Unknown

Ammonium thiocyanate (7.5 g) was dissolved in 25 ml distilled deionized water (thiocyanate solution). Barium chloride dihydrate (0.2 g) was dissolved in 25 ml of 0.4 N HCl (solution A). Ferrous sulfate heptahydrate (0.1 g) was dissolved in 10 ml distilled deionized water (solution B). Six milliliters of solution A was mixed with 6 ml of solution B by vortexing for 1 min, followed by centrifugation for 3 min. The clear solution of Fe(II) chloride was used immediately after preparation. Cumene hydroperoxide was dissolved in nonpolar solvent prior to mixing with methanol. To 10 ml of the nonpolar solvent/methanol (2:1) mixture, 50 ml of ammonium thiocyanate solution was added and vortexed for 2–4 s. Then 50 ml of iron(II) chloride solution was added and vortexed for 2–4 s. After a 20-min incubation period at room temperature, the absorbance was determined at 500 nm.