1. Today: Conclusion of Friedel-Crafts/GC
Introduction to NBS-Bromination (Exp. 3)
MiniQuiz

2. Friedel-Crafts Alkylations (Exp.II)
Reaction equation for the reaction of p-xylene with 1-bromopropane in the presence of aluminum trichloride (our lab experiment):
Mechanism… :
Which carbocation intermediates are formed?

3. Friedel-Crafts Alkylations
Which of the following Friedel-Crafts reactions would you expect to work well, which ones not at all and why?
a) Toluene reacting with chloromethane in the presence of aluminum chloride catalyst
b) Toluene reacting with chlorobenzene in the presence of aluminum chloride catalyst
c) Benzaldehyde reacting with chloromethane in the presence of aluminum chloride catalyst

4. Gas Chromatography
Which is the moving phase, which is the stationary phase in our GC?
What peaks do you expect to get in your GC of Exp.II? What determines their approximate sequence?
What is a mole ratio? And what is a mole fraction?

5. Calculations for Friedel-Crafts Experiment
II. Weight of product mixture
What is in product mixture?
Percent by weight of mono n-propyl product in product mixture Weight fraction… Remember: Different molecular weights…
Theoretical yield in grams of mono n-propyl product
Balanced equation (assuming that only mono n-propyl product is formed), mols, mol ratios …
Percent yield mono n-propyl product*
[Actual yield / theor. Yield] x %  
Ratio of n-propyl to isopropyl product*
GC! Area ratio =mol ratio   3. 1. 4. 2.

6. Synthesis of Bromoethylbenzene; H-NMR (Manual Exp.III)
What is the structure of N-Bromosuccinimide (NBS)?
What type of a reaction is this?
What is a “radical” in chemistry?
What is the geometry of a carbon radical?
What reaction conditions generally tend to lead to radical intermediates?
What are the major steps found in every radical reaction?

7. Synthesis of Bromoethylbenzene; H-NMR (Manual Exp.III)
Why does bromination in our reaction occur at the α-position only?
What is the function of NBS?
What is the function of dibenzoyl peroxide?

8. Propagation
How can you explain that the reaction mixture goes through a series of color changes?

9. Synthesis of Bromoethylbenzene (Manual Exp.III)
Properties of CCl4?
Why is CCl4 a good solvent for our reaction mixture?
What are criteria for a "good solvent" in general?
What is the purpose of adding cyclododecane?

10. Introduction to Diels-Alder (Exp.4) MiniQuiz on this lecture
Next time:
NMR (Concl. of Exp.3)
Introduction to Diels-Alder (Exp.4)
MiniQuiz on this lecture