Chem 216: Pre-Lab Example
The Pre-Lab assignment is simply a means to show that you are prepared for the
experiment for the day. Should you struggle in the preparation of the Pre-Lab or with any of the
calculations for each lab feel free to email your GSI or Dr. Koreeda. Your GSI will also go over
any details at the beginning of the lab period.
Your Pre-Lab should be written in you lab notebook before you come into the lab. Some
variation off this example is fine. Come up with a system that works for you, but the basic details
should still be there. If you would like to include an outline of the procedure, that would be
appropriate as well. The Pre-Lab is also a good launching point for writing your lab report.
Acetylation of Aniline & Identification of Unknown Aniline Derivative
The conversion of aniline or other amines to their corresponding acetamide allows for the
protection of the amine functionality from attack by electrophiles as well as oxidizing agents. As
a result of adding the protecting group, a crystalline solid is generally afforded that may be easily
purified through recrystallization. Once purified the solid then can be characterized using simple
lab techniques like IR spectroscopy, melting-point analysis, or the Beilstein test to verify proper
identity and synthesis.
NH2a) HCl/water
b) acetic anhydride
c) NaOAc
HN
O
MW: 135 g/mol
Theo. Yield: 0.73 g
mp: 114 oC
Equivalents
Compound
MW, d, M
Moles
Amount
1.0 eq
aniline
93.1 g/mol
5.4 mmol
500 mg
1.0 eq
conc. HCl
37% w/w,
36.5 g/mol
5.5 mmol
0.45 mL
1.2 eq
acetic anhydride
102 g/mol
1.08 g/mL
6.4 mmol
0.60 mL
1.2 eq
sodium acetate
82.0 g/mol
6.5 mmol
530 mg
When using concentrated HCl, the solution from the bottle is generally 37% HCl by weight of
solution. So, with a density of 1.2 g/mL,
€
0.45 mL conc. HCl ×1.2 g HCl
1 mL ×1 mol HCl
36.5 g HCl ×1000 mmol
1 mol ×0.37 =5.5 mmol HCl
