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VIDEO 5 – SUPPORTING MATERIALS
Safely Synthesizing Esters
Materials
Reagents
Lab Equipment (Continued)
Safety Equipment
- methanol (methyl
alcohol)
- salicylic acid (solid)
- concentrated sulphuric
acid
- water
-
- gloves (butyl and
nitrile)
- safety goggles
- lab coat with snaps
- sand bucket
- MSDS for all
chemicals used
400 mL beakers
scoopula
10 mL graduated cylinder
plastic squirt bottle
test tube
test tube holder
test tube rack
electronic balance
medicine or disposal droppers
hot plate
retort stand, clamp and string
thermometer
weigh boats
Procedure
Preparatory Work
1. Collect just enough glassware for each group of students.
2. The stock bottle of methanol should not be brought into the class room, but rather a small
volume of methanol should be transferred into a well-labeled 50 mL wash bottle equipped
with a spout, as shown in the video. The use of this type of bottle reduces the likelihood of
spills. It also allows vapours to escape preventing pressure build-up within the bottle.
3. The concentrated sulfuric acid should be dispensed from a glass dropper bottle as shown in
the video. Plastic squeeze bottles should not be used to dispense concentrated acids because
the tip of these bottles may clog.
4. Transport the methanol and salicylic acid in a separate container from the sulfuric acid
between the prep room and the lab.
5. Care must be taken to prevent concentrated sulfuric acid from accidentally coming in
contact with water or organic compounds like methanol. The addition of concentrated
sulfuric acid to water or other solvents like methanol releases a lot of energy. If sulfuric acid
is mixed improperly with methanol the energy released could initiate combustion.
Lab work
5. Add 300mL of water to the 400 mL beaker, and bring to 60˚C on the hotplate (so as not to
exceed the boiling point of methanol).
6. Weight 1 g of salicylic acid and add it to the test tube.
7. Measure 1 mL of methanol into the graduated cylinder and add to the test tube, shaking
horizontally to mix the alcohol and the acid.
8. Add 3 drops of concentrated sulfuric acid and gently mix again.
9. Use a test tube holder to hold the test tube in the water bath, pointed away from all other
persons in the lab. The test tube should be watched carefully and removed from the water
bath if the solution begins to boil.
10. The reactants should be heated for 5-10 minutes and the test tube removed from the water
bath.
11. Add 3 mL of water to the test tube and use wafting technique to detect the scent of methyl
salicylate ester. This compound has a distinctive winter green scent.
Clean-up and Disposal
13. Left over acid should be put into inorganic acids and acid salts waste.
14. Left over methyl alcohol and salicylic acid should be disposed of in a waste bin for
flammable liquids, and organic acids.
15. The test tube where the ester was synthesized should be placed in its own labeled organic
waste container because any sulfuric acid catalyst remaining in these test tubes is
incompatible with other organic waste.
Student Resource
Pre Lab - MSDS Interpretation
Review the MSDS sheets for the reagents being used in the activity. Pull out the most important
information and fill out the tables below.
Chemical Name:
Flammability Rating:
Boiling Point:
Toxicity Rating:
Appearance:
Disposal Protocol:
Health Hazards:
Chemical Name:
Flammability Rating:
Boiling Point:
Toxicity Rating:
Appearance:
Disposal Protocol:
Personal Protective Equipment:
Health Hazards:
Chemical Name:
Flammability Rating:
Boiling Point:
Toxicity Rating:
Appearance:
Disposal Protocol:
Personal Protective Equipment:
Personal Protective Equipment:
Health Hazards: