DECOLORIZATION
Experiment #5
CHEM 3(Organic
Chemistry)Group 6:
OBJECTIVE:At the end of this experiment, the
student shall have:
Purified an organic compound Compared the effectiveness of
heating and the addition of color–absorbing reagents to purify the compound
MATERIALS: Bunsen burner
MATERIALS: Tripod
MATERIALS: Wire gauze
MATERIALS: Test tube rack & 3 test tubes
MATERIALS: Spatula
MATERIALS: Test tube brush
MATERIALS: 2 250ml beaker
MATERIALS: Filter paper
MATERIALS: Graduated cylinder
MATERIALS: clay triangle
MATERIALS: iron stand
MATERIALS: glass funnel
MATERIALS: pipette
MATERIALS: aspirator
MATERIALS: stirring rod
MATERIALS: platform balance
MATERIALS: watch glass
CHEMICALS (REAGENTS) : brown sugar
CHEMICALS (REAGENTS) : activated carbon
CHEMICALS (REAGENTS) : distilled water
PROCEDURE 1
50ml H2O5g brown sugar
PROCEDURE 1
brown sugar solution
PROCEDURE 2
PROCEDURE 22ml brown sugar sol’n
test tube 1
PROCEDURE 22ml brown sugar sol’n
(for control)
test tube 1
PROCEDURE 2
2ml brown sugar sol’n
(for control) note the
color of the solution.
test tube 1
PROCEDURE 3
brown sugar sol’n
+heat
PROCEDURE 2
PROCEDURE 3
brown sugar sol’n
+heat
0.1 g activated carbon
PROCEDURE 3
brown sugar sol’n
+heat
PROCEDURE 4
test tube 2
PROCEDURE 4 2ml brown sugar sol’n with activated carbon
test tube 2
PROCEDURE 4 2ml brown sugar sol’n with activated carbon
test tube 2
PROCEDURE 4
2ml brown sugar sol’n with activated carbontest tube 2
note the color of the solution.
PROCEDURE 5
Cool the solution for few minutes and filter it using filter paper.
PROCEDURE 5
PROCEDURE 6 2ml filtrate
test tube 3
PROCEDURE 6 2ml filtrate
test tube 3
PROCEDURE 4
2ml filtratetest tube 2
note the color of the solution.
RESULTS
1st test tube: (BEFORE HEATING) ___________________________
2nd test tube: (AFTER HEATING) _____________________
3rd test tube: (AFTER FILTRATION) ____________________
Brown solution
black solution
Dark brown solution
After it undergone the process of filtration, it hasn’t been purified since the desired result is not achieved.
SET-UP:
HEATING
FILTRATION
DESIRED RESULTS:
COLOR
test tube 1 light browntest tube 2 blacktest tube 3 colorless
DISCUSSION
Through the process called decolorization, we aim to purify the brown sugar through the use of carbon.
In order to do so, activated charcoal was added to the solution to remove the impurities.
The activated carbon absorbed the impurities from the brown sugar and when it was filtered, the brown sugar solution became clear like water.
ERRORS: Contact time Temperature Amount of activated carbon
RECOMMENDATION Sufficient contact time is required to
reach adsorption equilibrium. To prevent darkening of the sugar, it is
recommended that low temperature should be maintained during the initial heating process of the brown sugar.
Amount of activated charcoal should be 2.3% of the weight of the sample.
RECOMMENDATION Decolorize your solution by adding a
small amount of activated carbon to the warm (NOT BOILING) sample solution.
GENERALIZATION :Decolorization process is the process of
removing colored impurities in the sol’n.
Activated carbon also called activated charcoal is a form of carbon processed to have a small, low-volume pores that increase the surface area available for absorption.
Temperature: Lower temperatures increase adsorption capacity.
Activated Carbon is non-polar which results in an affinity for non-polar compounds such as organics (eg. Brown sugar).
VALUES LEARNED When making chemical solutions, always use
the appropriate safety equipment. Always follow the appropriate procedures
when doing the experiment For a typical experiment, you should plan to
repeat it to obtain the desired result. Always consult the instructor for concerns.
REFERENCES: http://www.mctcteach.org/chemistry/
C2224/labman/rc/decolor.htm http://www.ids-environment.com/
environment/us/carbochem/activated_carbon/19_0/s_supplier.html