12. 1
General rxn- exercise
1. Predict the right product of below reaction
SN r e a c t i o n
2. Discuss reactions of n-butyl bromide with CH3CH2O-Na+
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13. SN r e a c t i o n
1
Kinetics
Experiment_1
- Rxn of methyl bromide with NaOH in aq. ethanol solvent.
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14. SN r e a c t i o n
1
Kinetics
Experiment_2
- Rxn of tert-butyl bromide with NaOH in aq. ethanol solvent.
Observation
Conclusion
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15. SN r e a c t i o n
1
Order of reactivity of RX
Experiments
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16. SN r e a c t i o n
1
Order of reactivity of RX
- Relation btwn RX and mechanisms
Order of
react iv ity
of RX is…
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18. SN r e a c t i o n
1
SN2 : mechanism
Collision btwn substrates Nu. attacks from back side.
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19. SN r e a c t i o n
1
SN2 : Stereochemistry
- Nu. attacks from back side
“back-side displacement,”
- E.g.
SN2
2018
complete inversion of configuration
20. SN r e a c t i o n
2
SN2 : Stereochemistry
Explaining mechanism with ball-stick model
(+) isomer of
reactant
(-) isomer of
product
back-side displacement
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23. SN r e a c t i o n
2
SN1 : Stereochemistry
- Nu. attacks from either side, back side or front side in step_2. so
racemic mixture may obtained as pdct.
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24. SN r e a c t i o n
2
SN1 : Stereochemistry
- But practically prdcts obtained with
of configuration.
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25. SN r e a c t i o n
2
SN1 : Stereochemistry
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26. SN r e a c t i o n
2
SN1 : Stereochemistry
I. After covalent bond breaking – initially both ions must be closed
together. (intimate pair)
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27. SN r e a c t i o n
2
SN1 : Stereochemistry
- Nu. can attack at all three conditions I, II & III.
22018
28. SN r e a c t i o n
rearrangement of carbocations:
- Stabilization of C+ intermediate.
- E.g.
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2
Explain Possible mechanisms
now
29. SN r e a c t i o n
rearrangement of carbocations:
Stability of Carbocation: 3o > 2o > 1o
Relative stability of 3o C+ favors rearrangement
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2
30. SN r e a c t i o n
Factor affecting SN reactions :
The Leaving Group
- In both SN reaction leaving group dissociates in Ts. It affects to the
reaction rate.
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3
C-X bond strength
31. SN r e a c t i o n
Factor affecting SN reactions :
The Nucleophile
- In SN2 rxn…
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3
32. SN r e a c t i o n
Factor affecting SN reactions :
The Nucleophile
- In SN1 rxn…
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3
33. SN r e a c t i o n
Factor affecting SN reactions :
Solvents
- Polar solvents like methanol and water stabilizes (decrease internal
energy) to charge species by intermolecular electrostatic intraction.
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3
34. SN r e a c t i o n
Factor affecting SN reactions :
Solvents
In SN1
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3
35. SN r e a c t i o n
Factor affecting SN reactions :
Solvents
In SN1
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3
36. SN r e a c t i o n
Factor affecting SN reactions :
Solvents
In SN1
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3
37. SN r e a c t i o n
Factor affecting SN reactions :
Solvents
In SN2
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3
42. Structure and Uses
Structure and Uses
1. Ethyl chloride
- Refrigerating agent
- In manufacturing of Tetraethyllead [is a highly toxic compound used
as a gasoline additive.]
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4
43. Structure and Uses
Structure and Uses
2. Chloroform
- Used as laboratory solvent. It was previously used as an anesthetic.
3. Dichloromethane
- Used as laboratory solvent.
- As mobile phase in chromatography
- As organic phase in liquid-liquid extractions with separating funnel.
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4
44. Structure and Uses
Structure and Uses
4. Tetrachloromethane
- Refrigerating agent
- As propellant in aerosol sprayers
5. Iodoform
- used as an antiseptic agent for minor skin diseases.
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4
45. of the topic
End
Reference:
Organic Chemistry– Morrison & boyd
Textbook of org. chem. – Bahl & Bahl
Organic Chemistry – Francis A. Carey
Organic Chemistry – Paula Bruice