1. The following Friedel-Crafts reactions do not work, i.e. no reaction occurs. Why? (Think of mechanism…) a) Toluene reacting with chlorobenzene in the presence of aluminum chloride catalyst b) Benzaldehyde reacting with chloromethane in the presence of aluminum chloride catalyst Questions of the Day:

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

3. 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): Evaluation of products by Gas Chromatography … Mechanism? Carbocation intermediate(s)?

4. Gas Chromatogram of a Crude Oil Sample

5. What is the mole ratio? What is the mole fraction?

6. 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 1. 2. 3. 4.

7. Synthesis of Bromoethylbenzene; H-NMR (Manual Exp.III) What is the structure of N-Bromosuccinimide (NBS)? What type of a reaction is this? 1.What is a “radical” in chemistry? 2.What is the geometry of a carbon radical? 3.What reaction conditions generally tend to lead to radical intermediates? 4.What are the major steps found in every radical reaction?

8. Synthesis of Bromoethylbenzene; H-NMR (Manual Exp.III) 1.Why does bromination in our reaction occur at the α- position only? 2.What is the function of NBS? 3.What is the function of dibenzoyl peroxide?

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

10. Synthesis of Bromoethylbenzene (Manual Exp.III) 1.Properties of CCl 4 ? 2.Why is CCl 4 a good solvent for our reaction mixture? 3.What are criteria for a "good solvent" in general? 4.What is the purpose of adding cyclododecane?

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