Octane rating
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Why do aromatic hydrocarbons have a high octane rating? What is its underlying principle? Why does naphtha, used as a finisher in riser reactors, lower the octane number of gasoline? What is the principle behind this?
The octane rating of gasoline is related to the amount of various hydrocarbons present. Aromatic hydrocarbons and isomeric olefins have the highest values, followed by isomeric alkanes and olefins, then naphthenes, with normal alkanes having the lowest values. The main factor affecting gasoline octane number is the olefin content, especially that of isomerized olefins. Among catalytic gasoline, olefins have the greatest impact on octane number. The lower the boiling range, the higher the content of olefins, and the higher the octane rating as well. The lower the initial boiling point of gasoline, the relatively higher the proportion of components with a low boiling point, and therefore the higher its octane rating
The octane rating of gasoline is related to the amount of various hydrocarbons present. Aromatic hydrocarbons and isomeric olefins have the highest values, followed by isomeric alkanes and olefins, then naphthenes, with normal alkanes having the lowest values. The main factor affecting gasoline octane number is the olefin content, especially that of isomerized olefins. Among catalytic gasoline, olefins have the greatest impact on octane number. The lower the boiling range, the higher the content of olefins, and the higher the octane rating as well. The lower the initial boiling point of gasoline, the relatively higher the proportion of components with a low boiling point, and therefore the higher its octane rating
Aromatic hydrocarbons contain benzene rings with high energy, and substances containing benzene rings release a large amount of heat during oxidation reactions; as a result, their octane rating is higher compared to other alkanes.
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