Effects of bubbling and stirring on mass transfer coefficients in liquids

In the hydrogenation of α‐methylstyrene by means of a suspended palladium‐alumina catalyst in a stirred reactor the mass transfer of hydrogen through the liquid is the rate‐controlling step and the resistance to chemical reaction at the catalyst surface is negligible except at extremely rapid rates of stirring. This system therefore provides an excellent means of establishing the effects of operating variables and mechanical construction on mass transfer coefficients in liquids in stirred reactors. It is convenient to consider the total resistance to mass transfer as consisting of two separate resistaces: in the liquid adjoining the bubbles and in the liquid adjoining the suspended solid particles; thus R = Rb + Rs. A general equation was evaluated from experimental data based upon unit volume of liquid.