Question

How do you convert:
Propene to 1-Iodopropane

Hint:

Hydroiodic acid (HI) adds to alkenes following Markovnikov's rule, with the iodine adding to the more substituted carbon.

Answer 1

Conversion of Propene to 1-Iodopropane:

The conversion of propene (CH₃CH=CH₂) to 1-iodopropane (CH₃CH₂CH₂I) can be achieved by an electrophilic addition reaction with iodine (I₂) in the presence of a strong acid, such as hydroiodic acid (HI).

Reaction:

CH₃CH=CH₂ + HI → CH₃CH₂CH₂I

Mechanism:
1. Electrophilic Addition of HI: In this reaction, HI (hydroiodic acid) adds to the double bond of propene. The double bond in propene acts as a nucleophile, attacking the electrophilic hydrogen (H⁺) from HI. This leads to the formation of a carbocation intermediate. 
2. Carbocation Formation: The intermediate carbocation is formed at the most stable position, which, in this case, is at the secondary carbon (CH₂) in propene, resulting in a secondary carbocation. 
3. Nucleophilic Attack by I⁻: The iodide ion (I⁻) from HI attacks the carbocation, forming 1-iodopropane (CH₃CH₂CH₂I) as the final product.

Conditions:
- The reaction occurs under acidic conditions (using HI), and heat may be applied to drive the reaction to completion.

Conclusion:
Propene reacts with HI through an electrophilic addition mechanism to produce 1-iodopropane.