Supported Bimetallic Catalysts for the Solvent-Free Hydrogenation of Levulinic Acid to γ-Valerolactone: Effect of Metal Combination (Ni-Cu, Ni-Co, Cu-Co)

Abstract

γ-valerolactone (GVL) is an important value-added chemical with potential applications as a fuel additive, a precursor for valuable chemicals, and polymer synthesis. Herein, different monometallic and bimetallic catalysts supported on γ-Al2O3 nanofibers (Ni, Cu, Co, Ni-Cu, Ni-Co, Cu-Co) were prepared by the incipient wetness impregnation method and employed in the solvent-free hydrogenation of levulinic acid (LA) to GVL. The influence of metal loading, metal combination, and ratio on the activity and selectivity of the catalysts was investigated. XRD, SEM-EDS, TEM, H2-TPR, XPS, NH3-TPD, and N2 adsorption were used to examine the structure and properties of the catalysts. In this study, GVL synthesis involves the single-step dehydration of LA to an intermediate, followed by hydrogenation of the intermediate to GVL. Ni-based catalysts were found to be highly active for the reaction. [2:1] Ni-Cu/Al2O3 catalyst showed 100.0% conversion of LA with >99.0% selectivity to GVL, whereas [2:1] Ni-Co/Al2O3 yielded 100.0% conversion of LA with 83.0% selectivity to GVL. Moreover, reaction parameters such as temperature, H2 pressure, time, and catalyst loading were optimized to obtain the maximum GVL yield. The solvent-free hydrogenation process described in this study propels the future industrial production of GVL from LA.

Enhanced Hydrogenation of Levulinic Acid over Ordered Mesoporous Alumina‐Supported Catalysts: Elucidating the Effect of Fabrication Strategy

“…Cu−OMA only exhibited weak acidic sites, whereas Ni−OMA contained both weak and strong acidic sites. The formation of moderate acidic centers, as well as the increase in the number of strong acidic sites, were demonstrated by Ni−Cu−OMA, indicating that the addition of Ni to Cu contributed to the acidic quantities and strengths of the catalysts [49] …”

“…The formation of moderate acidic centers, as well as the increase in the number of strong acidic sites, were demonstrated by NiÀ CuÀ OMA, indicating that the addition of Ni to Cu contributed to the acidic quantities and strengths of the catalysts. [49] Further, the nature of the acid sites was examined using pyridine FTIR spectroscopy. The bands at 1450, 1540, and 1490 cm À 1 can be assigned to the Lewis acid (LAS), Brønsted acid (BAS), and Lewis and Bronsted acid sites (LAS + BAS), respectively.…”

“…These results were consistent with those of previously reported studies. [15,49] Apart from the synergistic effect afforded by Ni and Cu, the acidic and metallic features of the prepared catalysts collaboratively facilitated the effective dehydration and hydrogenation steps of the reaction, respectively. Moreover, apart from the role of acidity in the dehydration reactions, it also disrupts the stability of GVL, thus ensuring the occurrence of the hydrogenation reaction.…”

Sustainable Combination Mechanism for Catalysts: A Game-Theoretical Approach

“…For example, mixed oxides were synthesized by the co-precipitation of a Cu source in combination with Al, Fe, or Mn corresponding salts as precursors. In order to crystallize the phases and to mimic the reaction conditions of the catalytic application, Everbroeck et al [1] considered reactive results when the materials were calcined at 600 • C and 1000 • C respectively; and, Gebresillase et al [2] investigated the influence of metal loading, metal combination, and ratio on the activity and selectivity of the catalysts. Ni-based catalysts were also found to be highly active for the related reaction; the review article, due to Losada-Garcia et al [3] provided an overview of the novel and recent achievements in enzyme cascade processes catalyzed by multi-enzymatic or chemoenzymatic systems.…”

Promotion effects of PrPO4 for the hydrogenation transformation of biomass-derived compounds over Pr–Ni–P composites

“….0 MPa as comparison references;10,13,15,17,[47][48][49][50][51][52] forMaterials Advances Accepted ManuscriptOpen Access Article. Published on 30 April 2021.…”