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Diethyl Sulfate
Diethyl sulfate (DES) is an organosulfur compound with the formula (C2H5)2SO4. It occurs as a colorless, oily liquid with a faint peppermint odor. It is toxic, combustible, and likely carcinogenic chemical compound. Diethyl sulfate is used as an ethylating agent. Structure and properties Although the formula for diethyl sulfate is typically written (C2H5)2SO4, a more descriptive formula would be (C2H5O)2SO2. It is a diester of sulfuric acid. Sulfur is tetrahedral. Diethyl sulfate hydrolyzes readily, forming ethanol and ethyl sulfate. Eventually sulfuric acid is formed with excess water. Reactions Diethyl sulfate is used to an alkylating agent to prepare ethyl ethers, ethyl amines and ammonium salts, and ethyl thioethers. In preparing ethyl esters of fatty acids, both equivalents of the ethyl electrophile are transferred, unlike the usual alkylation of phenoxides: : Both dimethyl sulfate and diethyl sulfate react with inorganic nucleophiles as well. For example, potassi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Dimethyl Sulfate
Dimethyl sulfate (DMS) is a chemical compound with formula (CH3O)2SO2. As the diester of methanol and sulfuric acid, its formula is often written as ( CH3)2 SO4 or Me2SO4, where CH3 or Me is methyl. Me2SO4 is mainly used as a methylating agent in organic synthesis. Me2SO4 is a colourless oily liquid with a slight onion-like odour. Like all strong alkylating agents, Me2SO4 is toxic. Its use as a laboratory reagent has been superseded to some extent by methyl triflate, CF3SO3CH3, the methyl ester of trifluoromethanesulfonic acid. History Impure dimethyl sulfate was prepared in the early 19th century. J. P. Claesson later extensively studied its preparation. It was investigated for possible use in chemical warfare in World War I in 75% to 25% mixture with methyl chlorosulfonate (CH3ClO3S) called "C-stoff" in Germany, or with chlorosulfonic acid called "Rationite" in France. The esterification of sulfuric acid with methanol was described in 1835: : Production Dimethyl s ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
IARC Group 2A Carcinogens
IARC group 2A agents are substances and exposure circumstances that have been classified as probable carcinogens by the International Agency for Research on Cancer (IARC). This designation is applied when there is limited evidence of carcinogenicity in humans, as well as ''sufficient evidence'' of carcinogenicity in experimental animals. In some cases, an agent may be classified in this group when there is ''inadequate evidence'' of carcinogenicity in humans along with ''sufficient evidence'' of carcinogenicity in experimental animals and ''strong evidence'' that the carcinogenesis is mediated by a mechanism that also operates in humans. Exceptionally, an agent may be classified in this group solely on the basis of ''limited evidence'' of carcinogenicity in humans. This list is focusing on the hazard linked to the agents. This means that the carcinogenic agents are capable of causing cancer, but this does not take their risk into account, which is the probability of causing a can ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Aqueous Ammonia
Ammonia solution, also known as ammonia water, ammonium hydroxide, ammoniacal liquor, ammonia liquor, aqua ammonia, aqueous ammonia, or (inaccurately) ammonia, is a solution of ammonia in water. It can be denoted by the symbols NH3(aq). Although the name ammonium hydroxide suggests a Salt (chemistry), salt with the chemical formula, composition , it is impossible to isolate samples of NH4OH. The ions and OH− do not account for a significant fraction of the total amount of ammonia except in extremely dilute solutions. The concentration of such solutions is measured in units of the Baumé scale (density), with 26 degrees Baumé (about 30% of ammonia by weight at ) being the typical high-concentration commercial product. Basicity of ammonia in water In aqueous solution, ammonia deprotonation, deprotonates a small fraction of the water to give ammonium and hydroxide according to the following chemical equilibrium, equilibrium: : NH3 + H2O ⇌ + OH−. In a 1 Molar concentra ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Laryngeal Cancer
Laryngeal cancer is a kind of cancer that can develop in any part of the larynx (voice box). It is typically a squamous-cell carcinoma, reflecting its origin from the epithelium of the larynx. The prognosis is affected by the location of the tumour. For the purposes of Cancer staging, staging, the larynx is divided into three anatomical regions: the glottis (true vocal cords, anterior and posterior commissures); the supraglottis (epiglottis, Arytenoid cartilage, arytenoids and aryepiglottic folds, and Vestibular fold, false cords); and the subglottis. Most laryngeal cancers originate in the glottis, with supraglottic and subglottic tumours being less frequent. Laryngeal cancer may spread by: direct extension to adjacent structures, metastasis to regional cervical lymph nodes, or via the blood stream. The most common site of distant metastases is the lung. Laryngeal cancer occurred in 177,000 people in 2018, and resulted in 94,800 deaths (an increase from 76,000 deaths in 1990). F ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Genotoxicity
