Renewable Platform Research Articles

Highly selective reduction of biomass-derived furfural by tailoring the microenvironment of Rh@BEA catalysts

Furfural is a renewable lignocellulose-derived platform molecule, which can be transformed into biofuels and value-added chemicals (e.g., furfuryl alcohol and 2-methylfuran over metal-supported catalysts). Despite a number of approaches proposed for designing hydrogenation catalysts, highly selective furfural hydrogenation towards furfuryl alcohol (FA) or 2-methylfuran (2-MF) is still challenging. Here, we report on selective transformation of furfural either to FA or 2-MF achieved over zeolite BEA-supported Rh catalysts by optimizing Si/Al ratio and charge-balancing cations of the support. Among studied H- and Na-exchanged aluminosilicate BEA zeolite supports (Si/Al = 12.5; 25; 68; 150), Rh@Na-BEA catalysts lacking Brønsted and strong Lewis acidity showed enhanced selectivity towards FA (75 – 94% depending on the Si/Al ratio) at 74 – 84% conversion of furfural. In turn, selective formation of 2-MF (98% selectivity at 87% conversion) was observed over Al-rich Rh@H-BEA catalyst (Si/Al=12.5) with the highest concentration of Brønsted acid sites. Weaker adsorption of FA on Na- vs. H-form of Rh@BEA-12.5 catalyst was verified by FTIR spectroscopy and is assumed a key factor governing selective hydrogenation of furfural to FA over Rh@Na-BEA catalysts.

Bifunctional crystalline microporous organic polymers: Efficient heterogeneous catalysts for the synthesis of 5-hydroxymethylfurfural

Developing efficient catalysts for the synthesis of 5-hydroxymethylfurfural (HMF) from biomass resources is very demanding as it is an important renewable platform chemical for the synthesis of biofuels, polymers and fine chemicals. Here, we have designed two new crystalline microporous bi-functional porous organic polymers through the extended aromatic substitution reaction under refluxing conditions. Porous polymers containing sulfonic acid and secondary amine groups are two reactive catalytic centres for carrying out the bi-functional heterogeneously catalysed reactions. Bifunctionalized porous polymers POPDS and POPSDS are synthesized through the reaction of 2,2′-benzidinedisulfonic acid and 4,4′-diaminostilbene-2,2′-disulfonic acid with cyanuric chloride, respectively. The materials were characterized thoroughly using powder X-ray diffraction, N2 sorption, FTIR, solid state 13C CP MAS NMR spectroscopy, FE-SEM, HR-TEM, XPS and TG/DTA analysis. These two crystalline porous polymers possesses good surface acidic and basic sites, and having flower-like and spherical particle morphologies. POPDS and POPSDS exhibited superior catalytic activity for the conversion of different small carbohydrates to 5-hydroxymethylfurfural (HMF) under microwave irradiation. Moreover, the recyclability tests of these catalysts revealed good durability up to sixth consecutive reaction cycles, suggesting the future potential of these catalysts in the sustainable synthesis of HMF.

Highly Selective Entrapment of His-Tagged Enzymes on Superparamagnetic Zirconium-Based MOFs with Robust Renewability to Enhance pH and Thermal Stability.

Metal-organic frameworks (MOFs), as a kind of poriferous nanoparticle, are promising candidates for enzyme immobilization to enhance their stability and reusability. However, most MOFs could not specifically immobilize enzymes and regenerate easily, which inevitably leads to serious high consumption and environmental pollution. In this study, renewable and magnetic MOFs were first constructed to specially immobilize His-tagged enzymes from the cell lysates without purification. The immobilized β-glucuronidase exhibited wider pH adaptability and temperature stability. The relative activity of immobilized β-glucuronidase was still maintained at ∼80% after eight cycles. Importantly, after simple treatment, the immobilization capacity of regenerated MOFs after simple treatment was restored to more than 90% in the first three times. The specific magnetic MOFs were proven to be an efficient and renewable platform for one-step immobilization and purification of His-tagged enzymes, showing great potential in industrial applications of nanotechnology and biocatalysis.

Furfuryl alcohol/tung oil matrix-based composites reinforced with bacterial cellulose fibres.

