isobutyl

Isobutyl, also known as 2-methylpropyl, is a common alkyl substituent used in organic chemistry. It is the butyl group derived from isobutane by removing one hydrogen from the primary carbon, yielding the substituent -CH2-CH(CH3)2. The isobutyl group has the molecular formula C4H9 and is one of the four constitutional isomers of butyl used as substituents.

In a molecule, the isobutyl group is attached through the terminal CH2 carbon, giving a branched connection with the adjacent carbon bearing two methyl groups. This differs from other C4H9 substituents: n-butyl attaches through a primary end without branching (-CH2-CH2-CH2-CH3), sec-butyl attaches through a secondary carbon (-CH(CH3)-CH2-CH3), and tert-butyl attaches through a tertiary carbon (-C(CH3)3).

Isobutyl is used in a variety of chemical contexts. Common derivatives include isobutyl alcohol (2-methyl-1-propanol) and isobutyl esters such as isobutyl acetate. These compounds occur in solvents, fragrances, and as intermediates in organic synthesis. The isobutyl group influences physical properties such as volatility and solubility, contributing to the behavior of the parent compound in reactions and formulations.

Safety and handling considerations for isobutyl-containing substances follow the general guidelines for flammable, volatile organic compounds. Proper storage in compatible containers and adherence to relevant regulatory limits are standard precautions in laboratory and industrial settings.