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Overall….
- Work in groups of 4
- Determine the bp of your unknown (as a group, share results)
- In groups of 2: Derivatize your unknown.
First Group: Formation of DNP Derivative
Second Group: Formation of Semicarbazone Derivative
- Share Result:
Take Proton NMR of your unknown sample Make copies of NMR spectrum for everyone in your group
Determining Boiling Point
- Work in the hood (no open flame allowed on the bench)Fill the tube with oil
Determining Boiling Point
Thermoprobe (not thermometer)
Rubber band SHOULD NOT touch the hot oil
Get the disposable tube from stock
room
Carefully break and use the closed end of the
capillary (1/4 of the tube)
Determining Boiling Point
- Put 2 drops of your unknown into the micro tube.
- Start the flame.- Keep heating until you see
vigorous bubbles in the micro tube (you are over the bp now).
- Stop the flame.- Let the solution cool down a
little until there are no bubbles.- Record temperature. This is the
high end of the bp range (i.e. 152.3 oC)
- Let the solution cool down even more until you see liquid goes up the capillary tube.
- Record temperature again. This is the low end of the bp range (i.e. 150.7 oC)
- Find the average and consider that as the bp for your unknown. i.e. 151.5 oC
Identification of an Organic
Unknown Based on NMR, solid
derivatives, and Boiling Point
- 151.5 oC
- 151.5 oC ????????????????
Identification of Aldehydes and Ketones:
Formation of DNP Derivative
Determine mp
Identification of Aldehydes and Ketones: Formation of Semicarbazone Derivative
Determine mp
Other derivatizations for identification…
Alcohols: Ester Formation
Amines: Amide Formation
OH
OH
O
H+
O
O
EsterAlcohol
NH2
Cl
O
AmideAmine
NH
O
1H NMR Assignment
!
1.681.68
2.362.36 2.672.67
3.703.70
1.551.55
O Cl
1.041.04 1.041.04
0.940.94
2.042.04 O4.124.12
1.261.26
O
012345PPM
1H NMR Assignment
0.980.98
1.671.67
2.342.34OH 11.011.0
O
024681012PPM
1H NMR Assignment
7.277.27
7.227.227.277.27
7.247.24
7.247.24 3.663.66H
9.729.72
O
0246810PPM
1H NMR Assignment
