1. Alcohols – nomenclature and reactions
L.O. To be able to name alcohols and assign primary, secondary and tertiary status.
To know some specific reactions of alcohols C OH H C OH C H OH

2. OH at junction of 2 chains
TYPES OF ALCOHOL
PRIMARY
ALCOHOLS
SECONDARY ALCOHOLS
TERTIARY ALCOHOLS    C H OH C OH H C OH
OH at end of a chain
OH at middle of a chain
OH at junction of 2 chains
CH3CH2CH2CH2OH
CH3CH2CH(OH)CH3
CH3C(CH3)(OH)CH3
Butan-1-ol
Butan-2-ol
Methyl propan-2-ol

3. SELECT PRIMARY (P), SECONDARY (S) OR TERTIARY (T)
ISOMERS OF PENTANOL
Make sure you can draw full displayed, structural and skeletal representations of each.
SELECT PRIMARY (P), SECONDARY (S) OR TERTIARY (T)
CH3CH2CH2CH2CH2OH Pentan-1-ol
CH3CH2CH2CH(OH)CH Pentan-2-ol
CH3CH2C(CH3)(OH)CH Methylbutan-2-ol
CH3CH2CH(OH)CH2CH Pentan-3-ol
CH3C(CH3)2CH2OH ,2-Dimethylpropan-1-ol
CH3CH(OH)CH(CH3)CH Methylbutan-2-ol
CH3CH(CH3)CH2CH2OH 3-Methylbutan-1-ol
CH3CH2CH(CH3)CH2OH Methylbutan-1-ol P S T P S T P S T P S T P S T P S T P S T P S T

4. Dehydration (removal of water) of alcohols ALKENES
Removal (elimination) of water by :
1.Heating with concentrated sulphuric acid at 170C
or 2. Passing vapour over Al2O3 at 350C C
Used to make ETHENE in countries where carbohydrate plentiful for fermentation but petroleum oil not avialable for cracking
+ HOH
NB H may be removed from more than one C adjacent to C-OH
 mixture of alkenes

5. 1. 2. 3. C OH H H C OH CH3 C OH H C H C CH3 H C CH2CH3 H + HOH C H CH3
Deduce the dehydration products of : 1. Ethanol?
2.  Methyl-propan-2-ol?
3.  Butan-2-ol ? 1. 2. 3. C OH H H C OH
CH3 C OH H C H C
CH3 H C
CH2CH3 H
+ HOH C H
CH3
+ HOH
+ HOH
E & Z!
and

6. C-OH + Na C-O- Na+ + ½ H2 HOH + Na Na+OH- + ½ H2
Reaction of an alcohol (R-OH) with sodium metal
 an alkoxide (R-O- Na+) + hydrogen gas (H2)
C-OH
+ Na
C-O- Na+
+ ½ H2
Notes :
1. The bonding is ionic between O and Na
2. The reaction is parallel (but slower) to the reaction of sodium with the OH group in water
HOH
+ Na
Na+OH-
+ ½ H2
Note : These are all redox reactions
because the Na is oxidised (electron loss)
and the H of OH is reduced (electron gain)

7. For isomeric alcohols:
PRIMARY
ALCOHOLS
SECONDARY ALCOHOLS
TERTIARY ALCOHOLS C H OH C OH H C OH
Rate decrease
For isomeric alcohols:
the rate of reaction with sodium decreases from primary to secondary to tertiary

8. 1. 2. 3. C OH H H C OH CH3 C OH H + Na + Na + Na C O- Na+ H H C O- Na+
Products of sodium with : 1. Ethanol?
2.  Methyl-propan-2-ol?
3.  Butan-2-ol ? 1. 2. 3. C OH H H C OH
CH3 C OH H
+ Na
+ Na
+ Na C
O- Na+ H H C
O- Na+
CH3 C
O-Na+ H
Sodium ethoxide
Sodium (methylprop-2-oxide)
Sodium but-2-oxide
+ ½H2
+ ½H2
+ ½H2

9. Try some more examples for yourself!
Write an equation, giving the full structure and name of the main organic product, for the reactions between :
1. Methanol + Na
2. Propan-1-ol + Na
3. Propan-2-ol + Na
4. Butan-1-ol + Na
5. Methyl-propan-1-ol + Na

10. C-OH + HBr C-Br + H2O Substitution of an alcohol by HBr
 a bromoalkane δ+ δ-
C-OH
+ HBr
C-Br
+ H2O
HBr produced by reacting KBr with conc. H2SO4.
KBr + H2SO4  KHSO4 + HBr
In practice, the alcohol is mixed with KBr in a reflux apparatus. The acid is then added to the mixture, drop wise.
Note : This is a nucleophilic substitution because the δ+C is attacked by the δ-Br

