Continuous Toluene Hydrogenation System Using Compressed Carbon Dioxide

Abstract

The effect of the addition of compressed carbon dioxide in continuous hydrogenation of toluene has been evaluated with process simulation software and tested with a fixed-bed reactor. The simulation results show that the temperature rise is significantly suppressed in the presence of compressed carbon dioxide and that the equilibrium conversion of toluene (toluene/hydrogen = 1/3) reaches 99.9%, whereas around 60% in the absence of carbon dioxide. Experimental results show that the continuous hydrogenation of toluene (toluene/hydrogen/carbon dioxide = 1/3.1/31, inlet temperature: 20 °C, outlet temperature: <70 °C, and total pressure: 11 MPa) over activated carbon-supported rhodium catalysts proceeds without deactivation. The conversion of toluene reaches 99% and methylcyclohexane is the only product detected.