Alkylation is a chemical reaction in which an alkyl group is added to a molecule. This process typically involves the replacement of a hydrogen atom with an alkyl group in a molecule, resulting in the formation of a new carbon-carbon bond. Alkylation reactions are commonly used in organic chemistry to introduce alkyl groups into a variety of molecules, including hydrocarbons, amines, and alcohols. This process can be carried out using various alkylating agents and catalysts, and can be used to synthesize a wide range of organic compounds with different properties and functionalities. Alkylation reactions are important in the production of pharmaceuticals, agrochemicals, and other fine chemicals, and are a key step in many organic synthesis pathways.