|
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 Phosphate, 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 mechanis ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Alexander R
Alexander is a male given name. The most prominent bearer of the name is Alexander the Great, the king of the Ancient Greek kingdom of Macedonia who created one of the largest empires in ancient history. Variants listed here are Aleksandar, Aleksander and Aleksandr. Related names and diminutives include Iskandar, Alec, Alek, Alex, Alexandre, Aleks, Aleksa and Sander; feminine forms include Alexandra, Alexandria, and 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 noun (, genitive: , ; meaning 'man'). It is an example of the widespread motif of Greek names expressing "battle-prowess", in this case the ability to withstand or push back an enemy battle line. The earliest attested form of the name, is the Mycenaean Greek feminine anthroponym , , (/Alexandra/), written in the Linear B syllabic script. Alaksandu, alternatively called ''Alakasandu'' or ' ... [...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 is derived from a cycloalkane by removal of a hydrogen atom from a 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 an important operation in refineries, for example in the production of high-octane gasoline. 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 other molecular fragments. For ex ... [...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 greener, more sustainable catalytic Appel reaction, free from chlorinated solvents, has also been reported. Mechanism The ... [...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 products, 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 of a chemical compound is defined as the mass of a sample of that compound divided by the amount of substance which is the number of moles in that sample, measured in moles. The molar mass is a bulk, not molecular, property of a substance. The molar mass is an ''average'' of many instances of the 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 molar mass is appropriate for converting between the mass of a substance and the amount of a substance for bulk quantities. The molecular mass and formula mass are commonly used as a synonym of molar mass, particularly for molecular compounds; however, the most authoritative sources define it differently. The difference is that molecular mass is the mass of one specific particle or molecul ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Stoichiometry
Stoichiometry refers to the relationship between the quantities of reactants and products before, during, and following chemical reactions. Stoichiometry is founded on the law of conservation of mass where the total mass of the reactants equals the total mass of the products, leading to the insight that the relations among quantities of reactants and products typically 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 balanced equation is: : Here, one molecule of methane reacts with two molecules of oxygen gas to yield one molecule of carbon dioxide and two molecules of water. This particular chemical equation is an example of complete combustion. St ... [...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 f ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Aniline
Aniline is an organic compound with the formula C6 H5 NH2. Consisting of a phenyl group attached to an amino group, aniline is the simplest aromatic amine In organic chemistry, an aromatic amine is an organic compound consisting of an aromatic ring attached to an amine. It is a broad class of compounds that encompasses aniline Aniline is an organic compound with the formula C6 H5 NH2. Consi .... It is an industrially significant Commodity chemicals, 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 Combustion, ignites readily, burning with a smoky flame characteristic of aromatic compounds. It is toxic to humans. Relative to benzene, it is electron-rich. It thus participates more rapidly in electrophilic aromatic substitution reactions. Likewise, it is also prone ... [...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 f ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Atherton Todd Reaction Part 2 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 f ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Atherton Todd Reaction Part 1 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 f ... [...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 () 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 The abbreviation "Bn" denotes ben ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
.svg "Click for more on -> Atherton–Todd Reaction")
