Products and mechanism of the OH-initiated photo-oxidation of perfluoro ethyl vinyl ether, C2F5OCF[double bond, length as m-dash]CF2

Recent Advances in the Synthesis and Transformation of Carbamoyl Fluorides, Fluoroformates, and Their Analogues

Carbamoyl fluorides, fluoroformates, and their analogues are a class of important compounds and have been evidenced as versatile building blocks for the preparation of useful molecules in organic chemistry. While major achievements were made in the synthesis of carbamoyl fluorides, fluoroformates, and their analogues in the last half of 20th century, an increasing number of reports have focused on using O/S/Se=CF2 species or their equivalents as the fluorocarbonylation reagents for the direct construction of these compounds from the parent heteroatom-nucleophiles in recent years. This review mainly summarizes the advances in the synthesis and typical application of carbamoyl fluorides, fluoroformates, and their analogues by the halide exchanges and fluorocarbonylation reactions since 1980.

Atmospheric Fate of a New Polyfluoroalkyl Building Block, C3F7OCHFCF2SCH2CH2OH

Many per- and polyfluoroalkyl substances (PFAS) have been regulated or phased-out of usage due to concerns about persistence, bioaccumulation potential, and toxicity. We investigated the atmospheric fate of a new polyfluorinated alcohol 2-(1,1,2-trifluoro-2-heptafluoropropyloxy-ethylsulfanyl)-ethanol (C₃F₇OCHFCF₂SCH₂CH₂OH, abbreviated FESOH) by assessing the kinetics and products of the gas-phase reaction of FESOH with chlorine atoms and hydroxyl radicals. Experiments performed in a stainless-steel chamber interfaced to an FTIR were used to determine reaction kinetics and gas-phase products. We report reaction rate constants of k(Cl + FESOH) = (1.5 ± 0.6) × 10^-11 cm³ molecule^-1 s^-1 and k(OH + FESOH) = (4.2 ± 2.0) × 10^-12 cm³ molecule^-1 s^-1. This leads to a calculated FESOH gas-phase lifetime of 2.8 ± 1.3 days with respect to reaction with OH, assuming [OH] = 10⁶ molecule¹ cm^-3. Gas-phase products of FESOH oxidation included at least two aldehydes, likely C₃F₇OCHFCF₂SCH₂C(O)H and C₃F₇OCHFCF₂SC(O)H, and secondary products including COF₂, SO₂ and C₃F₇OC(O)F. Additional gas-phase experiments performed in a Teflon chamber were used to assess aqueous products by collecting gaseous samples offline into an aqueous sink prior to analysis with ultrahigh performance liquid chromatography-tandem mass spectrometry, resulting in four acidic products: C₃F₇OCHFCF₂SCH₂C(O)OH, C₃F₇OCHFCF₂S(O)(O)OH, C₃F₇OCHFC(O)OH, and perfluoropropanoic acid (C₂F₅C(O)OH).