Today: - Conclusion of Exp.1 “Kinetics” - Exp. 2, “Friedel-Crafts” Next time: MiniQuiz on Exps. 1 and 2!

Calculations for Exp.1: Solvolysis of tert Butyl Chloride p

Calculations for Exp.1: Solvolysis at t 10%, [RCl] = 0.90 [RCl] o =kt 10% -ln 0.90[RCl] o [RCl] o -ln =kt 10% 0.90= t 10% =k Units of k? How could you calculate k by using the half life? Assume you want to determine k in a given solvent system at a given temperature, but the reaction is too fast to reasonably measure t 10%. What could you do to obtain k (same solvent/same temp.)?

Arrhenius Equation and Calculation of Ea and A What does E a tell us about the reaction? ln k = ln A -E a /RT Plot ln k vs. 1/T for each solvent mixture ln k 1/T y = b + m x R= cal/Kmol What is “b” in our equation, what is “m”?

Friedel-Crafts Alkylations (Exp.II) (Read your Organic text chapter on “Friedel-Crafts” reactions.) Reaction of p-xylene with 1-bromopropane in the presence of aluminum trichloride (our lab experiment): Mechanism? Aluminum trichloride is a Lewis acid. What is a “Lewis acid”? What problems can arise during Friedel-Crafts alkylations? Suggest a procedure to get pure n-propyl product and no isopropyl product. Friedel-Crafts reactions increase the number of C-atoms of the reactant. Do you know any other reactions that do this, too?

Why does the lab apparatus have to be very dry? Why is a gas trap needed? What is the meaning of "tared" (as in "tared flask")? Why is ice added after the reaction took place? And why ice and not water? Friedel-Crafts Alkylations (Exp.II) Lab Experiment (Microscale procedure. Remember “omission”!)

Gas Chromatography / Mass Spectrometry

Gas Chromatogram of a Crude Oil Sample

Calculations for Friedel-Crafts Experiment II. Weight of product mixture__________________ What compounds are in the mixture? Percent by weight of mono n-propyl product in product mixture __________________ Theoretical yield in grams of mono ______________ n- propyl product Percent yield mono n-propyl product* __________________ Ratio of n-propyl to isopropyl product* __________________

Gas Chromatography 1. What types of samples can be separated by GC? 2. Which is the moving phase, which is the stationary phase? 3. What peaks do you expect in your GC of Exp.II? How can you determine the approximate sequence? 4. What is the mole ratio? What is the mole fraction?

Next time: Friedel-Crafts (conclusion) NBS Bromination (Exp.3) MiniQuiz on Exps. 1 and 2!