11.6.6

Manufacture of Ethanol: Fermentation & Hydration

Test yourself

Manufacture of Ethanol: Fermentation & Catalytic Hydration

Ethanol is made by fermentation of glucose and catalytic hydration of ethene using yeast and acid catalysts.

Illustrative background for Fermentation overviewIllustrative background for Fermentation overview ?? "content

Fermentation overview

  • Fermentation produces ethanol using aqueous glucose.
    • Yeast acts as a catalyst during fermentation.
    • Temperature is kept between 25°C and 35°C.
    • Oxygen is absent during this process.
  • The process was discovered before 1850 and is traditional in brewing.
Illustrative background for Fermentation process detailsIllustrative background for Fermentation process details ?? "content

Fermentation process details

  • Glucose breaks down into ethanol and carbon dioxide.
    • The reaction is: C6H12O6 → 2C2H5OH + 2CO2.
  • Yeast enzymes speed up fermentation.
  • Fermentation stops if the temperature rises above 35°C.
  • Ethanol yield is limited to about 15% due to yeast sensitivity.
Illustrative background for Catalytic hydration overviewIllustrative background for Catalytic hydration overview ?? "content

Catalytic hydration overview

  • Ethanol also forms by adding steam to ethene.
  • Steam and ethene react at 300°C.
  • Pressure is high, about 6000 kPa (60 atm).
  • An acid catalyst, like phosphoric acid, speeds the reaction.
    • This method started in the early 20th century for industrial ethanol.
Illustrative background for Catalytic hydration process detailsIllustrative background for Catalytic hydration process details ?? "content

Catalytic hydration process details

  • Ethene (C2H4) and steam (H2O) form ethanol (C2H5OH).
    • Reaction: C2H4 + H2O → C2H5OH.
  • Acid catalyst helps break and form chemical bonds faster.
  • The process allows large-scale ethanol manufacturing.
  • It uses ethene from cracking hydrocarbons.
Illustrative background for Comparing both methodsIllustrative background for Comparing both methods ?? "content

Comparing both methods

  • Fermentation uses renewable glucose, is slower, and produces less pure ethanol.
  • Catalytic hydration uses ethene, allowing continuous production at high purity.
    • Fermentation of ethanol is important in food and drink.
    • Catalytic hydration of ethanol is useful for fuel and industry.
  • Both methods are key to the organic chemistry topic of alcohol manufacture.

Jump to other topics

1States of Matter

2Atoms, Elements & Compounds

3Stoichometry

4Electrochemistry

5Chemical Energetics

6Chemical Reactions

7Acids, Bases & Salts

8The Periodic Table

9Metals

10Chemistry of the Environment

11Organic Chemistry

11.1Formulae, Functional Groups & Terminology

11.2Naming Organic Compounds

11.3Fuels

11.4Alkanes

11.5Alkenes

11.6Alcohols

11.7Carboxylic Acids

11.8Polymers

12Experimental Techniques & Chemical Analysis

Unlock your full potential with Seneca Premium

  • Unlimited access to 10,000+ open-ended exam questions

  • Mini-mock exams based on your study history

  • Unlock 800+ premium courses & e-books

Get started with Seneca Premium