Insight into the hydrogenation of pure and crude HMF to furan diols using Ru/C as catalyst

Abstract

5-hydroxymethylfurfural (HMF) is one of the most important renewable platform-chemicals, a very valuable precursor for the synthesis of bio-fuels and bio-products. In this work, the hydrogenation of HMF to two furan diols, 2,5-bis(hydroxymethyl)furan (BHMF) and 2,5-bis(hydroxymethyl)tetrahydrofuran (BHMTHF), both promising renewable monomers, was investigated. Three commercial catalysts, Ru/C, Pd/C and Pt/C, were tested in the hydrogenation of aqueous HMF solutions (2-3 wt%), using a metal loading of 1 wt% respect to HMF content. By appropriate tuning of the process conditions, either BHMF or BHMTHF were obtained in good yields, and Ru/ C resulted the best catalyst for this purpose, allowing us to obtain BHMF or BHMTHF yields up to 93.0 and 95.3 mol%, respectively. This catalyst was also tested for in the hydrogenation of a crude HMF-rich hydrolyzate, obtained by one-pot the dehydration of fructose. The influence of each component of this hydrolyzate on the hydrogenation efficiency was investigated, including unconverted fructose, rehydration acids and humins, in order to improve the yields towards each furan diol. Moreover, ICP-OES and TEM analysis showed that the catalyst was not subjected to important leaching and sintering phenomena, as further confirmed by catalyst recycling study.

Multi-Step Exploitation of Raw Arundo donax L. for the Selective Synthesis of Second-Generation Sugars by Chemical and Biological Route

“…The enzymatic hydrolysis of raw Arundo donax L. and the CRR recovered by the hydrolysis of Arundo donax L., previously separated from the embedded Amberlyst-70 by sieving, was conducted at pH = 4.8 and 50 • C in a 150 mL flask employing 50 mL of the 0.05 M citrate buffer solution and the enzyme Cellic ® CTec2, shaking at 160 rpm. Different substrate loadings and dosages of enzymes were investigated in the present study, in agreement with the ranges reported in the literature [32,79,81]. Every 24 h, samples of 2 mL were withdrawn, cooled in ice in order to stop the enzymatic activities, centrifuged and analysed by HPLC for determining the glucose concentration.…”

“…Humins could be present on the CRR and Amberlyst-70 surfaces, contributing to hamper the conversion of cellulose into glucose. To partially remove humins, the whole solid recovered from run 13 was washed with acetone, which is efficient for this purpose [57,81], and subsequently dried under vacuum at 50 • C and reprocessed. The reaction was carried out with the CRR loading of 17 wt%, analogously to the conditions of the first step.…”

“…As reported in Figure 7, a linear profile was observed, reaching the glucose yield of 10.4 mol%, corresponding to the glucose concentration of 4.2 g/L, after 96 h, which was lower than that achieved starting from the CRR. Subsequently, on the basis of the promising results ascertained working with 15 FPU/g glucan, the enzyme concentration increased to 25 FPU/g glucan, which represents the typical dosage adopted in the literature [32,81,87,88], and the hydrolysis of both CRR and raw Arundo donax L. (blank test) were performed, maintaining the substrate loading at 9 wt%. The glucose yield increased up to 42.9 mol%, corresponding to the glucose concentration of 24.7 g/L, in the enzymatic hydrolysis of the CRR, and up to 16.6 mol%, corresponding to the glucose concentration of 6.7 g/L, in the respective blank test.…”

A Carbon Catalyst Co‐Doped with P and N for Efficient and Selective Oxidation of 5‐Hydroxymethylfurfural into 2,5‐Diformylfuran

“…The molecule 5‐hydroxymethylfurfural (HMF) possesses a hydroxyl group and an aldehyde group at the 2,5 positions of the furan ring, which enable it to perform different types of reactions, such as hydrogenation, [2,3] oxidation, [4,5] rearrangement, [6] decomposition [7] and polymerization [8] . HMF can be converted to value‐added fine chemicals and liquid fuels, such as levulinic acid, [7] 2,5‐furandialdehyde (DFF), [9,10] 2,5‐furandicarboxylic acid (FDCA) [11,12] .…”

Biotransformation of 5-hydroxymethylfurfural into 2,5-dihydroxymethylfuran by Ganoderma sessile and toxicological assessment of both compounds

“…Hence, the research on the biochemical synthesis of DHMF is meaningful to mechanism research, drugs development and clinical application. In fact, selective hydrogenation of 5-HMF and selective of catalysts are the key on the chemical synthesis of DHMF (Fulignati et al 2019). Meanwhile, there are also studies showing that this transformation can be accomplished through biotransformation (He et al 2018;Li et al 2017).…”