Value-added Platform Chemicals Research Articles

Efficient Conversion of Glucose to Hydroxymethylfurfural: One-pot Brønsted Base and Acid Promoted Selective Isomerization and Dehydration.

Development of elegant, selective, and efficient strategies for the production of value-added platform chemicals from renewable feedstocks are in high demand to achieve the future needs and sustainable goals. In this context, an efficient acid-promoted synthesis of highly valuable hydroxymethylfurfural (HMF) has been demonstrated from glucose, a major constituent of lignocellulosic biomass. The major challenge in the conversion of glucose to HMF is the selective isomerization of glucose to ketose, which in the present work has been successfully addressed through the amine-mediated rearrangement of glucose to aminofructose under Amadori rearrangement. Importantly, subsequent dehydration step affords HMF and regenerates the amine employed in the first step, which could be readily recovered. In addition, scale-up and successful integration into one-pot synthesis of HMF proves the efficiency and applicability of the present transformation in large scale application. In addition, the method was also successfully extended to other monosaccharides and disaccharides to produce HMF.

Review of: "Recycling of waste bamboo (Bambusa Vulgaris) into value-added platform chemicals: Bioethanol and Bioethylene"

Review of: "Recycling of waste bamboo (Bambusa Vulgaris) into value-added platform chemicals: Bioethanol and Bioethylene"

Selective colonization of multifunctional microbes that facilitates caproate production in microbial electrosynthesis system

As promising and value-added platform chemicals, the biosynthesis of medium-chain fatty acids (MCFAs, C6-C12) via chain elongation (CE) in microbial electrosynthesis systems (MES) has recently garnered significant attentions due to the unique bioelectrocatalytic behaviors and the reduction of exogenous electron donors (EDs). Caproate-synthesizing bacteria (CSB) played a crucial role in the generation of acetyl-CoA, which subsequently underwent reverse β oxidation to synthesize MCFAs. However, the presence of electrochemically active bacteria (EAB) was also pivotal for MES as they generated hydrogen in the cathodic electron transfer pathways, the specific colonization patterns of key symbionts remained unknown. The aim of this study was to investigate the selective colonization of EAB and CSB on the performance of caproate production in MES. The reactors colonized EAB and CSB achieved the maximum caproate concentration of 5332.5 mg COD/L, which was 7.9 and 1.3 times higher compared to that inoculated with either sole EAB or CSB, respectively. Moreover, the reactors colonized with mixed culture exhibited a clear redox peak and preferable electron transfer efficiency. CSB and EAB mutually interacted in metabolic activities, thereby resulting in increased substrate utilization and caproate production. The findings of this study provide a new strategy and insights for value-added chemicals recovery in microbial electrosynthesis platform.

Plasma-Enabled Selective Synthesis of Biobased Phenolics from Lignin-Derived Feedstock.

Converting abundant biomass-derived feedstocks into value-added platform chemicals has attracted increasing interest in biorefinery; however, the rigorous operating conditions that are required limit the commercialization of these processes. Nonthermal plasma-based electrification using intermittent renewable energy is an emerging alternative for sustainable next-generation chemical synthesis under mild conditions. Here, we report a hydrogen-free tunable plasma process for the selective conversion of lignin-derived anisole into phenolics with a high selectivity of 86.9% and an anisole conversion of 45.6% at 150 °C. The selectivity to alkylated chemicals can be tuned through control of the plasma alkylation process by changing specific energy input. The combined experimental and computational results reveal that the plasma generated H and CH3 radicals exhibit a "catalytic effect" that reduces the activation energy of the transalkylation reactions, enabling the selective anisole conversion at low temperatures. This work opens the way for the sustainable and selective production of phenolic chemicals from biomass-derived feedstocks under mild conditions.

Heterogeneous catalytic oxidation for lignin valorization into aromatic compounds over acid-redox bifunctional polyoxometalates

Lignin, as the largest renewable aromatic resource on the planet, has significant potential for the production of value-added platform chemicals. In this work, we synthesized a series of cesium-exchanged acid-redox bifunctional polyoxometalates (POMs) and evaluated their performance as catalysts for the depolymerization of birch lignin into low molecular weight aromatic compounds. The Cs3H2PMOV2O40 catalyst exhibited the highest activity, resulting in a monomer yield of approximately 13.6 %. Gel permeation chromatography (GPC), heteronuclear single quantum coherence (HSQC) spectroscopy, and gas chromatography-mass spectrometry (GC-MS) analysis confirmed the effective cleavage of β-O-4, β-5, and β-β linkages in the lignin polymer. The proposed reaction mechanism for the lignin depolymerization over cesium-exchanged POMs was also discussed. Our results demonstrate the potential of cesium-exchanged POMs as effective catalysts for the conversion of lignin into value-added chemicals, thereby contributing to the complete sustainable utilization of lignocellulose.

