JoVE Lab Manual
Lab: Chemistry
Lab: Chemistry
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Extraction
Extraction
Learning Objectives
At the end of this lab, students should know...
What property is liquid-liquid extraction based on?
Liquid-liquid extraction is a separation technique based on the difference in solubility of a solute in two immiscible liquids.
What is immiscibility?
Immiscibility means that two liquids do not form a homogenous solution when mixed and partition into different phases.
In general, which phase will non-polar and polar solutes partition to?
Non-polar solutes generally partition into the organic phase, while polar solutes partition into the aqueous phase.
What is the partition coefficient?
The partition coefficient is the ratio of solute concentration in the organic layer to the solute concentration in the aqueous layer.
What property does acid-base extraction harness?
Acid-base extraction is used to extract organic compounds from an organic solvent to an aqueous phase by transforming the solute to its ionic salt phase. This makes the solute more soluble in the aqueous phase than in the organic phase.
List of Materials
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Lab stand with ring fixture5
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Stirring hotplate5
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Vacuum pump (or house vacuum) with tubing5
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Medium 3-prong clamp5
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125-mL glass separatory funnel with stopper5
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125-mL Erlenmeyer flask5
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10-mL glass graduated cylinder15
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50-mL glass graduated cylinder10
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50-mL glass beaker10
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100-mL glass beaker15
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600-mL glass beaker5
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250-mL glass filter flask5
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Büchner funnel5
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60-mL glass funnel10
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100-mm watch glass10
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Glass stirring rod10
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24/40 rubber adapters10
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Pasteur pipette bulb10
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Small spatula10
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pH paper5 package
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Lab tape and labeling pen5
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Cellulose1 g
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Benozic acid5 g
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Caffeine5 g
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Anhydrous magnesium sulfate20 g
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Sodium bicarbonate50 g
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1 M sodium hydroxide300 mL
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3 M hydrochloric acid50 mL
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Dichloromethane300 mL
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20-mL glass vial with solvent-resistant cap1
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Powder funnel1
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Pasteur pipettesDependent on lab size
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90-mm filter paper1 box
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Top-loading balance (at least 1)Dependent on lab size
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Weighing boatsDependent on lab size
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SpatulasDependent on lab size
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Vacuum greaseDependent on lab size
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Lab wipesDependent on lab size
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Deionized waterDependent on lab size
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Crushed iceDependent on lab size
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Ice container (if no ice machine)Dependent on lab size
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Ice scoop (minimum 1)Dependent on lab size
Lab Prep
Source: Lara Al Hariri at the University of Massachusetts Amherst, MA, USA
- Preparation of the Laboratory
Here, we show the laboratory preparation for 10 students working in pairs, with some excess. Please adjust quantities as needed.
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Put on a lab coat, splash-proof safety glasses, and nitrile gloves.
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Place labeled containers for halogenated waste and solid reagent waste in a satellite waste hood. Place a glass waste container nearby.
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Label a 20-mL vial as ‘unknown mixture’.
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Measure out 0.5 g of cellulose and add it to the labeled vial. Measure out 4.75 g each of benzoic acid and caffeine and add them to the vial. Stir the solids well with a glass rod.
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Tightly cap the vial and place it by the balances. Set a box of 90-mm circular filter paper by the balances. Make sure that the area has enough weighing boats, laboratory wipes, and clean spatulas.
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Set out the following glassware and equipment at each student lab station (we suggest that students work in pairs):
1 Lab stand with ring fixture 1 Hotplate 1 Vacuum pump (or house vacuum) 1 Medium 3-prong clamp 1 125-mL separatory funnel with a stopper 1 125-mL Erlenmeyer flask 3 10-mL glass graduated cylinders 2 50-mL glass graduated cylinders 2 50-mL beakers 3 100-mL beakers 1 600-mL beaker 1 250-mL filter flask 1 Büchner funnel 2 60-mL glass funnels 2 100-mm watch glasses 2 Glass stirring rods 2 24/40 rubber adapters 2 Pasteur pipette bulbs 2 Small spatulas 1 Package of pH paper 1 Roll of lab tape and pen -
Distribute boxes of lab wipes and Pasteur pipettes around the lab so that each workstation has them nearby.
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Set out anhydrous magnesium sulfate, sodium bicarbonate, vacuum grease, and several spatulas on a common bench.
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Shortly before the lab, place labeled bottles of dichloromethane and 1 M NaOH in a fume hood.
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Put a bottle of 3 M HCl in a separate fume hood to avoid inadvertent contact between acids and bases.
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