Recrystallization Report

CHE 311 " Recrystallization"

Your lab report should follow the format and consist of the following:

Title (be specific)

Your Name

Date

Section Number (CHE 311-0X)

1. Introduction:

Purpose of Experiment
Important theory and/or background material
Structures and/or reactions
Approproate references to literature (if necessary).

2. Methods / Materials: Usually a simple list, but make sure it is accurate and complete.

3. Experimental Procedure:

Describes the process in chronological order
Explain all of the steps in the order they actually happened, NOT as they were supposed to happen.
If you've done it correctly, another researcher should be able to duplicate your experiment.

4. Results and Discussion:

Results are usually dominated by calculations, tables and figures; however, you still need to state all significant results explicitly in verbal form.
Discussion focuses on a question of understanding, "what is the significance or meaning of the results?".

Make a table:

weight of the unknown g

weight of product g

observed melting range of unknown

list of possible compounds and their literature

mp's, and the observed mixed mp's with your product.

How pure do you think the product is? Explain?

5. References and Post-Lab Questions:

a) For the following reported melting points, comment on the purity of the sample:

78-79 ^oC

299-301 ^oC

178 ^oC decomposes

137-149 ^oC

b) If, in any recrystallization, an "oil" (liquid phase) comes out of solution rather than a solid, why did this happen? What can you do about it?

c) What happens in this experiment if more than the minimum of hot solvent is used in the recrystallization?

d) What was the purpose of the hot filtration? Why didn’t you use gravity or suction filtration at this point?

e) In the CRC Handbook, look up 1-bromo-2-nitrobenzene (look under benzene) and list the mp, crystal form, and the solvent used in the recrystallization of this compound.