This work introduces a general framework for the selection of process designs through simultaneous exploitation of reaction and separation options. The synthesis scheme exploits rich superstructures comprised of two types of generic synthesis units. A reactor/mass exchanger unit enables a detailed representation of the reaction and mass exchange phenomena. Conceptual representations of separation systems is facilitated through separation task units. The synthesis scheme supports the decision making process in both, early and late process design stages. A screening stage reveals design insights into the performance of complex reaction-separation systems early in design. This enables the inclusion of the relevant design information into the superstructure formulations of the subsequent design stage. The design options are systematically explored using stochastic optimisation. An example is presented to illustrate the approach.