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Dicarbonate
A dicarbonate, also known as a pyrocarbonate, is a chemical containing the divalent or functional group, which consists of two carbonate groups sharing an oxygen atom. It is one of polycarbonate functional groups. These compounds can be viewed as derivatives of the hypothetical compound dicarbonic acid, or . Three important organic compounds containing this group are: * dimethyl dicarbonate * diethyl dicarbonate * di-''tert''-butyl dicarbonate , also known as Boc anhydride. It is one of the oxocarbon anions, consisting solely of oxygen and carbon. The anion has the formula or . Dicarbonate salts are apparently unstable at ambient conditions, but can be made under pressure and may have a fleeting existence in carbonate solutions. The term ''dicarbonate'' is sometimes used erroneously to refer to bicarbonate, the common name of the hydrogencarbonate anion or esters of the hydrogencarbonate functional group . It is also sometimes used for chemicals that contain two ca ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Di-tert-butyl Dicarbonate
Di-''tert''-butyl dicarbonate is a reagent widely used in organic synthesis. Since this compound can be regarded formally as the acid anhydride derived from a ''tert''-butoxycarbonyl (Boc) group, it is commonly referred to as Boc anhydride. This pyrocarbonate reacts with amines to give ''N''-''tert''-butoxycarbonyl or so-called Boc derivatives. These carbamate derivatives do not behave as amines, which allows certain subsequent transformations to occur that would be incompatible with the amine functional group. The Boc group can later be removed from the amine using moderately strong acids (e.g., trifluoroacetic acid). Thus, Boc serves as a protective group, for instance in solid phase peptide synthesis. Boc-protected amines are unreactive to most bases and nucleophiles, allowing for the use of the fluorenylmethyloxycarbonyl group (Fmoc) as an orthogonal protecting group. Preparation Di-''tert''-butyl dicarbonate is inexpensive, so it is usually purchased. Classically, this com ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Dimethyl Dicarbonate
Dimethyl dicarbonate (DMDC) is a colorless liquid with a pungent odor at high concentration at room temperature. It is primarily used as a beverage preservative, processing aid, or sterilant ( INS No. 242) being highly active against typical beverage spoiling microorganisms like yeast, bacteria, or mould. Usage Dimethyl dicarbonate is used to stabilize beverages by preventing microbial spoilage. It can be used in various non-alcoholic as well as alcoholic drinks like wine, cider, beer-mix beverages or hard seltzers. Beverage spoiling microbes are killed by methoxycarbonylation of proteins. It acts by inhibiting enzymes involved in the microbial metabolism, e.g. acetate kinase and L-glutamic acid decarboxylase. It has also been proposed that DMDC inhibits the enzymes alcohol dehydrogenase and glyceraldehyde 3-phosphate dehydrogenase by causing the methoxycarbonylation of their histidine components. [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Tricarbonate
In organic chemistry, a tricarbonate is a compound containing the divalent functional group, which consists of three carbonate groups linked in a chain by sharing of oxygen atoms. These compounds can be viewed as derivatives of a hypothetical tricarbonic acid, . An important example is di-''tert''-butyl tricarbonate , an intermediate in the synthesis of di-''tert''-butyl dicarbonate.Barry M. Pope, Yutaka Yamamoto, and D. Stanley Tarbell (1977)"Di-''tert''-Butyl Dicarbonate" ''Organic Syntheses'', Vol. 57, p.45; Coll. Vol. 6 (1988) p.418 The term ''tricarbonate'' is sometimes used for salt In common usage, salt is a mineral composed primarily of sodium chloride (NaCl). When used in food, especially in granulated form, it is more formally called table salt. In the form of a natural crystalline mineral, salt is also known as r ...s that contain three carbonate dianions in their covalent structure or stoichiometric formula, such as cerium tricarbonate . See also * Dica ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Polycarbonate (functional Group)
