FS14, CEM255, Week 5,6...Determining Boiling Point -Put 2 drops of your unknown into the micro...

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