Towards the development of efficient, economic and environmentally friendly downstream processing for bio-based succinic acid

Succinic acid (SA) is among the top value-added platform chemicals that can be produced from renewable resources including organic wastes via microbial fermentation. Extensive studies have been witnessed in the last decades on the feedstock pretreatment and fermentation processes for SA production. However, the recovery and purification of SA from fermentation broth, dubbed downstream processing (DSP), has been overlooked. The major challenge in the DSP of bio-based SA is associated with the availability of low concentration of SA in the complex fermentation broth. Hence, the current study was systematically designed to assess recent efforts in the development of efficient, economic and sustainable DSP for bio-based SA ranging from small-scale to large-scale production schemes. This review presents a critical discussion of SA with regards to bio-based and petrochemical production routes, recent attempts of DSP, commercial-scale production, techno-economic analyses, as well as challenges and prospects in the DSP of SA. In general, the effectiveness the DSP of bio-based SA can be evaluated in terms of process efficiency, economics, and environmental aspects. To this end, the current review is believed to provide a comprehensive up-to-date insights to build a competitive SA bioproducing industries that could assist the quest towards the development of circular economy and sustainable future.

High-quality petroleum-like fuels and/or profitable value-added platform chemicals manufactured via a solid acid-catalyzed two-stage fast oil shale pyrolysis

Catalyst-assisted oil shale (OS) pyrolysis has gained broad interest from academic/engineering communities. However, current state-of-the-art catalysts still face many problems, e.g., laborious fabrication, unsatisfactory selectivity, etc. Taking commercial titanium(IV) oxysulfate solid acid (TOSSA) as an example and using a two-stage flash pyrolysis protocol, we report that when TOSSA-assisted pyrolysis is conducted at the first shot (438 °C), the content of N-, O-containing compounds and medium/long-chain aliphatic hydrocarbons (M/LCAHCs), undesirable for petroleum-like fuels (PLFs), decreases by 41.2%, 36.5% and 22.7%, respectively. The content of hydrocarbons (HCs), which is beneficial for PLFs, increases by 12.9%, where that of short-chain aliphatic HCs (SCAHCs, ≤C13), which are desired for light PLFs, increases by 285.7%. The content of α-olefins, valuable tectons for polyolefins, increases from 0% to 6.4%. Fascinatingly, the content of thiophenes, refractory heteroatomic species for PLFs but valuable tectons used in flexible/foldable optoelectronics, increases by 329.7%. For the second shot (590 °C), heteroatomic compounds content declines by 36.5%, HCs content increases from 69.3% to as high as 80.5%, where SCAHCs and M/LCAHCs content increases and declines by 39.7% and 27.1%, respectively. The content of toluene, important species in chemical science/engineering, increases by 237.5%. The content of 1-hexene and 1-heptene, overwhelming precursors for functional molecules/materials, increases by 210.0% and 412.5%, respectively. The strength/concentration of Brønsted acids of TOSSA is stronger/higher than that of Lewis acids such that their competitive-synergistic effects might endow TOSSA with good catalytic performances.

Valorization of hexoses into 5-hydroxymethylfurfural and levulinic acid in acidic seawater under microwave hydrothermal conditions

ABSTRACT Typical value-added platform chemicals 5-hydroxymethylfurfural (HMF) and levulinic acid (LA) can be obtained from hexoses under microwave hydrothermal (MHT) conditions. This study explored the detailed transformation process regarding the MHT products in acidic seawater obtained using glucose and fructose as raw materials. The facile conversion of fructose compared with glucose was mainly ascribed to their different activation energies (56.721 and 88.594 kJ mol−1, respectively). The HMF and LA product yields were strongly affected by the MHT temperature and holding time in two types of hexose solution. Undesirable humins were found to inevitably form under each set of reaction conditions. The carbon balance results for reactants and products showed that up to 60% of fructose carbon was converted into value-added chemicals, while 47% of glucose carbon underwent the same conversion in acidic seawater under the optimal MHT conditions. This study provides further knowledge regarding the role of microwave heating combined with acidic seawater in green chemistry and is a useful reference for the biorefinery industry.

