Selective Hydrogenation of Anthracene to Symmetrical Octahydroanthracene over Al2O3-Supported Pt and Rh Catalysts Prepared by Strong Electrostatic Adsorption

The hydrogenation of polycyclic aromatic hydrocarbons (PAHs) over highly efficient and stable catalysts to fine chemicals and intermediates for producing chemical materials is an effective approach to realize the high value-added utilization of coal tar and slurry oil. Herein, two kinds of Al2O3-supported Pt and Rh catalysts are synthesized by strong electrostatic adsorption (SEA) and used to catalyze the hydrogenation of anthracene. Compared with the traditional catalysts synthesized by wet impregnation, the Pt/Al2O3-SEA and Rh/Al2O3-SEA catalysts have smaller active metal particle sizes and higher dispersion, which can expose more active centers, showing higher catalytic activity. Interestingly, anthracene may be preferentially adsorbed on the surface of the Pt/Al2O3 catalyst in a parallel manner but on the surface of the Rh/Al2O3 catalyst in a lateral manner, which leads to the different hydrogenation routes. 9,10-Dihydroanthracene is an initial product for the hydrogenation of anthracene, which is rearranged into tetrahydroanthracene and subsequently hydrogenated to symmetrical octahydroanthracene (sym-OHA) over the Pt/Al2O3 catalyst. The high selectivity to sym-OHA (93%) with the conversion of anthracene near 100% can be achieved in the hydrogenation of anthracene at 240 degrees C and 7 MPa for 10 h. Additionally, due to the strong anchoring effect, the Pt/Al2O3-SEA catalyst shows high stability for six cycles. This work supplies a new tactic to develop high-performance catalysts for selective hydrogenation of PAHs to important monomers for synthesizing chemical materials.

Automated summary

The hydrogenation of polycyclic aromatic hydrocarbons (PAHs) using highly efficient and stable catalysts can effectively utilize coal tar and slurry oil for the production of fine chemicals and intermediate materials. In this study, Pt and Rh catalysts supported by Al2O3 were synthesized using strong electrostatic adsorption (SEA), which exhibited smaller particle sizes and higher dispersion compared to traditional catalysts synthesized by wet impregnation. The Pt/Al2O3-SEA catalyst showed higher catalytic activity for the hydrogenation of anthracene, and the hydrogenation routes were found to differ between the Pt/Al2O3 and Rh/Al2O3 catalysts. The Pt/Al2O3 catalyst resulted in the selective production of symmetrical octahydroanthracene (sym-OHA) with high selectivity and conversion, and demonstrated excellent stability for multiple cycles.