• Created by: Hindleyc
  • Created on: 19-05-18 17:13
What uses to alcohols have?
scientific, medicinal and industrial
1 of 56
What is ethanol?
An alcohol produced using different methods and can be used as a biofuel
2 of 56
General formula of alcohol?
3 of 56
Suffix of alcohol?
4 of 56
What is other fg needs suffix ending?
Use prefix hydroxy
5 of 56
Bond angles in H-C-H and C-C-O? Shape? BP? what do the bp do?
109.5. Tetrahedral. 4 bp. Repel to a position of minimum repulsion.
6 of 56
Bond angle in H-O-C? shape? BP and LP? what repels more? what do this do?
104.5. Bent line. 2bp and 2 lp. LP repel more than BP. Reduces bond angle
7 of 56
What is the first type of alcohol?
Primary. 1 carbon is attached to carbon adjoining the oxygen
8 of 56
What is the second type of alcohol?
Secondary. 2 Carbon attached to carbon adjoining the oxygen
9 of 56
3rd type of alcohol?
Tertiary. 3 carbon attached to carbon adjoining the oxygen
10 of 56
How are alcohols produced?
Hydration and fermentation
11 of 56
Alcohols industrially produced?
Hydration of alkenes in presence of acid catalyst
12 of 56
How does it work?
Reacted in water in presence of an acid catalyst
13 of 56
What is hydration?
Addition of water to a molecule
14 of 56
What are the conditions?
High temp- 660k. High pressure- 6000-7000kPa. Acid catalyst
15 of 56
What is the acid catalyst?
Concentrated H3PO4 in silica pellets
16 of 56
Why is It called a catalyst?
Gives H+ but produced at end so is a catalyst
17 of 56
Why in silica pellets?
Would mix if liquid and react with water
18 of 56
Advantages of hydration?
No waste products so high atom economy. Faster reaction. Purer product. Continuous process (cheaper man power)
19 of 56
Disadvantages of hydration?
High technology equipment needed- expensive initial cost. Ethene non-renewable resource (more £ when raw materials run out. High energy costs for pumping to produce high pressure
20 of 56
What is the reagent?
Ethene from cracking of fractions from distilled crude oil
21 of 56
Electrons from double bond in ethene go to H+ (from conc H3PO4) forming carbocation then lone pair electrons from water on O goes to +ve carbon bonding to it leaving O with +ve charge. E- from oh bond to oxygen making ethanol and H+
22 of 56
How else is ethanol produced industrially?
Fermentation of glucose
23 of 56
Glucose= Ethanol+ Carbon dioxide. C6H12O6=2C2H5OH+2CO2
24 of 56
Yeast. No air. Temp 30-40
25 of 56
Type of reaction? optimum temp?
Fermentation. 38
26 of 56
What happens at lower temps? what happens at higher temps?
Reaction too slow. Yeast dies and enzymes denatures
27 of 56
Why no air?
Presence of air can cause extra reactions to occur- oxidises ethanol= ethanoic acid
28 of 56
Sugar= renewable resource. Production uses low level technology/ cheap equipment
29 of 56
Batch process- slow and gives high production costs . Ethanol made not pure and needs purifying by fractional distillation- then used as biofuel. Depletes land used for growing food crops
30 of 56
What is a biofuel?
Fuel produced from plants
31 of 56
What is carob neutral?
Activity that has no net annual carbon (gg) emissions to the atmosphere
32 of 56
What is ethanol produced from fermentation?
A biofuel
33 of 56
Why is it argued that ethanol produced from this method is carbon neutral?
Any co2 given off when burnt would have been extracted from the air by photosynthesis when the plant grew therefore no net co2 emissions into atmosphere.
34 of 56
EQN for removal of co2 by p/s
6CO2+6H20= C6H12O6+6O2 Therefore 6 CO2 molecules removed
35 of 56
EQN for production of CO2 by fermentation and combustion
C6H12O6=2C2H5OH+2CO2 Therefore 2 molecules emitted. 2C2H5OH+6O2=4CO2+6H20 Therefore 4 molecules when combusted
36 of 56
6 molecules absorbed and 6 molecules released so no net contribution of co2 to atmosphere
37 of 56
What doesn't this take into account?
Energy needed to water plants, fractionally distill ethanol from mixture or process fuel and transport.
38 of 56
What does this mean?
If energy for this comes from fossil fuels then ethanol produced is not carbon neutral.
39 of 56
Relatively Low
40 of 56
High due to their ability to form H bonds between alcohol molecules
41 of 56
What is the reaction of alcohols with dehydrating agents?
Alcohol to alkene
42 of 56
What are the reagents?
Concentrated sulphuric or phosphoric acid
43 of 56
What are the conditions ?
Warm under reflux
44 of 56
Role of reagent?
Dehydrating agent/ catalyst
45 of 56
Type of reaction
Acid catalysed Elimination
46 of 56
What Is a dehydration reaction?
Removal of a H2O molecule from a molecule
47 of 56
Propan-1-ol goes to
48 of 56
What can some secondary and tertiary alcohols give?
More than 1 product when the double bond forms between different carbon atoms
49 of 56
EG what can butan-2-ol form
Both alkenes- but-2-ene and but-1-ene but more but-2-ene would be formed
50 of 56
What could but-2-ene also exist as
E-Z isomer
51 of 56
What does producing alkenes from alcohols provide a possible route to ?
Polymers without using monomer derived from oil (addition polymers)
52 of 56
Mechanism for acid catalysed elimination
arrow from Lone pair of electrons on O atom to H+
53 of 56
Where is the H+ from?
Concentrated H3PO4/H2SO4
54 of 56
What next?
Oxygen now has positive charge and electrons from C-O bond move to oxygen
55 of 56
The electrons from the C-H bond next to where the water molecule was lost move to the C-C bond forming an Alkene and H+
56 of 56

Other cards in this set

Card 2


What is ethanol?


An alcohol produced using different methods and can be used as a biofuel

Card 3


General formula of alcohol?


Preview of the front of card 3

Card 4


Suffix of alcohol?


Preview of the front of card 4

Card 5


What is other fg needs suffix ending?


Preview of the front of card 5
View more cards


No comments have yet been made

Similar Chemistry resources:

See all Chemistry resources »See all Enthalpy resources »