Question

EXPERIMENT 8: BROMINATION OF TRANS-STILBENE glacial acetic acid Objective: Execute first step of two-step sequence to transform an alkene into an alkyne via a dihalide intermediate and use infrared spectroscopy to identify functional groups PRELAB NOTEBOOK: In the laboratory notebook, write the overall experimental objective, chemical equation(s), reaction mechanism (consider all possible stereoisomers), draw a diagram or outline of the procedural steps, and complete the chemical safety table for all chemicals. 1. Why is pyridinium tribromide used as a reagent instead of bromine? 2. Name the starting material and product. Identify the melting points of each compound. 3. Explain why the final product is in the trans-configuration.

here is the procedure if needed

Answer 1

Liquid Bra is hazardous to human tissue and hence dangerous to handle. This is why the sale pyridinium perboomide. pyt Boz is used which soled and hence easies to handle. This asalt produce Br2 is equillibrum Two Bro T B & Boz ② The reactant Name - stithene trans stilbene melting point = 1226 - 1246 The product Name: Meso -1,2-dibromo - 112-diphenyl ethane melting point = 237°c - 2410

( The reaction proceeds through an formation of a Bromonium in enfermediate which then undergues attack by Br- with inversion, so we get hans product. ph .ph Bo l ph Br (inversion) SN2 type V h odil bir ph b irine poleri n g