Recent advances and challenges in the bioconversion of acetate to value-added chemicals

Acetate is a major byproduct of the bioconversion of the greenhouse gas carbon dioxide, pretreatment of lignocellulose biomass, and microbial fermentation. The utilization and valorization of acetate have been emphasized in transforming waste to clean energy and value-added platform chemicals, contributing to the development of a closed carbon loop toward a low-carbon circular bio-economy. Acetate has been used to produce several platform chemicals, including succinate, 3-hydroxypropionate, and itaconic acid, highlighting the potential of acetate to synthesize many biochemicals and biofuels. On the other hand, the yields and titers have not reached the theoretical maximum. Recently, recombinant strain development and pathway regulation have been suggested to overcome this limitation. This review provides insights into the important constraints limiting the yields and titers of the biochemical and metabolic pathways of bacteria capable of metabolizing acetate for acetate bioconversion. The current developments in recombinant strain engineering are also discussed.

Biomass-derived 5-hydroxymethylfurfural (HMF) and 2,5-dimethylfuran (DMF) synthesis as promising alternative fuel: A prospective review

Biomass conversion can produce many value added platform chemicals and fuels wherein, 5-hydroxymethylfurfural (HMF) and 2,5-Dimethylfuran (DMF) synthesis had opened up wide horizon for many researchers as an alternative to fuel due to its environmental and economic benefits. The aim of this review is to bring recent advances on the direct synthesis of HMF using different biomasses and solvent/catalyst combinations. Recently, greener solvent called deep eutectic solvents (DES) elevated the scope of research in HMF and DMF synthesis to minor extent on laboratory scale. In current review, authors have systematically summarized the catalytic conversion for the synthesis of HMF from biomass using greener processes. Further, HMF on hydrogenation yields DMF through homogeneous and heterogeneous catalyst, which is future biofuel. In the current review, holistic research on directional utilization of biomass for HMF and DMF synthesis are discussed systematically.

Aqueous conversion of monosaccharides to furans: were we wrong all along to use catalysts?

Dehydration of the most relevant biomass derived monosaccharides, xylose, glucose and fructose, was investigated to attain value-added platform chemicals: furfural, hydroxymethylfurfural (5-HMF) and levulinic acid (LA).

Sustainable transformation of natural silica-rich solid and waste to hierarchical zeolites for sugar conversion to hydroxymethylfurfural (HMF)

The expansive development of using waste materials to synthesize multifaceted functional materials is imperatively important in both economic and environmental aspects. Herein, natural silica-rich solids and wastes, including sand and scrap glass were successfully transformed to high value-added nano-aluminosilicates with the particle size under 40 nm, using a simple sol-gel method in the absence of dispersing agent. To demonstrate the further utilization of this material, a bottom-up synthesis approach has been simply implemented to fabricate the well-defined micro-mesoporous ZSM-5 with low Si/Al ratio using the prepared nano-aluminosilicates derived from natural silica-rich solids and wastes as both silica and alumina raw materials. The zeolite synthesis was systematically investigated as a function of water content in the synthesis gel and hydrothermal synthesis time. It is distinctly elucidated that the water content and hydrothermal synthesis time strongly effect the formation of hierarchical ZSM-5. Intriguingly, the integrating benefits between high acidity of aluminum-rich ZSM-5 and combined micro-mesoporous zeolite features can highly enhance the catalytic performances of fructose dehydration to hydroxymethylfurfural (HMF) with almost 80% yield. This contribution demonstrates the scientific opportunities to utilize waste materials to multifaceted functional materials as well as its application for sugar transformation to high value-added platform chemicals in biorefinery application. • Nano-aluminosilicates have been successfully synthesized using natural silica-rich solid and waste materials. • Aluminum-rich hierarchical ZSM-5 has been fabricated using the obtained nano-aluminosilicates. • Outstanding high acidity and specific surface area of aluminum-rich hierarchical ZSM-5 can be observed. • The aluminum-rich hierarchical H-ZSM-5 demonstrates the promising catalytic activity toward sugar to HMF.

