Alcohols are one of the widely used organic compounds. They are the organic compounds which contain hydroxyl (-OH) group as their functional groups. In other words, alcohols can be defined as the hydroxyl derivative of aliphatic hydrocarbons. Alcohols are represented by ‘ROH’ where R is the methyl group. Alcohols can simply be categorized into different grades on the basis of their purity. Those grades of purity of alcohol are mentioned and described below:
1. Rectified spirit: The fermented liquor after fractional distillation contains higher percentage of alcohol (about 95%). This type of alcohol is known as rectified spirit.
2. Absolute alcohol: Absolute alcohol is the alcohol which is 100% pure. It is obtained by distillation of rectified spirit over calcium oxide (CaO) or calculated amount of sodium (Na) or calcium (Ca).
3. Methylated spirit: Alcohols are made available for industrial purposes by making them unsuitable for drinking purposes by the addition of small amount of methanol, ketone, pyridine etc. Such type of alcohols are known as denaturated alcohol or methylated spirit. The process of the preparation of such alcohol is known as denaturation of alcohol.
4. Alcoholic beverages: Alcohol is considered as the main intoxicating agent used in the drinking liquor. Such liquors containing alcohol are called alcoholic beverages. Alcoholic beverages can be divided into two types. They are:
(i) Distilled beverages: The fermented liquors after fractional distillation contain higher percentage of alcohol and are known as distilled beverages. For example, whiskey, vodka, rum, gin etc.
(ii) Undistilled beverages: The fermented liquors which are not distilled contain low percentage of alcohol. These are called undistilled beverages. They are prepared from different fruit juices. For example, wine, beer etc.