Polymeric materials have drastically changed the society in the last century. However, their non-renewable origin, together with their indiscriminate use and disposal, resulted in a huge accumulation of waste in the environment and raised a wide discussion about the emission of greenhouse gases, which must be considerably reduced to minimize global warming. Thus, the establishment of a consolidated production of polymers prioritizing the use of renewable sources of raw materials became a hot research topic. Vegetable oils are protagonists of this initiative, and their carbon–carbon double bonds are convenient reactive sites for chain growth polymerization reactions. However, typical vegetable oil-based homopolymers often do not display competitive thermo-mechanical properties, and the preparation of the corresponding copolymers and composites is therefore an interesting alternative strategy. Herein, the preparation of composites based on a tung oil/furfuryl alcohol co-continuous network reinforced with bacterial cellulose fibers is described. For this purpose, the cellulose nanofibers were suspended in furfuryl alcohol, and different amounts of the ensuing suspension were mixed with tung oil in the presence of trifluoroacetic acid as cationic initiator. Fourier-transform infrared spectroscopy analysis of all samples indicated the association of both tung oil and furfuryl alcohol in the final materials, with peaks belonging to cellulose superposed at the fingerprint regions of composites. Differential scanning calorimetry and thermogravimetry demonstrated an interesting relationship between the composition and the corresponding thermal properties, and the morphology of the materials was assessed by scanning electron microscopy (SEM), which revealed a homogeneous distribution of cellulosic fibers at lower concentrations. The results gathered here contribute to the development of original macromolecular materials exclusively based on the renewable platform.

Fettsäuren und Fettsäurederivate als nachwachsende Plattformmoleküle für die chemische Industrie

AbstractPflanzliche und tierische Öle und Fette bleiben ein wichtiger nachwachsender Rohstoff der chemischen Industrie. Ihre industrielle Nutzung hat sich in den letzten 10 Jahren von 31 auf 51 Millionen Tonnen pro Jahr erhöht. Dieser Aufsatz fasst die bedeutenden Fortschritte zusammen, die in dieser Zeit in der Oleochemie erzielt wurden, beispielsweise die Reduktion von Fettsäureestern zu Ethern, die selektive Oxidation und oxidative Spaltung von C‐C‐Doppelbindungen, die Synthese von alkylverzweigten Fettstoffen, die isomerisierende Hydroformylierung und Alkoxycarbonylierung sowie die Olefinmetathese. Auch die Nutzung von fettsäurebasierten Chemikalien in der Synthese einer Vielzahl polymerer Materialien hat stark zugenommen. Zusätzlich zu Lipasen und Phospholipasen haben mittlerweile viele weitere Enzyme in der biokatalytischen Fettchemie Anwendung gefunden. Wichtige Entwicklungen haben außerdem neue Eigenschaften bei den Ölen bestehender Nutzpflanzen hervorgebracht, was alternativ auch durch die Verwendung von metabolisch optimierten Mikroorganismen möglich ist.

Fatty Acids and their Derivatives as Renewable Platform Molecules for the Chemical Industry.

Oils and fats of vegetable and animal origin remain an important renewable feedstock for the chemical industry. Their industrial use has increased during the last 10 years from 31 to 51 million tonnes annually. Remarkable achievements made in the field of oleochemistry in this timeframe are summarized herein, including the reduction of fatty esters to ethers, the selective oxidation and oxidative cleavage of C–C double bonds, the synthesis of alkyl‐branched fatty compounds, the isomerizing hydroformylation and alkoxycarbonylation, and olefin metathesis. The use of oleochemicals for the synthesis of a great variety of polymeric materials has increased tremendously, too. In addition to lipases and phospholipases, other enzymes have found their way into biocatalytic oleochemistry. Important achievements have also generated new oil qualities in existing crop plants or by using microorganisms optimized by metabolic engineering.

A Congruent Approach to Normal Wiggly Interval-Valued Hesitant Pythagorean Fuzzy Set for Thermal Energy Storage Technique Selection Applications

Thermal energy is the energy from a substance in which molecules and atoms vibrate faster because of an increase in temperature. Thermal energy storage (TES) is an available energy resource for renewable energy platforms that enables them to meet sustainable technical requirements. The TES technique is divided into three categories; sensible TES, latent-heat TES, and thermo-chemical TES. The best of these techniques is selected in this research paper. Here the Interval-Valued Hesitant Pythagorean Fuzzy Set (IVPHFS) under the Normal Wiggly Mathematical Methodology is proposed and described for application to multi-criteria decision making (MCDM) technology. The MCDM methods, the Step-wise Weight Assessment Ratio Analysis (SWARA) method for determining weight values, and the Weighted Aggregated Sum Product Assessment (WASPAS) method for ranking alternative values are used employed here. The alternative values are selected based on the following criteria: capacity, efficiency, storage period, charging and discharging times, and cost

