11.6.6
Manufacture of Ethanol: Fermentation & Hydration
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Manufacture of Ethanol: Fermentation & Catalytic Hydration
Ethanol is made by fermentation of glucose and catalytic hydration of ethene using yeast and acid catalysts.

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.

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.

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.

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.

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.
1States of Matter
1.1Solids, Liquids, & Gases
2Atoms, Elements & Compounds
2.1Elements, Compounds & Mixtures
2.2Atomic Structure & the Periodic Table
2.3Isotopes
2.4Ions & Ionic Bonds
2.5Simple Molecules & Covalent Bonds
2.6Giant Covalent Structures
2.7Metallic Bonding
3Stoichometry
3.1Formulae
3.2Relative Masses of Atoms & Molecules
3.3The Mole & the Avogadro Constant
3.3.1Introducing Moles3.3.2Amounts of Substances3.3.3Moles & Equations3.3.4Calculations Involving Gases3.3.5Calculating Stoichiometric Reacting Masses3.3.6Calculating the Moles of Solute3.3.7Calculating Empirical Formula3.3.8Chemical Equations3.3.9Percentage Yield3.3.10Calculating Yield3.3.11Percentage Purity
4Electrochemistry
4.1Electrolysis
4.1.1Electrolytic Process4.1.2Electrolysis Examples4.1.3Electrolysis of a Binary Compound in Molten State4.1.4Electroplating4.1.5Transfer of Charge During Electrolysis4.1.6Electrolysis of Aqueous Solutions4.1.7Electrolysis of Copper Sulfate4.1.8Electrolysis of Halide Compounds4.1.9Half-Equations4.1.10Combustion of Hydrocarbons
4.2Hydrogen–Oxygen Fuel Cells
5Chemical Energetics
6Chemical Reactions
6.1Physical & Chemical Changes
6.2Rate of Reaction
6.3Reversible Reactions & Equilibrium
6.3.1Reversible Reactions6.3.2Conditions & Equilibrium6.3.3Dynamic Equilibrium6.3.4Changing Conditions - Heat & Water Effects6.3.5Factors Affecting Equilibria - Temperature6.3.6Factors Affecting Equilibria - Pressure6.3.7Factors Affecting Equilibria - Concentration6.3.8The Haber Process6.3.9The Haber Process Equation
7Acids, Bases & Salts
7.1The Characteristic Properties of Acids & Bases
7.1.1Acids & Alkali7.1.2Reactions of Metals with Acids7.1.3Reactions of Bases with Acids7.1.4Reactions of Carbonates with Acids7.1.5Identifying Acids7.1.6Properties & Effects of Acids7.1.7Properties of Bases - Reactions with Acids & Salts7.1.8Properties of Alkalis & Indicators7.1.9Strong vs Weak Acids7.1.10Strong vs Weak Bases7.1.11Understanding Universal Indicator Paper7.1.12Acids, Bases & the Neutralisation Reaction
8The Periodic Table
8.1Arrangement of Elements
8.2Group I Properties
8.3Group VII Properties
8.4Transition Elements
8.5Noble Gases
9Metals
9.1Properties of Metals
9.2Uses of Metals
9.3Alloys & Their Properties
9.4Reactivity Series
9.5Corrosion of Metals
9.6Extraction of Metals
10Chemistry of the Environment
10.1Water
10.2Fertilisers
11Organic Chemistry
11.1Formulae, Functional Groups & Terminology
11.2Naming Organic Compounds
11.3Fuels
11.4Alkanes
11.5Alkenes
11.6Alcohols
11.7Carboxylic Acids
11.8Polymers
11.8.1Polymers11.8.2Problems With Polymers11.8.3Polymers & Plastics11.8.4Problems with Plastics11.8.5Condensation Polymerisation11.8.6Condensation Polymerisation Examples11.8.7Addition Polymerisation11.8.8Addition Polymerisation Examples11.8.9Structure of Polymers11.8.10Natural Polyamides - Proteins & Amino Acids
12Experimental Techniques & Chemical Analysis
12.1Experimental Design
12.2Acid-base Titrations
12.3Chromatography
12.4Separation & Purification
12.5Identification of Ions & Gases
