For the conceptual design of countercurrently operated reactive distillation columns, fast methods are needed to estimate potential top and bottom products. The possible column bottom product composition can be determined from the stable singular points of a batch reactive reboiler. In a similar manner the top product composition can be obtained from the stable singular points of a batch reactive condenser. Geometrically, the singular points of both batch processes are located on a common potential singular point surface (PSPS) whose trajectory depends on the reaction stoichiometry and the phase equilibria. At the singular points, the PSPS intersects a reaction kinetic surface that is dependent on the reaction rate expression and the phase equilibrium of a reference component. Based on the singularity analysis, a single-feed reactive distillation column can be designed. Several hypothetical and real reaction systems are analyzed to illustrate the singularity analysis and the design procedure. (C) 2004 American Institute of Chemical Engineers.