Erythro-Dibromide Lab Report

Introduction:

In the lab, Bromide was combined with trans-cinnamic acid in order to see if the resulting product at the end of the experiment would yield either an erythro- or threo-dibromide. Based on how well this experiment was done there is a possible product that would have a melting point around 95°C, threo-, 205°C, erythro-, or somewhere in the middle which would be a combination of the two. The process of refluxing was used to purify the mixture followed by crystallization. In the end, the product that was yielded had a melting range of 188.4°C-190.1°C, which shows that the product was mainly comprised of erythro-dibromide.

Experimental Procedure:

To begin this experiment 10.0mmol, 1.481g, of trans-cinnamic acid must be collected and put into a 50mL round bottom flask. Then add
3) The melting range of the final product is 188.4°C-190.1°C, which is evidence of the erythro product that contains some impurities that lowered the melting point.
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6) Based on the data collected throughout the lab the dominant mechanism for this reaction was through the formation of the bromonium ion forming the erythro enantiomer.
7) (a)If the cinnamic acid were a mix of cis and trans than we would have gotten a mixture of erythro and threo product in the end. (b) If only 5mL of the bromine solution is added then the reaction would not be able to run to completion and bromine would be the limiting reagent causing less final product. (c) If cyclohexane was used then it would not react with the bromide nearly as much as the cyclohexene and there would be a larger amount of bromide in the final