trimer is unable to add any radical apart from atomic fluorine and is an almost inert medium in the radical processes under consideration.

Formation of long-lived perfluoroalkyl radicals in photopolymerization of tetrafluoroethylene in a solution of perfluoro-2,4-dimethyl-3-ethyl-2-pentene

1. Photopolymerization of tetrafluoroethylene takes place during UV irradiation (λ ⩾ 236 nm, vacuum, 300 K) of tetrafluoroethylene in a solution of hexafluoropropylene trimer, and the formation of long-lived perfluoroalkyl radicals is observed during the process. 2. The formation of long-lived radicals takes place in the stage of propagation of the polymer chain by formation of a not very active propagating radical and in the stage of chain inhibition due to addition of the solvent to the active propagating radical.

Photopolymerization of tetrafluoroethylene in solution of hexafluoropropylene trimer in the presence of long-lived perfluoroallyl radicals

In photolysis of tetrafluoroethylene in a solution of the hexafluoropropylene trimer containing long-lived perfluoroallyl radicals, the following processes can take place: 1) phototransformation of these radicals into active perfluoroalkyl radicals and their recombination, and participation in initiation of photopolymerization of tetrafluoroethylene; the formation of the long-lived perfluoroalkyl radical on addition of a molecule of solvent to the propagating radical and the formation of a long-lived radical captured by the propagating chain compete with these processes.

ChemInform Abstract: REACTION OF PERFLUORO‐2‐METHYL‐2‐PENTENE AND PERFLUOROISOBUTYLENE WITH α‐OXIDES IN THE PRESENCE OF CESIUM FLUORIDE

AbstractDie Umsetzung von Perfluor‐2‐methyl‐2‐penten (I) mit den Epoxyverbindungen (II) bzw. (V) in Gegenwart von CsF führt zu den im Formelschema angegebenen Derivaten (III) und (IV) bzw. (VI)‐(VIII).

Reaction of perfluoro-2-methyl-2-pentene and perfluoroisobutylene with ?-oxides in the presence of cesium fluoride

1. Perfluoro-2-methyl-2-pentene reacts withα-oxides in the presence of CsF like perfluoroisobutylene. Olefins containing a perfluoro(dimethylpropyl)methyl group and cesium perfluoro-2-methyl-penten-3-olate are formed. 2. The reaction of perfluoro-2-methyl-2-pentene with epichlorohydrin in the presence of CsP results in the formation of trans-1,1,1,7,7,8,8,9,9,9-decafluoro-2,6,6-tris(trifluoromethyl)-4-nonene, 2-fluoro-2-pentafluoroethyl-3,3-bis(trifluoromethyl)-5-[α,α-(uhydro-β,β-bis(trifluoromethyl)perfluoroamyl] tetrahydrofuran, and 2-H-perfluoro-2-methylpentane. 3. The hexafluoropropylene dimer perfluoro-2-methyl-2-pentene is partially converted under the action of CsF into the thermodynamically most stable hexafluoropropylene trimer perfluoro-2,4-dimiethyl-3-heptene.