Chemical reactors are considered where unknown parameter variations are model- led by stochastic parameters. The continuous-time process is transformed to an equivalent discrete-time system with stochastic parameters, which is a natural approach in the context of digital control making the analysis much easier. A stabilizability test for this discrete-time model is used to analyse three cases from the chemical engineering literature. It is shown that stability in a mean sense is too weak from an engineering point of view. One should study stability at least in a mean- square sense, which is the approach given here.