Monday, December 10, 2012

Distillation of Ethanol

Ingredients

  • solution of 40% ethanol and 60% water
  • 2 Erlenmeyer flasks
  • hot plate with magnetic stirrer
  • ring stand
  • clamps
  • aluminum foil
  • cotton balls
  • 2 double-hole rubber stoppers
  • thermometer
  • 3 pieces of 4 inch long, 4 mm wide glass tubing
  • 1 piece of 1 1/2 foot silicone tubing
  • 1 glass measuring cup (5 cups)
  • ice 
  • normal water

Procedure

  1. Weigh an empty flask and record the weight for further use.
  2. Pour 200 ml of the ethanol w/ water solution into the flask.
  3. Weigh the flask with the solution.
  4. Subtract the weight of the empty flask from the weight of the flask with the solution. Record for further use. 
  5. Cover the flask with cotton balls then wrap it up in aluminum foil.
  6. Slide one piece of glass tubing into a hole of the stopper, then, in the other hole, slide the thermometer in so it almost touches the bottom of the flask. 
  7. Drop a spin-bar into the flask and close the flask with the stopper that has the tubing and the thermometer in it.
  8. In the other stopper, slide a piece of glass tubing into one hole and another piece into the other hole. One will be your exhaust tube.
  9. Close the second flask with the second stopper.
  10. Put the hotplate to the left of the ring stand. Place the covered flask on top of the hotplate. Do not turn on the hotplate.
  11. Fill the measuring cup with 3 cups water.
  12. Place the measuring cup to the right of the ring stand, and put a clamp onto the ring stand so it hangs over the middle of the measuring cup.
  13. Put the empty flask into the water and clamp it at the neck. Surround the flask with ice.
  14. Attach the silicone tubing to the glass tube on the covered flask, and then attach the other side of the tube to one of the glass tubes on the other flask.
  15. Cover the silicone tubing near the covered flask with more cotton balls and cover it with aluminum foil. This will conserve the heat so the vapor will not condense inside the tubing.
  16. Turn on the hotplate to 120 degrees C and the stirrer to 150 revs./min.
  17. When the thermometer reads about 85 deg. C, the liquid will start to boil. Don't worry, the liquid will stay at that temperature, even with the hot plate a 120 deg. C. The hotplate at 120 deg. C is to make the liquid boil faster and make more vapor.
  18. When the level of liquid in the flask in the water reaches about 30 to 40 ml, turn off the hotplate.
  19. Disassemble every thing so you have one flask with mostly water, and the other flask with probably 90% of ethanol.
  20. Weigh the ethanol in the flask. Subtract the weight of the empty flask from the weight of the flask with ethanol. You will get the weight of the ethanol. Record for further use. 
  21. Store the ethanol for further use and...............
  22. THERES YOUR ETHANOL!
250 ml flask
Stopper with
thermometer


Flask with cotton balls and
aluminum wrap
Setup #1

Setup #2 with silicon tube covered
 with cotton balls and aluminum wrap

Flask in the measuring cup
and ice setup

Glass tube and exhaust pipe setup



My Results

To find my density of the ethanol and of the solution, I divided the weight of the ethanol/solution by the volume in ml of the ethanol/solution. For the density of my solution I got 0.94 g/ml. For the density of the ethanol I got 0.803 ±0.015.