Answer
🔬 IUPAC Naming of Aromatic Compounds
🧪 Objective
To determine the correct IUPAC name of an aromatic compound with:
- A sec-butyl group
- An ethyl group
- A phenol ring (benzene with –OH at position 1)
🔍 Step-by-Step Naming
1. Identify the Parent Structure
The molecule is a derivative of phenol. Phenol is used as the parent name because the hydroxyl (–OH) group is directly attached to the benzene ring.
2. Number the Carbon Ring
The carbon with the –OH group is assigned position 1. Numbering is done to give the substituents the lowest possible locants:
- Ethyl group: position 2
- sec-Butyl group: position 5
3. Determine Substituents
- Ethyl (–CH₂CH₃): a two-carbon linear alkyl group
- sec-Butyl (–CH(CH₃)CH₂CH₃): a branched four-carbon group
4. Alphabetical Order of Substituents
Substituents are listed alphabetically in the name, regardless of position:
- Ethyl comes before sec-butyl
✅ Final IUPAC Name
5-sec-butyl-2-ethylphenol
🧠 Summary Table
| Feature | Value |
|---|---|
| Parent Compound | Phenol |
| Main Functional Group | –OH at C1 |
| Substituent 1 | Ethyl at C2 |
| Substituent 2 | sec-Butyl at C5 |
| Final Name | 5-sec-butyl-2-ethylphenol |
Conclusion
Using IUPAC naming rules—prioritizing the hydroxyl group, assigning lowest locants to substituents, and ordering alphabetically—the correct name for the compound is 5-sec-butyl-2-ethylphenol.