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Some important organofluorine compounds. A: fluoromethane B: isoflurane C: a CFC D: an HFC E: triflic acid F: Teflon G: PFOS H: fluorouracil I: fluoxetine Organofluorine chemistry describes the chemistry of organofluorine compounds, organic compounds that contain a carbon–fluorine bond.
Many gases have toxic properties, which are often assessed using the LC 50 (median lethal concentration) measure. In the United States, many of these gases have been assigned an NFPA 704 health rating of 4 (may be fatal) or 3 (may cause serious or permanent injury), and/or exposure limits (TLV, TWA/PEL, STEL, or REL) determined by the ACGIH professional association.
The EPA issued health advisories for four specific PFASs in June 2022, significantly lowering their safe threshold levels for drinking water. PFOA was reduced from 70 ppt to 0.004 ppt, while PFOS was reduced from 70 ppt to 0.02 ppt. A safe level for the compound GenX was set at 10 ppt, while that for PFBS was set at 2000 ppt. While not ...
The observed probable serious effects for human health and the environment are thyroid hormonal disturbances and reproductive toxicity seen in rodents, and effects on liver, kidney and haematological system in rats, hormonal disturbances and effects on reproduction in marine medaka fish and effects on expression of hormone receptors in tadpoles.
Pentafluorophenol, a perfluorinated compound.. A perfluorinated compound (PFC) or perfluoro compound is an organofluorine compound that lacks C-H bonds. Many perfluorinated compounds have properties that are quite different from their C-H containing analogues.
Download QR code; Print/export ... Abundances are given as pollution free monthly mean mole fractions in parts-per-trillion. ... (ppt) in 2010 to near 25 ppt in 2020. [2]
trans-1,3,3,3-Tetrafluoropropene (HFO-1234ze(E), R-1234ze(E)) is a hydrofluoroolefin.It was developed as a "fourth generation" refrigerant to replace fluids such as R-134a, as a blowing agent for foam and aerosol applications, and in air horns and gas dusters. [3]
After the development of his electron capture detector, James Lovelock was the first to detect the widespread presence of CFCs in the air, finding a mole fraction of 60 ppt of CFC-11 over Ireland. In a self-funded research expedition ending in 1973, Lovelock went on to measure CFC-11 in both the Arctic and Antarctic, finding the presence of the ...