A tubular reactor that produces maleic anhydride from a gas mixture containing n-butane and oxygen includes a first reaction zone including an inlet for the gas mixture and a second reaction zone including an outlet for a reaction gas mixture, a plurality of tubes extending in an axial direction through the first and second reaction zones, a temperature control system, configured for controlling a reaction temperature in each of the reaction zones independently, includes a heat transfer system for each of the reaction zones configured for controlling the temperature of a liquid coolant flowing through one of the reaction zones, and a circulation pumping system configured for controlling flow conditions of the liquid coolant flowing through the reactor and one of the heat transfer systems, and a preheating arrangement configured for preheating the gas mixture such that the gas mixture enters the first reaction zone at a predefined inlet temperature.