To name aromatic hydrocarbons:

1. When naming branched aromatics, consider the benzene ring to be the parent chain (unless the benzene ring is attached to a larger molecule).
   
   
2. If you have more than one alkyl branch attached, they are listed in alphabetical order. Always number the benzene ring so that the branch numbers are the lowest possible. (In other words, you will always have a branch numbered 1). If you have a choice between two sets of lowest numbers, choose the set that is in both numerical and alphabetical order. Refer to Sample Problem 9.3 on page 383 of your textbook.
   
   
3. If there is a benzene ring attached to a larger molecule (usually one that contains four or more carbon atoms), the larger molecule is considered to be the parent chain and benzene is considered to be the branch. In these cases, benzene is referred to as a phenyl branch.

Examples of Aromatic Compounds

	methylbenzene (toluene)   The molecular formula of this compound is C7H8. Recall that the molecular formula of benzene is C6H6.  Therefore, for every alkyl branch substituted onto a benzene ring, a hydrogen atom must be removed!
	1-ethyl-3-methylbenzene
	2-methyl-3-phenylbutane

Check Your Understanding

Go to your textbook and complete Section 9.4 Question 5 on page 385.

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