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Atherton–Todd Reaction
The Atherton-Todd reaction is a name reaction in organic chemistry, which goes back to the British chemists F. R. Atherton, H. T. Openshaw and A. R. Todd. These described the reaction for the first time in 1945 as a method of converting Dialkyl phosphite, dialkyl phosphites into dialkyl chlorophosphates. The dialkyl chlorophosphates formed are often too reactive to be isolated, though. For this reason, the synthesis of Organophosphate, phosphates or Phosphoramidate, phosphoramidates can follow the Atherton-Todd reaction in the presence of alcohol (chemistry), alcohols or Amine, amines. The following equation gives an overview over the Atherton-Todd reaction using the Reagent, reactant dimethyl phosphite as an example: The reaction takes place after the addition of tetrachloromethane and a Base (chemistry), base. This base is usually a primary, secondary or tertiary amine. Instead of methyl groups other Alkyl group, alkyl or Benzyl group, benzyl groups may be present. Reaction m ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Alexander R
Alexander () is a male given name, name of Greek origin. The most prominent bearer of the name is Alexander the Great, the king of the Ancient Greek kingdom of Macedonia (ancient kingdom), Macedonia who created one of the largest empires in ancient history. Variants listed here are Aleksandar, Aleksander, Oleksandr, Oleksander, Aleksandr, and Alekzandr. Related names and diminutives include Iskandar (name), Iskandar, Alec, Alek, Alex, Alexsander, Alexandre (given name), Alexandre, Aleks (given name), Aleks, Aleksa (given name), Aleksa, Aleksandre, Alejandro, Alessandro, Alasdair, Sasha (name), Sasha, Sandy (given name), Sandy, Sandro, Sikandar (other), Sikandar, Skander, Sander (name), Sander and Xander; feminine forms include Alexandra, Alexandria (given name), Alexandria, and Sasha (name), Sasha. Etymology The name ''Alexander'' originates from the (; 'defending men' or 'protector of men'). It is a compound of the verb (; 'to ward off, avert, defend') and the no ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Alkyl Group
In organic chemistry, an alkyl group is an alkane missing one hydrogen. The term ''alkyl'' is intentionally unspecific to include many possible substitutions. An acyclic alkyl has the general formula of . A cycloalkyl group is derived from a cycloalkane by removal of a hydrogen atom from a Ring (chemistry), ring and has the general formula . Typically an alkyl is a part of a larger molecule. In structural formulae, the symbol R is used to designate a generic (unspecified) alkyl group. The smallest alkyl group is methyl, with the formula . Related concepts Alkylation is the addition of alkyl groups to molecules, often by alkylating agents such as Haloalkane, alkyl halides. Alkylating antineoplastic agents are a class of compounds that are used to treat cancer. In such case, the term alkyl is used loosely. For example, nitrogen mustards are well-known alkylating agents, but they are not simple hydrocarbons. In chemistry, alkyl is a group, a substituent, that is attached to ot ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Appel Reaction
The Appel reaction is an organic reaction that converts an alcohol into an alkyl chloride using triphenylphosphine and carbon tetrachloride. The use of carbon tetrabromide or bromine as a halide source will yield alkyl bromides, whereas using carbon tetraiodide, methyl iodide or iodine gives alkyl iodides. The reaction is credited to and named after Rolf Appel, it had however been described earlier. The use of this reaction is becoming less common, due to carbon tetrachloride being restricted under the Montreal protocol. Drawbacks to the reaction are the use of toxic halogenating agents and the coproduction of organophosphorus product that must be separated from the organic product. The phosphorus reagent can be used in catalytic quantities. The corresponding alkyl bromide can also be synthesised by addition of lithium bromide as a source of bromide ions. A more sustainable version of the Appel reaction has been reported, which uses a catalytic amount of phosphine that is regen ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Atom Economy
Atom economy (atom efficiency/percentage) is the conversion efficiency of a chemical process in terms of all atoms involved and the desired products produced. The simplest definition was introduced by Barry Trost in 1991 and is equal to the ratio between the mass of desired product to the total mass of reactants, expressed as a percentage. The concept of atom economy (AE) and the idea of making it a primary criterion for improvement in chemistry, is a part of the green chemistry movement that was championed by Paul Anastas from the early 1990s. Atom economy is an important concept of green chemistry philosophy, and one of the most widely used metrics for measuring the "greenness" of a process or synthesis. Good atom economy means most of the atoms of the reactants are incorporated in the desired products and only small amounts of unwanted byproducts are formed, reducing the economic and environmental impact of waste disposal. Atom economy can be written as: \text = \frac \tim ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Molar Mass
