ethanol

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ethanol

(ĕth`ənōl') or

ethyl alcohol,

CH3CH2OH, a colorless liquid with characteristic odor and taste; commonly called grain alcohol or simply alcoholalcohol,
any of a class of organic compounds with the general formula R-OH, where R represents an alkyl group made up of carbon and hydrogen in various proportions and -OH represents one or more hydroxyl groups.
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.

Properties

Ethanol is a monohydric primary alcohol. It melts at −117.3°C; and boils at 78.5°C;. It is miscible (i.e., mixes without separation) with water in all proportions and is separated from water only with difficulty; ethanol that is completely free of water is called absolute ethanol. Ethanol forms a constant-boiling mixture, or azeotrope, with water that contains 95% ethanol and 5% water and that boils at 78.15°C;; since the boiling point of this binary azeotrope is below that of pure ethanol, absolute ethanol cannot be obtained by simple distillation. However, if benzene is added to 95% ethanol, a ternary azeotrope of benzene, ethanol, and water, with boiling point 64.9°C;, can form; since the proportion of water to ethanol in this azeotrope is greater than that in 95% ethanol, the water can be removed from 95% ethanol by adding benzene and distilling off this azeotrope. Because small amounts of benzene may remain, absolute ethanol prepared by this process is poisonous.

Ethanol burns in air with a blue flame, forming carbon dioxide and water. It reacts with active metals to form the metal ethoxide and hydrogen, e.g., with sodium it forms sodium ethoxide. It reacts with certain acids to form esters, e.g., with acetic acid it forms ethyl acetate. It can be oxidized to form acetic acid and acetaldehyde. It can be dehydrated to form diethyl ether or, at higher temperatures, ethylene.

Preparation

Ethanol is the alcohol of beer, wines, and liquors. It can be prepared by the fermentation of sugar (e.g., from molasses), which requires an enzyme catalyst that is present in yeast; or it can be prepared by the fermentation of starch (e.g., from corn, rice, rye, or potatoes), which requires, in addition to the yeast enzyme, an enzyme present in an extract of malt. The concentration of ethanol obtained by fermentation is limited to about 10% (20 proof) since at higher concentrations ethanol inhibits the catalytic effect of the yeast enzyme. (The proof concentration of an alcoholic beverage is numerically double the percentage concentration.) For nonbeverage uses ethanol is more commonly prepared by passing ethylene gas at high pressure into concentrated sulfuric or phosphoric acid to form the corresponding ester; the acid-ester mixture is diluted with water and heated, forming ethanol by hydrolysis, and the alcohol is then removed from the mixture by distillation, usually with steam.

Uses

Ethanol is used extensively as a solvent in the manufacture of varnishes and perfumes; as a preservative for biological specimens; in the preparation of essences and flavorings; in many medicines and drugs; as a disinfectant and in tinctures (e.g., tincture of iodine); and as a fuel and gasoline additive (see gasoholgasohol,
a gasoline extender made from a mixture of gasoline (90%) and ethanol (10%; often obtained by fermenting agricultural crops or crop wastes) or gasoline (97%) and methanol, or wood alcohol (3%).
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). Many U.S. automobiles manufactured since 1998 have been equipped to enable them to run on either gasoline or E85, a mixture of 85% ethanol and 15% gasoline. E85, however, is not yet widely available. Denatured, or industrial, alcohol is ethanol to which poisonous or nauseating substances have been added to prevent its use as a beverage; a beverage tax is not charged on such alcohol, so its cost is quite low. Medically, ethanol is a soporific, i.e., sleep-producing; although it is less toxic than the other alcohols, death usually occurs if the concentration of ethanol in the bloodstream exceeds about 5%. Behavioral changes, impairment of vision, or unconsciousness occur at lower concentrations. See alcoholismalcoholism,
disease characterized by impaired control over the consumption of alcoholic beverages. Alcoholism is a serious problem worldwide; in the United States the wide availability of alcoholic beverages makes alcohol the most accessible drug, and alcoholism is the most
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.

ethanol

[′eth·ə‚nȯl]
(organic chemistry)
C2H5OH A colorless liquid, miscible with water, boiling point 78.32°C; used as a reagent and solvent. Also known as ethyl alcohol; grain alcohol.
References in periodicals archive ?
A fermentacao alcoolica foi conduzida por um periodo de 48h, pois de acordo com dados da literatura, esse e o tempo necessario para que praticamente todo o acucar seja convertido pelo Saccharomyces cerevisiae em etanol (BORTOLINI et al.
2008) resultou em rendimentos totais de 7,10 e 8,10%, utilizando, respectivamente, CCP e etanol absoluto como solventes na precipitacao de PST.
Kirk sekiz saat sureyle 10-8 M etanol uygulanmis primer hippokampal noron kulturune ait deney grubunun ise kontrol grubundan iNOS mRNA seviyeleri acisindan anlamli bir fark gostermedigi saptandi.
Los hisopos que contenian el etanol para la conservacion de la muestra se dejaron evaporar a temperatura ambiente en una cabina de extraccion durante un lapso de 30 a 48 horas; posteriormente, a cada uno se le adiciono 50[micro]l de reactivo PrepMan Ultra (Applied Biosystems[R]) siguiendo las indicaciones de la casa matriz.
As lenticelas hipertrofiadas e a maior porosidade do caule podem facilitar a difusao do oxigenio ate a rizosfera e possibilitar a saida de produtos toxicos, tais como o etanol, produzidos em decorrencia da hipoxia, como sugerido por Tsukahara e Kozlowski (1985).
9) Na sequencia, as amostras foram enxaguadas com agua deionizada, desengraxadas com etanol, de origem comercial, em banho ultrassonico por cinco minutos e secadas com ar levemente aquecido e, posteriormente, submetidas aos tratamentos detalhados na Tabela 2.
Ademas de las causas antemencionadas, el sindrome poliuria-polidipsia puede aparecer como consecuencia de enfermedades infiltrativas (sarcoidosis, histiocitosis, amiloidosis), aporte exogeno de NaCl, bicarbonato, otros diureticos, medios de contraste, nicotina, etanol, clonidina, demeclociclina, fenitoina, primidona, fenobarbital, fluoruros, metoxifluorano, cisplatino, acido etacrinico, exceso de proteina dietaria, hipercatabolismo proteico, infecciones (tuberculosis, meningitis, encefalitis), neoplasias (primarias y secundarias), mieloma multiple, lesiones postraumaticas, neurocirugia, aumento de la excrecion de aniones organicos (cetoacidos) y otras (17,36)
Los especimenes se sacrificaron tras aplicacion de un anestesico (xilocalna); posteriormente se conservaron en formalina (formol 37 al 10%); luego los individuos fueron etiquetados y posteriormente conservados en etanol 70% en frascos de vidrio y depositados en la coleccion herpetologica de la Universidad Tecnologica del Choco, Quibdo, Colombia.
Os fragmentos foram fixados por imersao em paraformaldeido a 4% em tampao fosfato 0,1 M (pH 7,2), desidratados em etanol, diafanizados em xilol e incluidos em Paraplast.
Among the projects Solano had under his wing before he was extradited are Etanol Dominicana, S.