Sun December 11, 2011 By: Nancy Mishra

im not able to understand the steps involved in the IUPAC nomenclature for branched chain saturated addition to this im not getting that how does 2-methylpropane differ from isobutane coz both of them have same structues?Can i write isobutane instead of methyl propane?What difference would it make?

Expert Reply
Mon December 12, 2011
Yes. Both the names are correct but according to IUPAC 2-methylpropane is correct.  
For branched chain nomenclature :
  • Identify each of the branches (side-chains).


  • Use the lowest number combinations for the branches (side-chains).


  • Name each branch or side-chain (alkyl group) :
    methyl CH3
    ethyl C2H5
    propyl C3H7


  • For more than 1 of the same alkyl group use:
    di = 2
    tri = 3
    tetra = 4


  • Use commas between numbers, eg, 1,2 or 2,3


  • Use hyphens between numbers and words, eg, 2-methyl or 2,3-dimethyl


  • If there is more than 1 type of branch or side-chain, arrange their names alphabetically, 
    ie, ethyl groups are named before methyl groups which are named before propyl groups
Related Questions
Sun September 10, 2017

what is covalent bond?

Home Work Help