A polycarbonate is an oxocarbon dianion consisting of a chain of carbonate units, where successive carbonyl groups are directly linked to each other by shared additional oxygen atoms. That is, they are the conjugate bases of polycarbonic acids, the conceptual anhydrides of carbonic acid, or polymers of carbon dioxide. They have the structure –O C=O)–Osub>''n''– and the molecular formula nO2''n''+1sup>2–. Whereas the carbonate dianion itself is well known, as found in many salts, many organic compounds containing esters of it have been made, and the parent carbonic acid is also well-known, higher homologs are substantially less stable. Only a few examples of covalent dicarbonate and tricarbonate structures and ionic dicarbonate salts have been made and their conjugate acids have only been studied theoretically. Polycarbonates up to ''n''=6 have been studied theoretically, with the dianions being only metastable but stabilized when paired with metal counterions or as their co ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Bicarbonate
In inorganic chemistry, bicarbonate (IUPAC-recommended nomenclature: hydrogencarbonate) is an intermediate form in the deprotonation of carbonic acid. It is a polyatomic anion with the chemical formula . Bicarbonate serves a crucial biochemical role in the physiological pH buffering system. The term "bicarbonate" was coined in 1814 by the English chemist William Hyde Wollaston. The name lives on as a trivial name. Chemical properties The bicarbonate ion (hydrogencarbonate ion) is an anion with the empirical formula and a molecular mass of 61.01 daltons; it consists of one central carbon atom surrounded by three oxygen atoms in a trigonal planar arrangement, with a hydrogen atom attached to one of the oxygens. It is isoelectronic with nitric acid (). The bicarbonate ion carries a negative one formal charge and is an amphiprotic species which has both acidic and basic properties. It is both the conjugate base of carbonic acid (); and the conjugate acid of , t ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Peroxodicarbonate
In chemistry, peroxydicarbonate (sometimes peroxodicarbonate) is a divalent anion with the chemical formula . It is one of the oxocarbon anions, which consist solely of carbon and oxygen. Its molecular structure can be viewed as two carbonate anions joined so as to form a peroxide bridge –O–O–. The anion is formed, together with peroxocarbonate , at the negative electrode during electrolysis of molten lithium carbonate. The anion can also be obtained by electrolysis of a saturated solution of rubidium carbonate in water. In addition, the peroxodicarbonate anion can be obtained by electrosynthesis on boron doped diamond (BDD) during water oxidation. The formal oxidation of two carbonate ions takes place at the anode. Due to the high oxidation potential of the peroxodicarbonate anion, a high anodic overpotential is necessary. This is even more important if hydroxyl radicals are involved in the formation process. Recent publications show that a concentration of 282 mmol/L of ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Diethyl Dicarbonate
Diethyl pyrocarbonate (DEPC), also called diethyl dicarbonate (IUPAC name), is used in the laboratory to inactivate RNase enzymes in water and on laboratory utensils. It does so by the covalent modification of histidine (most strongly), lysine, cysteine, and tyrosine residues. DEPC-treated (and therefore RNase-free) water is used in handling of RNA in the laboratory to reduce the risk of RNA being degraded by RNases. Water is usually treated with 0.1% v/v DEPC for at least 2 hours at 37 °C and then autoclaved (at least 15 min) to inactivate traces of DEPC. Inactivation of DEPC in this manner yields CO2 and ethanol. Higher concentrations of DEPC are capable of deactivating larger amounts of RNase, but remaining traces or byproducts may inhibit further biochemical reactions such as in vitro transcription. Furthermore, chemical modification of RNA such as carboxymethylation is possible when traces of DEPC or its byproducts are present, resulting in impaired recovery of intact R ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Space Group
In mathematics, physics and chemistry, a space group is the symmetry group of a repeating pattern in space, usually in three dimensions. The elements of a space group (its symmetry operations) are the rigid transformations of the pattern that leave it unchanged. In three dimensions, space groups are classified into 219 distinct types, or 230 types if chiral copies are considered distinct. Space groups are discrete cocompact groups of isometries of an oriented Euclidean space in any number of dimensions. In dimensions other than 3, they are sometimes called Bieberbach groups. In crystallography, space groups are also called the crystallographic or Fedorov groups, and represent a description of the symmetry of the crystal. A definitive source regarding 3-dimensional space groups is the ''International Tables for Crystallography'' . History Space groups in 2 dimensions are the 17 wallpaper groups which have been known for several centuries, though the proof that the list ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Pyrosulfate
