An alkylation reaction chamber for contacting acid catalysts with alkylation reactants. A heat exchanger, a plurality of baffles and a plurality of spray nozzle assemblies are disposed within a vertically positioned, elongated vessel. Acid catalyst flows upward in serpentine fashion through the vessel and alkylation reactants are sprayed into the catalyst at a plurality of elevations within the vessel. Exothermic heat of reaction is removed by the heat exchanger.