Selective Hydrogenation of Phenol to Cyclohexanol over Ni/CNT in the Absence of External Hydrogen

Abstract

Transfer hydrogenation is a novel and efficient method to realize the hydrogenation in different chemical reactions and exploring a simple heterogeneous catalyst with high activity is crucial. Ni/CNT was synthesized through a traditional impregnation method, and the detailed physicochemical properties were performed by means of XRD, TEM, XPS, BET, and ICP analysis. Through the screening of loading amounts, solvents, reaction temperature, and reaction time, 20% Ni/CNT achieves an almost complete conversion of phenol after 60 min at 220 °C in the absence of external hydrogen. Furthermore, the catalytic system is carried out on a variety of phenol derivatives for the generation of corresponding cyclohexanols with good to excellent results. The mechanism suggests that the hydrogenation of phenol to cyclohexanone is the first step, while the hydrogenation of cyclohexanone for the generation of cyclohexanol takes place in a successive step. Moreover, Ni/CNT catalyst can be magnetically recovered and reused in the next test for succeeding four times.

Catalytic Conversion of Lignin to Liquid Fuels with an Improved H/Ceff Value over Bimetallic NiMo-MOF-Derived Catalysts

“…It was interesting to find that the yield of phenol was slightly higher than ethylbenzene and the yield of cyclohexanol is 2–5% lower than that of ethylcyclohexane. The result confirmed again that ethylbenzene was more easily dearomatized than phenol, illustrating that phenol was more stable than ethylcyclohexane in the catalytic system . This corresponded to the results in Table entry 11 that a large amount of phenol could not be converted into cyclohexanol.…”

Selective aqueous‐phase hydrogenation of furfural to cyclopentanol over Ni‐based catalyst under mild conditions

“…Nickel-based catalysts have been widely known for excellent hydrogenation activity. [1][2][3][4][5][6][7][8] Although many noble metal-based catalysts witnessed considerable success in furfural (FFR) hydrogenation, it still faced many challenges, such as high prices, environmental pollution, and so on. [8][9][10] Therefore, non-noble metal catalysts, such as Ni, Cu, and so forth, have attracted increasing attention due to their good catalytic activity.…”

“…[8][9][10] Therefore, non-noble metal catalysts, such as Ni, Cu, and so forth, have attracted increasing attention due to their good catalytic activity. [1][2][3][4][5][6][7][8][11][12][13][14] FFR is an important platform chemical derived from biomass, [1,2] which could be converted into different value-added chemicals, such as tetrahydrofurfuryl alcohol, cyclopentanone (CPO), and cyclopentanol (CPL). [15] Zhang et al reported the selective hydrogenation of FFR to furfural alcohol (FFA) over Ni/MMO-NO 3 in isopropanol, with a selectivity of 97% toward FFA.…”

“…[ 8–10 ] Therefore, non‐noble metal catalysts, such as Ni, Cu, and so forth, have attracted increasing attention due to their good catalytic activity. [ 1–8,11–14 ]…”

Greenhouse gas emissions reduction by process intensification: Reactive distillation column with side decanter

“…23 The phenol process is still under study improving the catalysts and operation conditions, e.g. Ni-Co on biochar, 24 Ni-CNT, 25 Ni-Co on Carbon/ZrO 2 nanoparticles, 26 Ni-Co on silica-titania composite, 27 etc. Hydrodeoxygenation of lignin-derived phenolics such as guaiacol as renewable raw material to produce cyclohexanol have gained increasing research attention in recent years, e.g.…”