Ethanol production

Question 1

Why are alchols important in industry?

Answer 1

They are used as reactive intermediates

Question 2

What are the 2 ways of producing ethanol from ethene?

Answer 2

1. Hydration with steam
2. Fermentation

Question 3

What type of catalyst is used in the hydration of ethene?

Answer 3

Phosphoric acid

Question 4

How is ethanol produced from the hydration of ethene?

Answer 4

The addition of water breaks the double bond between cabon atoms

Question 5

What is the equation for the hydration of ethene?

Answer 5

C₂H₄ + H₂O —–> C₂H₅OH

Question 6

What is the bond angle between C-O-H in an alcohol?

Why is this not 109.5°

Answer 6

104.5°

2 lone pairs of electrons

Question 7

What is a primary alcohol?

Answer 7

An alcohol where the carbon attatched to the -OH group is joined to 1 other carbon

Question 8

What is a secondary alcohol?

Answer 8

An alcohol where the carbon attached to the OH group his joined to 2 other carbons

Question 9

Why do alcohols have higher bpts than alkanes of a similar Mr?

Answer 9

-OH group means that hydrogen bonding occurs which is stronger than the vdW forces between alkane molecules

Question 10

Are short chain alchols water soluble?

Answer 10

yes

Question 11

Are long chain alcoholsl soluble in water?

Answer 11

No

Question 12

Why are only some alcohols soluble in water?

Answer 12

Short chain alcohols are soluble because the -OH group ca hydrogn bond to water molecules

Long chain alcohols are not because the longer hydrocarbon chain dominates the hydroxyl group and the non-polar hydocarbon chain cannot form hydrogen bonds with water

Question 13

How is ethanol produced by the fermentation of ethene?

Answer 13

1. Carbohyrdrates from plants are broken down into sugars
2. Enzymes from yeast break down sugar into ethanol and carbon dioxide

Question 14

What is the equation for the fermentation of ethene?

Answer 14

C₆H₁₂O₆(aq) ——> 2C₂H₅OH(aq) + 2CO₂(g)

Question 15

Why is air kept out of thrh fermentation vessels during the production of ethanol?

Answer 15

To prevent the oxidation of ethanol to ethanoic acid

Question 16

Why does fermentation produce impure ethanol?

Answer 16

Once the fermenting solution contains about 15% ethanol the enzymes are unable to function and fermentation stops

Question 17

What process is used to purify ethanol after fermentation?

Why is this process effective?

Answer 17

Fractional distillation

Bpt of ethanol (78°C) < bpt of water (100°C)

Question 18

What type of process is fermentation?

Answer 18

Batch

Question 19

What type of process is the hydration of ethene?

Answer 19

Continuous