Spring Laboratory Follow-Up Assignment #1
Due: Friday, January 21, 2005 by 5:00 pm
1. Given the class results of your GCMS data, produce a TABLE of alkene isomers formed. In this table you will want to indicate the following information:
(a) retention time of the peak (in minutes)
(b) likely identification of the compound (name and structure)
(c) % of the compound
(d) molecular ion and base peaks from the mass spectra
2. Write up a 2-3 page DISCUSSION of the results. The discussion is where you INTERPRET your results. In this discussion, you will want to provide the following information:
(a) a description of the purpose of the experiment
(b) a description of the EVELYN EFFECT -- be sure to cite your sources here!!!!!!!
(c) a summary description of the results (of the information provided in your table)
(d) your interpretation of the results (what do they mean, what does the data tell you) -- be sure to emphasize the %'s and what they tell you, especially as it pertains to Zaitsev's rule and whether or not you observed the Evelyn effect.Also, describe how the mass spectral data allows you to differentiate among the various isomers (look for variations in the pattern!)
(e) your explanation as to WHY these results occurred -- this means that you will have to provide INFERENCES from the data (this means you will have to explain how certain isomers formed and why they formed in the various percentages -- the emphasis should be on mechanism -- an indication of which mechanistic pathway(s) (E1, E2, or E1cb) BEST explain(s) how each of the alkene isomers was formed from the starting alcohol (NOTE: there may be more than one viable pathway for each product)
* You will be evaluated on BOTH the content of your discussion and the quality of written communication (clarity, conciseness, mechanics, use of figures/schemes for description, and flow of the argument) – like a FORMAL REPORT.
3. How does the fact that there are both cis and trans isomers of 2-methycyclohexanol affect the mechanistic course of reaction? In order to answer this question, perform Experiment #6.15 (page 100) in your Molecular Modeling Workbook for Organic Chemistry. This reaction is the base-catalyzed version of the reaction you did in the lab -- notice how the OH group was first converted to a tosylate to enhance its leaving capability under basic reaction conditions (as opposed to the acidic activation of OH that we learned about in class). Provide the results from the WOC exercise as well as to the answer to the question above.
4. In this experiment, 85% phosporic acid was employed as a key reagent. What was its function? Verify its functionality by completing Experiment #8.7 (page 126) in your Molecular Modeling Workbook for Organic Chemistry. Provide the results from the WOC exercise as well as to the answer to the question above.
5. Why was the temperature on the thermometer reading a value that was considerably LOWER than the expected boiling points of the alkene products?
This is an open-ended question so they really is not a right or wrong answer here -- I am looking for your ability to provide a rational, thoughtful answer that is based in fundamental chemical principles.
6. Report the following information from your GCMS data:
(a) Injector temperature
(b) Detector temperature
(c) Initial and Final oven temperatures and programmed ramp rate
(d) Helium flow rate
(e) Solvent delay time
(f) Sample volume
NOTE: to acquire this information, you will need to log on to the GCMS computer in Smyth 302 and find the details for the method that we used (TIMMA)
Using these variables, suggest a method by which we could improve the quality of separation of the various isomers by GCMS.