In organic chemistry, propyl is a three- carbon alkyl

substituent A substituent is one or a group of atoms that replaces (one or more) atoms, thereby becoming a moiety in the resultant (new) molecule. (In organic chemistry and biochemistry, the terms ''substituent'' and ''functional group'', as well as ''side ...

with chemical formula for the linear form. This

form is obtained by removing one hydrogen atom attached to the terminal carbon of

propane Propane () is a three-carbon alkane with the molecular formula . It is a gas at standard temperature and pressure, but compressible to a transportable liquid. A by-product of natural gas processing and petroleum refining, it is commonly used a ...

. A propyl substituent is often represented in organic chemistry with the symbol Pr (not to be confused with the element praseodymium). An

isomer In chemistry, isomers are molecules or polyatomic ions with identical molecular formulae – that is, same number of atoms of each element – but distinct arrangements of atoms in space. Isomerism is existence or possibility of isomers. Iso ...

ic form of propyl is obtained by moving the point of attachment from a terminal carbon atom to the central carbon atom, named 1-methylethyl or isopropyl. To maintain four substituents on each carbon atom, one hydrogen atom has to be moved from the middle carbon atom to the carbon atom which served as attachment point in the ''n''-propyl variant, written as . Linear propyl is sometimes termed normal and hence written with a prefix ''n''- (i.e., ''n-''propyl), as the absence of the prefix ''n''- does not indicate which attachment point is chosen, i.e. absence of prefix does not automatically exclude the possibility of it being the branched version (i.e. ''i''-propyl or ''isopropyl''). In addition, there is a third, cyclic, form called cyclopropyl, or ''c''-propyl. It is not isomeric with the other two forms, having a different chemical formula ( vs ), not just a different connectivity of the atoms.

Examples

''n''-Propyl acetate is an ester which has the ''n''-propyl group attached to the oxygen atom of the

acetate An acetate is a salt (chemistry), salt formed by the combination of acetic acid with a base (e.g. Alkali metal, alkaline, Alkaline earth metal, earthy, Transition metal, metallic, nonmetallic or radical Radical (chemistry), base). "Acetate" als ...

group.

Other examples

* Isopropyl alcohol

References

{{Functional group Alkyl groups