Effect of molecular structure of cation and anions of ionic liquids and co-solvents on selectivity of 5-hydroxymethylfurfural from sugars, cellulose and real biomass

The concept of biorefinery still requires advancements in process development for energy and materials. Ionic liquids have been successfully used for several biorefinery applications including high yield synthesis of biofuels and value added platform chemicals. Designing suitable ionic liquid that is efficient in terms of cost as well as product selectivity is still highly needed. This study is carried out to check the effect of different anions of Bronsted acidic ionic liquids (BAILs), Bronsted Lewis acidic ionic liquids (BLAILs), Lewis acidic ionic liquids (LAILs) as well as organic electrolyte solutions (OES) for 5-HMF selectivities from monosaccharides, polysaccharides as well as lignocellulosic composite. Different variables and parameters such as Lewis acidity of anions, alkyl side chain of ionic liquid, metal chloride type and loading, time, temperature, substrate loading, polar protic and aprotic solvents are thoroughly studied for process optimization. Polar protic solvents added in [C1C4SO3HPy] based ionic liquids with CH3COO− and Cl− anions yielded 94 and 80% 5-HMF from fructose and glucose respectively in the presence of AlCl3 as Lewis acid. C4SO3H side chain yielding high from fructose and glucose is inefficient for conversion of cellulose and lignocellulose. High product selectivity from these biopolymers is achieved using butyl side chain with 3-methylpyridinium cation and chlorochromate anion.

Zero-valent iron driven bioconversion of glycerol to 1,3-propanediol using Klebsiella pneumoniae L17

1,3-PDO (1,3-propanediol) is a high value-added platform chemical used widely in adhesives, laminates, and food additives. For the efficient production of 1,3-PDO, the sustainable and non-toxic regeneration of NADH is of great importance. ZVI (Zero-Valent Iron) can provide a reducing equivalent for 1,3-PDO synthesis from glycerol as an electron donor. Klebsiella pneumoniae has a 1,3-PDO conversion pathway from glycerol and has been studied as an electrochemically active strain that can exchange respiratory electrons through the cell membrane. In this study, 1,3-PDO was produced using an electrochemically active strain, K. pneumoniae L17, and ZVI as an electron donor. The production of 1,3-PDO with ZVI increased significantly to 24.2 ± 1.3 mM compared to the control (12.0 ± 0.1 mM). These results suggest that an external reducing agent, such as ZVI, can regulate the bioconversion of K. pneumoniae L17, and improve the conversion of glycerol to value-added platform chemicals.

Synergistic benefits for hydrogen production through CO2-cofeeding catalytic pyrolysis of cellulosic biomass waste

Direct valorization of cellulosic biomass waste into energy is beneficial based on the concept of waste-to-energy. Pyrolysis of the biomass waste opens a chance to upgrade the valueless waste into value-added platform chemicals such as syngas (H2 and CO). This study focused on valorization of sesame seed waste (SSW), a biomass waste material collected after sesame oil extraction, into syngas. To enhance syngas production and make this process more environmentally benign, CO2 was added as co-reactant during SSW pyrolysis. In the presence of CO2, pyrolysis of SSW showed enhanced CO formation (670 %), comparing with pyrolysis under N2, due to the gas phase reactions (GPRs) between CO2 and volatile hydrocarbons resulted from pyrolysis of SSW. To enhance syngas production from SSW pyrolysis, mesoporous nickel-based catalyst was used for catalytic pyrolysis due to its known catalytic capability for chemical bond scissions of hydrocarbons and biomass-derived oxygenates. The enhanced production of syngas was proportionate to catalytic bed temperature (500, 600, and 700 °C) and catalyst loadings (0.2, 0.5, and 1 g), and the GPRs were independent with H2 formation. All experimental findings indicated that CO2-assisted catalytic pyrolysis significantly improved H2 and CO formations from a cellulosic biomass waste material, controlling the CO concentration with an introduction of CO2.

Selective Valorization of 5-Hydroxymethylfurfural to 2,5-Diformylfuran Using Atmospheric O2 and MAPbBr3 Perovskite under Visible Light

Selective production of value-added platform chemicals from renewable biomass feedstocks and their derivatives has attracted tremendous attention with high potential in addressing global problems o...

