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Procedure for Synthesis of Cyclohexene

Submitted by kwarny on Tue, 03/19/2019 - 22:38

To a tared flask, 2.003 g of cyclohexanol and 0.5 mL of 85% phosphoric acid were added with boiling chips. A fractional distillation column was setup to purify the cyclohexene. The purified sample was then extracted and placed in a reaction tube with 1.0 mL of distilled water. A bottom layer formed, it was thoroughly mixed and then left still to settle. The bottom distilled water layer was removed with a pipette and placed in a bin marked as waste. The sample was extracted with 1.0 mL of sodium hydroxide in reaction tube and thoroughly mixed. The lower layer was removed with a pipette and placed into the waste bin. The same procedure was repeated with 1.5 mL of saturated aqueous sodium chloride. The organic phase was then transferred to a clean vial. For the dehydration, calcium chloride spheres were added and left to dehydrate for five minutes. Once completed, the organic layer was pipetted into a clean vial that did not contain calcium chloride. Gas chromatography analysis  was then performed to determine the purity of cyclohexene. Infrared analysis was then used to determine which functional groups were present. The end product was used in two chemical tests to determine the functional groups present. In the first test, 4 drops of 3% dilute bromine solution in dichloromethane was added dropwise to the cyclohexene product, about 0.25 mL, where no color change was observed. However, in cyclohexane, about 0.25 mL, a red-brownish color was observed. In the second test, 2 drops of 1% potassium permanganate and 10% sulfuric acid was added to cyclohexene product, about 0.25 mL, where no color change was observed but there was a brown precipitate. 1% potassium permanganate and 10% sulfuric acid was added to cyclohexane product, about 0.25 mL, and a purple color was observed.

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