Amines

Question 1

What are amines?

Answer 1

• Amines are organic compounds derived from NH3 where on or more of the hydrogen atoms in ammonia has been replaced by a carbon ring or chain

Question 2

What is an aliphatic amine?

Answer 2

• the nitrogen atoms are attached to at least one straight or unbranched chains

Question 3

What is an aromatic amine?

Answer 3

• The nitrogen atom is attached to an aromatic ring

Question 4

How do you classify amines?

Answer 4

primary amine = attached to one carbon
secondary amine = attached to two carbons
tertiary amine = attached to three carbons

Question 5

How do you name primary amines?

Answer 5

• when the NH2 is at the end of the chain you addthe suffix amine and the prefix is the alkyl group
• for example methylamine
• if the amine is on another carbon then you use the prefix (x - amino)
• for example 2 aminobutane

Question 6

How do you name a secondary or tertiary amine?
kinda weird

Answer 6

• you use di or tri to indicate its position, for example dimethyl amine
• if there are multiple you use Number- alkylchain,amine

Question 7

Why can amines react

Answer 7

• Amines behave as bases as they have a lone pair of electrons on the nitrogen which can accept a proton
• when the amine accepts a proton, a dative covalent bond is formed between the lone pair of electrons on the nitrogen atom and the proton

Question 8

What forms when an amine reacts with an acid?

Answer 8

• the amine acts as a base and neutralises the acid, forming a salt

Question 9

Show the reaction between propylamine and hydrochloric acid

Question 10

What are the steps of preparing an aliphatic amine?

Answer 10

1. formation of salt
2. Amine formation

Question 11

How do you form a salt (aliphatic amine prep)?

Answer 11

• ammonia has a lone pair of electrons and can therefore act as a nucleophile, donating a pair of electrons in a substitution reaction with a haloalkane
• This forms a salt

Question 12

What is the reaction between 1 - chloropropane and ammonia?

Answer 12

• it forms propylammononium chloride

Question 13

How do you form an amine from a salt (aliphatic prep)

Answer 13

• You react the ammonium salt with sodium hydroxide, forming an amine, Nacl and H20

Question 14

What is the reaction between propylammonium chloride and sodium hydroxide?

Answer 14

• propylamine, Nacl and water

Question 15

What are the essential conditions to form an aliphatic amine?

Answer 15

• ethanol as a solvent to prevent further substitution of the haloalkane by water to produce alcohols
• excess ammonia to prevent further substitution of the amine group to form a secondary and tertiary amine

Question 16

How do you form a secondary amine and tertiary amine?

Answer 16

• primary amines still contain a lone pair of electrons on the nitrogen atom can further react with a haloalkane to form an ammonium salt
• the ammonium salt can then be reacted with NaOH which forms a secondary amine
• tertiary amines can be formed from further reacting a secondary amine

Question 17

How do you form an aromatic amine?

Answer 17

• phenylamine can be formed by reducing nitrobenzene
• nitrobenzene can be heated under reflux with tin and HCL to form an ammonium salt
• the ammonium salt can then be reacted with excess NaOH, producing an aromatic amine

Question 18

Draw the reduction of nitrobenzene.

Answer 18

• conc HCL/sn
• excess NAoh
• produces water
• 6(H)