Abstract: A method is provided for preparing(4-methylphenyl)(4-isobutylphenyl) iodonium hexafluorophosphate.Toluidine was diazotized by NaNO₂ and decomposed by KI to give 4-iodotoluene.4-iodotoluene reacted with isobutylbenzene in the presence of ammonium peroxodisulfate which acted as oxidant,and then reacted with ammonium chloride to give(4-methylphenyl)(4-isobutylphenyl) iodonium chloride salt.The resulting(4-methylphenyl)(4-isobutylphenyl) iodonium chloride salt reacted with KPF₆ in the solution of acetone to give the(4-methylphenyl)(4-isobutylphenyl)-iodonium hexafluorophosphate,its structure was identified by UV,IR,and ¹HNMR.The total yield is above 46.7%.

Key words: iodonium salt, cationic polymerization, photoinitiator