Commercial catalysts screening for the direct amination of cyclohexanol

Two groups of commercially available Niand Pd-based catalysts were used for the direct amination of cyclohexanol (CHOL) with NH3 as aminating agent and in the presence of H-2, aiming the selective production of cyclohexylamine (CHA) and aniline. The fresh catalysts were characterized in terms of metal loading, support composition (prevailing SiO2 and Al2O3) and metallic dispersion. Ni-based catalysts revealed to be highly active while Pd-based were more selective towards aniline, however requiring higher temperatures and catalyst loading to reach significant CHOL conversions (from 17 up to 67 %). The activity of the catalysts is intrinsically related to their metallic dispersion regardless the metal loading. The Ni-based catalyst with 46 wt. % of Ni is the most promising once it presents higher turnover frequency (TOF) values, as 10 fold high, particularly related to the ratio of desired to undesired byproducts. Moreover, operating conditions considerably affect catalysts' performance. (c) 2020 The Korean Society of Industrial and Engineering Chemistry. Published by Elsevier B.V. All rights reserved.

Automated summary

The experiment showed that Ni-based catalysts exhibit higher activity, while Pd-based catalysts are more selective towards aniline. The metallic dispersion of the catalysts is closely related to their activity, with the Ni-based catalyst containing 46wt. % Ni showing the most promising characteristics.