A general approach to the design of multicomponent mass transfer accompanied by chemical reactions is presented. Both homogeneous and heterogeneous reactions in liquid phase, as well as their combination, have been studied and incorporated into the film model. Because of the multicomponent nature of reactive separation, the mass transfer equations in the fluid phases are based on the Maxwell-Stefan approach. These equations are coupled by diffusional interactions in the gas (vapour) phase and by both diffusional and homogeneous chemical interactions in the liquid phase. Heterogeneous reaction mechanism has been accounted for by mass balance relationships. The solution obtained allows the determination of concentration profiles of the components along the contacting apparatus.