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Innovative industrial technology starts with iodine
Published in Tatsuo Kaiho, Iodine Made Simple, 2017
In order for fluoropolymers to manifest such superior properties, the role of iodine in their production process is very important. A typical production process of fluororesin is known as telomerization (see the diagram). (1) iodine (I2) and iodine pentafluoride (IF5) react in pentafluoroethylene to create pentafluoroethyl iodide (C2F5I), known as telogen. (2) the elongation reaction of tetrafluoroethylene is used to create a fluorocarbon chain from the telogen. (3) Ethylene is added to form perfluoroalkyl iodide, which modifies iodine into a hydroxyl, and fluorotelomer alcohol is obtained. (4) Ethyl acrylate is composed from perfluoroalkylethyl alcohol and acrylic acid, and by reacting this with other comonomers (acrylate, metacrylate, vinyl chloride, vinylidene chloride), water and oil repellent fluoropolymers are obtained [34]. In addition to C2F5I, heptafluoropropyl iodide((CF3)2CFI) is also used as a telogen.
Polymerization of 1,2-Epoxides
Published in F. E. Bailey, Joseph V. Koleske, Alkylene Oxides and Their Polymers, 2020
F. E. Bailey, Joseph V. Koleske
As a result of the chain transfer effects described, these initiators can function as telomerlzation initiators (115). Telomerization is a form of polymerization in which one molecule reacts to both initiate and terminate, or limit, the degree of polymerization of monomer. Thus, a species, XY, would initiate polymerization of a monomer, M, forming X—Mn—
Olefin Oligomerization
Published in Mark J. Kaiser, Arno de Klerk, James H. Gary, Glenn E. Hwerk, Petroleum Refining, 2019
Mark J. Kaiser, Arno de Klerk, James H. Gary, Glenn E. Hwerk
The term “olefin oligomerization” refers to the conversion of olefins by one or more olefin addition reactions occurring in succession. Historically, terms such as “polymerization” and “telomerization” were also employed. When only a single addition reaction takes place, it is called dimerization. However, for most refining processes that convert olefins by addition reactions, several addition reactions take place in parallel resulting in not only dimerization, but also trimerization, and to a lesser extent tetramerization and higher orders of addition.
Restricted substances for textiles
Published in Textile Progress, 2022
Arun Kumar Patra, Siva Rama Kumar Pariti
Presently, 23 PFCs are available including perfluorooctanoic acid (PFOA) and perfluorooctane sulphonate (PFOS), which are the predominant forms showing up in human and environmental samples. In addition to their persistence, the two products have shown to induce severe health consequences like neonatal mortality, neurotoxicity and immunotoxicity (Foresta, Tescari, & Di Nisio, 2018). PFOA and PFOS are also very toxic to aquatic organisms and can cause long-term adverse effects in aquatic environment. Above certain exposure levels, they affect the liver and may even result in development of cancer (https://mrsl.roadmaptozero.com). During both electrofluorination and telomerization a small amount of PFOA and PFOS are produced. PFOA has a chain length of eight carbons, seven of which are perfluorinated. It belongs to a broad class of chemicals known as the perfluoro carboxylic acids (PFCA) which in turn belong to the broader class of polyfluoro alkyls (PFOA is often called C8). On the other hand PFOS is a member of the larger family of polyfluoroalkyl sulphonate (PFAS)-based chemicals. PFAS include compounds of carbon chain lengths of four or greater while PFOS refers to specific PFAS compound with that has eight carbon-chain length and contains carbons that are completely substituted with fluorine.
Enantioselective behavior of environmental chiral pollutants: A comprehensive review
Published in Critical Reviews in Environmental Science and Technology, 2022
Marina Arenas, Julia Martín, Juan Luis Santos, Irene Aparicio, Esteban Alonso
PFASs have been manufactured in large amounts and used worldwide in many consumer products due to their stain- and water-repellent properties. These contaminants are ubiquitously found in industrial, urban and remote areas (Benskin et al., 2010). Perfluorooctanoіc acid (PFOA) and perfluorooctane sulfonate (PFOS) are two of the most widely used and persistent PFASs. The two most common methods for the synthesis of PFASs, electrochemical fluorination and telomerization, results in the manufacturing of compounds with very different isomeric purities (with multiple positions for methyl or ethyl substitution). For example, PFOA isomer profile is expected to be 78% linear and 22% branched (Benskin et al., 2010) and, although some of these іsomers are achiral, substitution at certain carbon positions results in chiral compounds.
Fluorinated Diluents- A Review
Published in Solvent Extraction and Ion Exchange, 2023
V. Babain, M. Alyapyshev, C. Ekberg, T. Todd
Fluorinated alcohols with a common formula H(CF2CF2)nCH2OH, where n = 1, 2, 3 etc. are available fluorine compounds that can be used as diluents. These alcohols are prepared by telomerization of tetrafluoroethylene with methanol[123] according to the reaction: