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Lab X: Nucleophilic
Substitution Reactions: Designer Experiment
Pre-lab Work
- Submit
your Designer Lab Plan Worksheet for approval by your Instructor.
The plan
is due on or before the date given by your Instructor.
As shown in the
lab plan worksheet, your plan should include:
- the overall reaction
that you will be doing
- the purpose or
reason for the experiment and/or the chemistry question you want to
answer
- a list of the
possible products
- how you will analyze
your products
- a TPC which includes
the amounts of reagents you will be using, all of your expected products,
and their theoretical yields, if applicable.
Introduction
This lab is intended to be modeled on the Competing
Nucleophiles lab done earlier this semester. Each student
will be doing her own individual experiment to answer her question
about
nucleophilic substitution or elimination reactions.
Experimental Work
Objectives:
- To obtain new
information from your designed experiment.
- To see if your
hypothesis, or your predicted outcome of the experiment, is correct.
- To answer your
chemistry question.
Experimental
Procedure
Since each student will be performing her own experiment,
there are no specific laboratory instructions. Things to keep in mind
are:
Post-lab
Work
- Print the MS for
a minimum of 4 of your GC peaks. On each MS, label the M+ peak and the
base ion peak. Show possible structures for these ions.
- Using your MS,
identify each product (to the best of your ability) using GC/MS. Use
any other analytical techniques for verification. (Note: some of your
'product' might also be reactants.)
- Write a short
paragraph summarizing the results of your lab. Determine if your hypothesis
is substantiated and explain why or why not.
- Discuss any errors
that impacted your experimental results and state what you would do differently if you were
to do this lab again.
Designer
Lab Presentation
You will give an oral presentation of your Designer Lab
results during the last lab of the semester. For details, please see your
Instructor.
DESIGNER LAB PLAN WORKSHEET
Here are the
chemicals that are available for your Designer Experiment:
Alcohols:
1-heptanol, 2-heptanol, cyclopentanol, cyclohexanol, 2-methyl-2-hexanol,
1-nonanol, 2-nonanol, 1-methylcyclohexanol, 2-methylcyclohexanol, benzyl
alcohol, phenethyl alcohol, sec- phenethyl alcohol, 2,4-dimethyl-3-pentanol,
3-hexanol, 3,3-dimethyl-2-butanol, trans-2-hexen-1-ol
Alkyl Halides:
bromocyclopentane,
chlorocyclopentane, bromocyclohexane, chlorocyclohexane, 1-iodoheptane,
1-chloroheptane, 1-bromoheptane, 2-bromoheptane, benzyl bromide, benzyl
chloride, bromomethylcyclohexane, 1-bromo-2-ethylhexane
Acids and
Bases: 18M sulfuric acid, 12M hydrochloric acid, 15M phosphoric
acid, glacial (100%) acetic acid, 12M sodium hydroxide, 12M potassium
hydroxide, saturated sodium bicarbonate
Salts and
Drying Agents: ammonium chloride, ammonium bromide, ammonium
iodide (Do not mix this with sulfuric acid!),
potassium acetate, sodium acetate, sodium bromide, sodium chloride, sodium iodide (Don't mix with sulfuric acid!), anhydrous magnesium
sulfate, silver nitrate in ethanol
Solvents:
dimethylformide [DMF] (a polar organic aprotic solvent), tetrahydrofuran
[THF] (another polar organic aprotic solvent), water, acetone, hexanes,
methylene chloride, diethyl ether
**NOTE:
Do not mix ammonium iodide or sodium iodide with sulfuric acid!!!**
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Designer
Lab Proposal Form:
Please model your
procedure after the Competing Nucleophiles Lab. This must be a synthetic
reaction!! Do not do a test tube lab as was done in the Alkyl Halide
lab!!
Name:
Lab day:
Question to be answered:
Prediction/Hypothesis:
Equation for expected reaction:
Predicted Major product (Show structure):
Predicted Minor product(s) (Show structures):
Do you expect the reaction to go SN1__ SN2___ Elimination___ Other___ (explain):
Instruments to be
used to analyze my product:
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Include
a copy of your TPC with the appropriate
amounts of each reactant.
(Use similar molar quantities as in the Competing Nucleophiles or the
Dehydration Labs.)
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