ATTN: answers to the below questions are due at the start of your second meeting; these answers should be part of your pre-lab write-up. There will be a quiz in lecture on Thursday 1/13/2005. Please make sure that you arrive on time since the quiz will be administered in the beginning of the lecture.

1. Referring to step 2, answer the following questions:

a. Why is an aqueous solution of formaldehyde used in this reaction and not 'absolute' formaldehyde?

b. Why is dichloromethane used as a extraction solvent? How much solvent would be appropriate to use? Rationalize your choice.

c. The removal of the solvent can be aided by using an air stream. How does this work?

d. What determines if the crude product is a solid or an oil?

e. Sketch the TLC plate (SiO₂, CH₂Cl₂/hexane (1:1)) with your product in lane 1, the starting phenol in lane 2 and the salicylaldehyde in lane 3.

f. Sketch the plate using SiO₂ as stationary phase and a CH₂Cl₂/hexane (1:5) using the same definitions as in e.

2. Referring to step 3, answer the following questions:

a. Show a balanced equation for the reaction. What type of reaction is this?

b. What is the function of the conc. HBr and DMSO in the reaction?

c. Why is it imperative that the temperature of teh reaction mixture does not exceed 115 ^oC?

d. Why is the crude product recrystallized from hot methanol and not from hexane?

e. The product exhibits a C=O stretching frequency that is relatively low. Where it located and how can its location be explained?

3. Give a definition for the following terms.

a. Chiral pool

b. Cram Chelate Model

c. Enantiomeric excess

d. Self immolation