18b - Amines, Amides Amino Acids

Question 1

How do you make a Primary Amine from a NITRILE?

Answer 1

• Reduce with LiAlH4 (dry ether) with dilute acid

- Platinum catalyst with HIGH temperature and pressure

Question 2

How do you make a Primary Amine from a Halogenoalkane?

Answer 2

• XS NH3 (ethanolic)

Question 3

Reaction of primary aliphatic amine with water

Answer 3

• OH- is formed and an alkaline solution aswell

Question 4

Basicities of amines

Answer 4

• More basic as the carbon chain is extended as more electrons available for the Nitrogen
• Phenylamines are acidic (pH=4.2) because of the ring structure Nitrogen has less electrons
• Depends on how many electrons the Nitrogen has access to

Question 5

How do amines react with acids?

Answer 5

• Form salts
  CH3CH2CH2CH2NH2 + HCl -> (CH3CH2CH2CH2NH3)+ + (Cl)-
• The salts are ionically attracted to each other

Question 6

Amine reaction with Acyl Chlorides

Answer 6

• Forms an amide
• N - R(group attached) (group attached)
• Butylamine + ethanoylchloride -> N- butylethanamide

Question 7

Amine reaction with Halogenoalkanes

Answer 7

Example : butylamine + chloroethane -> forms a secondary amine

• This product can react again as the Nitrogen atom is electron-rich
• Finishes when it becomes a tertiary amine
• Tertiary amine can react again to form a quaternary ammonium salt

Question 8

Amine reaction with Copper (II) (hexaaquacopper (II))

Answer 8

• Formation of a pale blue precipitate
  [Cu(H2O)6]2+ + 2CH3CH2CH2NH2 -> [Cu(H2O)6(OH)2] + 2CH3CH2CH2CH2NH3+
• Formation of a deep blue solution with XS amine

[Cu(H2O)6(OH)2] + 4CH3CH2CH2CH2NH2 -> [Cu(CH3CH2CH2CH2NH2)4(H2O)2]2+ + 2H2O + 2OH-

Question 9

How do you form a phenylamine?

Answer 9

• Reduce nitrobenzene
• Tin
• conc HCl
• Reflux
• then add NaOH

Question 10

What type of reaction forms polyamides and polymers?

Answer 10

• Condensation reaction

Question 11

What is an isoelectric point?

Answer 11

• pH at which zwitterions exist in an aqueous solution
• Low isoelectric point means the amino acid is more acidic
• pH Depends on the amount of COOH groups or NH2 groups

Question 12

How can we break peptide bonds?

Answer 12

• Hydrolysis with conc HCl(aq)

- Forms amino acids with the NH2 group protonated (NH3+)

Question 13

How do you separate and identify amino acids?

Answer 13

• Chromatography (TLC if possible)
• Spray with ninhydrin
• Use a variety of amino acids and compare their Rf values to known amino acids