Synthesis of Imidazoles from Fatty 1,2‐Diketones

AbstractUnsaturated vegetable oils and their corresponding fatty acid derivatives constitute interesting renewable platforms for the preparation of heterocycles, notably through the formation of oxygenated intermediates. In this work, fatty imidazoles were prepared from the corresponding 1,2‐diketones through Debus‐Radziszewski reaction. The reaction was optimized under microwave irradiation using a 1,2‐diketone derived from methyl oleate and ammonium acetate as a nitrogen source. Using benzaldehyde as a model substrate, the reaction occurs at 180 °C for 5 min and the desired imidazole was formed in 96 % GC yield. A range of aldehydes was tested under the optimized conditions and the corresponding imidazoles were obtained in 33–99 % isolated yields (20 examples).

Recent advances in the preparation of levulinic esters from biomass-derived furanic and levulinic chemical platforms using heteropoly acid (HPA) catalysts

• Heteropolyacids (HPAs) catalysts for the synthesis of levulinic esters (LEs) from biomass has been reviewed. • The synthetic routes to LEs from various renewable chemical platforms have been highlighted. • The role of various structural features of HPA-based catalysts on the selectivity and yield of LEs have been elaborated. • The applications of LEs have been discussed and their possible synthetic upgrading have been elaborated. The esters of biomass-derived levulinic acid (LA) have several potential applications, including cleaner-burning fuel additive, green solvent, fragrance ingredient, and a renewable chemical intermediate for downstream value addition. The levulinic esters (LEs) can be prepared by the acid-catalyzed alcoholysis of the biomass-derived furanic and levulinic chemical platforms such as LA, furfuryl alcohol (FAL), 5-(hydroxymethyl)furfural (HMF), and angelica lactone (AGL). The acid-catalyzed deconstruction of carbohydrates in an alcoholic medium affords the one-pot preparation of LEs. Choosing the right catalyst is of paramount importance for synthesizing LEs from both the economic and environmental perspectives. In this regard, heteropoly acids (HPAs), a class of polyoxometalates (POMs) bearing protons as the counter cation, have found widespread applications as acid catalysts in various organic transformations. HPAs are blessed with conducive properties such as controlled Brønsted and Lewis acidity, high thermal stability, robust structural features, non-toxic nature, tunable solubility, and less corrosiveness. Over the past several years, HPAs have found extensive applications as efficient and environment-friendly catalysts in biorefinery operations, including the synthesis of LEs. At this juncture, it is imperative to ascertain the achievements in this field to date and re-evaluate the challenges. This review attempts to provide up-to-date information about the preparation of LEs using HPA-based catalysts, critically analyze the literature cited, draw conclusions, and propose future prospects.

The Use of 5-Hydroxymethylfurfural towards Fine Chemicals: Synthesis and Direct Arylation of 5-HMF-Based Oxazoles

Abstract5-Hydroxymethylfurfural (5-HMF) is a renewable platform chemical used as a source for obtaining diverse fine chemicals. In this letter, we report the synthesis of 5-HMF-based oxazole compounds. While 5-HMF could be easily converted into the oxazole derivative through the Van Leusen reaction, the direct arylation step needed to access the final compounds was problematic at first. After optimization, a palladium-catalyzed procedure has been developed and used for the synthesis of a series of 33 derivatives. This article reports an extension of the late-stage CH arylation reaction as an application to the oxazole platform derived from biosourced 5-HMF. The challenges in the preparation of the derivatives containing some electron-withdrawing substituents were overcome by the use of a palladium-free method.

Capturing renewable isobutanol from model vapor mixtures using an all-silica beta zeolite

Isobutanol is a promising renewable platform chemical, produced via fermentation. In the conventional downstream processing, isobutanol is recovered from the fermentation broth via evaporation or gas-stripping, followed by purification via distillation. Alternatively, an adsorptive separation can be used to recover isobutanol from the generated vapor mixture, however this has remained unexplored in the literature. In this work, we investigate the use of a hydrophobic all-silica beta zeolite (Si-BEA) to recover isobutanol from model vapor mixtures via adsorption. The Si-BEA zeolite shows a high selectivity for isobutanol over water (α = 35) and ethanol (α = 10) and excellent mass transfer properties under dynamic conditions. Sharp isobutanol breakthrough profiles were obtained, leading to a fraction of unused bed of only 6% at a gas residence time of only 0.6 s. The adsorbed isobutanol could be fully desorbed via thermal regeneration and an isothermal purge allows to remove co-adsorbed ethanol and water. The results of this work thus show the promising properties of Si-BEA for the recovery of renewable isobutanol from vapor mixtures.

