Abstract: In a process for the production of VCM, the gaseous reactants and an inert carrier gas are fed into an adiabatic reaction zone in the oxychlorination section, both reaction zones being associated with an integral fluidised bed, the cooled reaction zone containing a vertically coaxial hollow cooling rod bundle forming a passage. A balanced production of VCM is to be achieved, this being done by selecting a ratio of 1 to 6 inclusive between the equivalent diameter of the passage cross-sectional area and the mean gas bubble pocket diameter of the fluidised bed.