The kinetics of the reaction between fluorine atoms and pentafluoropropionic acid has been studied experimentally at T = 262-343 K. The overall reaction rate constant decreases with temperature: k1(T) = 6.1 × 10(-13) exp(+1166 K)/T) cm(3) molecule(-1) s(-1). The potential energy surface of the reaction has been studied using quantum chemistry. The results were used in transition state theory calculations of the temperature dependences of the rate constants of the two channels of the reaction. The abstraction channel ultimately producing HF, C2F5, and CO2 is dominant at the experimental temperatures; the addition-elimination channel producing C2F5 and CF(O)OH becomes important above 1000 K.
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http://dx.doi.org/10.1021/jp5029382 | DOI Listing |
Polarity reversal, or "umpolung", is a widely acknowledged strategy to allow organic functional groups amenable to react in alternative ways to the usual preference set by their electronic features. In this article, we demonstrate that cyclohexyne umpolung, realized through complexation to zirconocene, makes the small strained cycloalkyne amenable to C-F bond functionalisation. Such strong bond activation chemistry is unprecedented in "free" aryne and strained alkyne chemistry.
View Article and Find Full Text PDFACS Phys Chem Au
January 2025
Departamento de Química, Universidade Federal de Santa Catarina, Campus Universitário Trindade, 88040-900 Florianópolis, SC, Brazil.
The present study elucidated the role of both hydrogen and halogen bonds, from an electronic structure perspective, in the anion recognition process by the [2]catenane () containing a moiety with hydrogen bond donors entangled with another macrocyclic halogen bond donor. Spherical and nonspherical anions have been employed. The roles of different σ-hole donors have also been considered.
View Article and Find Full Text PDFThe selective amination of aromatic C-H bonds is a powerful strategy to access aryl amines, functionalities found in many pharmaceuticals and agrochemicals. Despite advances in the field, a platform for the direct, selective C-H amination of electronically diverse (hetero)arenes, particularly electron-deficient (hetero)arenes, remains an unaddressed fundamental challenge. In addition, many (hetero)arenes present difficulty in common selective pre-functionalization reactions, such as halogenation , or metal-catalyzed borylation and silylation .
View Article and Find Full Text PDFSmall
January 2025
Institute of Chemical Materials, China Academy of Engineering Physics, Mianyang, 621999, China.
The combustion efficiency and reactivity of aluminum (Al) particles, as a crucial component in solid propellants, are constrained by the inert oxide layer aluminum oxide (AlO). Polytetrafluoroethylene (PTFE) can remove the oxide layer, however, carbon deposition generated during the reaction process still limits the reaction efficiency of Al/PTFE fuel. Here, a litchi-like Al/PTFE fuel with the nano-PTFE islands distributed on the Al particles surface is successfully designed, based on localized activation and synergistic reaction strategies, to solve the AlO layer and carbon deposition.
View Article and Find Full Text PDFJ Hazard Mater
January 2025
Department of Environmental Health Sciences, School of Public Health, Seoul National University, Seoul, South Korea; Institute of Health & Environment, Seoul National University, Seoul, South Korea. Electronic address:
Structural diversity can affect the degradability of per- and polyfluoroalkyl substances (PFASs) during water treatment. Here, three PFASs with different functional groups-CF-R, PFHpA, PFHxS, and 6:2 FTS-were degraded using vacuum ultraviolet (VUV/UV)-based treatments. While fully fluorinated PFASs-PFHpA and PFHxS-were degraded faster in the VUV/UV/sulfite reaction than in VUV/UV photolysis, VUV/UV photolysis was more effective for degrading 6:2 FTS by OH radicals produced through photolysis of water.
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