Alphanumeric preference between hexyl and heptyl Our chemistry teacher taught us that hexyl (five letters) is preferred to heptyl (six letters) as hexyl has lesser number of letters. After searching many sources I could not find any such rule.
Which one would be preferred while writing IUPAC names?
For example, will it be 8-heptyl-10-hexylheptadecane or 10-heptyl-8-hexylheptadecane?
According to the IUPAC nomenclature, preference for placing prefixes is given in accordance with alphabetical order (just like in a standard English dictionary). It has nothing to do with the number of letters in a prefix. Since &quot;P&quot; in heptyl comes before &quot;X&quot; in hexyl, heptyl will be placed before hexyl in IUPAC nomenclature.
Hence, the correct name will be the one where heptyl is placed before hexyl (8-heptyl-10-hexylheptadecane).