last updated Friday, May 6, 2005

Problem set  Meeting 12 

Announcement

The instructor will offer an in-lab demonstration of the Grignard setup on Monday May 9, 2005 at 4 pm in YH6086.

The Grignard reaction will be started on Thursday, May 12 2005.

Questions

1. Referring to the Grignard reaction, answer the following questions.

a. The glassware has to be dried very thoroughly before running the reaction. How is this done and why?

b. Why is it necessary to crush the Mg-turnings before placing them in the round-bottomed flask?

c. How is the moisture kept out during the reaction?

d. Why is it important to add the bromobenzene/diethyl ether solution slowly during the reaction?

e. Outline a separation scheme for the isolation of benzoic acid. Clearly indicate at each point which layer contains your product. Show appropriate chemical equations.

2. Ethers are most commonly used as solvents for Grignard reactions. Rationalize this choice.

3. Using Spartan 2002, show that the carbon atom in bromomethane is an electrophile, and a nucleophile in Methyl magnesium bromide.