last updated Thursday, May 19, 2005

Meeting 15 (Acetyl Ferrocene)

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

Important Announcements:

1. Proposal: due on May 27, 2005 at 5 pm in YH1217 (If you have problems please see me asap!)

2. The next quiz will be administered on Tuesday May 24,2005 at 11 pm. It will cover the nitration step of the Grignard reaction and the acylation of ferrocene.

3. In the lab, you will only carry out the acylation of ferrocene, but not the sythesis of ferrocene. This part will be done individually.

Homework assignments (due May 24 or 25)

1. Referring to the synthesis of ferrocene, answer the following questions.

a. Why is a relatively weak base like KOH enough to deprotonate cyclopentadiene? Explain briefly.

b. How is FeCl₂ obtained from Fe-metal?

c. Why is dimethylsulfoxide used as a solvent here?

d. How can the crude product be purified? Suggest two methods.

2. Referring to the synthesis of acetyl ferrocene, answer the following questions.

a. Suggest two methods to generate an acylium ion in the lab.

b. The acylium ion is considered a weak electrophile. Explain briefly why.

c. Why should moisture be eliminated as much as possible during the reaction?

d. You have a mixture of ferrocene, acetyl ferrocene and diacetyl ferrocene. You dissolve the mixture in acetone and then run a GC spectrum on a polar column. Sketch the GC spectrum obtained in this run.

e. In the lab, the crude product is purified using flash chromatography by using different solvents. Rationalize the choice.