OCTANE NUMBER AND CETANE NUMBER

These play an Important role in petroleum and petrochemicals which is a part of natural product organic chemistry……….

Octane number of a given fuel is the percent of iso-octane in a mixture of iso-octane and n-heptane that gives the same knocking properties as the fuel under test under the similar experimental conditions.

This is used for the evaluation of gasolines in petrol engines.

For eg:if we consider that the octane number of a fuel is 70 that it means it behaves like a mixture of 70 percent iso-octane and 30 percent n-heptane.generally,gasolines have an octane no-74 such are used in motor cars ,scooters and motor-cycles.these r called as regular gasolines.gasolines with octane no-81 are called as premium gasolines .

The octane no of gasolines can be improved by adding high octane gasolines and also anti-knocking compounds like TEL (tetra ethyl lead).

Cetane number of a diesel fuel is the percentage of cetane by volume in a mixture of cetane and α-methyl naphthalene which has the same ignition qualities as the sample fuel under similar conditions in a test engine.

For diesel engines,straight chain hydrocarbons are considerd to be superior to branched.since straight chain hc’s ignite faster than branched.

Diesel engines have high efficiency than petrol engines………………………………….