Renewable energy technologies on the path towards decentralized low-carbon energy systems

Renewable energy technologies (RET) that emerged as a result of the shift towards the renewable energy sources (RES) which aims at setting the path towards decentralized low-carbon energy systems intended for tackling global warming are becoming key elements of the smart grids of the future. Our paper applies the economic, social and technological model of the renewable energy platforms to the energy markets of the 21st century. The paper analyses the growing importance of the individual players (prosumers) on the energy market, especially when it comes to the renewable energy generation and trading. It shows that modern advanced information and communication technologies enabled the energy prosumers to trade their energy and information in two-way flows. All of these might be important for the transition towards sustainable economy and green technology.

Recent advances in the conversion of furfural into bio-chemicals through chemo- and bio-catalysis.

Furfural is a promising renewable platform molecule derived from hemi-cellulose, which can be further converted to fossil fuel alternatives and valuable chemicals due to its highly functionalized molecular structure. This mini-review summarizes the recent progress in the chemo-catalytic and/or bio-catalytic conversion of furfural into high-value-added chemicals, including furfurylamine, C6 carboxylic acid, i.e., furandicarboxylic acid, furfural alcohol, aromatics, levulinic acid, maleic acid, succinic acid, furoic acid, and cyclopentanone, particularly the advances in the catalytic valorization of furfural into useful chemicals in the last few years. The possible reaction mechanisms for the conversion of furfural into bio-chemicals are summarized and discussed. The future prospective and challenges in the utilization of furfural through chemo- and bio-catalysis are also put forward for the further design and optimization of catalytic processes for the conversion of furfural.

Prediction of Hydroxymethylfurfural Yield in Glucose Conversion through Investigation of Lewis Acid and Organic Solvent Effects

Hydroxymethylfurfural (HMF) is one of the important renewable platform compounds that can be obtained from biomass feedstocks through glucose conversion catalyzed by Bronsted and Lewis acids. Howev...

Fermentation of Organic Residues to Beneficial Chemicals: A Review of Medium-Chain Fatty Acid Production

Medium-chain fatty acids (MCFAs) have a variety of uses in the production of industrial chemicals, food, and personal care products. These compounds are often produced through palm refining, but recent work has demonstrated that MCFAs can also be produced through the fermentation of complex organic substrates, including organic waste streams. While “chain elongation” offers a renewable platform for producing MCFAs, there are several limitations that need to be addressed before full-scale implementation becomes widespread. Here, we review the history of work on MCFA production by both pure and mixed cultures of fermenting organisms, and the unique metabolic features that lead to MCFA production. We also offer approaches to address the remaining challenges and increase MCFA production from renewable feedstocks.

Synthesis of dihydrocapsaicin and dihydrocapsiate exclusively from lignocellulosic platform chemicals

Biorefinery is pivotal to the sustainability of modern chemical industry. However, since biomass is oxygen-enriched, new and green chemical strategies are required for expanding the biomass derived chemical space. In this work, synthesis of natural products dihydrocapsaicin and dihydrocapsiate was achieved exclusively from lignocellulosic platform chemicals. Natural products dihydrocapsaicin and dihydrocapsiate were synthesized exclusively from lignocellulosic platform chemicals, using furfural (from hemicellulose) and methyl isopropyl ketone (from cellulose) through aldol condensation-hydrolysis-hydrodeoxygenation to synthesize 8-methylnonanoic acid and then combined with vanillin derivates (from lignin). This synthesis demonstrates the feasibility of constructing natural products entirely from renewable biomass platform through green processes. The utilization of inherent functional groups of biomass demonstrates their potential to open up chemical space.