12.5.1Testing Aqueous Cations 112.5.2Testing Aqueous Cations 212.5.3Testing Cations - Flame Tests12.5.4Testing Cations12.5.5Testing for Aqueous Cations12.5.6Testing Anions - Sulfates12.5.7Testing Anions - Nitrates12.5.8Testing Gases - Hydrogen12.5.9Testing Gases - Oxygen12.5.10Testing Gases - Carbon Dioxide12.5.11Testing Gases - Chlorine12.5.12Identifying Gases
Jump to other topics
1States of Matter
1.1Solids, Liquids, & Gases
2Atoms, Elements & Compounds
2.1Elements, Compounds & Mixtures
2.2Atomic Structure & the Periodic Table
2.3Isotopes
2.4Ions & Ionic Bonds
2.5Simple Molecules & Covalent Bonds
2.6Giant Covalent Structures
2.7Metallic Bonding
3Stoichometry
3.1Formulae
3.2Relative Masses of Atoms & Molecules
3.3The Mole & the Avogadro Constant
3.3.1Introducing Moles3.3.2Amounts of Substances3.3.3Moles & Equations3.3.4Calculations Involving Gases3.3.5Calculating Stoichiometric Reacting Masses3.3.6Calculating the Moles of Solute3.3.7Calculating Empirical Formula3.3.8Chemical Equations3.3.9Percentage Yield3.3.10Calculating Yield3.3.11Percentage Purity
4Electrochemistry
4.1Electrolysis
4.1.1Electrolytic Process4.1.2Electrolysis Examples4.1.3Electrolysis of a Binary Compound in Molten State4.1.4Electroplating4.1.5Transfer of Charge During Electrolysis4.1.6Electrolysis of Aqueous Solutions4.1.7Electrolysis of Copper Sulfate4.1.8Electrolysis of Halide Compounds4.1.9Half-Equations4.1.10Combustion of Hydrocarbons
4.2Hydrogen–Oxygen Fuel Cells
5Chemical Energetics
6Chemical Reactions
6.1Physical & Chemical Changes
6.2Rate of Reaction
6.3Reversible Reactions & Equilibrium
6.3.1Reversible Reactions6.3.2Conditions & Equilibrium6.3.3Dynamic Equilibrium6.3.4Changing Conditions - Heat & Water Effects6.3.5Factors Affecting Equilibria - Temperature6.3.6Factors Affecting Equilibria - Pressure6.3.7Factors Affecting Equilibria - Concentration6.3.8The Haber Process6.3.9The Haber Process Equation
7Acids, Bases & Salts
7.1The Characteristic Properties of Acids & Bases
7.1.1Acids & Alkali7.1.2Reactions of Metals with Acids7.1.3Reactions of Bases with Acids7.1.4Reactions of Carbonates with Acids7.1.5Identifying Acids7.1.6Properties & Effects of Acids7.1.7Properties of Bases - Reactions with Acids & Salts7.1.8Properties of Alkalis & Indicators7.1.9Strong vs Weak Acids7.1.10Strong vs Weak Bases7.1.11Understanding Universal Indicator Paper7.1.12Acids, Bases & the Neutralisation Reaction
8The Periodic Table
8.1Arrangement of Elements
8.2Group I Properties
8.3Group VII Properties
8.4Transition Elements
8.5Noble Gases
9Metals
9.1Properties of Metals
9.2Uses of Metals
9.3Alloys & Their Properties
9.4Reactivity Series
9.5Corrosion of Metals
9.6Extraction of Metals
10Chemistry of the Environment
10.1Water
10.2Fertilisers
11Organic Chemistry
11.1Formulae, Functional Groups & Terminology
11.2Naming Organic Compounds
11.3Fuels
11.4Alkanes
11.5Alkenes
11.6Alcohols
11.7Carboxylic Acids
11.8Polymers
11.8.1Polymers11.8.2Problems With Polymers11.8.3Polymers & Plastics11.8.4Problems with Plastics11.8.5Condensation Polymerisation11.8.6Condensation Polymerisation Examples11.8.7Addition Polymerisation11.8.8Addition Polymerisation Examples11.8.9Structure of Polymers11.8.10Natural Polyamides - Proteins & Amino Acids
12Experimental Techniques & Chemical Analysis
12.1Experimental Design
12.2Acid-base Titrations
12.3Chromatography
12.4Separation & Purification
12.5Identification of Ions & Gases
12.5.1Testing Aqueous Cations 112.5.2Testing Aqueous Cations 212.5.3Testing Cations - Flame Tests12.5.4Testing Cations12.5.5Testing for Aqueous Cations12.5.6Testing Anions - Sulfates12.5.7Testing Anions - Nitrates12.5.8Testing Gases - Hydrogen12.5.9Testing Gases - Oxygen12.5.10Testing Gases - Carbon Dioxide12.5.11Testing Gases - Chlorine12.5.12Identifying Gases
Practice questions on Manufacture of Ethanol: Fermentation & Hydration
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