|
Acetamides
Acetamide (systematic name: ethanamide) is an organic compound with the formula CH3CONH2. It is an amide derived from ammonia and acetic acid. It finds some use as a plasticizer and as an industrial solvent. The related compound ''N'',''N''-dimethylacetamide (DMA) is more widely used, but it is not prepared from acetamide. Acetamide can be considered an intermediate between acetone, which has two methyl (CH3) groups either side of the carbonyl (CO), and urea which has two amide (NH2) groups in those locations. Acetamide is also a naturally occurring mineral with the IMA symbol: Ace. Production Laboratory scale Acetamide can be produced in the laboratory from ammonium acetate by dehydration: : H4CH3CO2] → CH3C(O)NH2 + H2O Alternatively acetamide can be obtained in excellent yield via ammonolysis of acetylacetone under conditions commonly used in reductive amination. It can also be made from anhydrous acetic acid, acetonitrile and very well dried hydrogen chloride gas, u ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Dimethylacetamide
Dimethylacetamide (DMAc or DMA) is the organic compound with the formula CH3C(O)N(CH3)2. This colorless, water-miscible, high-boiling liquid is commonly used as a polar solvent in organic synthesis. DMA is miscible with most other solvents, although it is poorly soluble in aliphatic hydrocarbons. Synthesis and production DMA is prepared commercially by the reaction of dimethylamine with acetic anhydride or acetic acid. Dehydration of the salt of dimethylamine and acetic acid also furnishes this compound: : CH3CO2H·HN(CH3)2 → H2O + CH3CON(CH3)2 Dimethylacetamide can also be produced by the reaction of dimethylamine with methyl acetate. : The separation and purification of the product is carried out by multistage distillation in rectification columns. DMA is obtained with essentially quantitive (99%) yield referred to methyl acetate. Reactions and applications The chemical reactions of dimethylacetamide are typical of ''N'',''N''-disubstituted amides. Hydrolysis of the acyl- ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Royal Society Of Chemistry
The Royal Society of Chemistry (RSC) is a learned society and professional association in the United Kingdom with the goal of "advancing the chemistry, chemical sciences". It was formed in 1980 from the amalgamation of the Chemical Society, the Royal Institute of Chemistry, the Faraday Society, and the Society for Analytical Chemistry with a new Royal Charter and the dual role of learned society and professional body. At its inception, the Society had a combined membership of 49,000 in the world. The headquarters of the Society are at Burlington House, Piccadilly, London. It also has offices in Thomas Graham House in Cambridge (named after Thomas Graham (chemist), Thomas Graham, the first president of the Chemical Society) where ''RSC Publishing'' is based. The Society has offices in the United States, on the campuses of The University of Pennsylvania and Drexel University, at the University City Science Center in Philadelphia, Pennsylvania, in both Beijing and Shanghai, People' ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
International Mineralogical Association
Founded in 1958, the International Mineralogical Association (IMA) is an international group of 40 national societies. The goal is to promote the science of mineralogy and to standardize the nomenclature of the 5000 plus known mineral species. The IMA is affiliated with the International Union of Geological Sciences (IUGS). The Association supports the activities of Commissions and Working Groups involved on certain aspects of mineralogical practice and facilitates interactions among mineralogists by sponsoring and organising meetings. In particular, the IMA holds its general meeting every four years. The last meeting was scheduled in 2022 in Lyon, France. Presidents The presidents of the IMA have been: * since 2024: Eiji Ohtani ** Tohoku University * 2022–2024: Hans-Peter Schertl ** Bochum University * 2020–2022: Anhuai Lu ** Peking University *2018–2020: Patrick Cordier ** Université de Lille *2016–2018: Peter C. Burns ** University of Notre Dame *2014–2016 ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Dielectric Constant
