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.
..... Click the link for more information. .

Properties

Ethanol is a monohydric primary alcohol. It melts at −117.3&degC; and boils at 78.5&degC;. 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&degC;; 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&degC;, 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%).
..... Click the link for more information. ). 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
..... Click the link for more information. .

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.

ethanol

[eth´ah-nol] a transparent, colorless, volatile, flammable liquid that is the major ingredient of alcoholic beverages. Excessive ingestion results in acute intoxication, with psychological, gastrointestinal, neurological, and motor abnormalities; ingestion during pregnancy can harm the fetus. See also alcoholism. The pharmaceutical preparation is called alcohol. Called also ethyl or grain alcohol.

eth·a·nol

(eth'ă-nol), CH₃CH₂OH; A clear, colorless liquid with a faint ethereal odor and a burning taste, which melts at -114.1°C, boils at 78.5°C, and has a density of 0.789 g/mL at 20°C. It is miscible with water and many organic liquids. Ethanol consumed in beer, wine, and distilled liquor is made by fermentation of sugars obtained from natural sources (grain, grapes, potatoes, sugar cane). Both the aroma of an alcoholic beverage and the smell noted on the breath of a person who has consumed it are due in part to the presence of congeners formed during brewing or fermentation and also due to added flavoring agents. Some alcohol used in industry is synthesized from ethylene or acetylene. Fermentation yields a maximum ethanol concentration of about 14%, above which fermentative enzymes are inhibited or destroyed. Higher alcohol concentrations in beverages are obtained either by addition of pure alcohol (fortified wines) or by distillation (whiskey, gin, vodka). The proof number of an alcoholic beverage represents twice the percent by volume of ethanol (for example, 120 proof = 60% ethanol by volume). Concentrations up to 95% can be obtained by fractional distillation. Because the combination of 95% ethanol and 5% water is an azeotropic mixture, incapable of being further concentrated by distillation, higher concentrations are obtained with dehydrating agents. In medicine, ethanol is used topically as a rubefacient, coolant, and disinfectant; internally as an analgesic and sedative; and as a solvent or vehicle for other agents. Alcohol USP contains not less than 92.3% nor more than 93.8% ethanol by weight. An alcoholic solution of a nonvolatile substance (for example, benzoin) is called a tincture. If the solute is volatile (for example, menthol), the solution is called a spirit. Ethanol is widely used in industry as a preservative, solvent, and antifreeze and in the manufacture of perfumes, paints, lacquers, and explosives. It also finds employment as an octane booster in automotive fuels. Most industrial ethanol is denatured by the adition of 1-2% of toxic substances to prevent its use as a beverage.

