Chemistry of Group 13 and Group 14 Elements

• Use of lithium aluminium hydride as reducing agent.

Slide 1

• Introduction to Group 13 elements
• General properties of Group 13 elements
• Electronic configuration: ns²np¹

Slide 2

• Specific properties of Boron
• Atomic number: 5
• Melting point: 2076 °C
• Boiling point: 4000 °C

Slide 3

• Specific properties of Aluminum
• Atomic number: 13
• Melting point: 660 °C
• Boiling point: 2519 °C

Slide 4

• Specific properties of Gallium
• Atomic number: 31
• Melting point: 29.76 °C
• Boiling point: 2204 °C

Slide 5

• Specific properties of Indium
• Atomic number: 49
• Melting point: 156.6 °C
• Boiling point: 2000 °C

Slide 6

• Specific properties of Thallium
• Atomic number: 81
• Melting point: 304 °C
• Boiling point: 1457 °C

Slide 7

• Applications of Group 13 elements
• Aluminum: construction, packaging, transportation
• Gallium: semiconductors, LEDs, solar cells
• Indium: touchscreens, transistors, solar panels

Slide 8

• Introduction to Group 14 elements
• General properties of Group 14 elements
• Electronic configuration: ns²np²

Slide 9

• Specific properties of Carbon
• Atomic number: 6
• Melting point: 3500 °C
• Boiling point: 4827 °C

Slide 10

• Specific properties of Silicon
• Atomic number: 14
• Melting point: 1414 °C
• Boiling point: 3265 °C

Slide 11

Chemistry of Group 13 and Group 14 Elements

• Lithium aluminium hydride (LiAlH4) as a reducing agent
• Structure and properties of LiAlH4
  • White crystalline powder
  • Ionic compound containing AlH4⁻ ions
  • Reacts violently with water
• Reduction reactions using LiAlH4
  • Reduces aldehydes and ketones to alcohols
  • Reduces carboxylic acids to alcohols
  • Reduces esters to alcohols
  • Reduces amides to amines
  • Reduces nitriles to primary amines

Slide 12

Mechanism of Reduction Reactions using LiAlH4

1. Nucleophilic attack
   • AlH4⁻ acts as a nucleophile and attacks the electrophilic carbon of the carbonyl group
   • Forms an intermediate complex

2. Hydride transfer
   • Hydride ion (H⁻) is transferred to the carbonyl carbon
   • Forms an oxygen-metal bond and breaks the carbon-oxygen double bond

Slide 13

Reduction of Aldehydes and Ketones

• Aldehydes are converted to primary alcohols
• Ketones are converted to secondary alcohols
• Example:
  • CH3C(=O)CH3 + LiAlH4 → CH3CH(OH)CH3

Slide 14

Reduction of Carboxylic Acids

• Carboxylic acids are converted to primary alcohols
• Example:
  • CH3COOH + LiAlH4 → CH3CH2OH

Slide 15

Reduction of Esters

• Esters are converted to primary alcohols
• Example:
  • CH3COOC2H5 + LiAlH4 → CH3CH2OH

Slide 16

Reduction of Amides

• Amides are converted to amines
• Example:
  • CH3CONH2 + LiAlH4 → CH3CH2NH2

Slide 17

Reduction of Nitriles

• Nitriles are converted to primary amines
• Example:
  • CH3CN + LiAlH4 → CH3CH2NH2

Slide 18

Precautions while using LiAlH4

• Handle with care: reacts violently with water
• Use in dry conditions and under inert atmosphere
• Protect from moisture and air
• Store in a cool, dry place

Slide 19

Application of LiAlH4

• Used in organic synthesis for reduction reactions
• Widely used in the pharmaceutical industry
• Example: converting a carbonyl group to a hydroxyl group in a drug synthesis

Slide 20

Summary

• Lithium aluminium hydride (LiAlH4) is a powerful reducing agent.
• It can reduce aldehydes, ketones, carboxylic acids, esters, amides, and nitriles to their corresponding reduced forms.
• LiAlH4 reacts via a nucleophilic attack and hydride transfer mechanism.
• Precautions should be taken while handling LiAlH4 due to its reactivity with water.
• LiAlH4 finds widespread use in organic synthesis and the pharmaceutical industry.

Slide 21:

• Reaction with aldehydes: RCHO + LiAlH4 → RCH2OH
  • Example: HCHO + LiAlH4 → CH2OH
• Reaction with ketones: R2CO + LiAlH4 → R2CH2OH
  • Example: CH3COCH3 + LiAlH4 → CH3CH(OH)CH3

Slide 22:

• Reaction with carboxylic acids: RCOOH + LiAlH4 → RCH2OH
  • Example: CH3COOH + LiAlH4 → CH3CH2OH
• Reaction with esters: RCOOR’ + LiAlH4 → RCH2OH
  • Example: CH3COOC2H5 + LiAlH4 → CH3CH2OH

Slide 23:

• Reaction with amides: RCONH2 + LiAlH4 → RCH2NH2
  • Example: CH3CONH2 + LiAlH4 → CH3CH2NH2
• Reaction with nitriles: RCN + LiAlH4 → RCH2NH2
  • Example: CH3CN + LiAlH4 → CH3CH2NH2

Slide 24:

• Reducing agents compared to LiAlH4
  • Sodium borohydride (NaBH4)
  • Diisobutylaluminum hydride (DIBAL-H)
  • Reducing agents used for milder reductions than LiAlH4

Slide 25:

• Limitations of LiAlH4
  • Reacts violently with water and other protic solvents
  • Not compatible with reactive functional groups like halides and nitro compounds
  • Difficult to control selectivity in complex molecules

Slide 26:

• Mechanism of LiAlH4 reaction with water
  • Formation of AlO(OH) and H2 gas
  • Violent release of hydrogen gas

Slide 27:

• Precautions while using LiAlH4
  • Wear protective clothing and gloves
  • Work under fume hood
  • Use in dry conditions and under inert atmosphere
  • Keep away from heat, sparks, and open flames

Slide 28:

• Handling and storage of LiAlH4
  • Store in a cool, dry place away from moisture and air
  • Use in well-ventilated areas
  • Keep containers tightly closed
  • Dispose of waste properly

Slide 29:

• Summary of LiAlH4 as a reducing agent
  • Lithium aluminium hydride (LiAlH4) is a powerful reducing agent used in organic synthesis.
  • It can reduce aldehydes, ketones, carboxylic acids, esters, amides, and nitriles to their corresponding reduced forms.
  • The reaction proceeds via a nucleophilic attack and hydride transfer mechanism.
  • Precautions should be taken while handling LiAlH4 due to its reactivity with water.
  • LiAlH4 finds widespread use in organic synthesis and the pharmaceutical industry.

Slide 30:

• Q&A session
  • Allow students to ask questions related to the topic
  • Answer their queries and provide clarification on any doubts they may have.