The hydrogenation of citral in a fixed-bed reactor by using supercritical carbon dioxide was studied. A numerical model was set up by using the commercial software Aspen Custom Modeler (R). By applying literature experimental data, a parameter estimation for the kinetic parameters was carried out. A good fit was reached with the presented model. Furthermore, a sensitivity analysis was performed. The influence of process pressure, inlet CO2 and H-2 concentration, and catalyst particle size on conversion, reactor length, space time yield, yield of the intermediate product 3,7-dimethyl-2-octenal, and pressure drop was investigated.