Basicity-Tuned Hydrotalcite-Supported Pd Catalysts for Aerobic Oxidation of 5-Hydroxymethyl-2-furfural under Mild Conditions

Abstract

An environmentally benign and homogeneous basefree route for 5-hydroxymethyl-2-furfural (HMF) aerobic oxidation to 2,5-furandicarboxylic acid (FDCA) in water was reported using Mg−Al−CO 3 hydrotalcite-supported Pd nanoparticles (xPd/HT-n) as catalyst. The influences of the Mg/Al molar ratio of hydrotalcite and Pd loading amount on the catalytic performance of these catalysts were originally systematically investigated. These catalysts exhibited excellent catalytic activity and FDCA selectivity in the HMF oxidation, especially for 2%Pd/HT-5 and 2%Pd/HT-6; >99.9% FDCA yields were achieved for 8 h under ambient pressure and homogeneous base-free conditions. The remarkably improved catalytic performance could be attributed to the suitable basicity of the Mg−Al−CO 3 hydrotalcite and the abundant OH − groups on the surface of hydrotalcite. The plausible reaction mechanism was proposed based on the results of a series of controlled experiments. Furthermore, these catalysts were quite stable and could be reused at least five times without obvious loss in reaction activity.

Nanohydrotalcite Supported Ruthenium Nanoparticles: Highly Efficient Heterogeneous Catalyst for the Oxidative Valorization of Lignin Model Compounds

“…Recently, hydrotalcite (HT; Mg 6 Al 2 CO 3 (OH) 16 .4(H 2 O)) has generated great interest in view of its potential application as support material in catalysis because of its unique advantages such as high surface area, high adsorption capacity and ion‐exchange ability. Micron sized (> 1 μm) crystalline hydrotalcite has already been used as efficient support material for guest Au, Ag, Pt, Pd and Ru nanoparticles, which have been employed as active nanocatalyst for various catalytic transformations . In addition to unique physicochemical properties of HT, the strong metal‐support interaction between guest metal nanoparticles and host HT framework provided in these studies prompted us to focus on the use of the HT matrix in the stabilization of metal nanoparticles.…”

Metal Catalysts for the Efficient Transformation of Biomass‐derived HMF and Furfural to Value Added Chemicals

“…Furthermore, Pd nanoparticles supported on Mg‐Al‐CO 3 hydrotalcite (Pd/HT) are also explored for an efficient catalytic oxidation of HMF to FDCA in water in the absence of any base additive . Recently, we explored oxidation of biomass‐derived furans (furfural and HMF) over bimetallic Ni 1− x Pd x (0.10≤ x ≤1) using air as an oxidizing agent .…”

“…[197] Furthermore, Pd nanoparticles supported on Mg-Al-CO 3 hydrotalcite (Pd/HT) are also explored for an efficient catalytic oxidation of HMF to FDCA in water in the absence of any base additive. [198] Recently,w ee xplored oxidation of biomass-derived furans (furfural and HMF) over bimetallic Ni 1Àx Pd x (0.10 x 1) using air as an oxidizing agent. [200] We demonstrated that by tuningt he Ni to Pd contentsi nt he bimetallic Ni 1Àx Pd x catalyst, catalytic efficacy of Ni 1Àx Pd x catalysts towards the oxidation of furans can be controlled.…”

Pt Nanoparticles Supported on Nitrogen‐Doped‐Carbon‐Decorated CeO2 for Base‐Free Aerobic Oxidation of 5‐Hydroxymethylfurfural

“…The main limiting factors are that the catalysts tability and processing efficiency are still not very satisfactory.M oreover,e xcess amountso fb ase additives can result in strong corrosion of equipment ands imultaneously lead to serious environmental pollution. To improve the catalytic performance of supported catalysts, numerousr esearchers have focusedo nt he study of different catalyst supports (e.g.,c arbon nanotubes, [14,21] layered double hydroxides (LDHs), [10,12,[20][21][22][23] zinc hydroxycarbonate, [19] carbon materials, [15,17,24,25] metal oxides [7-9, 20, 25] ). Commonly,astrongly alkaline aqueous medium or additional extra homogeneous base is required to achieve high yields of FDCA.…”