Tetralin Hydrogenation over Supported Nickel Catalysts

An investigation was carried out to study the feasibility of using 5% nickel/alumina catalysts synthesized with different methods and metal precursors for the hydrogenation of tetralin. The catalysts were characterized using atomic absorption spectroscopy, thermogravimetric analysis, X-ray powder diffraction, X-ray photoelectron spectroscopy (XPS), hydrogen chemisorption, and surface area and pore volume analyses. The catalysts were tested in a continuous-flow, fixed-bed, reactor using solvent-free tetralin feed under the conditions of 5 barg hydrogen, 210 degrees C, a weight hourly space velocity of 5 h(-1), and a H-2/HC ratio of 7.5 (gas hourly space velocity, 4220 h(-1)). These reaction conditions were much milder than the ones reported in literature but showed considerably higher catalytic activity even with low metal loadings. The study indicated that the product's isomer ratio was governed by kinetics. Indeed, a remarkable difference was observed in the selectivity for the catalysts synthesized with different metal precursors in relation to cis/trans decalin ratios, where catalysts derived from nickel carbonate showed higher selectivity to cis-decalin compared to catalysts prepared from nickel nitrate. It was speculated that the dispersion and particle size played an important role in this variance, as suggested by XPS and hydrogen chemisorption. It was also found that this change in selectivity was not related to conversion. Similarly, different deactivation patterns were observed over these catalysts.

Automated summary

An investigation was conducted to study the feasibility of using 5% nickel/alumina catalysts synthesized with different methods and metal precursors for the hydrogenation of tetralin. The study found that there was a significant difference in selectivity and deactivation patterns among these catalysts, with the isomer ratio of the product being governed by kinetics.