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Chemistry 1616:
Lab Notebook Format
Notebook Format - General
The laboratory notebook should be a complete record of the experimental
work. The criterion used in judging what should be in the notebook is that the record should be so thorough and so well organized
that another student who reads the notebook can find the procedure, can understand the data obtained, and can repeat the experiment,
if necessary, in precisely the same way the original work was done.
Data should be recorded in the notebook in ink, at the time they are obtained.
There is no reason for recording anything on scratch paper to be transferred into the notebook later. If a mistake is made
in the notebook, simply cross out the error and make the correct entry next to it. Neatness is desirable, but it is much less
important than completeness.
Use the following general format for setting up your notebook:
- Leave a few pages at the beginning of the notebook for a Table of Contents. Keep the
Table up to date.
- If the pages are not already numbered, number them. All consecutive pages must remain
in the notebook; do not remove any pages. If you really mess up a page, draw a diagonal line through it and start over on
a new page.
- Start every new experiment on a fresh page. If you have two experiments active at the
same time, leave enough pages between them in the notebook; any unused pages or portions of pages at the end of an experiment
should have a diagonal line drawn through them.
- It is not necessary to copy the details of an experimental procedure, provided you reference
the source of the procedure. However, any variations from the original procedure must be documented in the notebook. Remember,
your notebook should be a log of your laboratory operations; someone should be able to reconstruct later just what was done
and why it was done. Never delete anything-draw a line through it and amend it appropriately. What you consider wrong at one
time might turn out to be right later.
Format for Notebook
Before coming to lab.........
- Title: Title of experiment.
- Reactions (if applicable): Give the main chemical reaction(s) leading to the
product; where feasible, include the mechanisms of the reactions and possible side reactions that could diminish the yield
of desired product.
- Reference: Bibliographic citation of the experimental procedure.
- Procedure: Original procedure or deviations from referenced procedure.
- Amounts of Reagents Needed: If not included in the procedure, calculate the masses
and/or volumes necessary to use in the experiment. Be aware of any hazard mentioned in the lab textbook. You should also calculate
the limiting reactant and the theoretical yield of the product. Molecular weights and densities or any other properties
can be found using the "CRC Handbook", the "Merck Index", Merck Online, CCD Online, a chemical
supply company catalog, or ChemFinder.
In lab...
- Observations and Data: Observations, particularly those that were unanticipated;
any changes in experimental procedure not documented above; and raw data and results are to be recorded directly into the
notebook during the laboratory exercise.
After lab...
- Results: Actual yield; percent yield; measured physical properties of the product
-- mp, bp, color, purity, spectroscopic data as appropriate, etc.
A sample lab notebook is shown below:
Sample Lab Notebook Page
Jane Doe
9.1A
Date: 9-22-00
9.1A: Diels-Alder Reaction between
1,3-Butadiene and Maleic Anhydride
Microscale and Miniscale Organic Chemistry Laboratory Experiments
by Schoffstall, Gaddis, and Druelinger, pg. 265-269.
Changes to Procedure: Use 0.5 mL of xylene instead of
0.25 mL.
Reaction: (write in the balanced chemical reaction
here)
Reagents: volumes and masses specified in procedure
Observations: hard to control temperature-- fluctuated
a lot.
Results: Maleic anhydride is the limiting reactant
(9.2 x 10 -4 moles) leading to a theoretical yield of 140 mg of 4-cyclohexene-cis-1,2-dicarboxylic
anhydride.
Actual yeild obtained: 101 mg of white crystals (72% yield)
with a melting point of 99-101oC (compared to literature value of 104oC).
No further characterization was done.
About the Lab Write-up:
- Lab report (1 page minimum...typed) should contain the overall results with an in-depth
summary of what was learned from the experiment, plus the yellow copies from the lab notebook.
- The lab report should include:
Experiment Title
Reference to the Procedure (book and page
number)
Balanced chemical reaction (drawn)
Results (yields, physical characterizations, etc.)
Discussion
- Sample write-up: A sample is shown below:
Sample Lab Report: Org Chem 1616
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Name: |
Jane Doe
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9-5-04 |
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Expt. 9.1A:
Diels-Alder Reaction of 1,3-Butadiene with Maleic Anhydride
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Reaction |
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Results:
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I obtained 101 mg of 4-cyclohexene-cis-1,2-dicarboxylic
anhydride (72% yield). The product had a melting point of 99-10 oC, compared to a literature value of 104
oC. No other characterization was done.
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Discussion: |
The Diels-Alder reaction requires a conjugated diene and a dienophile
(with at least one pi bond) to form a new six-membered ring. The dienophile works better if it has electron-withdrawing
groups on it, as does maleic anhydride. The reaction between 1,3-butadiene (a conjugated diene)
and maleic anhydride (a dienophile) produces 4-cyclohexene-cis-1,2-dicarboxylic anhydride. The endo product predominates due
to the nature of the reaction. The 1,3-butadiene is produced by heating 3-sulfolene to approximately
200 oC, which generates sulfur dioxide as a byproduct. The product is precipitated from the reaction mixture using
a toluene-petroleum ether solvent pair. A possible side product is 4-cyclohexene-cis-1,2-dicarboxylic
acid, caused by hydrolysis of 4-cyclohexene-cis-1,2-dicarboxylic anhydride. This side product is minimized by using dry glassware.
Despite the difficulty in maintaining the high termperature required for
the reaction (the temperature varied between 170-200 oC), this was an excellent example of a Diels-Alder reaction.
Perhaps additional xylene should have been added to keep the temperature stable. The product was obtained in 72% yield
and the melting point was only 3 oC low from the literature value. This was a very successful experiment
and one I enjoyed very much. |
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© Copyright 1997, David
R. Anderson |
