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Meeting 15 (Acetyl Ferrocene)
Important Announcements:
1. Proposal: due on November 23, 2005 at 5 pm in YH1217 (If you have problems please see me asap!)
2. The next quiz will be administered on November 23, 2005 at 12 pm. It will cover the entire ferrocene project and organometallics.
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.
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
Homework assignments (due November 22/23, 2005)
1. Referring to the synthesis of ferrocene, answer the following questions.
a. How is cyclopentadiene obtained from commercial sources? Explain.
b. Most hydrocarbons are very weak acid which require very strong bases to deprotonate them. However, in case of cyclopentadiene a relatively weak base such as KOH is enough to do the same job. Explain.
c. Why is dimethylsulfoxide used as a solvent in this reaction? Could toluene be used as well?
d. How is the crude product purified?
2. Referring to the synthesis of acetyl ferrocene, answer the following questions.
a. Why is the acylium ion considered a weak electrophile? Which implication does this observation have?
b. How is the acylium ion generated in the lab?
c. Why is it avisable to minimize the presence of water in the reaction mixture?
d. A student obtains a TLC for his crude product using a mixture of ethyl acetate/petroleum ether (1:9). What would he observe?
3. Describe the reaction of acetyl ferrocene with
a. 3-bromobenzaldehyde in basic ethanolic solution
b. hydroxylamine hydrochloride/sodium acetate in ethanol
c. Phenylhydrazine