In this experiment, cyclohexene was synthesized via the dehydration of cyclohexanol using 85% phosphoric acid. First, 0.5 mol phosphoric acid and 2.003 g of cyclohexanol formed a mixture and proceeded through fractional distillation. The experimental boiling point was measured to be 68.5℃.
Two functional tests were used to determine which functional groups were present. In the first test, bromine in dichloromethane was added to cyclohexene product in a vial and into another separate vial containing cyclohexane. The vial containing the cyclohexene observed no change in color, which concludes that the compound contained an alkene because the reaction between bromine and alkene formed colorless dibromide. On the other hand, alkanes react slower with bromine by free radical mechanism initiated by light, which explains the color change of red-brownish. In the second test with 1% potassium permanganate and 10% sulfuric acid, the vial containing cyclohexene had no color change, however a brown precipitate was observed after all the drops were administered. The precipitate formed was manganese dioxide, which forms between reactions of potassium permanganate and alkenes. Lastly, the vial with cyclohexane turned purple because the potassium permanganate did not react with alkanes.
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