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.
Step by step (time-sensitive):
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.
Follow the literature procedure exactly. Proper execution is
essential- see selected topics below for more information.
Take a TLC of the reaction as soon as addition is complete.
Co-spot with your reactant sample(s).
Record all observations and
times in your notebook.
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).
Do not leave your reaction before
it is done or there might be
repercussions.
See
leaving the lab
for exceptions.
When one of the reactants has been consumed,
quench the reaction immediately.
PAY ATTENTION.
Many cases of experimental failure are
repercussions resulting from inattention,
or from leaving the lab while a reaction is underway.
BE PREPARED.
When you start an experiment, the clock starts ticking. Make sure everything is
ready beforehand.
MONITOR REGULARLY.
Many students do not track their experiment closely enough.
If the reaction stalls,
sometimes it is a good idea to add more reagent to ensure complete conversion.
However, this is not recommended the first time through.
If no reaction occurs, try raising the temperature.
If product appears to be decomposing faster
than it is forming, consider quenching the reaction before
reactants are completely consumed. This may be the best way to maximize your yield.