home
site map appendix about course read first lab manual
read first
site map read first about course lab manual appendix

Lab X: Nucleophilic Substitution Reactions: Designer Experiment
 
Pre-lab Work

  1. 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

  1. 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.
  2. 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.)
  3. Write a short paragraph summarizing the results of your lab. Determine if your hypothesis is substantiated and explain why or why not.
  4. 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!!!**

******************************************************************************
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:

******************************************************************************

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.)

******************************************************************************