What is the product of bromination of trans-stilbene?
Bromination of trans-stilbene produces predominantly meso-1,2-dibromo-1,2-diphenylethane (sometimes called meso-stilbene dibromide), in line with a mechanism involving a cyclic bromonium ion intermediate of a typical electrophilic bromine addition reaction; cis-stilbene yields a racemic mixture of the two enantiomers …
What reagent is used as a brominating agent in the electrophilic addition of stilbene?
Bromine and chlorine readily undergo addition reactions with alkenes. This practical involves the bromination of trans-stilbene using a 10% bromine dichloromethane solution.
What is bromination with example?
The bromination of benzene is an example of an electrophilic aromatic substitution reaction. In this reaction, the electrophile (bromine) forms a sigma bond to the benzene ring, yielding an intermediate. Then, a proton is removed from the intermediate to form a substituted benzene ring.
How do you distinguish CIS stilbene and trans stilbene by UV spectroscopy?
The key difference between cis and trans stilbene is that in cis stilbene, the two phenyl groups are on the same side of the double bond whereas, in trans stilbene, the two phenyl groups are on the opposite sides of the double bond.
Why is the melting point of Z stilbene so much lower than e stilbene?
(Z)-Stilbene is sterically hindered and less stable because the steric interactions force the aromatic rings 43° out-of-plane and prevent conjugation. (Z)-Stilbene has a melting point of 5–6 °C (41–43 °F), while (E)-stilbene melts around 125 °C (257 °F), illustrating that the two compounds are quite different.
Is cis or trans stilbene more stable?
This means there is no bumping taking place and so no electric repulsion. Therefore, generally speaking, the trans (E) isomers are more stable and lower in energy than the cis (Z) isomers.
How do you brominate trans-stilbene?
Bromination of trans-stilbene Weigh 0.4 g of trans-stilbene and place it in an 18 x 150 mm test tube. Add 4 mL of glacial acetic acid and heat the test tube in a water bath to dissolve the solid. Stir with a glass rod until it completely dissolves.
What type of reaction is trans-stilbene and bromine?
Hence, an addition reaction takes place an 1,2-dibromo-1,2-diphenylethane is formed. MECHANSIM: The alkene, trans-stilbene, acts as a nucleophile and the bromine acts as an electrophile. Hence, the nucleophilic double bond undergoes an electrophilic addition reaction by the bromine reagent.
How do you make stilbene dibromide?
Procedure – Preparation of Stilbene Dibromide from trans-Stilbene Rinse a clean 250 mL Erlenmeyer flask with acetone to remove traces of water. To this Erlenmeyer flask, add 40 mL of glacial acetic acid and 4.0 g of trans-stilbene. Add 25 mL of a 1 M solution of elemental bromine in CH.
How do you convert trans-stilbene to diphenylethane?
This practical involves the bromination of trans-stilbene using a 10% bromine dichloromethane solution. Hence, an addition reaction takes place an 1,2-dibromo-1,2-diphenylethane is formed. MECHANSIM: The alkene, trans-stilbene, acts as a nucleophile and the bromine acts as an electrophile.