On October 23rd, 2014, we updated our
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Water Hydrocarbons/Ethers Chlorinated solvents Water p K a = 4.2 p K a = 16 p K a = 4.2
The Extraction Setup
Make sure the stopcock of the separatory funnel is closed!
Prepare your solution in a beaker. Weigh 1.3 grams and mix with TBME. Transfer the solution into a separatory funnel.
Pour a measured amount of extraction liquid.
Place stopper securely in the funnel.
4. Using your fingers to secure the cover, shake the mixture several times. 5. Vent the pressure by inverting and opening the stopcock. (Vent often!) NOTE: The cover is always secured during the whole operation Experimental Procedure
6. Place the separatory funnel in the iron ring… 7. Remove the cover and allow the layers to separate. 8. Identify the layers (solvents). (Don't throw anything away until sure.) 9. Remove bottom solvent by draining through the stopcock. Pour the upper solvent through the top of the funnel. Experimental Procedure
Use the Microscale Flow Chart on page 135 as a guide (see the handout), but use the Macroscale procedure on page 134. Step 1. The mixture of the three compounds is already prepared for you. (TA will give you the breakdown of the components!!) Step 2. Weak base only deprotonates the strong acid , which means your compounds are in both phases. Step 3. Strong base deprotonates the weak acid , which means you will again have compounds in both phases. Step 4. Isolated p -toluic acid will need to dry in your drawer. Don't forget to pre-weigh your filter paper. Step 5. When heating, don't allow the temperature to exceed 60 degrees C. Before adding HCl , cool the solution in an ice bath. Allow the isolated p - tert -butylphenol to dry in your drawer. (Pre-weigh paper!!) ( Heating is done in the hood.) Step 6. Pre-weigh a round bottomed flask (not a beaker). Perform distillation by rotary evaporation instead of the evaporation procedure in the lab manual. See 2 nd handout for instructions. Use the house vacuum to remove any residual solvent. Make Note of the Following:
Waste Organic Solvents : a waste bottle will be in the hood that will be used for all of the organic solvents.
Waste Aqueous Solutions: a waste bottle will be in the hood for the acid/base solutions from your extractions.
Grading: approximately 2/3 of your grade will be based upon the written lab report (prelab and postlab questions, experimental procedures, conclusions, etc.).