Question

In this experiment, (E)- and (Z)-1-(4-bromophenyl)-2-phenylethene 6 and 7 are synthesized by a solvent-free, mechano-chemical Wittig reaction of benzyltriphenylphosphonium chloride 4, 4- bromobenzaldehyde 5, and potassium phosphate tribasic. These chemicals are placed in a mortar and ground up with a pestle for about 20 minutes to effect the reaction. You will track the completeness of the reaction and observe both 6 and 7 isomers by thin-layer chromatography of the crude product mixture. Although both the E and Z isomers are produced in this reaction, you will only isolate the E isomer 6 by recrystallization from ethanol. 640mg КРО, - Br neat 5 300mg 142.5 mg + | What is the limiting reagent? in the above

Answer 1

The given reaction is. K3 P04 PP hz cle to heat taph 30om 142.5 ng • molecular PPh₂ = 388.9 g/mol. clo E not calar weight of Emoleculen weight of n - 308. Plat. the 1850 glout molecular weigh = 185.02 g/mol. H PPh mass molecular mass 300 mg 388.9 g/mol C1035 = 0.77 milli mole

mole Mass Molecular Moss 142.5mg 185.02 glable - 0.77 millimole WWWLTHILLIGE FERIA the limiting reagent is the reagent & which has lower ratio of its mole To by reaction coefficient. ratio for ph3 = reaction coefficient nole 0.77 Cl . ave Same w - Hence, both have - limiting reagent are presentant in same ratio, therefore no is here because both exact proportion.