1. Organic Chemistry Lab 318 Spring, 2012

2. 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

3. 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

4. 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

5. 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)

6. Experiment Notes Solubility test – H 2 O and conc. H 2 SO 4 –Watch for color change or heat evolution with concentrated H 2 SO 4. Positive results indicates a reaction of >C=O with H + 2,4-DNP [no reagent available!!!] yelloworangered Precipitate color:yelloworangered Extent of conjugation in ald/ket:unconjugatedsomehighly

7. Experiment Notes Chromic Acid –Aldehydes are easily oxidized – ketones are not orange sol’n green ppt. Tollens Test –Aldehydes are easily oxidized – ketones are not –Show me the results of your test. silver mirror

8. 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.

9. 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.

10. 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.

11. Experiment Notes All waste goes into the WASTE JAR in the Hood

12. Experiment Notes Clean-up: Michael Chung and Cindy Tran