A systematic method presented synthesizes extractive reaction processes. The objective is to develop liquid-phase processes involving simultaneous reaction and separation by extraction to achieve improved yield, selectivity to a desired product, and separation of byproducts. The method is based on the equilibrium thermodynamic analysis of multicomponent reactive systems with multiple liquid phases. Using transformed coordinates, systems with three or fewer degrees of freedom can be conveniently analyzed regardless of the number of components in the system. Key features of the reactive phase diagrams relevant to achieving the process objectives are identified. The method is illustrated with several model examples to demonstrate the advantages of extractive reaction over conventional single-phase processes.