The present invention relates to a process for the endothermic, catalytic gas phase reaction of naphtha with hydrogen to form benzene, in which the reaction is carried out in 5 to 12 serial reaction zones under adiabatic conditions. A smart tag issued each visitor includes at least an electronic memory from which information from the memory may be provided andor information may be received and stored in the memory. One or more optional relays are disclosed for establishing the dependency.