|
Perfluorocarboxylic Acid
Perfluoroalkyl carboxylic acids (PFCAs), or perfluorocarboxylic acids are compounds of the formula CnF(2n+1)CO2H that belong to the class of per- and polyfluoroalkyl substances. The simplest example is trifluoroacetic acid. These compounds are organofluorine analogues of ordinary carboxylic acids, but they are stronger by several pKa units and they exhibit great hydrophobic character. Perfluoroalkyl dicarboxylic acids (PFdiCAs) are also known, e.g. C2F4(CO2H)2.Günter Siegemund, Werner Schwertfeger, Andrew Feiring, Bruce Smart, Fred Behr, Herward Vogel, Blaine McKusick "Fluorine Compounds, Organic" Ullmann's Encyclopedia of Industrial Chemistry, Wiley-VCH, Weinheim, 2002. Applications Trifluoroacetic acid is a widely employed acid, used for example in the synthesis of peptides. Its esters are useful in analytical chemistry. Longer-chain perfluoroalkyl carboxylic acids, e.g. with five to nine carbons, are useful fluorosurfactants and emulsifiers used in the production of poly ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Perfluorononanoic Acid
Perfluorononanoic acid, or PFNA, is a synthetic perfluorinated carboxylic acid and fluorosurfactant that is also an environmental contaminant found in people and wildlife along with PFOS and PFOA. Chemistry and properties In acidic form it is a highly reactive strong acid. In its conjugate base form as a salt it is stable and commonly ion paired with ammonium. In the commercial product Surflon S-111 (CAS 72968-3-88) it is the primary compound present by weight. PFNA is used as surfactant for the production of the fluoropolymer polyvinylidene fluoride.Supporting Information (PDF). It is produced mainly in Japan by the of a linear |
Montreal Protocol
The Montreal Protocol is an international treaty designed to protect the ozone layer by phasing out the production of numerous substances that are responsible for ozone depletion Ozone depletion consists of two related events observed since the late 1970s: a steady lowering of about four percent in the total amount of ozone in Earth's atmosphere, and a much larger springtime decrease in stratospheric ozone (the ozone l .... It was agreed on 16 September 1987, and entered into force on 1 January 1989. Since then, it has undergone nine revisions, in 1990 (London), 1991 (Nairobi), 1992 (Copenhagen), 1993 (Bangkok), 1995 (Vienna), 1997 (Montreal), 1998 (Australia), 1999 (Beijing) and 2016 (Kigali) As a result of the international agreement, the ozone hole in Antarctica is slowly recovering. Climate projections indicate that the ozone layer will return to 1980 levels between 2050 and 2070. Due to its widespread adoption and implementation, it has been hailed as an example of s ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Surflon S-111
Surflon S-111 (CAS 72968-3-88) is a commercial product consisting of perfluorinated carboxylic acids (PFCAs) in ammonium salt form. It is commonly used as a polymerization aid in the production of fluoropolymers. The dominant chemical compound is perfluorononanoic acid (PFNA) at 74% by weight, followed by the 11 carbon perfluoroundecanoic acid (20%), and the 13 carbon perfluorotridecanoic acid (5%).Supporting Information (PDF). Surflon S-111 is synthesized in Japan by oxidizing a mixture of olefins. Fluorotelomer olefins are synthesized using a |
Per- And Polyfluoroalkyl Substances
Per- and polyfluoroalkyl substances (PFASs) are synthetic organofluorine chemical compounds that have multiple fluorine atoms attached to an alkyl chain. An early definition, from 2011, required that they contain at least one perfluoroalkyl moiety, –CnF2n+1–. More recently (2021) the Organisation for Economic Co-operation and Development (OECD) expanded the definition, stating that "PFASs are defined as fluorinated substances that contain at least one fully fluorinated methyl or methylene carbon atom (without any H/Cl/Br/I atom attached to it), i.e. with a few noted exceptions, any chemical with at least a perfluorinated methyl group (–CF3) or a perfluorinated methylene group (–CF2–) is a PFAS." According to the OECD, at least 4,730 distinct PFASs are known with at least three perfluorinated carbon atoms. A United States Environmental Protection Agency (EPA) toxicity database, DSSTox, lists 14,735 PFASs, while PubChem lists approximately 6 million. A subgroup, the ' ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Perfluorodecanoic Acid
Perfluorodecanoic acid (PFDA) is a fluorosurfactant and has been used in industry, with applications as wetting agent and flame retardant The term flame retardants subsumes a diverse group of chemicals that are added to manufactured materials, such as plastics and textiles, and surface finishes and coatings. Flame retardants are activated by the presence of an ignition source and .... It was recently linked to health concerns, like other fluorosurfactants, leading to proposed restrictions on its use. In 2020, a California bill banned its use as an intentionally added ingredient in cosmetics. It has been proposed as a chemical probe to study peroxisome proliferation. References {{Scholia, Q27116511, chemical Perfluorocarboxylic acids Pollutants Anionic surfactants ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Perfluorooctanoic Acid
Perfluorooctanoic acid (PFOA; conjugate base perfluorooctanoate; also known colloquially as C8, for its 8 carbon chain structure) is a perfluorinated carboxylic acid produced and used worldwide as an industrial surfactant in chemical processes and as a material feedstock. PFOA is considered a surfactant, or fluorosurfactant, due to its chemical structure, which consists of a perfluorinated, ''n''-octyl "tail group" and a carboxylate "head group". The head group can be described as hydrophilic while the fluorocarbon tail is both hydrophobic and lipophobic. The tail group is inert and does not interact strongly with polar or non-polar chemical moieties; the head group is reactive and interacts strongly with polar groups, specifically water. The "tail" is hydrophobic due to being non-polar and lipophobic because fluorocarbons are less susceptible to the London dispersion force than hydrocarbons. PFOA is one of many synthetic organofluorine compounds collectively known as per- and po ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Perfluorohexanoic Acid
