ethanol


Also found in: Dictionary, Thesaurus, Medical, Legal, Acronyms, Wikipedia.
Related to ethanol: Ethanol fuel, Ethanol fermentation

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°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%).
..... 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.
.

The Columbia Electronic Encyclopedia™ Copyright © 2013, Columbia University Press. Licensed from Columbia University Press. All rights reserved. www.cc.columbia.edu/cu/cup/

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.
McGraw-Hill Dictionary of Scientific & Technical Terms, 6E, Copyright © 2003 by The McGraw-Hill Companies, Inc.
References in periodicals archive ?
Imported ethanol, according to the governor, was likewise cheaper than domestic ethanol by approximately P20 per liter.
Grassley called the proposal "a very good victory for agriculture," ethanol
Oil Marketin Companies (OMCs) have been advised to fix realistic transportation charges so that long-distance transportation of ethanol is not disincentivised.
The cellulose content of the residues was 28%, thus this resource may be a potential substrate for ethanol fermentation.
Cam Cast, Edeniq's Chief Operating Officer, remarked that, With the investment, partnership and success of existing corn ethanol plants like Flint Hills Resources, Edeniq is the clear market leader in its technology that is enabling todaymillions of gallons of EPA approved cellulosic ethanol to come online.
Additionally, D3MAX has signed a contract with AdvanceBio Systems LLC for a full-scale D3MAX design integrated with the Ace Ethanol plant in Stanley, Wisconsin
Projects range from integrating chemical reactors and recycling waste ethanol in pharmaceutical plants to producing high-quality potable and biofuel grade ethanol.
In general, chronic administration of ethanol or stress exposure enhances addiction-like behaviors.
To date, six plants have signed commercial agreements with Syngenta and now either use or plan to use Enogen grain to produce ethanol. By metering in a small percentage of Enogen corn (15% of the total corn required), ethanol plants have the potential to:
The 35-million-gallon-per-year plan will use the corn kernel fiber to produce an additional 2 million gallons of cellulosic ethanol without having to increase the amount of corn it buys.