In chemistry, disulfate or pyrosulfate is the anion with the molecular formula . Disulfate is the IUPAC name. It has a dichromate-like structure and can be visualised as two corner-sharing SO4 tetrahedra, with a bridging oxygen atom. In this anion, sulfur has an oxidation state of +6. Disulfate is the conjugate base of the hydrogen disulfate (hydrogen pyrosulfate) ion , which in turn is the conjugate base of disulfuric acid (pyrosulfuric acid). Role in sulfation Industrial production of sulfate ester-based surfactants involves the reaction (sulfation) of fatty alcohols with sulfur trioxide. For example, dodecyl alcohol is sulfated using sulfur trioxide. The reaction proceeds by initial formation of the pyrosulfate: : : Several million tons are produced annually. See also * Potassium pyrosulfate * Sodium pyrosulfate * Pyrophosphate * Pyrocarbonate A dicarbonate, also known as a pyrocarbonate, is a chemical containing the divalent or functional group, which consists o ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Oxalate
Oxalate (systematic IUPAC name: ethanedioate) is an anion with the chemical formula . This dianion is colorless. It occurs naturally, including in some foods. It forms a variety of salts, for example sodium oxalate (), and several esters such as dimethyl oxalate (). It is a conjugate base of oxalic acid. At neutral pH in aqueous solution, oxalic acid converts completely to oxalate. Relationship to oxalic acid The dissociation of protons from oxalic acid proceeds in a determined order; as for other polyprotic acids, loss of a single proton results in the monovalent hydrogenoxalate anion . A salt with this anion is sometimes called an acid oxalate, monobasic oxalate, or hydrogen oxalate. The equilibrium constant ( ''K''a) for loss of the first proton is ( p''K''a = 1.27). The loss of the second proton, which yields the oxalate ion, has an equilibrium constant of (p''K''a = 4.28). These values imply, in solutions with neutral pH, no oxalic acid and only t ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Carbon Dioxide
Carbon dioxide is a chemical compound with the chemical formula . It is made up of molecules that each have one carbon atom covalent bond, covalently double bonded to two oxygen atoms. It is found in a gas state at room temperature and at normally-encountered concentrations it is odorless. As the source of carbon in the carbon cycle, atmospheric is the primary carbon source for life on Earth. In the air, carbon dioxide is transparent to visible light but absorbs infrared, infrared radiation, acting as a greenhouse gas. Carbon dioxide is soluble in water and is found in groundwater, lakes, ice caps, and seawater. It is a trace gas Carbon dioxide in Earth's atmosphere, in Earth's atmosphere at 421 parts per million (ppm), or about 0.042% (as of May 2022) having risen from pre-industrial levels of 280 ppm or about 0.028%. Burning fossil fuels is the main cause of these increased concentrations, which are the primary cause of climate change.IPCC (2022Summary for pol ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Peroxydisulfate
The peroxydisulfate ion, , is an oxyanion, the anion of peroxydisulfuric acid. It is commonly referred to as persulfate, but this term also refers to the peroxomonosulfate ion, . It is also called ''peroxodisulfate''. Approximately 500,000 tons of salts containing this anion are produced annually. Important salts include sodium persulfate (Na2S2O8), potassium persulfate (K2S2O8), and ammonium persulfate ((NH4)2S2O8). These salts are colourless, water-soluble solids that are strong oxidants. Applications Salts of peroxydisulfate are mainly used to initiate the polymerization of various alkenes, including styrene, acrylonitrile, and fluoroalkenes. Polymerization is initiated by the homolysis of the peroxydisulfate: : 3SO–OSO3sup>2− 2 O4sup>•− Moreover, sodium peroxydisulfate can be used for soil and groundwater remediation Groundwater remediation is the process that is used to treat polluted groundwater by removing the pollutants or converting them into harmless ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
