Problem set #2 (Meeting 2)

ATTN: answers to the below questions are due at the start of meeting 2; these answers should be part of your pre-lab write-up.

1. What is the expected alkene product formed from the dehydration of the following alcohols? Show major products only. help

2. During the synthesis of cyclohexene, two distillations are performed.

a. Explain briefly which purpose each distillation serves.

b. Draw a sketch of the proper setup of a microscale distillation. Label all parts.

3. Anhydrous sodium sulfate is used as drying agent in this experiment. How do you know that enough drying agent was added?

4. Two qualitative tests are performed at the end of this project.

a. Which tests are performed? Show pertinent chemical equations including the correct stereochemistry of the product.

b. Why are these tests chosen?

5. What are the most important changes in the IR spectrum going from cyclohexanol to cyclohexene (functional groups and wavenumbers)?

6. Referring to the benzoin condensation, answer the following questions:

a. Why is sodium hydroxide added to the solution?

b. Why is it important that the reaction mixture is homogeneous?

c. How is the product separated from the byproducts and unreacted starting material in this reaction?

7. Using PC Spartan 2002 at the Science Learning Center (4th Floor Young Hall) do the following:

a. Do the following calculations for the alkenes: terpinolene, limonene, a-terpinene, isoterpinolene. Make sure that all hydrogen atoms are present.

b. Select Calculations from the Setup menu.

The following window should appear. Select the options shown.

Verify that the Charge is Neutral and Multiplicity is Singlet. Click OK.

Select Submit from Setup menu.

Then click OK to exit dialog. Close the previous window.

Select Submit from Setup menu. When the calculation is completed you will be notified. It should not take more than 2-3 minutes for the calculation to complete under normal circumstances. Make sure that you have only one window open at this point. The messages are usually displayed in the first window, and often not in the window you are working in at this point.

Under the Display menu, select Properties. Record the value for the Energy.

1. Based in the observed trends in trends in the heat of formation (=energy), which alkene is the most stable and which one is the least stable one? Can you rationalize these observations?

2. Can you explain the product distribution observed for the elimination of water from a-terpinol (see page 22)?

Problems: Check here