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Question of the Day:

Question of the Day: Which organic products can be formed during the hydrolysis of tert -butyl chloride? (write the structures of two). ??. Today: - Conclusion of Exp.1 “Kinetics” - Exp. 2, “Friedel-Crafts”. Calculations for Exp.1: Solvolysis. at t 10% , [RCl] = 0.90 [RCl] o.

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Question of the Day:

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  1. Question of the Day: Which organic products can be formed during the hydrolysis of tert-butyl chloride? (write the structures of two) ??

  2. Today:- Conclusion of Exp.1 “Kinetics”- Exp. 2, “Friedel-Crafts”

  3. Calculations for Exp.1: Solvolysis at t10%, [RCl] = 0.90 [RCl]o • 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.)? • How could you calculate k by using the half life? 0.90[RCl] o -ln = kt 10% [RCl] o = kt -ln 0.90 = 0.1053 10% 0.1053 = k t 10%

  4. Arrhenius Equation and Calculation of Ea and A R=1.987216 cal/Kmol What does Ea tell us about the reaction? ln k = ln A -Ea/RT y = b + m x Plot ln k vs. 1/T for each solvent mixture ln k What is “b” in our equation, what is “m”? 1/T

  5. 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? Friedel-Crafts reactions increase the number of C-atoms of the reactant. Do you know any other reactions that do this, too?

  6. Friedel-Crafts Alkylations (Exp.II)Lab Experiment(Microscale procedure. Remember “omission”!) 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?

  7. Evaluation of products byGas 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? • 4. What determines their approximate sequence?

  8. Gas Chromatography / Mass Spectrometry

  9. Gas Chromatogram of a Crude Oil Sample

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

  11. II.Weight of product mixture What is in product mixture? Percent by weight of mono n-propyl product in product mixtureWeight 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 Calculations for Friedel-Crafts Experiment 3. 1. 4. 2.

  12. Next time: Friedel-Crafts (conclusion) NBS Bromination (Exp.3) MiniQuiz on Exp1. and 2 (Kinetics and Friedel-Crafts) !

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