last updated Friday, October 31, 2014

Problem set  Meeting 11 

Announcement

1. Quiz 5

Quiz 5 will be administered on Thursday, November 6, 2014 at 11 am. It will cover the entire lidocaine project.

2. Lidocaine Project

a. The postlab report for the lidocaine project has to be written in the lab notebook and submitted to the teaching assistant. The due dates are November 13, 2014 or November 14, 2014 in your regular lab section. The report has to be written in the lab notebook and is worth 15 points.

3. Grignard Project

a. The Grignard project will start on November 6, 2014.

b.The instructor will provide an in-lab demonstration of the Grignard setup (setup, heating, etc.) on Wednesday, November 5, 2014 at 4:00 pm in YH 6086. Attendance in this demonstration is voluntary (no credit) and is highly advisable for students that feel intimidated by the larger setup. Part of the demonstation will already discussed in lecture prior to this in-lab demo, but certain aspects like heating cannot be shown in the lecture.

4. Research project (Week 9)

a. Please look start looking for a partner for the Ferrocene project. Your partner should be in a different time slot than yourself i.e., if you are in the T/R afternoon section, try to find somebody in the W/F afternoon section. This way nobody has to put in additional time outside their regular schedule, which means that each group has four lab meetings to complete the project. We have to avoid as much as possible to have the entire class running around in the lab (Safety!).

...and now back to the chemistry part of this course....the homework questions due on 11/6/2014 or 11/7/2014

1. Referring to the Grignard reaction, answer the following questions. Show chemical equations when appropriate.

a. The presence of water poses a significant problem in this reaction. How is its presence minimized?

b. How should the Mg-metal look like?

c. One method to help initiating the reaction is the addition of 1-2 iodine crystals to the mixture. How does this exactly work?

d. Why is it crucial to add the ethereal bromobenzene solution at the proper rate? What is the student looking for here?

e. Why is it important to use a large beaker when reacting the Grignard solution with the dry ice?

f. Which precautions does the student have to take when using dry ice in this reaction?

g. After the mixture obtained in e., was allowed to warm up, chipped ice and concentrated sulfuric acid are added. Which purpose does this step serve?

h. The combined organic layers are extracted with sodium hydroxide solution. Which layer contains the product then? In which form?

i. Why is it important to dry the benzoic acid very thoroughly? How is this accomplished?