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Organic conversion

Ethanol to ethene

1 step: elimination

Class 12, Chapter 7 Alcohols, Phenols and Ethers

  1. OH
    EthanolCH₃CH₂OHAlcohol
  2. Step 1

    conc. H₂SO₄

    443 K

    i

    Dehydration at 443 K gives the alkene; at 413 K with excess ethanol the product is the ether instead.

    EtheneCH₂=CH₂Alkene

Exam answer

  1. Step 1: Ethanol to ethene: conc. H₂SO₄, 443 K.
Alternative routes (4)
  • Ethanol → Chloroethane → Ethene
    1. Ethanol to chloroethane: SOCl₂.
    2. Chloroethane to ethene: alc. KOH, heat.
  • Ethanol → Bromoethane → Ethene
    1. Ethanol to bromoethane: red P + Br₂ (PBr₃).
    2. Bromoethane to ethene: alc. KOH, heat.
  • Ethanol → Ethanal → Ethane → Chloroethane → Ethene
    1. Ethanol to ethanal: PCC.
    2. Ethanal to ethane: Zn-Hg, conc. HCl.
    3. Ethane to chloroethane: Cl₂, UV light.
    4. Chloroethane to ethene: alc. KOH, heat.
  • Ethanol → Bromoethane → Ethane → Chloroethane → Ethene
    1. Ethanol to bromoethane: red P + Br₂ (PBr₃).
    2. Bromoethane to ethane: Zn, dilute HCl.
    3. Ethane to chloroethane: Cl₂, UV light.
    4. Chloroethane to ethene: alc. KOH, heat.
Why these reagents

Reagent and reason, step by step

  • Step 1: Ethanol to ethene: conc. H₂SO₄, 443 K Dehydration at 443 K gives the alkene; at 413 K with excess ethanol the product is the ether instead.
Good to know

Points to note

  • Step 1Dehydration at 443 K gives the alkene; at 413 K with excess ethanol the product is the ether instead.
Questions

Ethanol to ethene: quick answers

How many steps does it take to convert ethanol to ethene?

1 step: Ethanol, then ethene.

Which named reaction is used to convert ethanol to ethene?

None of the steps has a name. They are elimination, so write the reagent and the condition for each step.

What is the reagent for step 1 of ethanol to ethene?

Ethanol to ethene: conc. H₂SO₄, 443 K. Dehydration at 443 K gives the alkene; at 413 K with excess ethanol the product is the ether instead.

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