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2‐Hexanol (2‐HOL) is a versatile biomass‐derived platform molecule for synthesis of liquid transportation fuels, lubricants, or detergents. Herein, a one‐step preparation of 2‐HOL using 5‐hydroxymethylfurfural (HMF) as a substrate was reported for the first time. Several Au‐based catalysts supported on different metal oxides were prepared to explore the relationship between carrier and catalytic activity. The results showed that the highest 2‐HOL yield of 65.8 % was obtained at complete HMF conversion over the 5 %Au/ZrO2 catalyst. The 5 %Au/ZrO2 catalyst exhibited excellent durability after five consecutive recycling runs, while confirming its remarkable ring‐opening hydrogenolysis on other biomass‐derived furanics, furfural, with a total yield of 1‐pentanol and 2‐pentanol of 67.4 %. The distinguished ring‐opening hydrogenolysis performance of the Au/ZrO2 catalyst originated from a synergistic effect between the interfacial Au‐O‐Zr oxygen vacancies‐induced Lewis acidic sites (activating C−OH/C=O bonds) and metallic Au (activating H2). This work provides a possibility for producing 2‐HOL from HMF with high yield, expanding the sustainable application of lignocellulosic biomass. [ABSTRACT FROM AUTHOR]

2, 5‐Furandicarboxylic acid (FDCA) obtained from selective 5‐hydroxymethyfufural (HMF) oxidation is an important biodegradable polyester monomer and its production strongly depends on homogeneous base additives. The production of FDCA over solid base catalyst is green and environment‐friendly. Herein, Au/Mg(OH)2 as the metal‐solid base catalyst, was prepared by a simple colloidal method and applied to the oxidation of HMF. Detailed characterizations (XRD, TEM, XPS, TGA, CO2‐TPD, etc.) were performed to uncover the structure‐activity relationship of the catalyst. 92.6 % yield of FDCA was achieved under the optimal reaction condition. Moreover, a plausible mechanism for HMF oxidation over the metal‐solid base catalyst was proposed by combining the surface properties of catalyst with the oxidation reaction results. [ABSTRACT FROM AUTHOR]

The bi-functional Ni–W@C catalysts were prepared by one-pot reduction–carbonization method and used in hydrogenolysis of cellulose as well as raw lignocellulosic biomass to chemicals. The catalytic performance for cellulose conversion showed that it was more favorable for ethylene glycol (EG) production, obtaining the highest EG yield 60.1% over the Ni–W@C700 catalyst. The Ni–W@C bimetallic catalysts are systematically characterized with BET, XRD, Raman, XPS, TEM techniques and experiments to probe the active catalytic sites of the catalysts. The effects of calcination temperature of Ni–W catalysts, reaction time, temperature and H2 pressure on cellulose hydrogenolysis were investigated in detail. The Ni particles could lead to produce more W5+ active sites, which promotes the glucose retro-aldol condensation to break the target C–C bonds. Metallic Ni catalyzed C=O hydrogenation and C–C hydrogenolysis, which could also avoid the coke formation. The EG selectivity was dependent on the synergy of WOx and Ni metal sites. In addition, this synergistic effect between the metal and WOx could promote lignin component degradation in direct conversion of untreated raw lignocellulosic biomass, obtaining the propyl monophenolics including guaiacylpropane, syringylpropane and p-n-propylphenol with a total yield of 17.3 wt% besides EG. [ABSTRACT FROM AUTHOR]

Ethanol is an important bulk chemical with diverse applications. Biomass‐derived ethanol is traditionally produced by fermentation. Direct cellulose conversion to ethanol by chemocatalysis is particularly promising but remains a great challenge. Herein, a one‐pot hydrogenolysis of cellulose into ethanol was developed by using graphene‐layers‐encapsulated nickel (Ni@C) catalysts with the aid of H3PO4 in water. The cellulose was hydrolyzed into glucose, which was activated by forming cyclic di‐ester bonds between the OH groups of H3PO4 and glucose, promoting ethanol formation under the synergistic hydrogenation of Ni@C. A 69.1 % yield of ethanol (carbon mole basis) was obtained, which is comparable to the theoretical value achieved by glucose fermentation. An ethanol concentration of up to 8.9 wt % was obtained at an increased cellulose concentration. This work demonstrates a chemocatalytic approach for the high‐yield production of ethanol from renewable cellulosic biomass at high concentration. [ABSTRACT FROM AUTHOR]

