Porous Zirconium–Furandicarboxylate Microspheres for Efficient Redox Conversion of Biofuranics

Abstract

Biofuranic compounds, typically derived from C and C carbohydrates, have been extensively studied as promising alternatives to chemicals based on fossil resources. The present work reports the simple assembly of biobased 2,5-furandicarboxylic acid (FDCA) with different metal ions to prepare a range of metal-FDCA hybrids under hydrothermal conditions. The hybrid materials were demonstrated to have porous structure and acid-base bifunctionality. Zr-FDCA-T, in particular, showed a microspheric structure, high thermostability (ca. 400 °C), average pore diameters of approximately 4.7 nm, large density, moderate strength of Lewis-base/acid centers (ca. 1.4 mmol g ), and a small number of Brønsted-acid sites. This material afforded almost quantitative yields of biofuranic alcohols from the corresponding aldehydes under mild conditions through catalytic transfer hydrogenation (CTH). Isotopic H NMR spectroscopy and kinetic studies verified that direct hydride transfer was the dominant pathway and rate-determining step of the CTH. Importantly, the Zr-FDCA-T microspheres could be recycled with no decrease in catalytic performance and little leaching of active sites. Moreover, good yields of C (i.e., furfural) or C products [i.e., maleic acid and 2(5H)-furanone] could be obtained from furfuryl alcohol without oxidation of the furan ring over these metal-FDCA hybrids. The content and ratio of Lewis-acid/base sites were demonstrated to dominantly affect the catalytic performance of these redox reactions.

Catalytic transfer hydrogenation of furfural into furfuryl alcohol over Ni–Fe‐layered double hydroxide catalysts

“…On the basis of the above discussion, we put forward a plausible reaction mechanism for the CTH of FF to FAOL over Ni–Fe (3/1) LDH (Scheme ), which is consistent with previous studies . We considered the synergistic effect of acidic sites (resulting from Ni 2+ and Fe 3+ ) and basic sites (originating from –OH) of Ni–Fe (3/1) LDH in CTH of FF to FAOL.…”

“…We considered the synergistic effect of acidic sites (resulting from Ni 2+ and Fe 3+ ) and basic sites (originating from –OH) of Ni–Fe (3/1) LDH in CTH of FF to FAOL. First, 2‐propanol was adsorbed on the Ni–Fe (3/1) LDH and interacted with the acidic sites (Ni 2+ and Fe 3+ ) and basic sites (–OH) on the catalyst, causing it to dissociate into the corresponding alkoxide and protons . Subsequently, the carbonyl group of furfural may be activated by the acidic site to form a transitional state with six links .…”

One‐Step Lignocellulose Fractionation by using 2,5‐Furandicarboxylic Acid as a Biogenic and Recyclable Catalyst

“…For example, it has been proposed as an alternative polyester building block to replace terephthalic acid by forming the polyethylene furanoate (PEF) or as a precursor for fine chemicals . Interestingly, its use as a catalyst has hitherto been scarce, and only some recent examples illustrate its potential for dehydration or oxidoreduction processes . This is somewhat surprising, as FDCA displays a high intrinsic acidity and stability, and a (temperature‐dependent) low solubility in aqueous solutions and many solvents, which could enable straightforward recovery after reactions .…”

Porous Zirconium Hydroxyphosphonoacetate: Catalyst for Conversion of Furfural into Furfuryl Alcohol

“…The crystallinity of Zr‐HPAA was determined by XRD and the pattern was shown in Figure a. The pattern of Zr‐HPAA showed a clear and intense peak at 2θ of 9.5° which was most likely due to the special structure of zirconium carboxylate . The observation of the two broad and strong peaks at around 25° and 50° indicated that the Zr‐HPAA had an amorphous structure or was poorly ordered .…”