alkylated

Alkylated is a chemical term describing a molecule that has been modified by the introduction of one or more alkyl groups. An alkyl group is a saturated hydrocarbon fragment such as methyl (−CH3), ethyl (−C2H5), or propyl. Alkylation is the set of reactions that attach these groups to a substrate, changing its properties such as reactivity, volatility, or solubility.

Alkylation can proceed by several mechanisms. In organic synthesis, common routes include Friedel–Crafts alkylation of arenes using alkyl halides under Lewis acid catalysts, or alkylation of alcohols and carbonyl compounds with olefins or alkylating agents via SN1 or SN2 pathways. Reactions may require catalysts, dehydrating conditions, or protecting groups. The term "alkylated" may refer to the substrate after such a reaction, or to a product bearing alkyl substituents on the main framework.

Industrial uses include production of high-octane fuels. In petroleum refining, alkylation combines light olefins with isobutane to form C8 branched alkanes known as alkylates, a key gasoline component. Aromatic and hydrocarbon streams may be described as alkylated when they bear appended alkyl groups, such as alkylated benzenes or alkylated naphthalenes used as solvents, lubricants, or chemical intermediates.

In biochemistry and medicine, alkylating agents transfer alkyl groups to nucleophilic sites in biomolecules, notably DNA and proteins. These reagents are used in research to probe structure and function, and in chemotherapy, though they pose safety hazards and are strictly controlled.