Dynamic simulation is presented as a tool to; asses operational and control issues for reactive distillation systems. READYS is applied to three examples showing interesting behavior during start-up. It can be seen, through the examination of the cases studied in this work, how a given start-up policy can be better or worse for the overall process. Sometimes, it can send the column to a completely inappropriate operating condition. The transient responses of a reactive distillation column with multiplicity of solutions yielding different steady states during start-up operation are presented.