Question

Neoprene is the polymer of a monomer X. IUPAC name of X is

• A. 1,3-Butadiene
• B. 2-Methyl-1,3-butadiene
• C. 2-Iodo-1,3-butadiene
• D. 2-Chloro-1,3-butadiene

Hint:

Memorize the monomers of the most important industrial polymers: - Polyethylene \(\rightarrow\) Ethene - PVC \(\rightarrow\) Vinyl chloride (Chloroethene) - Teflon \(\rightarrow\) Tetrafluoroethene - Natural Rubber \(\rightarrow\) Isoprene (2-Methyl-1,3-butadiene) - Neoprene \(\rightarrow\) Chloroprene (2-Chloro-1,3-butadiene) - Buna-S \(\rightarrow\) 1,3-Butadiene + Styrene

Answer 1

The Correct Option is D

Step 1: Identify the Monomer of Neoprene: Neoprene is a synthetic rubber formed by the polymerization of Chloroprene.
Step 2: Structure of Chloroprene: Chloroprene is derived from 1,3-butadiene by replacing the hydrogen at the 2nd position with Chlorine. Structure: \( \text{CH}_2=\text{C(Cl)}-\text{CH}=\text{CH}_2 \).
Step 3: IUPAC Name: Numbering from the end giving the substituent lowest locant (while maintaining lowest locants for double bonds). C1=C2(Cl)-C3=C4. Name: 2-Chloro-1,3-butadiene. Note on other options: (A) 1,3-Butadiene \(\to\) Buna-S / Buna-N (copolymer). (B) 2-Methyl-1,3-butadiene (Isoprene) \(\to\) Natural Rubber.