Friedel-Crafts Alkylation of Bezene


Compiled by Vlad Ladziata 4/15/2020

Week 8

Friedel-Crafts Alkylation of Bezene

Chapter 29, Expt. 1, pp. 438-440

Experimental Procedure.

1. Add 0.40 mL of dry t-butyl chloride (2-chloro-2-methylpropane) and 0.20 mL of dry benzene into a 10

100 reaction tube.

2. Cool the tube in ice bath; be sure to place the ice bath into a hood.

3. Weight 0.035 – 0.040 g AlCl


(no need to have exactly 0.040 g, but take no more than

0.060 g), add AlCl


in to the tube. Perform this step quickly (to avoid absorption of water from the air by AlCl


). Please note: AlCl


is highly hydroscopic and loses catalytic activity after hydratation.

4. Mix the contents of reaction tube by using a wooden stick.

5. After an induction period of about 2 min, a vigorous reaction sets in, with bubbling and releasing HCl ( work in a hood ). There is no need to have tubing setup depicted in

Fig. 29.1 p. 439 as long as you work in the hood and hood shutter is low.

6. Near the end of the reaction the product separates as a white/yellow solid. Then remove the tube from ice bath and let it stand in room temp for 3-5 min

7. Add 1.0 mL of ice water to the reaction tube, then extract with three 0.8 mL portions of methyl tbutyl ether (MTBE), take off the MTBE layer to a clean 10 mL Erlenmeyer flask

8. Then add 1.5 mL saturated NaCl solution to ether followed by sufficient amount of anhydrous Na




(drying agent).

9. After 3 min, transfer the MTBE layer to a dry clean reaction tube, use 0.8 mL of

MTBE to wash the drying agent. Transfer the MTBE washings to the test tube too.

10. Evaporate the ether using the evaporator in the class.

11. Remove the product from the tube. If the product is oily, put the test tube in ice bath and scratch the walls of the test tube with glass rod or spatula to induce crystallization.

Dry product between folds of filter paper.

12. Weigh the product, record the yield and calculate % yield.

13. Run IR and prepare samples for GC/MS and NMR.

Compiled by Vlad Ladziata 4/15/2020

Mystery modification:


Repeat this experiment with 2 modifications: take from 2 to 3 mL of dry t-butyl chloride (2-chloro-2-methylpropane). Amounts of other reagents are the same.


Also at step #6 after warming up the reaction mixture to room temperature put the reaction tube into warm (50 – 60 o

C) for 5-7 minuts.


Check purity of this product by GC/MS and NMR.


The structure of the “Mystery” product was given in the presentation. You should propose the reasonable reaction mechanism in your lab report. Note: you may use

SciFinder or any other literature.