Perfluorohexanoic acid (PFHxA) is a fluorinated carboxylic acid derivative of hexanoic acid. It is produced as a byproduct in the production of some fluoropolymers, and up until 2002, it was used in the manufacturing process of polytetrafluoroethylene. Perfluorohexanoic acid bioaccumulates and is detectable in the blood nearly every individual in the United States. In 2020 Michigan Michigan () is a state in the Great Lakes region of the upper Midwestern United States. With a population of nearly 10.12 million and an area of nearly , Michigan is the 10th-largest state by population, the 11th-largest by area, and t ... adopted drinking water standards for 5 previously unregulated PFAS compounds including PFHxA which has a maximum contaminant level (MCL) of 400 parts per billion ( ppb).{{Cite web , date=3 August 2020 , title=New state drinking water standards pave way for expansion of Michigan's PFAS clean-up efforts , url=https://www.michigan.gov/egle/0,9429,7-135- ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Perfluorobutanoic Acid
Perfluorobutanoic acid (PFBA) is a perfluoroalkyl carboxylic acid with the formula C3F7CO2H. As the perfluorinated derivative of butyric acid, this colourless liquid is prepared by electrofluorination of the corresponding butyryl fluoride.{{Citation , last=Siegemund , first=Günter , title=Fluorine Compounds, Organic , date=2000 , work=Ullmann's Encyclopedia of Industrial Chemistry , pages= , place=Weinheim, Germany , publisher=Wiley-VCH Verlag GmbH & Co. KGaA , language=en , doi=10.1002/14356007.a11_349 , isbn=978-3-527-30673-2 , last2=Schwertfeger , first2=Werner , last3=Feiring , first3=Andrew , last4=Smart , first4=Bruce , last5=Behr , first5=Fred , last6=Vogel , first6=Herward , last7=McKusick , first7=Blaine Applications PFBA has a variety of niche applications in analytical and synthetic chemistry. It is an ion pair reagent for reverse-phase HPLC. It is used in the sequencing, synthesis, and solubilizing of proteins and peptides. Esters derived from PFBA readily ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Perfluoropropanoic Acid
Perfluoropropionic acid (PFPrA) or pentafluoropropionic acid is the perfluoroalkyl carboxylic acid with the formula CF3CF2CO2H. It is a colorless liquid that is strongly acidic and soluble in water and polar organic solvents. A convenient, safe method for generating tetrafluoroethylene is the pyrolysis of the sodium salt Sodium salts are salts composed of a sodium cation and the conjugate base anion of some inorganic or organic acids. They can be formed by the neutralization of such acids with sodium hydroxide. Categorization Sodium salts can be categorized ... of pentafluoropropionic acid:{{cite journal , doi = 10.1016/j.jfluchem.2016.10.004, title = Preparation of tetrafluoroethylene from the pyrolysis of pentafluoropropionate salts, year = 2017, last1 = Hercules, first1 = Daniel A., last2 = Parrish, first2 = Cameron A., last3 = Sayler, first3 = Todd S., last4 = Tice, first4 = Kevin T., last5 = Williams, first5 = Shane M., last6 = Lowery, first6 = Lauren E., last7 = Bra ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
CAS Registry Number
A CAS Registry Number (also referred to as CAS RN or informally CAS Number) is a unique identification number assigned by the Chemical Abstracts Service (CAS), US to every chemical substance described in the open scientific literature. It includes all substances described from 1957 through the present, plus some substances from as far back as the early 1800s. It is a chemical database that includes organic and inorganic compounds, minerals, isotopes, alloys, mixtures, and nonstructurable materials (UVCBs, substances of unknown or variable composition, complex reaction products, or biological origin). CAS RNs are generally serial numbers (with a check digit), so they do not contain any information about the structures themselves the way SMILES and InChI strings do. The registry maintained by CAS is an authoritative collection of disclosed chemical substance information. It identifies more than 182 million unique organic and inorganic substances and 68 million protein and DNA seq ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Molecular Weight
A molecule is a group of two or more atoms held together by attractive forces known as chemical bonds; depending on context, the term may or may not include ions which satisfy this criterion. In quantum physics, organic chemistry, and biochemistry, the distinction from ions is dropped and ''molecule'' is often used when referring to polyatomic ions. A molecule may be homonuclear, that is, it consists of atoms of one chemical element, e.g. two atoms in the oxygen molecule (O2); or it may be heteronuclear, a chemical compound composed of more than one element, e.g. water (two hydrogen atoms and one oxygen atom; H2O). In the kinetic theory of gases, the term ''molecule'' is often used for any gaseous particle regardless of its composition. This relaxes the requirement that a molecule contains two or more atoms, since the noble gases are individual atoms. Atoms and complexes connected by non-covalent interactions, such as hydrogen bonds or ionic bonds, are typically not consi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Molecular Formula
In chemistry, a chemical formula is a way of presenting information about the chemical proportions of atoms that constitute a particular chemical compound or molecule, using chemical element symbols, numbers, and sometimes also other symbols, such as parentheses, dashes, brackets, commas and ''plus'' (+) and ''minus'' (−) signs. These are limited to a single typographic line of symbols, which may include subscripts and superscripts. A chemical formula is not a chemical name, and it contains no words. Although a chemical formula may imply certain simple chemical structures, it is not the same as a full chemical structural formula. Chemical formulae can fully specify the structure of only the simplest of molecules and chemical substances, and are generally more limited in power than chemical names and structural formulae. The simplest types of chemical formulae are called ''empirical formulae'', which use letters and numbers indicating the numerical ''proportions'' of atoms o ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
