An experimental investigation of the catalytic hydrogenation of 1,3,5-trimethylbenzene to 1,3,5-trimethylcyclohexane in a simulated countercurrent moving-bed chromatographic reactor is reported. A multiple column configuration of the simulated countercurrent moving-bed chromatographic reactor has been designed and assembled. A microcomputer has been interfaced with the reactor and an analytical gas chromatograph for computer control, data acquisition and analysis. This separative reactor gives a reaction product that contains relatively small amounts of unconverted reactant, and conversions that are considerably in excess of the thermodynamic equilibrium that would be the maximum achieved in non-separative reactors. With appropriate operating conditions, a product purity of 96% and reactant conversion of 0.83 was obtained. Under the conditions of the experiment the equilibrium conversion is 0.4.