Iodine‐modified Pt nanoparticles accelerate the hydrogenative ring‐opening of furfurals to linear alcohols

Abstract

The hydrogenative ring‐opening of furfurals (furfural and 5‐methylfurfural) to linear diols (1,4‐pentanediol and 2,5‐hexanediol) is of great significance for bioderived fine chemical synthesis. Unfortunately, the catalytic activity and selectivity are unsatisfactory because of the interference of various side reactions, such as overhydrogenation to tetrahydrofurans. Herein, the preparation of an iodine (I) modified Pt‐based catalyst with abundant Pt‐I pairs is reported for the first time and shows high catalytic efficiency for linear diol synthesis with a yield of 80%–90% via the hydrogenative ring‐opening route, whereas bare Pt counterpart only shows tetrahydrofuran synthesis via the overhydrogenation route. The catalytic reaction mechanism shows the in‐situ hydrogen spillover‐promoted H−‐Pt‐I‐H+ pairs not only supply hydrogenation sites for the C=O hydrogenation step but also provide Brønsted acidic sites for the ring‐opening step. This work presents a feasible and convenient strategy for bifunctional catalysis with powerful linear diol synthesis over iodine‐modified noble metals.

Switching between Hydrogenative Hydrogenolysis and Rearrangement of Furfurals via Hydrogen Pressure-Driven Acid–Base Transformation over Br–Pt Pairs

“…Furthermore, high-angle annular dark-field scanning TEM displayed an interlayer spacing of 0.221 nm for the standard Pt(111) plane (Figures B, S1E). The linear energy-dispersive X-ray spectroscopy (EDS) analysis showed an identical trend of Br and Pt signal intensities, indicating that Br is preferentially attached to the Pt species instead of to the Al 2 O 3 support (Figure C). In addition, TEM–EDS mapping also shows the intimacy of the Pt and Br elements (Figure S1F–H).…”

“…The Pt 4d spectra of Pt/Al 2 O 3 show a 4d 3/2 peak (at 332.1 eV) and a 4d 5/2 peak (at 314.8 eV) for metallic Pt 0 (Figure 1D). 27,32 However, after Br modification, the Pt 4d spectra show the emergence of new peaks at 332.7 eV (4d 3/2 peak) and 315.4 eV (4d 5/2 peak) for Pt δ+ . Correspondingly, the Br 3d peaks centered at 69.2 and 68.2 eV are ascribed to the 3d 3/2 and 3d 5/2 signals of Br δ− rather than the electroneutral Br atoms (3d 3/2 , 69.5 eV and 3d 5/2 , 68.5 eV) and Br − anions (3d 3/2 , 68.7 eV and 3d 5/2 , 67.7 eV), which indicates that Br has a state between −1 and 0.…”

“…Recently, various Br, chlorine (Cl), and iodine­(I)-modified precious metal with metal–halogen pairs (I–Pd, I–Pt, Br–Ru, Br–Pd, and Cl–Ru) have been fabricated and facilitated the metal–acid bifunctional reactions, including hydrodeoxygenation of 5-hydroxymethyl furfural, , hydrogenative isomerization of 5-methyl furfural, and hydrogenolysis of diphenyl ether and guaiacol , by the transformation of metal–halogen pairs to H – –metal–halogen–H + triggered by hydrogen spillover. However, the base-catalyzed properties of the metal–halogen pairs have rarely been investigated, let alone complex metal–base concerted catalysis in biomass conversion. , Herein, Br-modified Pt nanoparticles were prepared for the aqueous hydrogenation–base/acid catalyzed reaction of furfurals.…”

Catalytic Hydrodehydroxylation of Biomass-Related Chemicals via Water-Mediated Hydrogen Heterolysis over a Pd–S Interface

“…However, F-modified noble metals have rarely been reported, possibly due to the stronger bond energy of C–F bonds than C–Br/C–I bonds. H + –H – can be generated over these noble metal–I/Br pairs through a hydrogen spillover mechanism, in which the valence of noble metal becomes higher due to the strong electronegativity of H atoms, while the valence of halogen becomes lower due to the redox reaction with H atoms. ,− Similarly, these catalysts also exhibit a stable catalytic performance in bifunctional reactions without halogen loss. However, as stated, our system represents a novel H 2 O-mediated H 2 heterolysis mechanism, which could shift the H atoms on the naked Pd surface to Pd δ+ –H – and FPhS – –H 3 O + on the modified Pd surface at a great extent, which can be hereby experimentally and theoretically identified (see DFT calculations in the later section).…”

Catalytic production of 1,4-pentanediol from lignocellulosic biomass

“…Deng et al fabricated an iodine-modified Pt-based catalyst with abundant Pt–I pairs. 77 The 1,4-PDO yield reached 80.1% on this catalyst at 100 °C and 2.0 MPa H 2 (entry 3). The in situ hydrogen spillover-induced H − Pt–I–H + pairs not only generate hydrogenation sites, but also supply Brφnsted acid sites, thus enabling strong synergistic catalysis for tandem conversion of furfural to 1,4-PDO.…”