3.3.5 - Alcohols Flashcards
1
Q
Dehydration of alcohols products
A
Alcohol = alkene + water
2
Q
Dehydration reaction catalysts
A
Conc Sulfuric/Phosphoric acid
3
Q
Describe an elimination (dehydration) reaction
A
- Lone pair on oxygen attaches to H+
- Oxygen takes bond from C-O bond, forms carbocation
- Adjacent hydrogen leaves to carbon form double bond
- Products = alkene + water + H+
4
Q
Cyclohexene preparation step 1
A
- Add conc sulphuric acid and cyclohexanol to the round bottom flask + bumping granules
5
Q
Cyclohexene preparation steps 2-3
A
- Use heating mantle to wam reactants
- Chemicals with less than 83C boiling point evaporate and condense through the condenser
6
Q
Cyclohexene preparation steps 4-5
A
- Put products into separating funnel and add water
- 2 layers form, drain off the bottom layer (water + soluble impurities
7
Q
Cyclohexene preparation step 6
A
- Add cyclohexene + calcium chloride (drying agent) to round bottom flask, invert for 20-30 min
8
Q
Hydration reaction conditions (3)
A
- H2SO4 + steam
- 300 degrees
- 30 atm
9
Q
Hydration of alkenes to give alcohol reaction mechanism
A
- C=C attracts H+, breaks the double bond, forms carbocation
- +OH2 joins carbocation via lone pair
- OH2 loses H, forms alcohol + H+
10
Q
Fermentation equation (2)
A
Glucose = Ethanol + carbon dixide
C6H12O6 = 2 C2H5OH + 2 CO2
11
Q
What is fermentation used for?
A
Used to obtain pure ethanol, alternative to crude oil
12
Q
Optimum conditions for fermentation
A
- Anaerobic condtions
- Yeast catalyst
13
Q
Fermentation advantages (2)
A
- Cheap, little equipment needed
- Uses renewable resources
14
Q
Biofuel advantages (2)
A
- Renewable
- Carbon neutral (CO2 released is absorbed by sugar cane)
15
Q
Biofuel disadvantages (2)
A
- Expensive to convert engines
- Land usage = food shortages?
