2 ‫ מתוך‬1 ‫עמוד‬
6 ‫ניסוי מספר‬
Nucleophilic Substitutions.
There will be 3 different substitution reactions; your lab assistant will inform you
which one you will do. You will be tested on your knowledge of nucleophilic
substitution reactions and reactivity of alkyl and aryl halides. You must be ready to
do any of the procedures so read them very carefully. We will be using magnetic
stirrers instead of boiling stones in all the procedures.
1- t-Butyl chloride
HCl
OH
Cl
+
H2O
Reference: Vogel’s Textbook of practical organic chemistry, 5th Ed. Procedure 5.49
Page 556.
Notes: Use the calcium chloride procedure and half the amounts of reagents, also
when adding sodium bicarbonate to your reaction product use an Erlenmeyer and not
the separatory funnel. Only introduce the mixture in the separatory funnel once gas
evolution has subsided (stopped). After you have finished and isolated your
compound proceed to the reactivity of halides section below.
2- t-Pentyl chloride
OH
HCl
Cl
+
H2O
Reference: Introduction to Organic Laboratory Techniques, 3rd Ed. Pavia, Lampman,
Kriz. Procedure 23B; Page 177.
Notes: When adding sodium bicarbonate to your reaction product use an Erlenmeyer
and not the separatory funnel. Only introduce the mixture in the separatory funnel
once gas evolution has subsided (stopped). After you have finished and isolated your
compound proceed to the reactivity of halides section below.
3- n-Butyl bromide
OH
+
H2SO4 (aq.)
NaBr
Br
Reference: Introduction to Organic Laboratory Techniques, A small scale approach.
Pavia, Lampman, Kriz, Engel. Experiment 23A; Pages 189-191. (This is not the same
procedure as last year!)
Use a magnet instead of boiling stones and don’t heat the bromide with the calcium
chloride. Be extremely careful when handling concentrated sulfuric acid! Only
proceed to the reactivity of halides section if you have enough time (you probably
6 ‫ניסוי מספר‬
2 ‫ מתוך‬2 ‫עמוד‬
won’t). If you don’t have enough time copy the results table from a lab partner and
make your own conclusions about the results (include them in the report!).
Reactivity of alkyl and aryl halides.
You will check the reactivity of different halide substrates towards SN1 and SN2 type
reactions. You will receive a 15% sodium iodide solution in acetone and a 1% silver
nitrate solution in ethanol. You will test how these solutions react in a dry and clean
test tube with 5 drops of:
1) n-Butyl chloride
2) n-Butyl bromide (if possible what you or a lab partner have made)
3) sec-Butyl chloride
4) t-Butyl chloride (or t-pentyl chloride)
5) Bromobenzene
Add 2 ml of the sodium iodide solution to the first 5 test tubes. Note whether there is
a reaction and what is the rate.
Now add 2 ml of the silver nitrate solution to the other 5 test tubes. Again note if
there is any change and how fast it occurs (use a stopwatch).
After 5 minutes take all the tubes that did not react in the first series and heat them to
550C for 15 minutes. Note any changes.
Summarize the results in a table and draw your conclusions. What are the reactions
that are happening? What is the mechanism in each case?
6 ‫ניסוי מספר‬