What is the IUPAC name of iso-octane?
I know that the IUPAC name of iso-octane 2,2,4-trimethyl pentane but why is it not 2-methyl heptane. As far as i know, prefix-iso is used for those paraffins in whch a methyl group is attached to the second last carbon atom of the continous chain.
Why isn't this rule applicable here.
I know that the IUPAC name of iso-octane 2,2,4-trimethyl pentane but why is it not 2-methyl heptane. As far as i know, prefix-iso is used for those paraffins in whch a methyl group is attached to the second last carbon atom of the continous chain.
Why isn't this rule applicable here.
1 Answer
Jan 2, 2016
It is used as reference for the octane number, so the reason is historical.
Explanation:
Strictly speaking, you are correct. However, from all the isomers of octane, 2,2,4-trimethyl-pentane is the most important because of it's anti-knocking character in gasoline fuels. Specifically the octane number is defined:
A gasoline fuel with an octane number of 95 has the same antiknocking character as a mixture of 95% v/v of iso-octane (2,2,4-trimethyl-pentane) and 5% v/v n-heptane.
