Lab Experiment > University of California, Davis - CHE 118B Lab GRep Sheet

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2. Consider the IR of the starting 2-methylcyclohexanol and the dehydration product. What differences do you see to indicate that a reaction has taken place? 3. 2-Methycyclohexanol is prepared com... mercially by catalytic hydrogenation of o-cresol (2- methylphenol) and consists of a mixture of cis- and trans- isomers. 1. Describe how you can determine the ratio of cis- and trans-2-methylcyclohexanols from the 1H NMR spectrum provided. (Hint: What do the peaks at 3.05 ppm and 3.75 ppm represent and what does their integration show?) 2. Give the ratio of the two isomers. cis-:trans - 4. Using the 13C NMR spectrum and DEPT of a typical sample of the 2-methylcyclohexanol dehydration product provided answer the following. (The triplet at 77.00 ppm in the 13C NMR is due to solvent.) (Hint: How might the DEPT of the two cycloalkenes differ?) 1. What is the major alkene formed? 3. Give a reason why this product would be the major product considering the mechanism. 4. Using the GLC trace for the alkene products provided and the method of triangulation described in the pre-lab reading to estimate peak areas. (Note: The two peaks are overlapped. The peak marked ?? is an artifact and can be ignored.) Ratio major to minor = It follows Zaitsev's rule. 2. Which substance elutes more quickly? Why might that compound have a shorter retention time? 6. Consider the boiling points of 2-methylcyclohexanol, 1-methylcyclohexene, 3- methylcyclohexene and phosphoric acid. What is happening when we heat the mixture to 110°C? Why do we not see 2-methylcyclohexanol in the collection flask? 7. Discuss how this reaction follows (or doesn’t follow) the principles of green chemistry outlined on pg. 6 of this manual. 8. Predict the major organic products of the following reactions. [Show More]

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