A tubular reactor provided with means whereby the tube may be rotated through reciprocating arcs about the longitudinal axis of the tube to provide radial mixing combined with plug flow wherein process material continuously passes through the tubular reactor operating at predetermined reaction conditions and the path of the process material through the rector is diverted from axial flow preferably by means of static and/or dynamic agitators provided within the tubular reactor in order to increase path length, increase process material flow velocity and improve plug flow.