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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 |
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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 |
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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 |
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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.