This paper is dedicated to the dynamical analysis of tubular reactor models, namely plug-flow and axial dispersion reactors involving sequential reactions for which the kinetics only depends on the concentrations of the reactants involved in the reaction. This analysis is performed by describing these models as infinite-dimensional state-space systems, with bounded observation and control operators. It is shown that these systems are exponentially stable, and that (a) the plug-flow reactor model is observable when the component concentrations are measured at the reactor output and observable with respect to its physical domain when only the product concentration is measured, and it is reachable with respect to its physical domain when it is controlled at the reactor input; and (b) any finite set of dominant modes of the axial dispersion reactor model is observable, when either all the component concentrations or only the product concentration are measured, and reachable, by using appropriate sensors and actuators. The dynamical properties of related finite-dimensional models are;also discussed.