Organic Chemistry Lab 318

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• Organic Chemistry Lab 318
• Spring, 2012

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DUE DATES

• Today
• At beginning of lab Grignard Reaction Report
• At end of lab -- copy of laboratory notebook
  pages for today's experiment
• Next Week
• Qualitative Analysis Report

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The Experiment

• Qualitative Analysis
• Identification and characterization of unknown
  compounds
• Chemical and spectroscopic methods
• Chemical classification test tube reactions
  that are fast and give a visual result
• Spectroscopy IR H-NMR/C-NMR mass spectroscopy
• The unknowns are either aldehydes or ketones
• You will perform chemical tests, take an IR and
  receive/take an NMR

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Experiment Notes

• Follow the instructions in the Manual and in
  Pavia, beginning on p. 446.
• Simple distillation to purify unknown and get a
  b.pt. or m.pt. determination
• Refractive index remember to record room temp.
• Perform qual tests.
• Record all observations in your notebook do not
  merely record positive or negative.
• Do not fill in the table on the Handout it is
  part of your report.
• Use 1,2-dimethoxyethane instead of di(ethylene
  glycol) diethyl ether for Tollens

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Experiment Notes

• When you are finished with your qual tests, write
  a paragraph in your notebook that summarizes the
  results.
• You then should be able to justify the conclusion
  that you have either an aldehyde or a ketone (and
  if you have a ketone, whether it is a methyl
  ketone or not).
• After you have successfully convinced me of your
  conclusion (orally and in writing), you can take
  an IR.
• (Of course, you will be able to tell whether or
  not you have an aldehyde by the specific IR
  absorptions)

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Experiment Notes

• Solubility test H2O and conc. H2SO4
• Watch for color change or heat evolution with
  concentrated H2SO4. Positive results indicates a
  reaction of gtCO with H
• 2,4-DNP no reagent available!!!
• Precipitate color yellow orange red
• Extent of conjugation in ald/ket unconjugated som
  e highly

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Experiment Notes

• Chromic Acid
• Aldehydes are easily oxidized ketones are not
• orange soln
  green ppt.
• Tollens Test
• Aldehydes are easily oxidized ketones are not
• Show me the results of your test.
• 
  silver mirror

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Experiment Notes

• Iodoform Test
• Test for methyl ketones
• 
  yellow ppt
• Use a large test tube.
• It may take a long time, so do this test first.
• Show me the results of your test.

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Experiment Notes

• Each student gets his/her own unknown.
• You may work in groups on the known compounds (I
  will divide the class).
• One person sets up each test for knowns and
  unknowns. Both people perform the tests and
  observe and interpret results.
• Both people are responsible for the results.
• DO NOT divide the work by giving one person sole
  responsibility for a test.

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Experiment Notes

• Pavia tells you what knowns to use for each test.
  Use them.
• This should correspond to the Table that is part
  of the Handout (please let me know of any
  discrepancies).
• Unknown possibilities are listed in the Manual
  appendix.

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Experiment Notes

• All waste goes into the WASTE JAR in the Hood

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Experiment Notes

• Clean-up Michael Chung and Cindy Tran