Genotoxicity is the chemical property, property of chemical agents that damage the genetic information within a cell causing mutations, which may lead to cancer. While genotoxicity is often confused with mutagenicity, all mutagens are genotoxic, but some genotoxic substances are not mutagenic. The alteration can have direct or indirect effects on the DNA: the induction of mutations, mistimed event activation, and direct DNA damage leading to mutations. The permanent, heritable changes can affect either somatic cells of the organism or germ cells to be passed on to future generations. Cells prevent expression of the genotoxic mutation by either DNA repair or apoptosis; however, the damage may not always be fixed leading to mutagenesis. To bioassay, assay for genotoxic molecules, researchers assay for DNA damage in cells exposed to the toxic substrates. This DNA damage can be in the form of single- and double-strand breaks, loss of excision repair, cross-linking, alkali-labile sites, ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Alkylating Agent
Alkylation is a chemical reaction that entails transfer of an alkyl group. The alkyl group may be transferred as an alkyl carbocation, a free radical, a carbanion, or a carbene (or their equivalents). Alkylating agents are reagents for effecting alkylation. Alkyl groups can also be removed in a process known as dealkylation. Alkylating agents are often classified according to their nucleophilic or electrophilic character. In oil refining contexts, alkylation refers to a particular alkylation of isobutane with olefins. For upgrading of petroleum, alkylation produces a premium blending stock for gasoline. In medicine, alkylation of DNA is used in chemotherapy to damage the DNA of cancer cells. Alkylation is accomplished with the class of drugs called alkylating antineoplastic agents. Nucleophilic alkylating agents Nucleophilic alkylating agents deliver the equivalent of an alkyl anion ( carbanion). The formal "alkyl anion" attacks an electrophile, forming a new covalent bond b ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Redistribution Reaction
In chemistry, redistribution usually refers to the exchange of anionic ligands bonded to metal and metalloid centers. The conversion does not involve redox Redox ( , , reduction–oxidation or oxidation–reduction) is a type of chemical reaction in which the oxidation states of the reactants change. Oxidation is the loss of electrons or an increase in the oxidation state, while reduction is t ..., in contrast to disproportionation reactions. Some useful redistribution reactions are conducted at higher temperatures; upon cooling the mixture, the product mixture is kinetically frozen and the individual products can be separated. In cases where redistribution is rapid at mild temperatures, the reaction is less useful synthetically but still important mechanistically. Examples Redistribution reactions are exhibited by methylboranes. Thus monomethyldiborane rapidly converts at room temperature to diborane and trimethylborane:. The authors refer to redistributions as "dis ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Sodium Sulfate
Sodium sulfate (also known as sodium sulphate or sulfate of soda) is the inorganic compound with formula Na2SO4 as well as several related hydrates. All forms are white solids that are highly soluble in water. With an annual production of 6 million tonnes, the decahydrate is a major commodity chemical product. It is mainly used as a filler in the manufacture of powdered home laundry detergents and in the Kraft process of paper pulping for making highly alkaline sulfides. Forms *Anhydrous sodium sulfate, known as the rare mineral thénardite, used as a drying agent in organic synthesis. *Heptahydrate sodium sulfate, a very rare form. *Decahydrate sodium sulfate, known as the mineral mirabilite, widely used by chemical industry. It is also known as Glauber's salt. History The decahydrate of sodium sulfate is known as Glauber's salt after the Netherlands, Dutch–Germany, German chemist and apothecary Johann Rudolf Glauber (1604–1670), who discovered it in Austrian spring water i ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Chlorosulfuric Acid
Chlorosulfuric acid (IUPAC name: sulfurochloridic acid) is the inorganic compound with the formula HSO3Cl. It is also known as chlorosulfonic acid, being the sulfonic acid of chlorine. It is a distillable, colorless liquid which is hygroscopic and a powerful lachrymator. Commercial samples usually are pale brown or straw colored. Salts and esters of chlorosulfuric acid are known as chlorosulfates. Structure and properties Chlorosulfuric acid is a tetrahedral molecule. Its structure was debated for many decades until in 1941 Shrinivasa Dharmatti proved by magnetic susceptibility that chlorine is directly bonded to sulfur. The formula is more descriptively written SO2(OH)Cl, but HSO3Cl is traditional. It is an intermediate, chemically and conceptually, between sulfuryl chloride (SO2Cl2) and sulfuric acid (H2SO4). The compound is rarely obtained pure. Upon standing with excess sulfur trioxide, it decomposes to pyrosulfuryl chlorides: :2 ClSO3H + SO3 → H2SO4 + S2O5Cl2 Synt ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Diethyl Ether
Diethyl ether, or simply ether, is an organic compound with the chemical formula , sometimes abbreviated as . It is a colourless, highly Volatility (chemistry), volatile, sweet-smelling ("ethereal odour"), extremely flammable liquid. It belongs to the ether class of organic compounds. It is a common solvent and was formerly used as a general anesthetic. Production Most diethyl ether is produced as a byproduct of the vapor-phase Hydration reaction, hydration of ethylene to make ethanol. This process uses solid-supported phosphoric acid Catalysis, catalysts and can be adjusted to make more ether if the need arises: Vapor-phase Dehydration reaction, dehydration of ethanol over some Aluminium oxide, alumina catalysts can give diethyl ether yields of up to 95%. : Diethyl ether can be prepared both in laboratories and on an industrial scale by the acid ether synthesis. Uses The dominant use of diethyl ether is as a solvent. One particular application is in the production of cell ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