In chemistry, the molar mass () (sometimes called molecular weight or formula weight, but see related quantities for usage) of a chemical substance ( element or compound) is defined as the ratio between the mass () and the amount of substance (, measured in moles) of any sample of the substance: . The molar mass is a bulk, not molecular, property of a substance. The molar mass is a ''weighted'' ''average'' of many instances of the element or compound, which often vary in mass due to the presence of isotopes. Most commonly, the molar mass is computed from the standard atomic weights and is thus a terrestrial average and a function of the relative abundance of the isotopes of the constituent atoms on Earth. The molecular mass (for molecular compounds) and formula mass (for non-molecular compounds, such as ionic salts) are commonly used as synonyms of molar mass, as the numerical values are identical (for all practical purposes), differing only in units ( dalton vs. g/mol o ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Stoichiometry
Stoichiometry () is the relationships between the masses of reactants and Product (chemistry), products before, during, and following chemical reactions. Stoichiometry is based on the law of conservation of mass; the total mass of reactants must equal the total mass of products, so the relationship between reactants and products must form a ratio of positive integers. This means that if the amounts of the separate reactants are known, then the amount of the product can be calculated. Conversely, if one reactant has a known quantity and the quantity of the products can be empirically determined, then the amount of the other reactants can also be calculated. This is illustrated in the image here, where the unbalanced equation is: : : However, the current equation is imbalanced. The reactants have 4 hydrogen and 2 oxygen atoms, while the product has 2 hydrogen and 3 oxygen. To balance the hydrogen, a coefficient of 2 is added to the product H2O, and to fix the imbalance of oxygen, ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Atherton Todd Reaction FV1
Atherton may refer to: Places Australia * Atherton, Queensland, a town on the Atherton Tablelands of Far North Queensland * Atherton Tableland, a fertile plateau in Queensland * Shire of Atherton, a former local government area of Queensland on the Atherton Tableland ** Atherton Courthouse ** Atherton Performing Arts Theatre, former military depot and now theatre ** Atherton War Cemetery, built in 1942 ** Atherton War Memorial, memorial at Kennedy Highway Canada * Atherton, Ontario, a hamlet in Norfolk County, Ontario * Mount Atherton, a mountain in Yukon Malaysia * Ladang Atherton, part of the electoral district N.31 Bagan Pinang, Port Dickson United Kingdom * Atherton, Greater Manchester, town in Wigan district, historically in Lancashire, England ** Atherton (ward), electoral ward ** Atherton Hall, Leigh, country house and estate ** Atherton Urban District, local government district from 1863 until 1974 **Atherton High School, Greater Manchester, mixed secondary ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Aniline
Aniline (From , meaning ' indigo shrub', and ''-ine'' indicating a derived substance) is an organic compound with the formula . Consisting of a phenyl group () attached to an amino group (), aniline is the simplest aromatic amine. It is an industrially significant commodity chemical, as well as a versatile starting material for fine chemical synthesis. Its main use is in the manufacture of precursors to polyurethane, dyes, and other industrial chemicals. Like most volatile amines, it has the odor of rotten fish. It ignites readily, burning with a smoky flame characteristic of aromatic compounds. It is toxic to humans. Relative to benzene, aniline is "electron-rich". It thus participates more rapidly in electrophilic aromatic substitution reactions. Likewise, it is also prone to oxidation: while freshly purified aniline is an almost colorless oil, exposure to air results in gradual darkening to yellow or red, due to the formation of strongly colored, oxidized impurities. Ani ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Atherton Todd Reaction Part 3 MV1
Atherton may refer to: Places Australia * Atherton, Queensland, a town on the Atherton Tablelands of Far North Queensland * Atherton Tableland, a fertile plateau in Queensland * Shire of Atherton, a former local government area of Queensland on the Atherton Tableland ** Atherton Courthouse ** Atherton Performing Arts Theatre, former military depot and now theatre ** Atherton War Cemetery, built in 1942 ** Atherton War Memorial, memorial at Kennedy Highway Canada * Atherton, Ontario, a hamlet in Norfolk County, Ontario * Mount Atherton, a mountain in Yukon Malaysia * Ladang Atherton, part of the electoral district N.31 Bagan Pinang, Port Dickson United Kingdom * Atherton, Greater Manchester, town in Wigan district, historically in Lancashire, England ** Atherton (ward), electoral ward ** Atherton Hall, Leigh, country house and estate ** Atherton Urban District, local government district from 1863 until 1974 **Atherton High School, Greater Manchester, mixed secondary ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Benzyl Group
In organic chemistry, benzyl is the substituent or molecular fragment possessing the structure . Benzyl features a benzene ring () attached to a methylene group (). Nomenclature In IUPAC nomenclature, the prefix benzyl refers to a substituent, for example benzyl chloride or benzyl benzoate. Benzyl is not to be confused with phenyl with the formula . The term benzylic is used to describe the position of the first carbon bonded to a benzene or other aromatic ring. For example, is referred to as a "benzylic" carbocation. The benzyl free radical has the formula . The benzyl cation or phenylcarbenium ion is the carbocation with formula ; the benzyl anion or phenylmethanide ion is the carbanion with the formula . None of these species can be formed in significant amounts in the solution phase under normal conditions, but they are useful referents for discussion of reaction mechanisms and may exist as reactive intermediates. Abbreviations Benzyl is most commonly abbreviated Bn. For ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
