Alkylation is a chemical process where an alkyl group, which is a type of hydrocarbon chain, is added to a molecule. This process is commonly used in organic chemistry to modify the structure and properties of compounds, making them more useful in various applications, such as pharmaceuticals and fuels. In the petroleum industry, alkylation is crucial for producing high-octane gasoline. It involves combining smaller hydrocarbons, like propene and butene, to create larger, branched molecules that improve fuel performance. This process helps enhance the efficiency of engines and reduce harmful emissions.