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Things You'll Need
Instructions
Set up the hot plate/stirrer on the base of the ring stand inside the fume hood. Conduct the remainder of the experiment in the fume hood. Put the sandbath atop the hot plate, and clamp the thermometer to the ring stand so the bulb of the thermometer is below the surface of the sand.
Add a boiling chip to the conical vial, followed by 0.5 mL of the isopentyl alcohol, the spin vane and 1.5 mL of the glacial acetic acid. Add one drop of concentrated sulfuric acid. Be aware that glacial acetic acid is quite corrosive, and concentrated sulfuric acid is extremely corrosive. Be careful when working with both of these chemicals.
Using an o-ring and screw cap, connect the conical vial to the reflux condenser. Connect a drying tube with an o-ring and screw cap to the other end of the reflux condenser.
Clamp the condenser and conical vial to the ring stand. Position them so the vial is in the sand bath with its base just below the surface of the sand.
Connect a hose from the water outlet to the bottom nipple on the reflux condenser, and connect the other hose from the top nipple to the drain. This way, water will flow through the reflux condenser from bottom to top, then out the top hose into the drain.
Turn on the water gently. Do not turn it on all at once, because then you could cause one of the hoses to disconnect and create a small flood. You only need a gentle flow of water through the reflux condenser.
Turn on the magnetic stirrer so the spin vane inside the conical vial begins to rotate; it will keep the reactants well-mixed. Turn on the hot plate and heat the sandbath up to 160 to 180 degrees Celsius. You should see the mixture gently boiling and condensate forming on the lower end of the reflux condenser, then dripping back into the vial.
Keep the mixture in between 160 and 180 for one hour.
Turn off the hot plate and magnetic stirrer. Using the clamps, elevate the conical vial and reflux condenser apparatus so they are now a couple inches above the sand bath. Remove the sand bath and allow the conical vial to cool.
Turn the magnetic stirrer back on once the conical vial is at room temperature (or close to it). Move the vial back down so that the spin vane inside begins to spin again. Remove the reflux condenser from the conical vial and turn off the water.
Add 1.5 mL of sodium bicarbonate solution to the conical vial slowly (not all at once). This will neutralize the sulfuric acid catalyst and some of the excess acetic acid. You should see the mixture bubble somewhat.
Add 1 mL of MTBE and make sure the contents of the flask mix. If necessary, remove the conical vial from the clamp, cap it and shake the contents gently, then reattach it to the ring stand with the clamp and remove the cap again.
Wait for the two layers to separate. You should see a layer of MTBE floating atop a layer of water in the conical vial.
Suck out the bottom water layer with your Pasteur pipette, being careful not to suck up any of the top layer as well. Transfer the water layer to one of the test tubes.
Add another 1.5 mL of sodium bicarbonate solution, mix and allow the layers to separate then transfer the water layer to another test tube. Repeat this procedure once more (for a total of three 1.5 mL washes in all).
Test the pH of the last wash with pH paper to make sure it's neutral or basic. If not, do a fourth wash with another 1.5 mL of sodium bicarbonate solution.
Add a little sodium sulfate (~50 mg or so) to the conical vial and cap it tightly.
Push a small plug of cotton down from the top of a Pasteur pipette and into its neck using some wire. It's important that the cotton plug be big enough it doesn't become completely dislodged and yet small enough it will not totally block the flow of fluid. A small pinch of cotton wool should be enough.
Connect this plugged Pasteur pipette to the ring stand with a clamp and secure it so the top of the cotton is horizontal.
Pour a little sea sand into the pipette. (A conical funnel may be helpful here.) The layer of sand should be 1 or 2 mL thick. Tap the pipette until the layer of sand lies horizontal.
Pour some silica gel into the pipette -- enough to raise the level by 5 cm or so. Add another couple millimeters of sea sand to the top of the silica gel. Place a small beaker or Erlenmeyer flask beneath the plugged pipette.
Put on another pair of gloves so that you are now wearing double gloves. Methylene chloride is potentially toxic and should always be handled in the fume hood and while wearing double gloves.
Add 1 mL of the methylene chloride to the plugged pipette and allow it to drain all the way through. Add the contents of your conical vial to the plugged pipette using another Pasteur pipette. Try not to remove the sodium sulfate along with the liquid (if you remove a little of the sodium sulfate by accident, however, that's okay.)
Rinse the conical vial with 0.5 mL of methylene chloride and add the rinse to the top of the plugged pipette. Add another 2.5 mL of methylene chloride to the plugged pipette and allow the whole volume to flow through.
Put the beaker or Erlenmeyer flask back in your sand bath and heat the sand bath up to 80 to 90 degrees C. The contents should begin to boil. You want to remove all of the methylene chloride and MTBE without evaporating off your product. This is basically a simple distillation, although you are merely evaporating your solvent without trying to recondense it. You can do this, because MTBE and methylene chloride have much lower boiling points and are much more volatile than isopentyl acetate. Make sure you carry this out in the fume hood. Continue to heat the mixture until all your solvent has evaporated and at this point you are done.