The continuous gas phase hydrogenation of benzonitrile has been studied over Pd/C and Pd/Al2O3 (mean Pd size = 2.5–3.0 nm from STEM). Toluene was the predominant product over Pd/C whereas benzylamine was preferred over Pd/Al2O3. This is linked to differences in Pd electronic character (from XPS) that impact on nitrile adsorption. Greater surface acidity and hydrogen availability (based on chemisorption/TPD) for Pd/C resulted in higher conversion rates. Operation at lower contact time for multiple Pd/Al2O3 beds in series promoted exclusive formation of benzylamine at an appreciably higher rate than reported in the literature.
Hao, Y., Li, M., Cárdenas-Lizana, F., & Keane, M. A. (2016). Selective production of benzylamine via gas phase hydrogenation of benzonitrile over supported Pd catalysts. Catalysis Letters, 146(1), 109-116. https://doi.org/10.1007/s10562-015-1655-8