Recrystallization Lab Report

Solids: Recrystallization and Melting Points Lab Report

Introduction:

The purpose of this lab is to learn and practice the separation, purification, and identification of mixtures of organic compounds that are solid at room temperature. These skills will be invaluable in future experimentation. Since chemical reactions always have side reactions, creating impurities in the product, we must develop skills to purify these products. In one part of the experiment we will purify solids using recrystallization. Recrystallization will require the use of hot gravity filtration and vacuum filtration using a Buchner funnel. In the other part we will identify an unknown solid using its melting point and mixed melting point depression techniques. Melting point determination will use the DigiMelt device. In addition, thermometers will be calibrated for use in future experiments.

Experimental Procedures:

Recrystallization

Purification of Benzoic Acid

1. Added impure benzoic acid into Erlenmeyer flask

2. Boiled dH2O in Erlenmeyer flask

3. Placed fluted filter paper in funnel over Erlenmeyer flask

4. Added boiling dH2O and boiling stones to benzoic acid

5. Swirled and boiled benzoic acid. Added ~5mL boiling dH2O

6. Hot gravity filtration:

a. Small amount of boiling dH2O added to filter paper setup

b. Added a boiling stone and placed flask on hot plate

c. Poured (5) through filter

d. Used ~2mL boiling dH2O to rinse original flask, poured through filter paper

Purification of Acetanilide

7. Added ~2g Acetanilide to Erlenmeyer flask

8. Added ~40mL boiling dH2O and boiling stones to (9), boiled until the acetanilide dissolved

9. Removed flask from heat and added ~5mL of cold dH2O and ~0.2g of decolorizing carbon

10. Swirled and boiled mixture for 3 min

11. Hot gravity filtration into Erlenmeyer flask

Both

12. Boiled each filtered solution down

13. Covered each flask lightly and allowed to...