propyyl

Propylyl is not a standard term in modern organic chemistry; the correct and widely used name is propyl. The propyl substituent is a C3H7 group derived from propane by removing one hydrogen. In IUPAC naming, the substituent is propan-1-yl for the straight-chain form (n-propyl) and propan-2-yl for the branched form (isopropyl). Older literature may refer to n-propyl and isopropyl or use “propyl” with locants, but current practice favors propan-1-yl and propan-2-yl.

The term propylyl could appear in nonstandard usage or as an archaic spelling that does not denote a distinct substituent from propyl. There is also cyclopropyl, a separate three-carbon substituent derived from cyclopropane (C3H5), which is sometimes discussed alongside propyl groups but is chemically distinct.

Propyl groups are common in a wide range of compounds, including 1-propyl alcohol (propan-1-ol), propyl halides, and various propyl derivatives used in synthesis. They influence physical properties such as boiling points, polarity, and solubility, and are routinely encountered in organic synthesis, petrochemicals, and pharmaceutical chemistry. For precise terminology, it is preferable to use propan-1-yl, propan-2-yl, or simply propyl when the context clearly indicates the straight-chain substituent.