Organic conversion

Propan-1-ol to propan-2-ol

2 steps: elimination, then Markovnikov addition

Class 12, Chapter 7 Alcohols, Phenols and Ethers

Alternative routes (4)

Propan-1-ol → Propene → 2-Bromopropane → Propan-2-ol
1. Propan-1-ol to propene: conc. H₂SO₄, 443 K.
2. Propene to 2-bromopropane: HBr.
3. 2-Bromopropane to propan-2-ol: aq. NaOH (or aq. KOH).
Propan-1-ol → Propene → Ethanal → Propan-2-ol
1. Propan-1-ol to propene: conc. H₂SO₄, 443 K.
2. Propene to ethanal: (i) O₃ (ii) Zn, H₂O.
3. Ethanal to propan-2-ol: (i) CH₃MgBr, dry ether (ii) H₂O.
Propan-1-ol → 1-Bromopropane → Propene → Propan-2-ol
1. Propan-1-ol to 1-bromopropane: red P + Br₂ (PBr₃).
2. 1-Bromopropane to propene: alc. KOH, heat.
3. Propene to propan-2-ol: H₂O, H⁺ (dilute H₂SO₄).
Propan-1-ol → 1-Bromopropane → Propene → 2-Bromopropane → Propan-2-ol
1. Propan-1-ol to 1-bromopropane: red P + Br₂ (PBr₃).
2. 1-Bromopropane to propene: alc. KOH, heat.
3. Propene to 2-bromopropane: HBr.
4. 2-Bromopropane to propan-2-ol: aq. NaOH (or aq. KOH).

Why these reagents

Reagent and reason, step by step

Step 1: Propan-1-ol to propene: conc. H₂SO₄, 443 K Acid-catalysed dehydration of a primary alcohol.
Step 2: Propene to propan-2-ol: H₂O, H⁺ (dilute H₂SO₄) Markovnikov hydration gives the secondary alcohol.

Questions

How many steps does it take to convert propan-1-ol to propan-2-ol?

2 steps: Propan-1-ol, then propene, then propan-2-ol.

Which named reaction is used to convert propan-1-ol to propan-2-ol?

Markovnikov addition. When an unsymmetrical reagent adds to an unsymmetrical alkene, the negative part goes to the carbon with fewer hydrogen atoms.

What is the reagent for step 1 of propan-1-ol to propan-2-ol?

Propan-1-ol to propene: conc. H₂SO₄, 443 K. Acid-catalysed dehydration of a primary alcohol.