Synthesis and Characterization of Nickel(II) Homogeneous and Supported Complexes for the Hydrogenation of Furfural to Furfuryl Alcohol

Abstract

Nickel(II) complexes have been synthesized and characterized using nuclear magnetic resonance (NMR), infrared spectroscopy, high resolution mass spectroscopy, and elemental analysis. The complexes were evaluated as pre-catalysts in the direct hydrogenation of furfural to furfuryl alcohol. The pre-catalysts C1 and C4 gave higher furfural conversion (97% and 96%, respectively), as a result, they were also evaluated in the transfer hydrogenation of furfural using formic acid as the hydrogen source where higher furfural conversion (93%) was obtained and selectivity (100%) toward the formation of furfuryl alcohol at 4 h. The catalyst C1 was recycled three times with and it was observed that the catalytic activity might be due to a mixture of both molecular catalysis and nanoparticles, as evidenced by the decrease in activity in mercury poisoning experiments. The hydrogenation reactions were also extended to alpha-β unsaturated substrates and were selective toward saturation of the carbonyl functionality over alkene groups.

Nickel Catalyzed Alkylation of Oxindoles with Alkyl Alcohols

“…To confirm the homogeneity of the catalyst, alkylation reaction was conducted in the presence of 3.0 equiv. of Hg(0), however, does not affect the yield of 3 (Scheme 5d and Scheme S10) [14] . Intermolecular competitive experiments showed that, alkylation reaction of primary alkyl alcohols are quite slow in compare to aryl alcohols.…”

“…of Hg(0), however, does not affect the yield of 3 (Scheme 5d and Scheme S10). [14] Intermolecular competitive experiments showed that, alkylation reaction of primary alkyl alcohols are quite slow in compare to aryl alcohols. When an equimolecular mixture of 2 q-d2 and 2 q were used with 1 a, only a trace amount of 19-d3 was detected (Scheme 5e and Scheme S11-12).…”

Highly efficient hydrogenation of furfural to valuable products catalysed by Rh (III), Pd (II), Ni (II), Fe (II) and Ru (II) half‐sandwich picolinamide and the SBA‐15 supported molecular complexes as pre‐catalysts

“…6,9,10 To the best of our knowledge, very few reports are found in the literature on the application of homogenous Rh, Ni, Pd and Fe complexes as pre-catalysts in the hydrogenation of FF. [11][12][13][14] Lately, EL is mainly synthesised from various feedstocks such as LA and FA via catalytic reaction with ethanol. Some researchers have obtained EL from FA catalysed by sulfuric acid.…”

“…Catalytic hydrogenation of FF has been widely investigated in the presence of transition and precious metal‐based catalysts 6,9,10 . To the best of our knowledge, very few reports are found in the literature on the application of homogenous Rh, Ni, Pd and Fe complexes as pre‐catalysts in the hydrogenation of FF 11–14 . Lately, EL is mainly synthesised from various feedstocks such as LA and FA via catalytic reaction with ethanol.…”

Convenient hydrogenation of furfural to furfuryl alcohol in metal-catalyzed and organo-catalyzed environments

“…Common hydrogen donors such as isopropanol, ethanol, methanol and formic acid are widely used with metal catalysts in TH, specifically, ruthenium, 33 iridium, 34 platinum, 35 palladium, 36 iron, 37 manganese 38 and nickel 39 homogeneous catalysts. The versatile tridentate architecture of pincer ligands has been identified as effective in altering and regulating metal complex characteristics across the periodic table.…”