Problems Set (Meeting 9)

Announcements (Please read!)

1. A problem that has arisen several times this quarter in this and the other class in the 6th floor is improper waste management. This is particularly true for the disposal of glass waste and syringe needles. The instructor and the janitor found glass trash and needles in the regular trash bin last week. On Wednesday, the janitor found more needles in the trash bin. These objects pose a huge hazard to the janitors and therefore cannot be disposed of in the regular trash. As stated in the course reader, the glass waste has to be placed in the blue-white boxes, while the needles should be disposed of in a sharp's container located in the hood.

2. Another issue is the return of glassware. The lab support usually closes at 5 pm sharp every day. If you do not return the glassware by then, you will not be able to retrieve your student ID. This can become a huge problem if this is your access key to your university apartment and your dinner. So please make sure to return the glassware clean and on time.

3. You should finish the first two steps of the lidocaine project on the first day of the project.

4. The instrumentation room in the sixth floor (YH 6076) should be left in proper conditions. Lately, there has been an increasing mess i.e. dirty Kim wipes all over the place (which should not be used to clean the ATR setup!), unclaimed solutions and glassware, etc. In addition, students do not seem to feel that it is necessary to wear goggles in this room, which is not acceptable either. Please keep in mind that you are still handling chemicals!

5. There will be no quiz on Wednesday, February 3, 2010. The lecture is canceled as well (Instructor has another trip downtown to talk to the INS). The next quiz (quiz 4) will be administered on February 8, 2010 at 11 am. It will cover the entire Lidocaine project.


Questions (due on 2/2 or 2/3):

1. Referring to the conversion of 2,6-dimethylnitrobenzene to 2,6-dimethylaniline (step 1), answer the following questions. Show pertinent chemical equations where appropriate.

a. Why is it necessary to use two different solvents here?

b. Why is it important the mixture is strongly acidic during the reduction?

c. The initial reaction affords a white solid. In lecture it was emphasized that the solid should not be washed with water. Explain.

d. A student dissolves his solid in the 30 mL of water and adds concentrated KOH. Explain briefly why. What should he observe?

e. He then proceeds to extract the mixture from d. with diethyl ether. How much is appropriate here?

f. A student wants to dry his organic layer and decides to use anhydrous magnesium sulfate like in many previous experiments. What would you tell him?

g. Why is a simple distillation used in this experiment?

h. How is the FTIR spectrum acquired here? Provide a brief procedure.

2. Referring to the conversion of 2,6-dimethylaniline to a-chloro-2,6-dimethylacetanilide (step 2), answer the following questions. Show a pertinent chemical equations where appropriate.

a. Glacial acetic acid used as solvent in this reaction. Rationalize this choice.

b. The supply bottle for the acyl chloride should be kept close. Explain.

c. Why does the amide precipitate upon the addition of sodium acetate solution?

d. Why should this step be completed in the first meeting?