When two liquid phases are contacted in a stirred tank reactor, dispersed phase mixing can affect average reaction rate and product selectivity in nonfirst order or mass transfer controlled reactions, as shown theoretically in Part I. This work is concerned with experimental measurement of the dispersed phase mixing rate. Various organic phase dispersions in water were studied in stirred tanks with a dye transfer light transmission technique. Batch experiments were performed in 0.30, 5.5, and 86-901. vessels. The variables studied were power input per unit volume, phase fraction, impeller type, and vessel scale. Dispersed phase mixing rates were found to be in the range where they can have significant effects on chemical reactions. A typical value of the mixing rate is 10 volumes of dispersed phase/min. a t a power input of 10 hp./1,000 gal. The information given here and in Part I shows for the first time the importance of these effects in reactor design. Fully Draft Marine propeller 2311. 1.1 0.50 0.66 0.65 Sin. 1.6 0.48 -0.48 Flat blade turbine 2 in. -0.50 6.0 -Sin. -0.48 4.9 -86-gal. vessel Power coefficient Pitch D i n l p . --Fully Draft Diam. Diam. D t m k baffled tube 1.3313. 0.91 0.50 -0.16