Slide 2: Nitrogen-Containing Organic Compounds

• Definition: Organic compounds containing nitrogen atoms
• Types of nitrogen-containing organic compounds:
  • Amines
  • Amides
  • Nitriles
  • Nitro compounds
  • Diazonium salts

Slide 3: Aryl Diazonium Salts

• Definition: Organic compound with a diazonium group (N2+) attached to an aromatic ring
• General structure: Ar-N2+
• Examples:
  • Phenyl diazonium chloride (C6H5N2Cl)
  • Benzenediazonium tetrafluoroborate (C6H5N2BF4)

Slide 4: Preparation of Aryl Diazonium Salts

• Preparation: Diazotization process
• Steps:
  1. Preparation of primary aromatic amine
  2. Diazotization using sodium nitrite (NaNO2) and hydrochloric acid (HCl)
  3. Formation of aryl diazonium salt

Slide 5: Replacement Reactions of Aryl Diazonium Salts

• Definition: Reactions in which the diazonium group is replaced by another functional group
• Importance: Allows the introduction of various functional groups onto aromatic compounds

Slide 6: Types of Replacement Reactions

• Sandmeyer reaction:

  • Conversion of diazonium salt to halide compound
  • Example: Conversion of aryl diazonium salt to aryl halide

• Coupling reaction:

  • Formation of azo compounds by coupling with aromatic compounds
  • Example: Formation of azobenzene from aryl diazonium salt and phenol

• Diazotization:

  • Formation of new diazonium salts from primary aromatic amines
  • Example: Diazotization of aniline to form aryl diazonium salt

Slide 7: Sandmeyer Reaction

• Conversion of diazonium salt to halide compound
• Mechanism:
  1. Replacement of diazonium group by copper(I) ion
  2. Reaction with halide ion to form aryl halide
• Example equation: Ar-N2+ + CuX → Ar-X + N2 + CuX+

Slide 8: Coupling Reaction

• Formation of azo compounds by coupling with aromatic compounds
• Mechanism:
  1. Attack of diazonium ion on aromatic compound
  2. Formation of azo compound
• Example equation: Ar-N2+ + Ar’OH → Ar-N=N-Ar’ + H2O

Slide 9: Diazotization

• Formation of new diazonium salts from primary aromatic amines
• Mechanism:
  1. Conversion of primary amine to diazonium salt
  2. Formation of diazonium salt
• Example equation: Ar-NH2 + NaNO2 + HCl → Ar-N2+ + NaCl + H2O

Slide 10: Summary

• Nitrogen-containing organic compounds play important roles in various chemical reactions.
• Aryl diazonium salts are versatile compounds that can undergo replacement reactions.
• Various types of replacement reactions include the Sandmeyer reaction, coupling reaction, and diazotization.
• These reactions allow the introduction of different functional groups onto aromatic compounds.

11. Sandmeyer Reaction (continued)

• Reaction conditions:
  • Copper(I) ion is needed as a catalyst
  • Reaction is usually performed in the presence of a halide ion source (e.g., CuX, KX)
• Examples:
  • Conversion of phenyl diazonium salt to chlorobenzene: Ar-N2+ + CuCl → Ar-Cl + N2 + CuCl+
  • Conversion of aryldiazonium salt to bromobenzene: Ar-N2+ + CuBr → Ar-Br + N2 + CuBr+

12. Coupling Reaction (continued)

• Reaction conditions:
  • Coupling agents (e.g., phenols, anilines, naphthols) are used as reactants
  • Acidic conditions help in the formation of azo compounds
• Examples:
  • Formation of azobenzene by coupling phenol with phenyl diazonium salt: Ar-N2+ + Ar’OH → Ar-N=N-Ar’ + H2O
  • Formation of Sudan I dye by coupling aniline with diazonium salt derived from naphthol: Ar-N2+ + Ar’NH2 → Ar-N=N-Ar’ + N2 + H2O

13. Diazotization (continued)

• Reaction conditions:
  • Sodium nitrite (NaNO2) and hydrochloric acid (HCl) are used as diazotization reagents
  • Low temperatures (around 0-5°C) are required
• Example:
  • Diazotization of aniline to form benzenediazonium chloride: Ar-NH2 + NaNO2 + HCl → Ar-N2+ + NaCl + H2O

14. Applications of Aryl Diazonium Salts

• Used in the manufacturing of dyes and pigments:
  • Diazonium salts act as intermediates for producing various colorants
• Used in organic synthesis:
  • Diazonium salts can be used to introduce new functional groups onto aromatic compounds
• Used in pharmaceuticals:
  • Some diazonium salts exhibit antimicrobial and antitumor properties

15. Safety Considerations

• Aryl diazonium salts are highly reactive and potentially explosive.
• Proper safety precautions must be taken when working with these compounds:
  • Use appropriate protective equipment (gloves, goggles, lab coat).
  • Perform reactions in a well-ventilated area or under a fume hood.
  • Handle diazonium salts with care and avoid shock or friction.
  • Dispose of waste according to appropriate regulations and protocols.

