Amines and Amides

Back to: CHEMISTRY SS3

 

Welcome to class! 

In today’s class, we will be talking about amines and amides. Enjoy the class!

Amines and Amides

Amines

It has a functional group of NH₂.

Preparation

They are derivatives of ammonia where one or more hydrogen atoms have been replaced by alkyl or aryl groups e.g. RNH_z, R₂NH.

Classification

Amines can be classified according to an alkyl group.

• Primary amine with one alkyl group e.g. RNH₂ or

• Secondary amine with 2 alkyl groups e.g. R₂NH or

• Tertiary amine with 3 alkyl groups e.g. R₃N or

         

Physical properties

1. They can dissolve in water.
2. They are gases and liquid.
3. They have a fishy odour.

Chemical properties

1. As bases, they neutralize acids.
2. They dissociate/ionize in water e.g. CH₃NH₂ + H₂O CH₃NH₃⁺+ OH^–

Uses

1. Used in making nylon
2. They can also be used in making polyamide.

Evaluation

1. State two (2) physical properties and two (2) chemical properties of amine.
2. Give the classes of amine according to the number of their alkyl groups.

Amides

It has a functional group of –C     which is known as the carbonamide group.

NH₂

Structure

Preparation

• Amide e.g. ethanmide can be derived from ethanoic acid in the presence of ammonia.
• Amide is commonly prepared by reacting esters with concentrated aqueous ammonia.

E.g. CH₃COOC₂H₅  + NH₃         →            Ethanamide CH₃CONH₂ + C₂H₅OH

• They can also be prepared by removing a molecule of water from ammonium salt of carboxylic x acids.

e.g. CH₃COONH₄       →       CH₃CONH₂ + H₂O

Physical properties

1. The only methanamide is a liquid while others are solid.
2. They have a high melting point and high boiling point.

Chemical properties

1. Amide can be hydrolysed in the presence of alkali and mineral acid e.g.

CH₃CONH₂  +  H₂O       →             CH₃COOH + NH₃

2. In the presence of sodium hydroxide and bromine, amides produce amines with the elimination of one carbonyl group.

e.g. CH₃CONH₂  +  Br₂ + 4NaOH        →            CH₃NH₂ + 2NaBr + Na₂CO₃ + 2H₂O

Uses

1. Used in the preparation of amines.
2. Used in making synthetic resins and plastics.
3. It can also be used in making fertilizer.

Carbamide/urea

This is an amide of hydrogen trioxo carbonate (IV) acid.  It is produced by compressing CO₂ and NH₃ at high pressure at 200⁰C.

N.B.: Urea is produced in our body and excreted in the urine.

General evaluation

1. Write the structural formula of amide.
2. Give one different between amine and amide.

Reading assignment

New School Chemistry by O.Y. Ababio pages 520-521

Weekend assignment

1. The tertiary amine is represented as follow A. R₂NH₂ B.  (CH₃)₂NH   C.R₂NH₃    D.  R₂N
2. Which of the following has fishy odour A. alkanoic acid B.  alkanol    C.  amide     D.  amine
3. Amide can be regarded as derivatives of ………… A. alkanol B.  polycarboxylic acid   C.  monocarboxylic acid  D.  carboxamide group

4.During the hydrolysis of amides, one of the following is produced. A. monocarboxylic acids B.  water    C.  H₂SO₄    D. NaOH

1. Carbamide is an example of A. amine    B.  alkane       C.  alkyl    D.  amide

Theory

1(a).   State two (2) physical properties of amide.

(b).   How would you prepare ethanamide from an ester?

2(a).   State two (2) chemical properties of amide.

(b).   How would you identify an example of amine in the laboratory?

 

We hope you enjoyed the class.

Should you have any further question, feel free to ask in the comment section below and trust us to respond as soon as possible.

Ready to make school management and growth easy? Book your free onboarding session now

Get more class notes, videos, homework help, exam practice on Android [DOWNLOAD]

Get more class notes, videos, homework help, exam practice on iPhone [DOWNLOAD]