High-Active Metallic-Activated Carbon Catalysts for Selective Hydrogenation

Abstract

A series of low-loaded metallic-activated carbon catalysts were evaluated during the selective hydrogenation of a medium-chain alkyne under mild conditions. e catalysts and support were characterized by ICP, hydrogen chemisorption, Raman spectroscopy, temperature-programmed desorption (TPD), temperature-programmed reduction (TPR), X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR micro-ATR), transmission electronic microscopy (TEM), and X-ray photoelectronic spectroscopy (XPS). When studying the effect of the metallic phase, the catalysts were active and selective to the alkene synthesis. NiCl/C was the most active and selective catalytic system. Besides, when the precursor salt was evaluated, PdN/C was more active and selective than PdCl/C. Meanwhile, alkyne is present in the reaction media, and geometrical and electronic effects favor alkene desorption and so avoid their overhydrogenation to the alkane. Under mild conditions, nickel catalysts are considerably more active and selective than the Lindlar catalyst.

Role of the support and chloride during the purification of 1‐pentene in alkyne/alkene streams over Pd catalysts

“…32 Different supports, like metal oxides (TiO 2 , Al 2 O 3 , Fe 3 O 4 , MgO, CaCO 3 , and MnO 2 ), metal-organic frameworks (MOF), or activated carbon (C), are widely used synthesizing catalysts for the selective hydrogenation of alkynes. 6,[33][34][35] To optimize the performance of catalysts, it is essential to understand the effect of the support on the catalytic activity during the selective hydrogenation reaction. On the other hand, to study the effect of the residual chloride species of the chlorinated precursors is of great importance in the purification processes.…”

Selective hydrogenation of phenylacetylene over TiO2 supported Ni2P nanoparticles under visible light irradiation

“…17 Nowadays, despite some progress, nickel-based catalysts are still plagued by low olefin selectivity or over-hydrogenation, which is the main obstacle to the semi-hydrogenation of alkynes. [18][19][20][21][22] Meanwhile, these catalytic processes are usually carried out at a high temperature and high pressure, which will lead to uncontrollable selectivity of products and high energy waste. Therefore, it is very important to conduct the reaction under mild conditions.…”

Fabrication of stable and selective non‐noble metal catalysts for selective alkyne hydrogenation

“…Ni is a non-precious metal that is extensively employed in hydrogenation reactions within industry because of its ability to dissociate hydrogen. 3,4 For instance, Raney-Ni has been employed as the standard industrial catalyst for the hydrogenation of simple nitroarenes for a long time. 5 However, more sensitive/reactive substrates such as alkynes cannot be selectively converted over continuous Ni ensembles owing to a combination of over-hydrogenation of the desired alkene product to an alkane and polymerization which forms oligomers which can then build up and cause deactivation.…”

“…Accordingly, the substitution of precious metals for more abundant alternatives is crucial. Ni is a non‐precious metal that is extensively employed in hydrogenation reactions within industry because of its ability to dissociate hydrogen 3,4 . For instance, Raney‐Ni has been employed as the standard industrial catalyst for the hydrogenation of simple nitroarenes for a long time 5 .…”