Sn-β zeolite and PTSA-POM, made from the copolymerization of p-toluenesulfonic acid (PTSA) and paraformaldehyde (POM), were used for the production of 5-(hydroxymethyl)furfural (HMF) from glucose in an environmentally friendly solvent system including γ-valerolactone (GVL) and H2O. The effects of reaction temperature, reaction time, solvent, and catalyst-to-reactant ratio on the production of HMF were investigated. The combination of the Brønsted acid and Lewis acid catalysts largely improved the catalytic system and resulted in the production of HMF in 60.1 % yield at 140 °C in 30 min. The presence of water in the solvent had a positive influence on the production of HMF from glucose. The combination of the two catalysts also improved the catalytic performance for the production of HMF from cellulose and corn stalk. [ABSTRACT FROM AUTHOR]

Upon adding biomass under the action of water, heat, and catalyst, a wonderful chemical reaction occurs to obtain the ethanol. With the aid of Ni@C catalyst and H SB 3 sb PO SB 4 sb , cellulose is directly converted into ethanol with a high yield of 69.1 %, and an ethanol concentration up to 89 g L SP -1 sp . [Extracted from the article]

Molten salt hydrates (MSHs) are remarkable in breaking through the recalcitrant structure of microcrystalline cellulose and raw biomass. After being pretreated in 60 wt% LiBr at 130 °C for 2 h, cellulose crystallinity as well as degree of polymerization (DP) decreased. It was found that 91.3% yield of pretreated cellulose was removed from MSHs by filteration followed by being hydrolyzed into glucose with a high yield of 75.3% by dilute acid under mild reaction conditions. The pretreatment process also works on raw corn stover hydrolysis. After being pretreated at 100 °C for 5 h, 88.4% yield of cellulose in biomass was recovered and can be hydrolyzed into 54.9% yield of glucose with dilute acid. It was found that the cellulose in corn stover can be easier degraded compared with microcrystalline cellulose during MSHs pretreatment, which dues to the formation of acetic acid from hemicellulose hydrolysis. The proposed pretreatment technique presents a promising potential for glucose production from biomass in a commercial way. Unlabelled Image • MSHs pretreatment effectively decreased cellulose crystallinity and DP. • After being pretreated at 130°C for 2 h, 91.3% of cellulose was removed from MSHs via filtration. • Enhanced glucose yield of 75.3% was obtained from pretreated cellulose hydrolysis at mild condition. • 88.4% cellulose recovery and 54.9% glucose yield were obtained from MSHs pretreatment and hydrolysis, respectively. [ABSTRACT FROM AUTHOR]

2-Hexanol (2-HOL) is a versatile biomass-derived platform molecule for synthesis of liquid transportation fuels, lubricants, or detergents. Herein, a one-step preparation of 2-HOL using 5-hydroxymethylfurfural (HMF) as a substrate was reported for the first time. Several Au-based catalysts supported on different metal oxides were prepared to explore the relationship between carrier and catalytic activity. The results showed that the highest 2-HOL yield of 65.8 % was obtained at complete HMF conversion over the 5 %Au/ZrO 2 catalyst. The 5 %Au/ZrO 2 catalyst exhibited excellent durability after five consecutive recycling runs, while confirming its remarkable ring-opening hydrogenolysis on other biomass-derived furanics, furfural, with a total yield of 1-pentanol and 2-pentanol of 67.4 %. The distinguished ring-opening hydrogenolysis performance of the Au/ZrO 2 catalyst originated from a synergistic effect between the interfacial Au-O-Zr oxygen vacancies-induced Lewis acidic sites (activating C-OH/C=O bonds) and metallic Au (activating H 2 ). This work provides a possibility for producing 2-HOL from HMF with high yield, expanding the sustainable application of lignocellulosic biomass., (© 2022 Wiley-VCH GmbH.)

