Experiment 8: Synthesis of Adipic Acid

Performed November 8th & 10th
By
Jennifer Seitz

Organic Chemistry 344
Section 803
Fall 2011

Objective: The purpose of this experiment was to synthesize adipic acid from cyclohexanol via an oxidation reaction that was catalyzed by sulfuric acid. Purity of the product was assessed by measuring the melting point.

Physical Properties/Structures:

Name | Formula | Molecular Weight (g/mol) | Boiling Point (0C) | Melting Point(0C) | Density(g/mL) | Hazards | Sodium Dichromate Dihydrate | Na2Cr2O7 . 2H2O | 297.98 | 400.0 | 357.0 | 2.35 | -Eye/skin irritant-Affects Respiratory System | Water | H2O | 18.02 | 100.0 | 0.0 | 1.00 | N/A | Sulfuric Acid (98%) | H2SO4 | 98.08 | 337.0 |
As a result, instead of adding approximately 2 mL of water, which was calculated for a water temperature of 87.00C based upon the amount of crude product yielded, 22.0 mL of water was added which is necessary if the water temperature is 50.00C. Yet, the solution was heated to boiling meaning the temperature was actually around 100.00C which could have had an effect on the recrystallization of the pure product.

The melting point of the pure adipic acid crystals was 151.00C – 154.00C, which is relatively close to the theoretical melting point of 152.10C. In comparison to the melting point of the crude adipic acid obtained, the more accurate and narrower range of melting points of the pure product shows that while the recrystallization process was not very successful in producing an adequate yield, it was quite successful in purifying the product. The low melting point and wide range of the crude product was most likely due to the fact that not all of the water or solvent had evaporated from the crystals. This error could have been avoided had the product been washed and/or dried more efficiently or had the crude melting point been determined the following lab period after it