16. Summary

• Aryl diazonium salts are versatile compounds that can undergo various replacement reactions.
• Sandmeyer reaction converts diazonium salts to aryl halides.
• Coupling reactions form azo compounds by coupling diazonium salts with aromatic compounds.
• Diazotization converts primary aromatic amines to diazonium salts.
• Aryl diazonium salts find applications in dyes, organic synthesis, and pharmaceuticals.
• Safety precautions should be followed when working with aryl diazonium salts.

17. References

• Organic Chemistry by Paula Y. Bruice
• Inorganic Chemistry by Gary L. Miessler and Paul J. Fischer
• Advanced Organic Chemistry by Jerry March

18. Acknowledgements

• The content of this presentation is based on curriculum guidelines and various reputable chemistry resources.
• Special thanks to the educational institutions and authors who have contributed to the knowledge in this field.

19. Questions

• What are the main types of replacement reactions of aryl diazonium salts?
• What is the significance of the Sandmeyer reaction?
• How does diazotization contribute to the synthesis of aryl diazonium salts?
• Can you provide an example of a coupling reaction involving an aryl diazonium salt?
• What safety precautions should be taken when working with aryl diazonium salts?

20. Quiz

• Identify the different types of nitrogen-containing organic compounds.
• True or False: Aryl diazonium salts are highly stable compounds.
• What is the purpose of coupling reactions involving aryl diazonium salts?
• What reagents are needed for diazotization?
• Which reaction converts diazonium salts to aryl halides?

Slide 21:

• Example of Sandmeyer reaction:
  • Conversion of phenyl diazonium salt to chlorobenzene:
    • Ar-N2+ + CuCl → Ar-Cl + N2 + CuCl+

Slide 22:

• Example of coupling reaction:
  • Formation of azobenzene by coupling phenol with phenyl diazonium salt:
    • Ar-N2+ + Ar’OH → Ar-N=N-Ar’ + H2O

Slide 23:

• Example of diazotization:
  • Diazotization of aniline to form benzenediazonium chloride:
    • Ar-NH2 + NaNO2 + HCl → Ar-N2+ + NaCl + H2O

Slide 24:

• Applications of aryl diazonium salts:
  • Manufacturing of dyes and pigments:
    • Diazonium salts act as intermediates for producing various colorants
  • Organic synthesis:
    • Diazonium salts can be used to introduce new functional groups onto aromatic compounds
  • Pharmaceuticals:
    • Some diazonium salts exhibit antimicrobial and antitumor properties

Slide 25:

• Safety considerations when working with aryl diazonium salts:
  • Highly reactive and potentially explosive
  • Use appropriate protective equipment (gloves, goggles, lab coat)
  • Perform reactions in a well-ventilated area or under a fume hood
  • Handle with care and avoid shock or friction
  • Dispose of waste according to appropriate regulations and protocols

Slide 26:

• Summary of the main points covered:
  • Aryl diazonium salts undergo replacement reactions
  • Sandmeyer reaction converts diazonium salts to aryl halides
  • Coupling reactions form azo compounds by coupling with aromatic compounds
  • Diazotization converts primary aromatic amines to diazonium salts
  • Applications of aryl diazonium salts in dyes, organic synthesis, and pharmaceuticals
  • Safety precautions must be followed when working with these compounds

Slide 27:

• References:
  • Advanced Organic Chemistry by Jerry March
  • Organic Chemistry by Paula Y. Bruice
  • Inorganic Chemistry by Gary L. Miessler and Paul J. Fischer

Slide 28:

• Acknowledgements:
  • The content of this presentation is based on curriculum guidelines and various reputable chemistry resources.
  • Special thanks to the educational institutions and authors who have contributed to the knowledge in this field.

Slide 29:

• Questions for review:
  • What are the main types of replacement reactions of aryl diazonium salts?
  • Can you provide an example of a coupling reaction involving an aryl diazonium salt?
  • How does diazotization contribute to the synthesis of aryl diazonium salts?
  • What are the applications of aryl diazonium salts?
  • What safety precautions should be taken when working with aryl diazonium salts?

Slide 30:

• Quiz:
  • Identify the different types of nitrogen-containing organic compounds.
  • True or False: Aryl diazonium salts are highly stable compounds.
  • What is the purpose of coupling reactions involving aryl diazonium salts?
  • What reagents are needed for diazotization?
  • Which reaction converts diazonium salts to aryl halides?