Microcalorimetric adsorption and infrared spectroscopic studies of supported nickel catalysts for the hydrogenation of diisopropylimine to diisopropylamine

摘要

Diisopropylimine (DIPI) was used as a probe molecule to investigate the hydrogenation of C=N on the Ni/Al2O3, Ni/LaAIO and Ni/LaOx catalysts. Microcalorimetric adsorption and infrared spectroscopy were applied to determine the surface bond strengths and structures of the reactant and product. It was found that the acidic support favored the adsorption and activation of DIPI and H-2 on Ni, leading to the increased activity (TOF) for the hydrogenation of DIPI, while the basic support promoted the dehydrogenation of the amine product on Ni, being unfavorable for the hydrogenation of DIPI. In particular, the conversion of DIPI was significantly increased when isopropanol (IPA) was used as a solvent, due to the hydrogen transfer reaction (HTR) between IPA and DIPI, which was further evidenced by the infrared spectrum of co-adsorbed IPA and DIPI. (C) 2018 Elsevier Inc. All rights reserved.