Catalytic behavior of CoMo/ZSM5 catalysts for CS2 conversion

Catalysts based upon ZSM-5 zeolites (SiO2/Al2O3 molar ratio of 30 and 150) were synthesized and tested for the carbon disulfide (CS2) conversion. First, the zeolites were shaped in pellets using alumina (20 wt%) as binder. The pellets containing ZSM5 (SiO2/Al2O3 = 30) were exchanged with Co2+. Afterwards, this material and the other one, having the zeolite with SiO2/Al2O3 ratio of 150, were co-impregnated with Mo and Co salts. The structural variations were explored by means of X-Ray Diffraction. The progressive reduction of the metal phases was studied by Thermal Programmed Reduction (TPR); the acidity distribution was evaluated by FTIR-pyridine adsorption and the aggregation state of the crystalline phases was characterized by High Resolution Transmission Electron Microscopy (HRTEM) and EDS. The catalytic properties were evaluated in a fixed bed reactor at 350 °C, P = 20 kg/cm2 with a H2/CS2 molar ratio equal to 2. The results suggest a hindering of catalytic activity by the metal phase, which is deposited either on the alumina or over the external surface of the zeolite crystallites.