Alcohol

Miguel A. Nieves Prof. M. Santiago

What’s Alcohol?

In chemistry, an alcohol is an organic compound in which the hydroxyl functional group (-OH) is bound to a carbon atom. In particular, this carbon center should be saturated, having single bonds to three other atoms.[1]

An important class of alcohols are the simple acyclic alcohols, the general formula for which is CnH2n+1OH. Of those, ethanol (C2H5OH) is the type of alcohol found in alcoholic beverages, and in common speech the word alcohol refers specifically to ethanol.

Other alcohols are usually described with a clarifying adjective, as in isopropyl alcohol (propan-2-ol) or wood alcohol (methyl alcohol, or methanol). The suffix -ol appears in the IUPAC chemical name of all substances where the hydroxyl group is the functional group with the highest priority; in substances where a higher priority group is present the prefix hydroxy- will appear in the IUPAC name. The suffix -ol in non-systematic names (such as paracetamol or cholesterol) also typically indicates that the substance includes a hydroxyl functional group and, so, can be termed an alcohol. But many substances, particularly sugars (examples glucose and sucrose) contain hydroxyl functional groups without using the suffix.

Simple alcohols

The most commonly used alcohol is ethanol, C2H5OH, with the ethane backbone. Ethanol has been produced and consumed by humans for millennia, in the form of fermented and distilled alcoholic beverages. It is a clear flammable liquid that boils at 78.4 °C, which is used as an industrial solvent, car fuel, and raw material in the chemical industry. In the US and some other countries, because of legal and tax restrictions on alcohol consumption, ethanol destined for other uses often contains additives that make it unpalatable (such as denatonium benzoate) or poisonous (such as methanol). Ethanol in this form is known generally as denatured alcohol; when methanol is used, it may be referred to as methylated spirits or “surgical spirits”.

The simplest alcohol is methanol, CH3OH, which was formerly obtained by the distillation of wood and, therefore, is called “wood alcohol”. It is a clear liquid resembling ethanol in smell and properties, with a slightly lower boiling point (64.7 °C), and is used mainly as a solvent, fuel, and raw material. Unlike ethanol, methanol is extremely toxic: As little as 10 ml can cause permanent blindness by destruction of the optic nerve and 30 ml (one fluid ounce) is potentially fatal.[2]

Two other alcohols whose uses are relatively widespread (though not so much as those of methanol and ethanol) are propanol and butanol. Like ethanol, they can be produced by fermentation processes. (However, the fermenting agent is a bacterium, Clostridium acetobutylicum, that feeds on cellulose, not sugars like the Saccharomyces yeast that produces ethanol.) Saccharomyces yeast are known to produce these higher alcohols at temperatures above 75 °F (24 °C). These alcohols are called fusel alcohols or

fusel oils in brewing and tend to have a spicy or peppery flavor. They are considered a fault in most styles of beer.[3]

Simple alcohols, in particular, ethanol and methanol, possess denaturing and inert rendering properties, leading to their use as anti-microbial agents in medicine, pharmacy, and industry.[citation needed]

History and Etymology

The first alcohol (today known as ethyl alcohol) was discovered by the tenth-century Persian alchemist al-Razi. Kuḥl (kohl) was originally the name given to the very fine powder, produced by the sublimation of the natural mineral stibnite to form antimony sulfide Sb2S3 (hence the essence or "spirit" of the substance), which was used as an antiseptic, eyeliner and cosmetic (see kohl (cosmetics) for information on this). Bartholomew Traheron in his 1543 translation of John of Vigo introduces the word as a term used by "barbarous" (Moorish) authors for "fine powder":

the barbarous auctours use alcohol, or (as I fynde it sometymes wryten) alcofoll, for moost fine poudre.

The word alcohol appears in English, as a term for a very fine powder, in the 16th century, loaned via French from medical Latin, ultimately from the Arabic الكحل (al-kuḥl, "the kohl, a powder used as an eyeliner"). Al- is the Arabic definitive article, equivalent to the in English.

William Johnson in his 1657 Lexicon Chymicum glosses the word as antimonium sive stibium. By extension, the word came to refer to any fluid obtained by distillation, including "alcohol of wine", the distilled essence of wine. Libavius in Alchymia (1594) has vini alcohol vel vinum alcalisatum. Johnson (1657) glosses alcohol vini as quando omnis superfluitas vini a vino separatur, ita ut accensum ardeat donec totum consumatur, nihilque fæcum aut phlegmatis in fundo remaneat. The word's meaning became restricted to "spirit of wine" (the chemical known today as ethanol) in the 18th century, and was extended to the class of substances so-called as "alcohols" in modern chemistry, after 1850.

Miguel A. Nieves Prof M. Santiago

Alcoholic Beverage

An alcoholic beverage is a drink containing ethanol, commonly known as alcohol. Alcoholic beverages are divided into three general classes: beers, wines, and spirits. They are legally consumed in most countries, and over 100 countries have laws regulating their production, sale, and consumption.[1] In particular, such laws specify the minimum age at which a person may legally buy or drink them. This minimum age varies between 16 and 25 years, depending upon the country and the type of drink. Most nations set it at 18 years of age.[1]

The production and consumption of alcohol occurs in most cultures of the world, from hunter-gatherer peoples to nation-states.[2][3] Alcoholic beverages are often an important part of social events in these cultures.

Alcohol is a psychoactive drug that has a depressant effect. A high blood alcohol content is usually considered to be legal drunkenness because it reduces attention and slows reaction speed. Alcohol can be addictive and addiction to alcohol is known as alcoholism.

• Types

Beer and wine are produced by fermentation of sugar- or starch-containing plant material. Beverages produced by fermentation followed by distillation have a higher alcohol content and are known as liquor or spirits.

Beer

Beer is one of the world's oldest[2][4] and most widely consumed[3] alcoholic beverages, and the third most popular drink overall after water and tea.[5] It is produced by the brewing and fermentation of starches which are mainly derived from cereal grains — most commonly malted

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