E-Stilbene

The melting point is the temperature at which a solid precipitate changes into its liquid form upon heating. It also helps when determine which isomers predominate. The experimental melting point of the E-stilbene was 242 degrees Celsius. The actual melting point of the E-stilbene was 241 degrees Celsius. This verifies that the predominating isomer is meso indicating that the cyclic intermediate remained. Therefore, almost no error occurred within the reaction since the two melting points are almost identical. The error potentially was caused by not fully rinsing the precipitate with cold DCM. If not rinsed completely, impurities and D/L isomers could possibly still remain in the precipitate. With this, impurities can cause the melting point to fluctuate based on the amount present. Impurities …show more content…
Therefore, errors in the data obtained were caused more than likely by human error in reading the thermometer or heating the reaction a little longer than past its desired melting point. The percent yield obtained from the experiment was 62.78%. This was calculated by taking the beginning E-stilbene amount which was 0.9 grams of E-stilbene and multiplying it by the molecular weight of the E-stilbene which was 180.245 g/mol. The resulting value was 0.0049932 moles of E-stilbene. This value was then multiplied by the molecular weight of dibromostilbene which was 340.058 g/mol. Therefore, the expected value was 1.698 grams of dibromostilbene. The actual value from the experiment was 1.066 grams of dibromostilbene. The actual value, 1.066, was divided by the expected value of 1.698. Then, the resulting number