Amines

Question 1

what are the two methods of producing aliphatic amines

Answer 1

• reduction of a nitrile
• nucleophilic substitution of a haloalkane

Question 2

what are the reactants in the production of an aliphatic amine via nucleophilic substitution of a haloalkane

Answer 2

• bromoethane ( haloalkane) and excess ammonia

Question 3

what are the disadvanatages of using a haloalkane to form an aliphatic amine

Answer 3

• a low yield of desired amine as its likely to react further
• large excess of ammonia is required

Question 4

describe how the reactants of the nucleophilic substitution of a haloalkane with ammonia can affect the products

Answer 4

• large excess of haloalkane leads to high yield of quarternary ammonium salt
• large excess of ammonia leads to be a better yield of primary amine

Question 5

what is the use of quaternary ammonium salts

Answer 5

• fabric softeners and hair conditioner

Question 6

what are the reactants in the reduction of a nitrile to form an aliphatic amine

Answer 6

• hydrogen gas and nickel catalyst

Question 7

what is an advantage of forming an amine via reduction of a nitrile

Answer 7

• produces a high yield of desired amine as the product doesn’t undergo further substitution

Question 8

what is the general equation for the reduction of a nitrile

Answer 8

• RCN + 2H₂ → RCH₂NH₂

Question 9

describe how to make an aromatic amine and the reactants needed

Answer 9

• reduction of nitrobenzene
• HCL and tin catalyst

Question 10

what is the equation for the formation of an aromatic amine

Answer 10

• C₆H₅NO₂ + 6[H] → C₆H₅NH₂ + 2H₂O

Question 11

what is an aromatic amine

Answer 11

• an amine which contains a benzene ring
• also called an arene

Question 12

what is the trend in strength of amines as a base and why

Answer 12

• strength of amines as bases increases upon the availability of the lone pair due to the increasing positive inducing effect
• The R groups (alkyl groups) push the electrons towards the N atom making the lone pair more available

Question 13

why are aromatic amines generally weaker bases

Answer 13

• lone pair on N overlaps with delocalised ring making the lone pair on the N less available

Question 14

why are aliphatic amines generally stronger bases

Answer 14

• the R group pushes electrons towards the N atom making the lone pair on N more available