Alcohol consumption and its effects

Topics: Alcohol, Ethanol, Metabolism Pages: 26 (8117 words) Published: April 27, 2014
1.0 Introduction
This assignment is based on a study of alcohol metabolism and its impacts to human health. The assignment explains that how the body can dispose of alcohol and discern some of the factors that influence this process and influences of the process to the metabolism of food, hormones, and medications.

1.1 History of alcohol
The word “alcohol” appears in English as a term for a very fine powder in the 16th century. It was borrowed from French, which took it from medical Latin. Ultimately the word is from the Arabic (al-kuḥl; "kohl, a powder used as an eye liner"). Al- is the Arabic definitive article, equivalent to “the” in English. The term “alcohol” was originally used for 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.  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. The first alcohol (today known as ethyl alcohol) was discovered by the tenth-century Persian alchemist al-Razi. The current Arabic name for alcohol (ethanol) is “al-ġawl” – properly meaning "spirit" or "demon" – with the sense "the thing that gives the wine its headiness" (in the Qur'an sura 37 verse 47). The term “ethanol” was invented 1838, modeled on the German word äthyl (Liebig), which is in turn based on Greek (“aither” ether and “hyle" stuff).

1.2 Properties of alcohol
Alcohols have an odor that is often described as “biting” and as “hanging” in the nasal passages. Ethanol has a slightly sweeter (or more fruit-like) odor than the other alcohols. In general, the hydroxyl group makes the alcohol molecule polar. Those groups can form hydrogen bonds to one another and to other compounds (except in certain large molecules where the hydroxyl (-OH) is protected by steric hindrance of adjacent groups). This hydrogen bonding means that alcohols can be used as parotic solvents. Two opposing solubility trends in alcohols are: the tendency of the polar -OH to promote solubility in water, and the tendency of the carbon chain to resist it. Thus, methanol, ethanol, and propanol are miscible in water because the hydroxyl group wins out over the short carbon chain. Butanol, with a four-carbon chain, is moderately soluble because of a balance between the two trends. Alcohols of five or more carbons (pentanol and higher) are effectively insoluble in water because of the hydrocarbon chain's dominance. All simple alcohols are miscible in organic solvents. Because of hydrogen bonding, alcohols tend to have higher boiling points than comparable hydrocarbons and ethers. The boiling point of the alcohol ethanol is 78.29 °C, compared to 69 °C for the hydrocarbon hexane (a common constituent of gasoline), and 34.6 °C for diethyl ether. Alcohols, like water, can show either acidic or basic properties at the -OH group. With a pKa of around 16-19, they are, in general, slightly weaker acids than water, but they are still able to react with strong bases such as sodium hydride or reactive metals such as sodium. The salts that result are called “alkoxides”, with the general formula RO- M+. Meanwhile, the oxygen atom has lone pairs of nonbonded electrons that render it weakly basic in the presence of strong acids such as sulfuric acid. For example, with methanol:

Alcohols can also undergo oxidation to give aldehydes, ketones, or carboxylic acids, or they can be dehydrated to alkenes. They can react to form ester compounds, and they can (if activated first) undergo nucleophilic substitution reactions. The lone pairs of electron on the oxygen of the hydroxyl group also make alcohols nucleophiles. As one moves from primary to secondary to tertiary alcohols with the same backbone, the hydrogen bond strength, the boiling point, and...
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