Butyl group

In <a href="/facts/Organic_chemistry/djxhxaNg">organic chemistry</a>, butyl is a four-<a href="/facts/Carbon/ukrgQexo">carbon</a> <a href="/facts/Alkyl/vmEk8X4v">alkyl</a> <a href="/facts/Radical_(chemistry)/qFymuVoT">radical</a> or <a href="/facts/Substituent/6y9IE6G0">substituent group</a> with general <a href="/facts/Chemical_formula/hghUtthl">chemical formula</a> −C4H9, derived from either of the two <a href="/facts/Isomer/PXlvDVdg">isomers</a> (n-butane and isobutane) of <a href="/facts/Butane/InIHpYlY">butane</a>.
The isomer n-butane can connect in two ways, giving rise to two "-butyl" groups:

<ul><li>If it connects at one of the two terminal carbon <a href="/facts/Atom/FoQ4kGN5">atoms</a>, it is normal butyl or n-butyl: −CH2−CH2−CH2−CH3 (preferred IUPAC name: butyl)</li>
<li>If it connects at one of the non-terminal (internal) carbon atoms, it is secondary butyl or sec-butyl: −CH(CH3)−CH2−CH3 (preferred IUPAC name: butan-2-yl)</li></ul>
The second isomer of butane, isobutane, can also connect in two ways, giving rise to two additional groups:

<ul><li>If it connects at one of the three terminal carbons, it is isobutyl: −CH2−CH(CH3)2 (preferred IUPAC name: 2-methylpropyl)</li>
<li>If it connects at the central carbon, it is tertiary butyl, tert-butyl or t-butyl: −C(CH3)3 (preferred IUPAC name: tert-butyl)</li></ul>

Butyl group open-in-new

Butyl group