Make sure that you work on your final version of the report for the epoxidation project. If you have any questions, please stop by in the instructor's office or office hour asap. The final version of the paper is due by Friday, February 5, 2016 at 4:30 pm. Late papers will receive a 10 % deduction per day. Make also sure that you don't forget to submit the electronic version for the final version (not for the draft!) online at www.turnitin.com (CourseID: 11153249, Password: Chem30CL, (case sensitive!)) by Friday, February 5, 2016 at 5:00 pm). Late online submission will also receive point deduction. If you do not have an account there, you will have to open one first before you can enroll in the class and submit your paper. Any plagiarism will be reported to the Dean of Students immediately.
Step 1 and step 2 have to be completed during the first meeting so that the anilide has enough time to dry. If the chloroanilide is wet, the formation of the final product (=lidocaine) does not work well!
Step 1: Formation of 2,6-Dimethylaniline (2,6-Xylidine)
Part I: Formation of Iron nanoparticles
The reduction of iron(II) sulfate using the sodium borohydride leads to the formation of iron nanoparticles. These particles are highly magnetic and stick to the stir bar, hence the need to remove the stir bar before allowing them to settle.
The nanoparticles should be kept wet in order to avoid that they get airborne. They should also be used right away in order to make sure that they are still reactive.
It is imperative that the temperature is propely controlled during the reaction. The target temperature is 40 oC. At lower and higher temperatures, the reaction appears to encounter a lot of problems, being too slow a lot at low temperatures and are showing side reactions (i.e., oxidation of iron by water) at high temperatures.
The extraction of the organic layer with hydrochloric acid serves the separation of the amine and nitro compound. The amine is protonated and becomes more water soluble. The addition of potassium hydroxide to the aqueous layer deprotonates the ammonium ion causing the product to separate as a yellowish oil on the top.
Anhydrous potassium carbonate is used as drying agent because it is a base and therefore does not absorb the the amine as strongly as sodium sulfate or magnesium sulfate.
The use of an excessive amount of drying agent (K2CO3) has to be avoided. Also, it has to be removed prior to the removal of the solvent! Why?
Step 2: Formation of the Amide (chloroanilide)
Glacial acidic acid is used as a solvent here again. Why?
The bottle containing the a-chloroacetyl chloride has to be closed when not needed. Why?
After the reaction is completed, a dilute solution of sodium acetate is added. Why?
The obtained product has to be dried very thoroughly. Why?