16.1 Synthetic Routes

Question 1

Alkene -> Haloalkane

Answer 1

Hydrogen halide at RTP (halogenation)

Question 2

Alcohol -> Haloalkane

Answer 2

Substitution reaction
Heated under reflux
Sodium halide + H2SO4

(Hydrogen halide formed in situ, which reacts with alcohol to form haloalkane)

Question 3

Alkane -> Haloalkane

Answer 3

Radical substitution
Halogen + UV

Question 4

Alkene -> Alkane

Answer 4

H2, in the presence of Ni catalyst at 423K
Hydrogenation reaction

Question 5

Haloalkane -> Alcohol

Answer 5

NaOH (Aq), heat under reflux
Hydrolysis (nucleophilic substitution)

Question 6

Alcohol -> Alkene

Answer 6

Heated under reflux
Concentrated H3PO4
Dehydration elimination reaction

Question 7

Alkene -> Alcohol

Answer 7

H2O (g) + H3PO4 / Phosphoric (V) acid Catalyst
300 degrees C, 60-70 atm
Hydration reaction

Question 8

Primary alcohol -> Carboxylic acid

Answer 8

K2Cr2O7/H2SO4 + heat under reflux
Colour change orange -> green

Question 9

Primary alcohol -> Aldehyde

Answer 9

K2Cr2O7/H2SO4 + heat gently, distil immediately
Colour change orange -> green

Question 10

Secondary alcohol -> Ketone

Answer 10

K2Cr2O7/H2SO4 + Heat under reflux
Colour change orange -> green

Question 11

Aldehyde -> Primary alcohol

Answer 11

Warmed in an aqueous solution with a reducing agent, e.g. Sodium tetrahybridoborate
NaBH4/H2O

Question 12

Ketone -> Secondary alcohol

Answer 12

Warmed in an aqueous solution with a reducing agent, e.g. Sodium tetrahybridoborate
NaBH4/H2O

Question 13

Aldehyde -> Hydroxynitrile

Answer 13

Sodium cyanide + sulfuric acid (H2SO4/NaCN)
Forms HCN, then CN- nucleophile in situ

Question 14

Ketone -> Hydroxynitrile

Answer 14

Sodium cyanide + sulfuric acid (H2SO4/NaCN)
Forms HCN, then CN- nucleophile in situ

Question 15

Acyl chloride -> Ester

Answer 15

Nucleophilic acyl substitution
Heat with alcohol or phenol under reflux

Question 16

Acyl chloride -> carboxylic acid

Answer 16

Nucleophilic acyl substitution
Heat with water under reflux

Question 17

Acyl chloride -> amide

Answer 17

Nucleophilic acyl substitution
Heat with ammonia or amine under reflux, depending on target molecule.

Question 18

Acid anhydride -> Ester

Answer 18

Nucleophilic acyl substitution
Heat with alcohol/phenol under reflux.

Question 19

Acid anhydride -> Carboxylic acid

Answer 19

Nucleophilic acyl substitution
Heat with water under reflux.

Question 20

Acid anhydride -> amide

Answer 20

Nucleophilic acyl substitution
Heat with ammonia/amine under reflux.

Question 21

Ester -> carboxylic acid

Answer 21

Acid hydrolysis
Nucleophilic acyl substitution
Reflux with dilute aqueous acid

Question 22

Ester -> carboxylate salt

Answer 22

Saponification/alkaline hydrolysis
Heat with NaOH under reflux

Question 23

Primary Haloalkane -> Primary amine

Answer 23

Reagents: Excess ammonia, ethanol solvent, NaOH
Step 1: Primary haloalkane + ammonia -> alkylammonium salt
Step 2: Alkylammonium salt + NaOH -> primary amine + water + sodium halide

Question 24

Haloalkane -> Nitrile

Answer 24

Nucleophilic substitution
NaCN/KCN in ethanol solvent
Optionally heat under reflux to increase rate

Question 25

Nitrile -> Amine

Answer 25

React with 2 H2 (per nitrile group) in the presence of a nickel catalyst High temperature and pressure

Question 26

Nitrile -> carboxylic acid

Answer 26

Hydrolysis reaction Heat with dilute aqueous acid, e.g. HCl (aq)

Question 27

Amino acid -> Ester

Answer 27

React with alcohol and strong acid catalyst (Usually H2SO4)