As the most abundant polysaccharide in lignocellulosic biomass, a clean and renewable carbon resource, cellulose shows huge capacity and roused much attention on the methodologies of its conversion to downstream products, mainly including platform chemicals and fuel additives. Without appropriate treatments in the processes of cellulose decompose, there are some by-products that may not be chemically valuable or even truly harmful. Therefore, higher selectivity and more economical and greener processes would be favored and serve as criteria in a correlational study. Aqueous phase, an economically accessible and immensely potential reaction system, has been widely studied in the preparation of downstream products of cellulose. Accordingly, this mini-review aims at making a related summary about several conversion pathways of cellulose to target products in aqueous phase. Mainly, there are four categories about the conversion of cellulose to downstream products in the following: (i) cellulose hydrolysis hydrogenation to saccharides and sugar alcohols, like glucose, sorbitol, mannose, etc.; (ii) selective hydrogenolysis leads to the cleavage of the corresponding glucose C-C and C-O bond, like ethylene glycol (EG), 1,2-propylene glycol (PG), etc.; (iii) dehydration of fructose and further oxidation, like 5-hydroxymethylfurfural (HMF), 2,5-furandicarboxylic acid (FDCA), etc.; and (iv) production of liquid alkanes via hydrogenolysis and hydrodeoxygenation, like pentane, hexane, etc. The representative products were enumerated, and the mechanism and pathway of mentioned reaction are also summarized in a brief description. Ultimately, the remaining challenges and possible further research objects are proposed in perspective to provide researchers with a lucid research direction., (Copyright © 2020 Xin, Hu, Cai, Wang, Zhu, Li, Xiu, Zhang, Liu and Ma.)

Ni/La 2 O 3 /ZrO 2 catalysts were prepared by a step-by-step impregnation method through regulation of the contents of the active component and alkali. The introduction of an alkaline promoter not only enhanced the alkalinity of the catalyst but also improved the dispersion of Ni on the catalyst owing to the strong interaction between Ni 2+ and alkali promoter. The synergistic effect between Ni and La 2 O 3 was beneficial to selective hydrogenolysis of sorbitol. Under the optimal reaction conditions, sorbitol conversion reached nearly 100% and target products (ethylene glycol, 1,2-propanediol, and glycerol) selectivity reached 74.8%. Metal-alkali coordination mechanism and possible pathways for target products formation were proposed., Competing Interests: There are no conflicts to declare., (This journal is © The Royal Society of Chemistry.)

The lignin-first biorefinery method appears to be an attractive approach to produce phenolic chemicals. Herein, corn stover was employed for the production of phenolic monomers using an unsupported non-noble MoS 2 catalyst. The yield of phenolic monomers was enhanced from 6.65% to 18.47% with MoS 2 at 250 °C and about 75% lignin was degraded with more than 90% glucan reserved in the solid residues. The Fourier-Transform Infrared (FT-IR) and heteronuclear single quantum coherence-nuclear magnetic resonance ( 1 H- 13 C HSQC-NMR) characterization suggested that the cleavage of the β-O-4, γ-ester and benzyl ether linkages were enhanced, promoting the delignification and the depolymerization of lignin. The catalyst performance was relatively effective with 14.30% phenolic monomer yield after the fifth run. The effects of the reaction temperature, the initial hydrogen pressure, the dosage of catalyst, and the reaction time were investigated. The model reactions were also proposed for the potential mechanism study. This work provides some basic information for the improvement of the graminaceous plant lignin-first process with a non-noble metal catalyst., Competing Interests: There are no conflicts to declare., (This journal is © The Royal Society of Chemistry.)