Exothermic reversible reactions are an industrially important class of processes, and many have complex kinetics associated with them. This article shows how experimentally measured variables such as residence time, temperature, and conversion can be used to construct a three-dimensional attainable region for a typical exothermic reversible reaction without taking into consideration the kinetics associated with the reaction. The experiments were conducted using an adiabatic batch reactor fitted with a thermistor for temperature measurement. The article also shows how the two-dimensional conversion temperature plot was obtained from the three-dimensional residence trine temperature conversion plot. The two-dimensional plot was then used to propose the optimal process configuration for the process where preheating, reaction, and mixing are allowed. Examination of the boundary of the two-dimensional attainable region of the conversion temperature plot provided the optimal combination of reaction and mixing and thus the optimal reactor structure. The optimal reactor consists of the following reactors in series: a CSTR, a PER, a differential reactor, and finally another PER. The article therefore concludes that, in principle, without knowledge of the kinetics, measured variables such as residence times, temperatures and conversions can be used to generate the attainable region of the process which can be used to propose the optimal process structure for the process. This result can provide the process engineer with a benchmark for what can be obtained and also what the optimal reactor configuration should be for the process.