The desorption of an inert material from a mixed fixed-bed of absorbent and catalyst can be exploited to provide an efficient means of cooling for heterogeneously catalyzed exothermic reactions without the need for extensive heat exchange surface within an adiabatically operated reactor. The use of desorptive heat effects enables one to extend the regenerative cycle times by roughly an order of magnitude over simple, sensible heat uptake and thus attain operating periods long enough to be of technical interest.