Single-Pot Reductive Rearrangement of Furfural to Cyclopentanone over Silica-Supported Pd Catalysts

Abstract

Direct one-pot hydrogenation of furfural (FFR) to cyclopentanone (CPO) was investigated over different silica-supported Pd catalysts. Among these, 4% Pd on fumed silica (4%Pd/f-SiO 2 ) showed remarkable results, achieving almost 98% furfural (FFR) conversion with ∼89% selectivity and 87% yield to cyclopentanone at 165 °C and 500 psig H 2 pressure. More interestingly, the fumed-silica-supported catalyst tuned the selectivity toward the rearrangement product, i.e., cyclopentanone, whereas all of the other supports were found to give ring hydrogenation as well as side chain hydrogenation products due to their parent Brönsted acidity and specific support properties. X-ray diffraction data revealed the presence of different phases of the face-centered cubic lattice of metallic Pd along with lowest crystallite size of 15.6 nm in the case of the silica-supported Pd catalyst. However, Pd particle size was found to be in the range of 5–13 nm with even dispersion over the silica support, confirmed by high-resolution transmission electron microscopy analysis. While studying the effect of reaction parameters, it was observed that lower temperature gave low furfural conversion of 58% with only 51% CPO selectivity. Similarly, higher H 2 pressure lowered CPO selectivity with subsequent increase in 2-methyl furan and ring hydrogenation product 2-methyl furan and 2-methyl tetrahydrofuran. Thus, as per the requirement, the product selectivity can be tuned by varying the type of support and/or the reaction parameters suitably. With the help of several control experiments and the characterization data, a plausible reaction pathway was proposed for the selective formation of cyclopentanone.

One-pot Selective Conversion of Biomass-derived Furfural into Cyclopentanone/Cyclopentanol over TiO2 Supported Bimetallic Ni-M (M = Co, Fe) Catalysts

“…1 [16,30]. In fact, the selectivity of THFalc was remained unchanged at relatively higher reaction temperature or longer reaction time.…”

“…By using similar Pt/NC-BS catalyst, Liu et al reported that maximum yield of CPO (76%) was obtained from FFald at 150 °C and 3.0 MPa H2 [15]. Date et al reported that efficient reductive rearrangement of furfural using Pd/SiO2 catalyst resulted cyclopentanone with 87% yield (at 98% conversion of FFald) at 165 °C and 5 MPa H2 [16]. However, precious metals, such as Au, Ru, Pd, and Pt were utilized in these catalyst systems.…”

Effect of Oxide Supports on the Activity of Pd Based Catalysts for Furfural Hydrogenation

“…The Pd/Al 2 O 3 and Pd/TiO 2 catalysts showed similar results in that the CPO selectivity decreased or changed slightly. Nandan et al reported that the Lewis acid sites of PdO affect the rearrangement of FAL to CPO [32]. Based on the XPS results, the Pd 2+ /Pd ratio of the Pd/TiO 2 catalyst was lower than that of the Pd/Al 2 O 3 catalyst.…”

Effect of Ni Metal Content on Emulsifying Properties of Ni/CNTox Catalysts for Catalytic Conversion of Furfural in Pickering Emulsions

“…In Scheme 2 the reported catalytic rearrangement of FAL to CPO is depicted. [47] Initially, FAL is hydrogenated towards FURÀ OH over the active sites of the metal. Afterwards, the water molecules attack via the fifth position of the furan ring to form the oxycation.…”

“…[36][37][38][39][40] Particular focus has been put on the transformation of furfural to aliphatic cyclic molecules such as cyclopentanone and cyclopentanol because they are important intermediate in fine chemical industry with a broad range of application in the perfume, medicine, and agriculture field. [40,41] Several catalytic studies (Table S1, supplementary material) have been focusing on the effect of the active phase, [42][43][44] metal content, [34] nature of the catalytic support [34,[45][46][47] and the reaction media, [48] among others. In this regard, Jia et al [49] studied the aqueous phase hydrogenation of furfural to cyclopentanone over NiFe-supported catalysts.…”