Dehydrobromination of meso-Stilbene Dibromide
Introduction
This procedure was performed in order to synthesize an alkyne from meso-stilbene dibromide through double dehydrohalogenation. The removal of the two bromine and two hydrogen atoms allows for the formation of the carbon triple bond and thus the formation of an alkyne. The alkyne formed is diphenylacetylene.
Data and Results The melting point of the product was measured to be between 60C and 62C. The actual melting point of diphenylacetylene is 62.5C, which is essentially the same as the measured melting point. The weight of the product was measured to be 0.038 grams. As the molecular weight of diphenylacetylene is 178.24 grams per mole, this gives a yield of 0.000213 moles. The molecular weight of the reactant, meso-stilbene dibromide, is 340.06 grams and with 0.15 grams used, this gives an initial amount of 0.000441 moles. When comparing the final number of moles to the initial number, this gives a percent yield of 48.3%.
Discussion and Conclusion …show more content…
The first hydrogen atom to depart and the bromine must be on opposite sides of the molecule. Potassium hydroxide acts as a base, removing the hydrogen atom, which causes the formation of a carbon-carbon double bond and thus causes the departure of the opposite bromine atom. The carbon-carbon bond can no longer rotate after a double bond is formed and thus the remaining groups are in a synperiplanar conformation. Owing to this, high heat is needed for the removal of the second HBr molecule. The same mechanism occurs with the removal of the hydrogen atom and subsequent formation of the carbon-carbon triple bond and the departure of the bromine atom. This leaves the final product of diphenyl
Introduction
This procedure was performed in order to synthesize an alkyne from meso-stilbene dibromide through double dehydrohalogenation. The removal of the two bromine and two hydrogen atoms allows for the formation of the carbon triple bond and thus the formation of an alkyne. The alkyne formed is diphenylacetylene.
Data and Results The melting point of the product was measured to be between 60C and 62C. The actual melting point of diphenylacetylene is 62.5C, which is essentially the same as the measured melting point. The weight of the product was measured to be 0.038 grams. As the molecular weight of diphenylacetylene is 178.24 grams per mole, this gives a yield of 0.000213 moles. The molecular weight of the reactant, meso-stilbene dibromide, is 340.06 grams and with 0.15 grams used, this gives an initial amount of 0.000441 moles. When comparing the final number of moles to the initial number, this gives a percent yield of 48.3%.
Discussion and Conclusion …show more content…
The first hydrogen atom to depart and the bromine must be on opposite sides of the molecule. Potassium hydroxide acts as a base, removing the hydrogen atom, which causes the formation of a carbon-carbon double bond and thus causes the departure of the opposite bromine atom. The carbon-carbon bond can no longer rotate after a double bond is formed and thus the remaining groups are in a synperiplanar conformation. Owing to this, high heat is needed for the removal of the second HBr molecule. The same mechanism occurs with the removal of the hydrogen atom and subsequent formation of the carbon-carbon triple bond and the departure of the bromine atom. This leaves the final product of diphenyl