The implementation of chemical reactions in batch or semibatch reactors is strongly limited by the constraints linked to the dissipation of the heat generated by the reactions. A novel concept of heat exchanger reactors offers enhanced thermal performances in a continuously operating reactor. A study program is proposed to assess the feasibility and potentialities of this concept. Two kinds of reactions are carried out to characterize simultaneously the reactor performances in terms of reaction and heat exchange: the oxidation of sodium thiosulfate by hydrogen peroxide and an acidobasic reaction (NaOH/H2SO4). The resultant experimental data emphasize a significant thermal efficiency: the reactant concentrations and therefore the heat generation can be increased without risk of thermal runaway.