11. 1. 2. 3. C OH H H C OH CH3 C OH H + HBr + HBr + HBr C Br H H C Br CH3
HBr substitution products of :1. Ethanol?
2.  Methyl-propan-2-ol?
3.  Butan-2-ol ? 1. 2. 3. C OH H H C OH
CH3 C OH H
+ HBr
+ HBr
+ HBr C Br H H C Br
CH3 C Br H
Bromoethane
Methyl-2-bromopropane
2-Bromobutane
+ H2O
+ H2O
+ H2O

12. C-Cl (l) +HCl (g) + POCl3 (l) R-OH (l) + PCl5 (s)
Reaction of alcohols with phosphorus pentachloride (PCl5)
R-OH (l)
+ PCl5 (s)
C-Cl (l)
+HCl (g) + POCl3 (l)
Fumes of HCl being given off makes this a useful reaction to identify the presence of an alcohol functional group.

13. Try some more examples for yourself!
Give the full structure and name of the main organic product produced by :
1. Methanol + HBr
2. Propan-1-ol + HBr
3. Propan-2-ol + HCl
4. Butan-1-ol + HBr
5. Methyl-propan-1-ol + HCl

14. AS Chemistry
OXIDATION OF ALCOHOLS

15. OXIDATION OF ALCOHOLS Oxidised to aldehydes and acids or ketones
NOT SIGNIFICANT for TERTIARY alcohols!
for PRIMARY alcohols
for SECONDARY alcohols
-CH2OH
-C-CH(OH)-C-
NB Oxidant
= hot acidified Cr2O72-
[dichromate(VI)] ion]
Provided by mixture of potassium dichromate(VI), K2Cr2O7, and excess dilute sulphuric acid, H2SO4.
Oxidant is represented by :
[O]
OBSERVATION: Orange Cr2O72- reduced to green Cr3+

16. C H OH C H OH C OH    + [O] + [O] + [O] C O H C O + H2O + H2O
SECONDARY
PRIMARY
TERTIARY C H OH C H OH C OH   
+ [O]
+ [O]
+ [O] C O H C O
NO SIGNIFICANT OXIDATION
+ H2O
+ H2O
- no C–H bond
Aldehyde
Ketone
Any oxidation that does occur involves breaking C-C bonds  loss of original structure.
+ [O] 
+ [O]  C O OH
NO FURTHER OXIDATION
Acid
- no C – H bond

17. What are the oxidation products of :
1. Ethanol? 2.  Methyl-propan-2-ol? 3.Butan-2-ol?
CH3CH2OH
CH3C(CH3)(OH)CH3
CH3CH2CH(OH)CH3
Primary
Tertiary
Secondary

18. Controlling Oxidation Products
To Maximise the Production of an ALDEHYDE
To Maximise the Production of an ACID or a KETONE
This is PARTIAL oxidation
This is FURTHER oxidation
Use only molar proportions of dichromate and acid
Use excess of dichromate and acid
Use minimum contact time between alcohol and oxidant by use of immediate distillation
Use maximum contact time between alcohol and oxidant by use of reflux
Add acidified dichromate to the alcohol to avoid the presence of excess oxidant
Pre-mix acidified dichromate and alcohol to ensure excess oxidant at all times

19. 1 2 3 4 5 Halogeno- alkane C-Br Alcohol C-OH Primary amine C-NH2
Alkene(s)
C=C
Ketone
C-CO-C
(if alcohol
SECONDARY)
Aldehyde
CHO
PRIMARY)
Acid
COOH
Ester
CO.OC
1. Reflux with conc. NaOH in ethanol
3. Heat with excess conc. NH3 in ethanol
2. + HBr
3. Reflux with aq. NaOH
3. Heat with NaBr + conc. H2SO4 1 2 3 4 5
1. Heat with conc. H2SO4
Eliminations
Electrophilic addition
5. Heat with carboxylic acid (-COOH) + conc. H2SO4 cat.
Nucleophilic substitutions
Oxidations
4. Reflux with excess K2Cr2O7 + dil. H2SO4
5. Heat with alcohol (C-OH) + conc. H2SO4 catalyst
Condensations
4. Heat with molar propns. of K2Cr2O7 + dil. H2SO4 ; distil
4. Reflux with excess K2Cr2O7 + dil. H2SO4