Williamson Ether Synthesis

Material:

160 L p-cresol

3 mL diethyl ether

260 L of 25%, aq, NaOH

Silica gel

18 mg Bu₄N⁺Br^- (tetrabutylammonium bromide)

Anhydrous sodium sulfate

150 L 1-Iodopropane

Carborundum granules

Procedure:

1. Attach the sand bath mantle to power controller unit (keep the knob at 6-7) check the temperature, maintain the temperature around 100-120 ^oC.
2. Professor use heat gun to melt p-cresol with cap vented.
3. Set up reflux condenser attached with water tubing and check the water flow. (bottom in, top out).
4. Add 2 carborundum granules.
5. Add 160 L p-cresol into 5mL conical base micro-vial.
6. Add 260 L NaOH (25% aq)
7. Shake gently, the chemical may stick to the wall.
8. Add 18 mg Bu₄N⁺Br^- (tetrabutylammonium bromide).
9. Add 150 L 1-Iodopropane.
10. Attach the vial to the reflux condenser on sand bath.
11. Maintain the temperature around 100-120 ^oC.
12. After 40 min turn off the heating, lift up the vial and cool to room temperature.

Extraction and Purification

1. Add 1mL diethyl ether in to the reaction vial, shake it and stand for 2 min until 2 separate layers appear.
2. Take the glass pipette and remove the upper layer (Product) without mixing any bottom layer (aq. layer) in to a clean micro-vial.
3. Repeat the extraction on aq. layer twice.
4. Fill the glass pipette with cotton, silica gel, and anhydrous sodium sulfate.
5. Weight your net weight of round bottom flask with cap.
6. Place your product in the glass pipette column and collect your pure product with round bottom flask.
7. Bring it to professor for rotovap evaporation. (diethyl ether)
8. Weight the round bottom flask again. (To find out your product weight) & add 0.7mL chloroform
9. Transfer your product in to a vial and label it for NMR next week.

RESULTS:

Weight of bottom round flask- 17.37 g. Weight of flask with product- 17.48 g

1.) Write about the overall purpose of the experiment and anything of note about the experiment (e.g. cis/trans isomerism).

2.) Please be sure to include an appropriate reaction scheme. Keep in mind the difference between a reaction scheme and a mechanism. Provide a brief explanation / description of the scheme.

3.) Please include your final yield, theoretical yield, percent yield, and limiting reagent calculations for the theoretical yield. For the limiting reagent calculations, this will involve calculating the moles used of the main reactants (not catalysts or solvents); show calculations for both reactants.

4.) Please tell me the merits of your yield (what did you accomplish / did you obtain the desired product?), whether it was good or bad, what may have gone wrong, what can be done to improve the yield, etc.