Propyl group

From left to right: the two isomeric groups prop-1-yl and prop-2-yl, and the non-isomeric cyclopropyl group.

In organic chemistry, propyl is a three-carbon alkyl substituent with chemical formula -C₃H₇. It is the substituent form of the alkane propane. A propyl substituent is often represented in organic chemistry with the symbol Pr (not to be confused with the element praseodymium).

There are two isomeric forms of propyl:

• with the substituent attached to one of the end carbons (called prop-1-yl in the IUPAC nomenclature, or n-propyl (Pr-n) in the old naming system); and
• with the substituent attached to the middle carbon (called methylethyl in the IUPAC system, or isopropyl in the old system).

In addition there is a third, cyclic, form called cyclopropyl, or c-propyl. It is not isomeric with the other two forms, having the chemical formula -C₃H₅.

Examples

Propyl ethanoate, also called propyl acetate.

This is propyl ethanoate, an ester. The propyl group is attached to the molecule after the middle oxygen.

Other examples

• Isopropyl alcohol

See also

• Methyl
• Ethyl
• Butyl
• Isopropyl