The formation of 5-hydroxymethylfurfural and hydrochar during the valorization of biomass using a microwave hydrothermal method

5-Hydroxymethylfurfural (HMF) and levulinic acid (LA) are regarded as value-added platform chemicals that can be derived from biomass waste. However, humins are inevitably produced during valorization processes, reducing the product yields. Previous studies indicated that microwave heating combined with acidic seawater as a reaction medium promotes HMF formation. The present work therefore investigated the relationship between the production of HMF and LA in the liquid phase and that of insoluble humins (that is, hydrochar) under microwave heating in acidic seawater. The selectivities for HMF and LA were found to decrease as the reaction time was increased, as a result of hydrochar formation, and both dehydration and decarboxylation evidently dominated the production of hydrochar in succession. HMF evidently played the most important role in hydrochar formation, and was consumed approximately seven times more rapidly than either fructose or LA. The hydrochar formation mechanism reported herein may be applicable to other similar hydrothermal processes.

Sustainable production of liquid biofuels and value-added platform chemicals by hydrodeoxygenation of lignocellulosic bio-oil over a carbon–neutral Mo2C/CNF catalyst

For the first time, this work addresses the hydrodeoxygenation (HDO) of lignocellulosic bio-oil over a carbon–neutral Mo2C/CNF catalyst for the production of liquid biofuels and value-added chemicals, thoroughly examining the effect of the temperature, initial H2 pressure, reaction time and catalyst/bio-oil ratio. These variables had a significant influence on the process, allowing the transformation of the original bio-oil into different fractions in varying yields, including an upgraded bio-oil (17–72%), a solid product (4–44%), an aqueous phase (5–39%) and a gaseous stream (1–15%). The upgraded bio-oil comprised a mix of phenols (56–78%), cyclic ketones (7–30%), carboxylic acids (2–8%), esters (0–9%) and aromatic compounds (0–20%). The relative amounts of C, H and O of this product shifted by 34–78 wt%, 3–8 wt% and 13–62 wt%, while its HHV ranged between 9 and 35 MJ/kg. Process optimisation revealed that using a temperature of 350 °C, an initial H2 pressure of 40 bar and 0.19 g cat/g bio-oil for 1 h, it was possible to convert 65% of the organic content of the bio-oil into a liquid bio-fuel with a HHV of 30 MJ/kg (twice the value of the original feedstock), which represents a deoxygenation degree of 70% and an energy efficiency of 62%. Besides, all the bio-oil organic content can be converted into a liquid product with a high proportion of phenols (79%) at 250 °C, applying an initial H2 pressure of 20 bar and 0.14 g cat/g bio-oil for around 0.5 h. This liquid can be used as a sustainable phenolic-rich antioxidant additive as well as a bio-based source of aromatic compounds. Therefore, these results are a step forward in the biomass conversion over carbon–neutral catalysts.

Investigation towards the reductive amination of levulinic acid by B(C6F5)3/hydrosilane system

The selective transformation of the renewable biomass resources into the highly value-added platform chemicals is essentially important for sustainable chemistry. Here we report a simple and highly efficient strategy for the synthesis of N-heterocyclic compounds from the reductive amination of the bio-derived levulinic acid and a wide range of anilines by metal-free B(C6F5)3/hydrosilane catalyst system. Through adjusting the amounts of hydrosilane, we can synthesize a series of pyrrolidones or pyrrolidines, respectively. Isotope-labeled NMR experiments were conducted to investigate the possible reaction pathway.

Understanding the role of the substrate and the metal triflate acidic catalyst in sugar platform biorefineries: A comprehensive systematic approach to catalytic transformations of (poly)carbohydrates in ethanol

We systematically explore a range of model conversions of mono- and disaccharides, and of linear and branched polysaccharides under the catalytic action of metal trifluoromethanesulfonates (metal triflates) in ethanol. This highlights the preferred reactivity of specific (poly)carbohydrates, and the interplay between selectivities of the reactions and the dominating catalyst activity (Brønsted or Lewis). It unambiguously delineates that selectivities of acid-catalysed transformations of (poly)carbohydrates into value added platform chemicals rely on the origin of the substrate, any (pre)treatment, the acidic catalyst, and the reaction conditions. The optimised catalytic systems enable very efficient conversion of cellulosic carbohydrates into significantly value added ethyl glucosides (yields up to 63%), ethyl xylosides (yields up to 69%), ethyl levulinate (yields up to 75%), ethyl lactate (yields up to 98%), ethoxyacetaldehyde diethylacetal (yields up to 33%), and furfural diethylacetal (yields up to 44%), depending on the substrate and reaction conditions.