AlcoholBall-and-stick model of the hydroxyl (-OH) functional group in an alcohol molecule (R3COH). The three "R's" stand for carbon substituents or hydrogen atoms.[1]

The hydroxyl (-OH) functional group with bond angle.In chemistry, an alcohol is an organic compound in which the hydroxyl functional group (-O H ) is bound to a carbon atom. In particular, this carbon center should be saturated, having single bonds to three other atoms.[2]An important class of alcohols are the simple acyclic alcohols, the general formula for which is CnH2n+1OH. Of these ethanol (C2H5OH) is the alcohol found in alcoholic beverages; in common speech the word alcohol refers 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.In everyday life "alcohol" without qualification usually refers to ethanol, or a beverage based on ethanol (as in the term "alcohol abuse").

"Alcohol" is a generic name for large group of organic chemical compounds. There are many types of alcohols. They all are derivatives of hydrocarbons in which one or more of the hydrogen atoms have been replace by a hydroxyl (-OH) functional group. Hydrocarbons are compounds with contain hydrogen (H) and carbon (C) only. The hydroxyl group imparts particular properties to the radical to which it is attached.

Alcohols are named according to the radical to which the –OH group is attached. For example if the –OH group is attached to the methyl radical CH3 so that the compound is CH3OH, then one has methyl alcohol. If it is attached to the ethyl (C2H5) radical then one has ethyl alcohol (CH3CH2OH) - the alcohol we consume in beverages. The general formula for alcohol is ROH, where R signifies a hydrocarbon radical attached to an -OH group. A list of some of the common alcohols is given below:

Alcohol Name FormulaMethyl alcohol (methanol) CH3OHEthyl alcohol (ethanol) CH3CH2OHn - propyl alcohol CH3CH2CH2OH

Isopropyl alcohol (propanol -2) CH3CHOHCH3

n-butyl alcohol (butanol -1) CH3(CH2)2CH2OHbutyl alcohol (butanol -2) CH3CH2CHOHCH3

n-hexyl alcohol (hexanol-1) CH3(CH2)4CH2OHn-heptyl alcohol (heptanol-1) CH3(CH2)5CH2OHn-octyl alcohol (octanol-1) CH3(CH2)6CH2OHethylene glycol CH2OHCH2OH

USES OF ALCOHOLSThis page has a brief look at some of the more important uses of the simple alcohols like methanol, ethanol and propan-2-ol.

Uses of ethanol

Drinks

The "alcohol" in alcoholic drinks is simply ethanol.

Industrial methylated spirits (meths)

Ethanol is usually sold as industrial methylated spirits which is ethanol with a small quantity of methanol added and possibly some colour. Methanol is poisonous, and so the industrial methylated spirits is unfit to drink. This avoids the high taxes which are levied on alcoholic drinks (certainly in the UK!).

As a fuel

Ethanol burns to give carbon dioxide and water and can be used as a fuel in its own right, or in mixtures with petrol (gasoline). "Gasohol" is a petrol / ethanol mixture containing about 10 - 20% ethanol.

Because ethanol can be produced by fermentation, this is a useful way for countries without an oil industry to reduce imports of petrol.

As a solvent

Ethanol is widely used as a solvent. It is relatively safe, and can be used to dissolve many organic compounds which are insoluble in water. It is used, for example, in many perfumes and cosmetics.

Uses of methanol

As a fuel

Methanol again burns to form carbon dioxide and water.

It can be used a a petrol additive to improve combustion, or work is currently being done on its use as a fuel in its own right.

As an industrial feedstock

Most methanol is used to make other things - for example, methanal (formaldehyde), ethanoic acid, and methyl esters of various acids. In most cases, these are in turn converted into further products.

Uses of propan-2-ol

Propan-2-ol is widely used in an amazing number of different situations as a solvent. Details on this are probably not required by UK A level syllabuses, but if you need them, an internet search on propan-2-ol solvent uses will give you more examples than you can cope with!

Sources 0f alcohol

Ethanol

Ethanol (ethyl alcohol) has been produced since prehistoric times, mostly through the fermentation of fruit juices. The fermented juice could be stored in a sealed container, and this primitive wine remained safe to drink throughout the winter. Many different sources can provide the sugars and starches that are broken down to simpler compounds during fermentation. Ethanol is called grain alcohol because it is often made from grains, such as corn (maize), wheat, rye, and barley. The grain is first boiled in water to produce the mash, which is incubated with malt (sprouted barley) to yield the wort. Malt provides an enzyme (diastase) that converts starches in the grain to the sugar maltose. The wort is incubated with brewer’s yeast, which secretes the enzyme maltase to convert maltose to glucose and the enzyme zymase to convert glucose to ethanol. Two of the six carbon atoms in glucose are oxidized to carbon dioxide (CO2); this oxidation provides energy to the yeast cells.

Natural products

The common sources of methanol, ethanol, and isopropyl alcohol have been discussed above. Larger, more complicated alcohols are often isolated from volatile oils of plants by the process of steam distillation. The plant material is boiled in water, and the volatile oils are carried over by the steam, condensed, and separated from the water. Substances such as cholesterol, found in most animal tissues (and abundant in egg yolks), and retinol (vitamin A alcohol), extracted from fish liver oils, are examples of naturally occurring sources of alcohols.

Examples of alcohol