Alcohols

Alcohols are compound which contain one or more hydroxyl groups. Proof is the unit of measuring the purity of alcohol. Lucas test and Victor meyer test are related with Alcohols. Alcohols are classified as primary, secondary and tertiary alcohols. The classification is done in accordance with the carbon atom is bonded to the hydroxyl group. For primary alcohols (1°), carbon atom is bonded to only one other carbon atom,  for secondary alcohols (2°), carbon atom is bonded to two other carbon atom and for tertiary alcohols (3°), carbon atom is bonded to three other carbon atom. Most of the alcohols are colourless liquids or even behave as solid at room temperatures. There are several kinds of commercially important alcohols. They are as follows.

1. Ethyl Alcohol (Ethanol)

Ethyl Alcohol (C2H5OH) is drunk in liquids. Ethyl Alcohol is also called as Grain Alcohol. Ethanol is used in the preparation of various beverages. The grape spirit is a continuous boiling mixture of ethanol and water. The percentage of alcohol in spirit is 95%. The most alcoholic beverage is whiskey. Whiskey is made from barley. The least alcoholic beverage is beer. Brandy is made from grapes. Russia is the birthplace of vodka.

2. Methyl Alcohol (Methanol)

Methyl Alcohol (CH3OH) is used in such products as antifreeze or solvents. Methanol is a type of alcohol used for many industrial purposes. It is also called Methyl Alcohol or wood alcohol. Methanol is a clear, colourless organic compound, is flammable and highly poisonous. Drinking it, or inhaling its fumes for prolonged periods, can cause blindness or even death. It is also harmful to the skin. It has a molecular weight of 32.04. It boils at 65°C and freeze at -94°C. At 20°C, its density is 0.7915 grams per cubic centimetre. Methanol mixes readily with water and with such organic compounds as benzene and ether. Some of these mixtures are used in motor vehicles as antifreezes for windshield washer fluids and fuel lines. Such mixtures lower the temperature at which ice forms. Methanol is an alcohol used as a solvent in paint manufacturing and in the manufacture of varnishes and formalin. Hydrogen is a gas that is added with carbon monoxide in the industrial production of methanol.

3. Ethylene Glycol

Ethylene glycol is used as automotive antifreeze, ingredient in hydraulic fluids and in the manufacturing of plastics, paint solvents and printing inks. It is also used as a chemical reagent in the manufacture of alkyd resins, polyesters, synthetic waxes and explosives.

4. Isopropyl alcohol 

It is manufactured by indirect hydration of propylene. It is most commonly used as an industrial solvent and as a rubbing alcohol applied to the skin.

5. Glycerol 

Glycerol, often known as glycerine, is a sweet, syrupy material that contains three alcohol hydroxyl groups. Glycerol was first made as a by-product of soap manufacture, through the process of saponification of fats. 

Other Alcohols

1. Rectified Spirit and Methylated Spirit

Mixture of Ethyl Alcohol (95.87%) and water (4.13%) is known as rectified spirit.  Ethyl Alcohol containing 5 to 10% methyl alcohol is called methylated spirit (denatured spirit). 

2. Absolute Alcohol

99.5% ethanol is called absolute alcohol. The mixture of petrol and absolute alcohol is called as power alcohol.