The Schlogl-1 and bistable Schlogl-2 models in a spatially extended system are studied with the aid of a probabilistic cellular automaton (PCA) emulating chemical dynamics in a dispersed medium. Among the unusual effects observed are the significant deviation of the steady-state behavior from the deterministic value for Schlogl-1 model and two new bifurcations for Schlogl-2 model found under the conditions of intensive stirring and low rate constant k(ex) of mass exchange between the adjacent cells of the PCA. One of these bifurcations results from the suppression of bi- and trimolecular reactions under the condition that the average number of particles [n(X)] in a cell is smaller than 1 and mass exchange rate is slow. The other bifurcation results from the competition between the mass exchange rate and the rate of autocatalysis in separate cells.