Synthesis of a ZIF-derived hollow yolk–shell Co@CN catalyst for the oxidative esterification of 5-hydroxymethylfurfural

Abstract

A ZIF-derived hollow yolk–shell Co@CN catalyst is synthesized for the oxidative esterification of 5-hydroxymethylfurfural.

Oxidative Esterification of 5‐Hydroxymethylfurfural with an N‐doped Carbon‐supported CoCu Bimetallic Catalyst

“…We also performed this reaction by using 5 bar air as oxidant (5.6 mol % Co, 5 bar air, 80 °C, 6 h), a moderate FDMC yield of 82 % at full HMF conversion was obtained. In particular, Co 7 Cu 3 ‐NC catalyst could afford an impressive FDMC formation rate of 6.1 mol FDMC mol Co −1 h −1 under optimum conditions, which is the highest FDMC formation rate among these reported Co‐based catalysts so far (Table , entries 7, 9–13) . More importantly, the oxidative esterification of a highly concentrated HMF methanol solution (20 wt % HMF) can also process smoothly in the presence of Co 7 Cu 3 ‐NC under base‐free condition, yielding a high FDMC yield of 93 % within only 9 h (Table , entry 8).…”

“…Nevertheless, the involvement of extra base additives during the oxidation process makes these systems less eco‐friendly. Hollow yolk‐shell Co@CN and N‐doped carbon supported single‐atom Co catalysts were also developed for the conversion of HMF to FDMC with yields of 86–95 % under base‐free condition (1 bar O 2 , 65–80 °C, 9–12 h) . However, these reported Co‐based catalytic systems still suffer from relatively low catalytic efficiency without base additives.…”

Solvent‐Free Hydrogenation of 5‐Hydroxymethylfurfural and Furfural to Furanyl Alcohols and their Self‐Condensation Polymers

“…The N 1s region of Co−NC‐600 as well as Co−NC‐700 shows an additional Gaussian peak at around 401.5 eV, which can be attributed to the formation of graphitic N at a high pyrolysis temperature greater than 600 °C. Upon further increasing temperature up to 800 or 900 °C, the N 1s region can be deconvoluted into four Gaussian peaks located at around 398.9, 400.8, 401.8, and 403.4 eV, respectively [12] . The newly generated peak at 403.4 eV can be explained by the conversion of pyridinic N into oxidized N as evidenced by the corresponding N 1s curve of Co−NC.…”

“…Upon further increasing temperature up to 800 or 900 °C, the N 1s region can be deconvoluted into four Gaussian peaks located at around 398.9, 400.8, 401.8, and 403.4 eV, respectively. [12] The newly generated peak at 403.4 eV can be explained by the conversion of pyridinic N into oxidized N as evidenced by the corresponding N 1s curve of CoÀ NC. In the Co 2p spectra, the signals of metallic Co (778.8 eV) and mixed valence state of cobaltous oxide (782.1 and 786.0 eV) are found, and the peak at around 780.8 eV is associated with more active CoÀ N x C y sites.…”

Ultrafine Copper Oxide Particles Dispersed on Nitrogen‐Doped Hollow Carbon Nanospheres for Oxidative Esterification of Biomass‐Derived 5‐Hydroxymethylfurfural

“…They concluded that the hollow structure obtained from the removal of SiO 2 facilitates the mass transfer of reactants and products during the reaction thereby regenerating the catalytically active sites. [35] Inspired by the excellent performance of cobalt, a wide variety of materials containing cobalt were designed and fabricated for one-pot conversion of HMF into FDMC. [36][37][38][39][40][41][42][43] The above-mentioned processes are highly efficient and provides excellent yield of FDMC from oxidative esterification of HMF using air or molecular oxygen as an economical and readily available oxidizing agent.…”