Selective Hydrogenation of Benzonitrile by Alumina-Supported Ir–Pd Catalysts

Abstract

The kinetics of liquid-phase hydrogenation of benzonitrile have been examined alumina supported Ir, Pd and Ir-Pd catalysts. Benzonitrile disappearance TOF is 10-fold higher for Pd catalyst than it is for Ir catalyst. Benzylamine is produced preferentially over Pd, whereas dibenzylamine is produced principally over Ir. Non-monotonic activity and selectivity relationships with bimetallic composition are obtained.

Supported Ir–Pd nanoalloys: Size–composition correlation and consequences on tetralin hydroconversion properties

“…Indeed, while the heating of Ir(acac) 3 /ASA in H 2 yields 1.5 ± 0.3 nm Ir particles, that of Pd(acac) 2 /ASA gives rise to 4.5 ± 1.3 nm Pd particles. This suggests a faster diffusion of Pd species on the support, as already proposed by López-De Jesús et al In regard to the similarities of our results with those for Ir-Pd/c-Al 2 O 3 synthesized from chlorinated precursors by these authors [32], the difference of interaction with the ASA surface, which is aluminarich [41]. In summary, appears to arise from the metal atoms themselves, that is, Ir interacts more strongly than Pd with the support.…”

“…Recently, López-De Jesús et al have synthesized Ir-Pd/c-Al 2 O 3 catalysts by impregnation of chlorinated precursors and calcinationreduction [32]. As in our case, the authors have observed an increase in the particle size with the Pd content.…”

“…However, the previously cited studies on Au-Pd [47] and Ir-Pd [32] used chemical preparation methods, as well as the present work. This shows that the previous concept is extendable to practical bimetallic catalysts.…”

“…Ir-Pd/c-Al 2 O 3 was prepared by impregnation using IrCl 3 and Pd(NO 3 ) 2 precursors, but separate particles were obtained [31]. López-De Jesús et al prepared Ir-Pd/c-Al 2 O 3 catalysts from IrCl 3 and PdCl 2 for liquidphase hydrogenation of benzonitrile and evidenced a nanoparticle size-composition correlation [32]. Using a colloidal method, Shen et al synthesized Ir-Pd/C catalysts and observed a positive effect of Ir addition to Pd for ethanol oxidation in alkaline media [33].…”

IrPd nanoalloys: simulations, from surface segregation to local electronic properties

“…Although the bulk immiscible iridium-palladium has been only scarcely studied till now (Tripathi 1991;Turchi 2006;Kolb 2006), a few experimental reports on this system show its actual interest for catalysis (López-De Jésus et al 2010;Shen et al 2010;Piccolo et al 2012). In particular, it has been shown that supported IrPd nanoalloys are more selective than their pure counterparts in the preferential oxidation of CO in hydrogen excess, a reaction used for the elimination of CO impurities in the H 2 production process (Morfin et al 2012;Zlotea et al 2014).…”