Trans-1 2-Dibromocyclohexane Lab Report

The purpose of this experiment was to perform a bromination reaction that converts cyclohexane to trans-1,2-dibromocyclohexane. To do this, 1 mL of 30% hydrogen peroxide was mixed with 3 mL of bromic acid in a round bottom flask containing a spin vane. The solution turned from clear to orange, dark red. The color change is a useful indicator to identified whether reaction was completed before moving to another step. Next, 1 mL of cyclohexene was pipet into this mixture, which changed the solution from red to orange and eventually yellow. The mixture was transferred into a centrifuge tube with brine solution. Two layers were formed, with a yellow layer on top and the clear bottom layer. The bottom layer is the only organic layer because it is denser. NaHSO3 was used to washed the mixture. The bottom layer was extracted by pipette and rinsed with NaSO4 for drying. The organic layer was transfer into a vial and placed under NEVEP to attain a solid product. The product was a mixture of white solids with liquid.

The experimental yield was 1.034 g of trans-1,2-dibromocyclohexane, which leads to a 42.9% yield. The yield is probably lower because the product had liquid. The mixture was placed in a NEVAP for a long time, but the mixture did not evaporate. If the mixture was completely evaporated, the results will be more accurate especially if the product are still in the aqueous phase. Overall, the amount of H_2 O_2 added contribute to the percent yield as it is the limiting reagent of this reaction. Not having a high yield was probably due to poor technique that failed to extract a solution that is clear. There may have been contamination with NaSO4 because a pipette filter was not used. In the future, the drying agent should be filtered by a pipette filter rather than extracting the organic layer directly with a