Off-grid and decentralized hybrid renewable electricity systems data analysis platform (OSDAP): A building block of a comprehensive techno-economic approach based on contrastive case studies in Sub-Saharan Africa and Canada

Off-grid and decentralized Hybrid Renewable Electricity Systems (OHRES) play a promising role in providing sustainable energy access to 860 million people around the globe with no access to electricity. However, the diversity of global geographies, lack of performance analysis standardization, and modeling limitations hinder the scalability of OHRES. This study outlines the creation of a data analysis platform (OSDAP) and irradiance forecasting models for OHRES that can be used to support the provision of global energy access. The paper presents the technical layout of OHRES in two case studies in Canada and Uganda and outlines an assessment and modeling platform that can be used to assess OHRES performance across widely varying geographic locations. Two irradiance forecasting models are developed using artificial neural networks, which can be used to increase solar energy utilization in OHRES.

An Account of the Catalytic Transfer Hydrogenation and Hydrogenolysis of Carbohydrate‐Derived Renewable Platform Chemicals over Non‐Precious Heterogeneous Metal Catalysts

AbstractSustainable and eco‐friendly catalytic processes for renewable lignocellulose biomass conversion into liquid fuels and useful chemicals offer solutions to minimize greenhouse gases emission and associated negative climate impacts. Lignocellulose derived cellulose and hemicellulose can be converted into platform chemicals including glucose, fructose, xylose, 5‐hydroxymethylfurfural, furfural, levulinic acid, levulinate esters, etc. These platform chemicals can be subsequently converted into liquid fuels and value‐added chemicals using heterogeneous catalytic processes such as; oxidation, hydrogenation, hydrogenolysis, etc. The catalytic transfer hydrogenation and hydrogenolysis (CTH) over non‐precious metal catalysts have recently drawn considerable research interest. This review summarizes recent progress on non‐precious metals catalyzed CTH processes, which also include photocatalysis and electrocatalysis, for the transformation of 5‐hydroxymethylfurfural, furfural, levulinic acid, and, levulinate esters into furfuryl alcohol, 2‐methylfuran, 2,5‐dimethylfuran, and, gamma‐valerolactone; elucidate structure‐function relationship and highlights the underlying reaction mechanisms. This review is timely and provides detailed fundamental insights about the nature of active sites and CTH processes that will be useful for the researchers willing to work in this exciting area.

Renewable photoelectrochemical cytosensing platform for rapid capture and detection of circulating tumor cells

Determination of circulating tumor cells (CTCs) is crucial for cancer diagnosis and therapy at an early stage. However, extremely low concentration of CTCs in peripheral blood makes the detection of CTCs challenging. In this study, a reusable cytosensor was developed for rapid detection of CTCs based on excellent photoelectrochemical (PEC) characteristic of semiconductor nanoarrays. Using typical breast cancer cell, MCF-7 cell, as a target model, a PEC sensing platform was constructed with polymerized aminophenylboronic acid (APBA) layer coated CdS/ZnO nanorod arrays, exhibiting outstanding performance for the capture and detection of CTCs. In this design, the polymerized APBA provides abundant binding sites for capturing terminal sialic acid (SA) molecules in CTCs. As a result, the PEC cytosensor shows good sensitivity and specificity with concentrations ranging from 50 to 1.0 × 106 cells/mL MCF-7 cells. Moreover, the PEC cytosensor can be rapidly and effectively recovered via a short-time bias triggered cell release and subsequent repair of APBA. This study establishes a new approach to refine a PEC cytosensor for stable monitoring and provides a robust PEC electrode with high sensitivity and low cost for clinical diagnosis related to CTCs.

Influence of initial uncontrolled pH on acidogenic fermentation of brewery spent grains to biohydrogen and volatile fatty acids production: Optimization and scale-up

This two-phase, two-stage study analyzed production of biohydrogen and volatile fatty acids by acidogenic fermentation of brewery spent grains. Phase-1 served to optimize the effect of pH (4–10) on acidogenic fermentation; whereas phase-2 validated the optimized conditions by scaling up the process to 2 L, 5 L, and 10 L. Alkaline conditions (pH 9) yielded excellent cumulative H2 production (834 mL) and volatile fatty acid recovery (8936 mg/L) in phase-1. Extended fermentation time (from 5 to 10 days) upgraded the accumulated short-chain fatty acids (C2–C4) to medium-chain fatty acids (C5–C6). Enrichment for acidogens in modified mixed culture improved fatty acid production; while their consumption by methanogens in unmodified culture led to methane formation. Increased CH4 but decreased H2 content enabled biohythane generation. Scaling up confirmed the role of pH and culture type in production of renewable fuels and platform molecules from brewery spent grains.