Jove Lab Chem
Esterification — 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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First, put on a lab coat, safety glasses, and nitrile gloves. Note: Some of the reagents are volatile or have unpleasant odors, so you will handle them in a fume hood.
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Ensure that you have glass and organic waste containers and that each sink has paper towels.
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Follow the table to designate codes for the carboxylic acids and alcohols used in this lab. The carboxylic acids are coded A through C, and the alcohols are coded D through I. The students will use a 3:1 molar ratio of alcohol to carboxylic acid in the reaction.
Code Compound MW
(g/mol)Density at RT (g/cm3) Moles per vial Grams per vial cm3 per vial Number of vials A Acetic acid 60.05 1.049 0.07 4.2035 4.0 3 B Butyric acid 88.11 0.953 0.07 6.1677 6.5 3 C Anthranilic acid 137.14 - 0.07 9.5998 - 1 D 1-Propanol 60.10 0.803 0.21 12.6210 15.7 1 E Isoamyl alcohol 88.15 0.810 0.21 18.512 22.8 1 F 1-Butanol 74.12 0.810 0.21 15.565 19.2 1 G Ethanol 46.07 0.789 0.21 9.6747 12.3 1 H Methanol 32.04 0.791 0.21 6.7284 8.5 2 I 1-Octanol 130.23 0.830 0.21 27.348 32.9 1 -
Prepare the three carboxylic acids: acetic acid, butyric acid, and anthranilic acid. Each group will need 0.07 moles of their assigned carboxylic acid in a vial.
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Tare a 10-mL glass vial on an analytical balance in a fume hood. Use a Pasteur pipette to measure 4.2035 g of acetic acid, which will be about 4 mL. Cap the vial and label it ‘A’. Prepare two more labeled vials of acetic acid in the same way.
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Weigh 6.1677 g of butyric acid, which will be about 6.5 mL, in a tared 10-mL vial. Cap the vial and label it ‘B’. Prepare two more vials of butyric acid in the same way.
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Use a small spatula to weigh 9.5998 g of solid anthranilic acid in a tared 10-mL vial. Cap the vial and label it ‘C’. You should now have a total of seven vials of carboxylic acid.
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Prepare the 7 alcohols. Each group will need 0.21 moles of their assigned alcohol in a vial. Use the table as a guide to prepare and label one vial of each alcohol. Prepare and label two vials of methanol.
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You should now have a total of seven vials of alcohol. Keep the reagent vials in the instructor's hood for now and put away the stock bottles of the carboxylic acids and alcohols.
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Assign each student group one of these seven combinations of reagents.
Ester code Carboxylic acid Alcohol Ester product Scent AD Acetic acid 1-Propanol Propyl acetate Pear AE Acetic acid Isoamyl alcohol Isoamyl acetate Banana AI Acetic acid 1-Octanol Octyl acetate Orange BF Butyric acid 1-Butanol Butyl butyrate Pineapple BG Butyric acid Ethanol Ethyl butyrate Strawberry BH Butyric acid Methanol Methyl butyrate Apple CH Anthranilic acid Methanol Methyl anthranilate Grape -
Prepare or obtain seven vials of the fruit scents and label them with the fruit names as references.
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Set out the following glassware and equipment at each student lab station (we suggest that students work in pairs):
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Put bottles of saturated sodium bicarbonate and 3 M sulfuric acid in a dedicated fume hood, along with a roll of plastic paraffin film and scissors.
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Set out filter paper and Pasteur pipettes in a central area so that every student group can easily access them.
1 Lab stand 2 3-prong clamps 1 Stir plate 1 Lab jack 1 Heating mantle 1 Temperature controller 2 Pieces of tubing (for condenser) 1 Joint clip 1 Tube of vacuum grease 1 Box of laboratory wipes 1 10-mL graduated cylinder 1 600-mL beaker 1 50-mL round-bottom flask and flask stand 1 Standard condenser 1 Small stir bar 1 Glass rod 1 Package of pH paper 2 Pasteur pipette bulbs -
Just before the lab, fill a large insulated cooler with crushed ice. Place the cooler and an ice scoop in a central area in the lab.
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When the students arrive, show them how to safely waft vapors before giving them their assigned reagents.
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