Summary Of The Lab: Extraction Of Caffiene
Anza Thomas
10/24/2013
CHE 261 (KC)
Dr . McAtee
Lab : Extraction of Caffiene
Purpose: the purpose of this experiment is to extract caffeine from tea using solvent extraction techinques.
Reference: Williamson, K.; Minard, R.; Masters, K. Macroscale and Microscale Organic Experiments, 2007, p. 137 to 171.
Procedure:
In a 50 mL beaker place 15 mL of water, 2.0059 g of sodium carbonate, and a wooden boiling stick. Bring the water to a boil on the ceramic heating plate. Remove the beaker from the hot plate and remove the boiling stick. Immerse a tea bag in the beaker right after taking it off the hot plate for 4 to 5 minutes. After the tea bag cools enough to handle, squeeze out water as much as possible, being careful not to …show more content…
Again bring the water to boil and add a brand new tea bag to the very hot solution for another 4 to 5 minutes. Squeeze out water as much as possible. This time rinse the tea bag with a few mL of very hot water. The more aqueous tea is squeezed out, the more amount of caffeine can be extracted at the end of the experiment. The total volume of aqueous extract was about 10 to 12 mL. Pour the extraction into a 15-mL centrifuge tube. Fill the centrifuge tube about half and use another tube if needed. Use ice bath to bring the temperature of centrifuge tube to room temperature. Add 2 mL of dichloromethane to the tube, cap tube and invert once and open the cap to release any pressure build-up. Repeat this few times. Use the vortex mixer for 10-15 seconds, this shakes the test-tube vigorously. Centrifuge for 60 seconds to accelerate layer separation. Remove the bottom organic layer into a clean, dry 50 mL Erlenmeyer flask using a disposable glass pipette leaving emulsion behind. Repeat the previous two steps for three more times and remove the bottom layer, add it to the same 50-mL Erlenmeyer flask. Carefully swirl the organic layers in the 50 mL Erlenmeyer flask. Dry Erlenmeyer flask either by pipette …show more content…
Crude caffeine should be very dry with no solvent remaining.
Turn on aspirator water full force.
Connect the filter flask to a water aspirator
Control the amount of vacuum by placing the thumb in the Hirsch funnel.
If too much vacuum is applied, the solvent will boil violently and leave the flask.
By admitting a small amount of air, the solvent can be evaporated in a controlled manner.
Heat can be supplied by holding the filter flask in the palm of the
10/24/2013
CHE 261 (KC)
Dr . McAtee
Lab : Extraction of Caffiene
Purpose: the purpose of this experiment is to extract caffeine from tea using solvent extraction techinques.
Reference: Williamson, K.; Minard, R.; Masters, K. Macroscale and Microscale Organic Experiments, 2007, p. 137 to 171.
Procedure:
In a 50 mL beaker place 15 mL of water, 2.0059 g of sodium carbonate, and a wooden boiling stick. Bring the water to a boil on the ceramic heating plate. Remove the beaker from the hot plate and remove the boiling stick. Immerse a tea bag in the beaker right after taking it off the hot plate for 4 to 5 minutes. After the tea bag cools enough to handle, squeeze out water as much as possible, being careful not to …show more content…
Again bring the water to boil and add a brand new tea bag to the very hot solution for another 4 to 5 minutes. Squeeze out water as much as possible. This time rinse the tea bag with a few mL of very hot water. The more aqueous tea is squeezed out, the more amount of caffeine can be extracted at the end of the experiment. The total volume of aqueous extract was about 10 to 12 mL. Pour the extraction into a 15-mL centrifuge tube. Fill the centrifuge tube about half and use another tube if needed. Use ice bath to bring the temperature of centrifuge tube to room temperature. Add 2 mL of dichloromethane to the tube, cap tube and invert once and open the cap to release any pressure build-up. Repeat this few times. Use the vortex mixer for 10-15 seconds, this shakes the test-tube vigorously. Centrifuge for 60 seconds to accelerate layer separation. Remove the bottom organic layer into a clean, dry 50 mL Erlenmeyer flask using a disposable glass pipette leaving emulsion behind. Repeat the previous two steps for three more times and remove the bottom layer, add it to the same 50-mL Erlenmeyer flask. Carefully swirl the organic layers in the 50 mL Erlenmeyer flask. Dry Erlenmeyer flask either by pipette …show more content…
Crude caffeine should be very dry with no solvent remaining.
Turn on aspirator water full force.
Connect the filter flask to a water aspirator
Control the amount of vacuum by placing the thumb in the Hirsch funnel.
If too much vacuum is applied, the solvent will boil violently and leave the flask.
By admitting a small amount of air, the solvent can be evaporated in a controlled manner.
Heat can be supplied by holding the filter flask in the palm of the