NOVELTY - Radial flow reactor (1) for carrying out chemical and catalytic reactions with an isothermal reaction regime, comprises a cylindrical casing (3), which is arranged around a central axis (6), an annular reaction chamber (7), a perforated central pipe, an outer cavity (12), and a perforated outer wall. The annular reaction chamber is formed in the cylindrical casing. The annular reaction chamber surrounds the perforated central pipe and is surrounded by the outer cavity. The outer cavity and the reaction chamber are separated by the perforated outer wall.    USE - The reactor comprising directly and adjacently arranged heat exchange tubes, which form the radial flow channels, and molten salt as heat transfer medium is useful in the heat exchange tubes for obtaining isothermal reaction regime, for carrying out a reaction under evolution of heat with isothermal reaction regime with molten salt as heat transfer medium within the heat exchange tubes, for gas phase reactions, preferably exothermic or endothermic catalytic reactions, and for oxidation-, hydrogenation-, dehydrogenation-, nitration-, alkylation reaction or for the preparation of hydrocarbons from alcohols or dimethyl ether, preferably for gasoline synthesis from methanol and methanol synthesis from the synthesis gas (all claimed).    ADVANTAGE - The reactor carries out chemical and catalytic reactions in a cost efficient and easy manner.    DETAILED DESCRIPTION - Radial flow reactor (1) for carrying out chemical and catalytic reactions with an isothermal reaction regime, comprises a cylindrical casing (3), which is arranged around a central axis (6), an annular reaction chamber (7), a perforated central pipe, an outer cavity (12), and a perforated outer wall. The annular reaction chamber is formed in the cylindrical casing. The annular reaction chamber surrounds the perforated central pipe and is surrounded by the outer cavity. The outer cavity and the reaction chamber are separated by the perforated outer wall. The outer cavity and the central pipe are provided for supplying the reaction gas and for discharging the product gas. The reaction chamber is penetrated by many heat exchange tubes. The heat exchange tubes are arranged parallel to the central axis and in many groups such that the groups form solid series, which are arranged in the radial direction in the reaction chamber. The outer contours of the adjacent heat exchange tubes of the series lies close together such that the radial flow channels are formed.    DESCRIPTION OF DRAWING(S) - The figure shows a schematic longitudinal representation of the reactor.    Reactor (1)    Cylindrical casing (3)    Central axis (6)    Reaction chamber (7)    Outer cavity (12)