Lab B: Synthesis of Aspirin Flashcards
what are the 6 classifications based on chemical hazards?
- Flammable(low flash point): Flash point is the lowest temperature at which a liquid can from an ignitable mixture in air near the surface of the liquid. The lower the flash point, the easier it is to ignite the material.
- Corrosives: Corrosives are materials that can attack and chemically destroy exposed body tissues, causing chemical burns. most corrosives are strong oxidizers and they are mostly either strong acids or strong bases.
- Lachrymator: An irritant that causes tearing(watering of the eyes)
- Carcinogen: A substance that is capable of causing cancer
- Teratogen: a teratogen is a drug or other substance capable of interfering with he development of an embryo fetus that may lead to birth defects or developmental malformations
- reactive: things that go boom
What is the flash point of diethyl ether?
-45 degrees celsius
What is the flash point of tert-butyl methyl ether?
-33 degrees celsius
What is the flashpoint of acetone?
-17.2 degrees celsius
What are some examples of corrosives
H2SO4, NaOH, HNO3, Ca(OH)2, Br2
What are some examples of lachrymators?
Thionyl chloride, acrolein, methacryloyl chloride
What are some examples of carcinogens?
Benzene, arsenic, methylene chloride
What are some examples of teratogen?
Phenol, benzene, dinitrotoluene, dioxane
What are some examples of reactive materials?
Na metal, odium hydride, calcium carbide
Draw the NFPA fro phosphoric acid
Refer to notes
Draw the NFPA for acetone
Refer to notes
Draw the NFP for bromine
Refer to notes
On the NFPA what is blue?
Blue: health hazard
4: deadly
3: extreme danger
2: hazardous
1: slightly hazardous
0: no health threat
On the NFPA, what is Red?
Red: Fire hazard
Flashpoints
4: Below 73 F
3: Below 100F
2: Below 200 F
1: Above 200 F
0: Will not burn
On the NFPA, what is the white?
White: specific hazard
W: Water reactive
OX: oxidizing agent
ACID: Acid
CORR: Corrosive
On the NFPA, what is yellow?
Yellow: reactivity hazard
4: may detonate
3: shock or heat may detonate
2: violent chemical reaction; water reactive
1: unstable if ehated
0: stable
What is the waste disposal for this lab/
Acid filtrate must be neutralized
the solution counting ethanol must go into the C,H,O non-halogenated container
Al FeCl3 solutions must be poured into the specially labeled contained “Aq. FeCl3 waste”
What goes in the non-halogenated container? What goes in the halogenated container?
Non-halogenated container: chemicals containing only C, H, O
Halogenated contained: chemicals consigning C, H, O, and halogens
What are the health precautions with acetic anhydride?
Corrosive chemical
irritating to the nose
What are the health precautions with H3PO4
Corrosive.
Describe the purity check with Aq. FeCl3 solution
Phenols react with FeCl3 to produce a deep purple solution
In separate test tubes, add 1 mL of Ethanol, 3 drops of 0.02 M FeCl3, and a small quantity of salicylic acid/aspirin.
A purple coloured solution indicates the presence of a phenolic OH group, hence traces of salicylic acid are present
What is the small scale solvent test?
Add a sample of crude aspirin to two test tubes and fill with solvent(H2O or ethanol(C2H5OH)). Whatever doesn’t dissolve is the solvent of choice
To favori the formation of aspirin, the reaction used _____ equivalents of acetic anhydride to ______ equivalent of salicylic acid
3
1
Draw the reaction scheme for the synthesis of aspirin
Drawn in notes.
The synthesis of aspirin is an equilibrium reaction that is an example of an estrificaiton reaction
Draw the hydrolysis of excess acetic anhydride
drawn in notes
Why do we need to very careful when recrystallizing aspiring?
Aspirin will react with water to revert back to salicylic acid
What is thermometer lag? how will it affect measurements
the delay between a change in the actual temp of a solution and the thermometers response I displaying the new temp. it will overestimate the melting point
what is the boiling point range for acetic anhydride
138-140
Summarize this procedue
- Boil water
how can you force this reaction to go forward?