The relative permittivity (in older texts, dielectric constant) is the permittivity of a material expressed as a ratio with the electric permittivity of a vacuum. A dielectric is an insulating material, and the dielectric constant of an insulator measures the ability of the insulator to store electric energy in an electrical field. Permittivity is a material's property that affects the Coulomb force between two point charges in the material. Relative permittivity is the factor by which the electric field between the charges is decreased relative to vacuum. Likewise, relative permittivity is the ratio of the capacitance of a capacitor using that material as a dielectric, compared with a similar capacitor that has vacuum as its dielectric. Relative permittivity is also commonly known as the dielectric constant, a term still used but deprecated by standards organizations in engineering as well as in chemistry. Definition Relative permittivity is typically denoted as (som ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Acrylonitrile
Acrylonitrile is an organic compound with the formula and the structure . It is a colorless, volatile liquid. It has a pungent odor of garlic or onions. Its molecular structure consists of a vinyl group () linked to a nitrile (). It is an important monomer for the manufacture of useful plastics such as polyacrylonitrile. It is reactive and toxic at low doses. Acrylonitrile is one of the components of ABS plastic (acrylonitrile butadiene styrene). Structure and basic properties Acrylonitrile is an organic compound with the formula and the structure . It is a colorless, volatile liquid although commercial samples can be yellow due to impurities. It has a pungent odor of garlic or onions. Its molecular structure consists of a vinyl group () linked to a nitrile (). It is an important monomer for the manufacture of useful plastics such as polyacrylonitrile. It is reactive and toxic at low doses. Production Acrylonitrile was first synthesized by the French chemist Charle ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Acetonitrile
Acetonitrile, often abbreviated MeCN (methyl cyanide), is the chemical compound with the formula and structure . This colourless liquid is the simplest organic nitrile (hydrogen cyanide is a simpler nitrile, but the cyanide anion is not classed as organic). It is produced mainly as a byproduct of acrylonitrile manufacture. It is used as a polar aprotic solvent in organic synthesis and in the purification of butadiene. The skeleton is linear with a short distance of 1.16 Å. Acetonitrile was first prepared in 1847 by the French chemist Jean-Baptiste Dumas. Applications Acetonitrile is used mainly as a solvent in the purification of butadiene in refineries. Specifically, acetonitrile is fed into the top of a distillation column filled with hydrocarbons including butadiene, and as the acetonitrile falls down through the column, it absorbs the butadiene which is then sent from the bottom of the tower to a second separating tower. Heat is then employed in the separa ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hydration Reaction
In chemistry, a hydration reaction is a chemical reaction in which a substance combines with water. In organic chemistry, water is added to an unsaturated substrate, which is usually an alkene or an alkyne. This type of reaction is employed industrially to produce ethanol, isopropanol, and butan-2-ol.. Organic chemistry Any unsaturated organic compound is susceptible to hydration. Epoxides to glycol Several million tons of ethylene glycol are produced annually by the hydration of oxirane, a cyclic compound also known as ethylene oxide: : C2H4O + H2O → HO–CH2CH2–OH Acid catalysts are typically used. Alkenes The general chemical equation for the hydration of alkenes is the following: :RRC=CH2 + H2O → RRC(OH)-CH3 A hydroxyl group (OH−) attaches to one carbon of the double bond, and a proton (H+) adds to the other. The reaction is highly exothermic. In the first step, the alkene acts as a nucleophile and attacks the proton, following Markovnikov's rule. In the seco ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Dehydration Reaction
In chemistry, a dehydration reaction is a chemical reaction that involves the loss of an H2O from the reacting molecule(s) or ion(s). This reaction results in the release of the H2O as water. When the reaction involves the coupling of two molecules into a single molecule it is referred to as a condensation reaction. Dehydration reactions are common processes in the manufacture of chemical compounds as well as naturally occurring within living organisms. The reverse of a dehydration reaction is called a hydration reaction. The reverse of a condensation reaction yielding water is called hydrolysis. Condensation reactions occurring in living organisms Condensation dehydration reactions are fundamental to the existence of life as this type of reaction produces proteins from amino acids, DNA and RNA from nucleotides, fats from fatty acids, and polysaccharides (eg. cellulose, starch, sugar, lactose) from monosaccharides (eg. glucose and fructose). The formation of the pyrophosphat ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Acetyl Chloride
