Natural and synthetic (BEA, MOR) zeolite-supported nickel catalysts (∼ 5% by weight) were produced and used for the hydrogenation of toluene and the hydrodeoxygenation of anisole in a continuous flow reactor. Compared to the Ni / NZ and Ni / Escott catalysts, Ni / BEA and Ni / MOR have a higher metal dispersion and a stronger metal-carrier interaction, which leads to a higher concentration of charge-compensating Ni species and a greater high-temperature reduction Summit. Ni / BEA and Ni / MOR also have a significant mass of H desorbed at low temperatures. on2 (centered at 150 ° C) based on H.2-TPD, suggesting that the H species are weakly adsorbed on small Ni clusters. In contrast, the H species were strongly adsorbed by the massive Ni crystal via Ni / Escott and Ni / NZ, which were desorbed at maxima between 211 and 222 ° C. We propose that the strongly adsorbed H species play a crucial role in the hydrogenation of toluene, which leads to a significantly higher yield of methylcyclohexane versus Ni / Escott and Ni / NZ compared to Ni / BEA and Ni / MOR. Both metal and acid sites are required in the hydrodeoxygenation of anisole. The strong Brønsted acid centers and numerous smaller Ni species compared to Ni / BEA facilitated the transalkylation of anisole to phenol and methyl anisole and then the hydrogenolysis of phenol to benzene, followed by the hydrogenation of benzene to cyclohexane.

Graphic summary: Ni catalysts on natural zeolites for the hydrodeoxygenation of anisole


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