Antiknock Compounds - Characteristics of Hydrocarbons
To decrease the knocking property or to enhance the octane number of a fuel certain chemicals are included in it. These are termed as antiknock compounds. One such type of substance, which is widely used, is tetraethyl lead (TEL). TEL is utilized in the form of following mixture,
TEL = 63%, Ethylene bromide = 26%, Ethylene chloride = 9% and a dye = 2%.
Though, there is a drawback that the lead is deposited in the engine. To eradicate the free lead, ethylene halides are added that combine with lead to form volatile lead halides.