Taken internally in low doses, ethanol acts as a mild CNS stimulant and euphoriant, perhaps by enhancing acetylcholine neuroreceptor activity. Larger doses cause a reversible neurotoxicity manifested by altered sensorium, mydriasis, diplopia, nystagmus, dysequilibrium, tremor, slurred speech, incoordination, and general CNS depression proceeding from disorientation and deterioration of judgment to stupor, coma, and death due to respiratory arrest. Suppression of the gag reflex can lead to aspiration of vomitus. Nonneurologic effects of ethanol include tachycardia, vasodilatation, diaphoresis, diuresis, nausea, vomiting, and acute gastritis. Toxic effects of ethanol can be modified or aggravated by other substances (medicines, drugs of abuse) consumed along with it. About 25% of swallowed alcohol is absorbed through the gastric mucosa, and most of the rest from the duodenum. The rate at which ethanol is absorbed from the digestive tract depends on the concentration consumed, the type and quantity of food also present, and collateral factors such as disease or medicine that affect gastrointestinal function and motility. At least 90% of absorbed ethanol is converted in the liver to acetaldehyde, which is in turn converted to acetate. Acetaldehyde is also toxic, and is responsible for some of the symptoms of acute alcoholic intoxication and of a hangover. Small amounts of ethanol are excreted unaltered by the lungs and kidneys. For medical and forensic purposes, the level of ethanol in the blood is measured as the weight of ethanol per volume of blood and expressed as a percentage. Thus, an ethanol concentration of 100 mg/dL (21.7 mmol/L) corresponds to 0.1% (a level widely used in legal definitions of alcoholic intoxication). One ounce (30 mL) of 100-proof whiskey, 4 ounces (120 mL) of wine, or 12 ounces (360 mL) of beer yield a blood alcohol concentration of about 0.02% in a 150-pound human subject. Because this is roughly the amount of ethanol that can be cleared from the blood in 1 hour, consumption of alcoholic beverages at a rate exceeding one such drink per hour leads to a gradual increase of blood alcohol concentration. Women achieve higher blood levels than men with equivalent doses of ethanol. Measurable cognitive impairment occurs at a blood alcohol level of about 0.05%, gait disturbances at 0.10%, slurred speech at 0.15%. A level of 0.3-0.4% leads to unconsciousness, and respiratory arrest occurs around 0.5%. Regular consumption of alcohol in moderation (one drink/day for women, two/day for men) confers a modest reduction in the risk of coronary artery disease and in all-cause mortality, a benefit that is lost with even slightly higher levels of alcohol consumption. Ethanol is the most frequently abused drug in the United States. U.S. residents spend $116 billion each year on alcoholic beverages and the annual cost of alcohol abuse to the national economy is $200 billion. Thirty percent of U.S. adults drink to excess at least occasionally, and 30% of U.S. high school students admit to binge drinking at least once a month. Among young people, there exists a strong association between alcohol abuse and the use of tobacco and illicit drugs. Integral to much drinking behavior is the decline in resistance to further drinking with a rise in blood alcohol level. The chronic abuse of alcohol is associated with an increased incidence of hypertension, stroke, cirrhosis, gastritis, pancreatitis, malnutrition, vitamin deficiency, Wernicke encephalopathy, and Korsakoff psychosis. A child born to an alcoholic mother may bear the stigmata of fetal alcohol syndrome. Regular heavy alcohol consumption is an established cause of cancers of the oral cavity, pharynx, larynx, esophagus, liver, and breast.

ethanol

See Alcohol.

al·co·hol

(al'kŏ-hol) 1. One of a series of organic chemical compounds in which a hydrogen (H) attached to carbon is replaced by a hydroxyl (OH); alcohols react with acids to form esters and with alkali metals to form alcoholates. 2. Ethanol, C₂H₅OH, made from carbohydrates by fermentation and synthetically from ethylene or acetylene. It has been used in beverages and as a solvent, vehicle, and preservative; medicinally, it is used externally as a rubefacient, coolant, and disinfectant, and internally as an analgesic, stomachic, and sedative.
Synonym(s): ethanol, ethyl alcohol. 3. The azeotropic mixture of CH₃CH₂OH and water (92.3% by weight of ethanol). [Ar. al, the, + kohl, fine antimonial powder, the term being applied first to a fine powder, then to anything impalpable (spirit)]

ethanol

The chemical name for ethyl alcohol, the main constituent of alcoholic drinks. The drug is on the WHO official list.

ethanol

an alcohol produced in ALCOHOLIC FERMENTATION.

eth·a·nol

(eth'ăn-ol) Clear, colorless liquid with a faint ethereal odor and a burning taste; consumed in beer, wine, and distilled liquor; is made by fermentation of sugars obtained from natural sources (grain, grapes, potatoes, sugar cane). Toxic effects of ethanol can be modified or aggravatd by other substances (medicines, drugs of abuse) consumed along with it. About 25% of swallowed alcohol is absorbed through the gastric mucosa, and most of the rest from the duodenum. Regular heavy alcohol consumption is an established cause of cancers of the oral cavity, pharynx, larynx, esophagus, liver, and breast.

ethanol

eth·a·nol

ethanol

al•co•hol

eth·a·nol

ethanol

ethanol

ethyl alcohol,

Properties

Preparation

Uses

ethanol

ethanol

ethanol

eth·a·nol

ethanol

al·co·hol

ethanol

ethanol

eth·a·nol

ethanol

Synonyms for ethanol

noun the intoxicating agent in fermented and distilled liquors

Synonyms

Related Words