Acetyl chloride () is an acyl chloride derived from acetic acid (). It belongs to the class of organic compounds called acid halides. It is a colorless, corrosive, volatile liquid. Its formula is commonly abbreviated to AcCl. Synthesis On an industrial scale, the reaction of acetic anhydride with hydrogen chloride produces a mixture of acetyl chloride and acetic acid: : Laboratory routes Acetyl chloride was first prepared in 1852 by French chemist Charles Gerhardt by treating potassium acetate with phosphoryl chloride. Acetyl chloride is produced in the laboratory by the reaction of acetic acid with chlorodehydrating agents such as phosphorus trichloride (), phosphorus pentachloride (), sulfuryl chloride (), phosgene, or thionyl chloride (). However, these methods usually give acetyl chloride contaminated by phosphorus or sulfur impurities, which may interfere with the organic reactions. Other methods When heated, a mixture of dichloroacetyl chloride and acetic aci ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Reductive Amination
Reductive amination (also known as reductive alkylation) is a form of amination that converts a carbonyl group to an amine via an intermediate imine. The carbonyl group is most commonly a ketone or an aldehyde. It is a common method to make amines and is widely used in green chemistry since it can be done catalytically in One-pot synthesis, one-pot under mild conditions. In biochemistry, Dehydrogenase, dehydrogenase enzymes use reductive amination to produce the amino acid Glutamic acid, glutamate. Additionally, there is ongoing research on alternative synthesis mechanisms with various metal catalysts which allow the reaction to be less energy taxing, and require milder reaction conditions. Investigation into biocatalysts, such as imine reductases, have allowed for higher selectivity in the reduction of chiral amines which is an important factor in pharmaceutical synthesis. Reaction process Reductive amination occurs between a carbonyl such as an aldehyde or ketone and an amine i ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Acetylacetone
Acetylacetone is an organic compound with the chemical formula . It is classified as a 1,3-diketone. It exists in equilibrium with a tautomer . The mixture is a colorless liquid. These tautomers interconvert so rapidly under most conditions that they are treated as a single compound in most applications. Acetylacetone is a building block for the synthesis of many coordination complexes as well as heterocyclic compounds. Properties Tautomerism The Keto–enol tautomerism, keto and enol tautomers of acetylacetone coexist in solution. The enol form has C2v molecular symmetry, symmetry, meaning the hydrogen atom is shared equally between the two oxygen atoms. In the gas phase, the equilibrium constant, ''K''keto→enol, is 11.7, favoring the enol form. The two tautomeric forms can be distinguished by NMR spectroscopy, IR spectroscopy and other methods. The equilibrium constant tends to be high in nonpolar solvents; when ''K''keto→enol is equal or greater than 1, the enol form ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ammonolysis
In chemistry, ammonolysis (/am·mo·nol·y·sis/) is the process of splitting ammonia into NH2- + H+. Ammonolysis reactions can be conducted with organic compounds to produce amines (molecules containing a nitrogen atom with a lone pair, :N), or with inorganic compounds to produce nitrides. This reaction is analogous to hydrolysis in which water molecules are split. Similar to water, liquid ammonia also undergoes auto-ionization, , where the rate constant is k = 1.9 × 10−38. Organic compounds such as alkyl halides, hydroxyls (hydroxyl nitriles and carbohydrates), carbonyl (aldehydes/ketones/esters/alcohols), and sulfur (sulfonyl derivatives) can all undergo ammonolysis in liquid ammonia. Organic synthesis Mechanism: Ammonolysis of Esters This mechanism is similar to the hydrolysis of esters, the ammonia attacks the electrophilic carbonyl carbon forming a tetrahedral intermediate. The reformation of the C-O double bond ejects the ester. The alkoxide deprotonates the ammo ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
