Selective Hydrogenation of Phenol to Cyclohexanone in Water over Pd@N‐Doped Carbon Derived from Ionic‐Liquid Precursors

Abstract

In this report, a kind of mesoporous N‐doped carbon (CN‐x) derived from N‐containing ionic‐liquid (IL) precursors were synthesized, and Pd@CN‐x prepared by a simple ultrasound‐assisted method showed higher catalytic activity for the selective hydrogenation of phenol and its derivatives under mild reaction conditions in water than commercial Pd@C and other common Pd heterogeneous catalysts. The catalytic activities of Pd@CN‐x derived from different ILs were different, and further study into the influencing factors, including physical properties, N species of CN‐x, and Pd status of Pd@CN‐x, were performed.

Efficient Room-Temperature Aqueous-Phase Hydrogenation of Phenol to Cyclohexanone Catalyzed by Pd Nanoparticles Supported on Mesoporous MMT-1 Silica with Unevenly Distributed Functionalities

“…As shown in After further grafting with TVS groups, the resulting sample D exhibited decreased mesopore size of 3.8 nm, surface area of 971 m 2 g -1 and total pore volume of 0.89 cm 3 g -1 . The TVS groups gave rise to additional lines in the 1 H spectrum at 5.8 and 6.1 ppm, and the relative amounts of TVS, TMS and Q n species were estimated to be 6 : 6 : 100 by 29 Si MAS NMR (cf. Figure 2).…”

“…[7][8][9][10][11][12][13][14][15][16][17][18][19][20][21][22][23][24][26][27][28][29] Traditionally, the reaction has been conducted in the gas phase at high temperatures, but it often suffers from catalyst deactivation due to coking. 7-13, 15, 16 Numerous recent studies focused on the development of new types of Pd catalysts for the liquid-phase phenol hydrogenation at relatively low temperatures.…”

“…33 To date, only very few Pd catalysts comprising metallic NPs that are either stabilized in polymers 25,31 or dispersed on mesoporous nitrogen-containing carbons, 24,[27][28][29] polymer-functionalized carbon nanotubes, 26 and metal-organic framework MIL-101 22 have been reported to be capable of catalyzing aqueous-phase phenol hydrogenation. For the MIL-101-supported catalyst, there is concern on possible release of hazardous chromium ions in aqueous conditions.…”

Hydrogenation of allyl alcohols catalyzed by aqueous palladium and platinum nanoparticles

“…[7][8][9] In general, the hydrogenation reactions have a crucial role in the preparation of required products for biorefinery and for the flavor, fragrance and pharmaceutical industries, [10][11][12][13][14][15] which are obtained from highly oxygenated biomasses by lowering their O/H ratio. [21][22][23][24][25][26] Metal nanoparticles (NPs) are becoming increasingly attractive for industrial catalysis, thanks to their high surface-to-volume ratio, easy preparation and tunable dimensions. [17][18][19][20] The selectivity in the reduction of the C=C group in the presence of other functional substituents (e.g., C=O or OH), can be controlled by a variety of parameters, such as the nature of the metal catalyst, the presence of a second metal (bimetallic catalysts), the size of metal particles and the nature of the supporting materials (electron-donating or -withdrawing ligand effects, metal-support interactions and solvent effect).…”

Selective Hydrogenation of Phenol

“…On the other hand, the N contained in mpg‐C 3 N 4 resulted in not only a very stable and uniform dispersion of Pd with high proportions of Pd 0 on the surface of the catalyst (70%) but also the additional electronic activation of the Pd NPs ,. Our following study proved that the Pd/CN‐1 catalyst with a lower N content (11.98%), which was synthesized by using ionic liquids as precursors and Ludox HS‐40 colloidal silica as the hard template, could achieve the same catalytic performance for phenol hydrogenation as the mpg‐C 3 N 4 with N content of nearly 60 wt% . Afterwards, many different kinds of nitrogen‐doped carbon materials were taken to support transition metals and applied in phenol hydrogenation, which showed the elevated catalytic reactivity exceeded that of nitrogen‐free carbons ,…”