The Reaction: Analysis I

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A Perfect Reaction (see all): Combination of reactants is simple, and goes smoothly. The reaction is homogenous, and stirs easily. You can follow the progress of the reaction by periodic analysis using simple TLC or GC, and can stay with the reaction until it is complete. All the starting material is consumed, and one new product is formed cleanly (aka "spot to spot").

A Nightmare Scenario (see all): The reaction takes hours to complete: however, the product is unstable and decomposes slowly under the reaction conditions. Progress cannot be monitored by TLC.

Common Rookie Mistakes: Running Reactions

Step by step (time-sensitive):

  1. Save a small sample of each reactant in a vial, for TLC comparison. An NMR sample works nicely, or a milligram or so in solvent.
  2. Follow the literature procedure exactly. Proper execution is essential- see selected topics below for more information.
  3. Take a TLC of the reaction as soon as addition is complete. Co-spot with your reactant sample(s).
  4. Record all observations and times in your notebook.
  5. TLC or GC the reaction at regular intervals. The appropriate interval to employ will depend on the reaction rate- (e.g. every 10 minutes, or 30 minutes, or every hour). Always co-spot with reactant(s).
  6. Do not leave your reaction before it is done or there might be repercussions. See leaving the lab for exceptions.
  7. When one of the reactants has been consumed, quench the reaction immediately.

Tips (see all):

See also: Rookie Mistakes, First Time Through, How to Improve Your Yield, Big Complaints, Adding Reagents, Reaction Vessels, Stirring, Syringes and Needles, Temperature Control, TLC How to, TLC Notes, 1H NMR How to, Reaction Checklist, Troubleshooting the Experiment