Catalytic strategy for conversion of fructose to organic dyes, polymers, and liquid fuels

Economical production of 5-hydroxymethylfurfural from sorghum juice as inexpensive feedstock in an acetone/water solvent system

5-Hydroxymethylfurfural (HMF), regarded as a vital link between bio-refining and petrochemical refining, demonstrates significant potential to produce sustainable chemicals, fuels, and materials. However, its reliance on food-grade sugars as feedstock limits economic feasibility. This study demonstrates that sweet sorghum juice, rich in fructose, glucose, and sucrose, is an ideal, low-cost raw material for HMF production. Using HCl as catalyst, fructose in sweet sorghum juice was fully converted, yielding over 90% HMF in 80/20 (v/v) acetone/ water solvent system, with more than 85% of glucose retained for recycling. When AlCl3 was used as catalyst, all sugars were efficiently converted, yielding over 70% HMF. Impurities in the pretreated juice did not impede sugar conversion but did partially neutralize the acidic catalyst. Techno-economic analysis revealed that utilizing sweet sorghum juice as feedstock produces HMF at a minimum selling price of $1909 per ton, a 39.6% reduction compared to fructose-based.

Heparin/UiO-66 nanocomposite: Synergistic catalytic Lewis and Brønsted acids for efficient monosaccharides conversion to 5-hydroxymethylfurfural

A new bio-based catalyst was fabricated by synthesizing a zirconium(III) (Zr)-based metal-organic framework, UiO-66, in the presence of natural sulfonic acid, heparin (Hep) oligosaccharide. Various characterization techniques were utilized to validate the successful synthesis of the nanocomposite, Hep/UiO-66. The catalytic efficiency of the resulting nanocomposite was assessed in the acid-catalyzed conversion of mono-saccharides (fructose and glucose) to 5-hydroxymethylfurfural (HMF). Optimization of reaction variables using Response Surface Method revealed that using 34 % of the catalyst at 100 and 110 °C for 30 and 50 min led to high yields of 98.5 % and 96.5 % for fructose and glucose conversion to HMF, respectively. The catalyst showed good recyclability, sustaining its productivity over 4 cycles. Comparative analyses with pristine Hep and UiO-66 indicated the superior performance of the catalyst, highlighting the synergistic effect between the Lewis and Brønsted acids originating from UiO-66 and Hep on the catalytic activity.

Molecular Insights of 5-Hydroxymethylfurfural in a Mixture of Ionic Liquids and Alkylated Phenolic Solvents

This paper presents all-atom molecular dynamics to understand the separation behavior of 5-hydroxymethylfurfural (5-HMF) from 1-butyl-3-methylimidazolium tetrafluoroborate [BMIM]+[BF4]- using alkylated phenols as extractants. We have utilized four solvents such as 4-methyl phenol (4-MP), 4-ethyl phenol (4-EP), 4-propyl phenol (4-PP), and 4-butyl phenol (4-BP). We perform structural, dynamic, and rigorous thermodynamic analyses of 5-HMF in the mixture of ILs and solvents. The [BMIM]+[BF4]- show a strong interaction with phenols. The self-diffusion coefficient of 5-HMF shows a 3-fold increase with a decrease in the methyl group on the phenol. The solvation-free energy (ΔGsolvation) of 5-HMF shows favorably in phenols. On the other hand, the transfer free energy (ΔGtransfer) of 5-HMF presents favorable from ILs to phenols. The partition coefficient (log P) values show favorability for separation of 5-HMF using phenols. Overall, the molecular level analysis provides the role of the alkyl group effect on the phenols for extracting 5-HMF from the ILs.

Diels-Alder Cycloaddition of 2,5-Bis(hydroxymethyl)furan (BHMF) and N-Phenylmaleimide Derivatives

Currently, amidst atmospheric menace where natural calamities such as wildfire and floods are becoming more frequent than ever, biobased derivatives offer a sustainable alternative to conventional ways, for instance, petrochemical commodities. Biobased products, obtained from agricultural waste, including 5-(hydroxymethyl)furfural (HMF), 2,5-bis(hydroxymethyl)furan (BHMF), and 2,5-furandicarboxylic acid (FDCA) are promising chemical platforms in the biorefinery, which is yet to be explored. The Diels-Alder cycloaddition of BHMF and N-phenylmaleimide derivatives under optimal reaction conditions is investigated in this report. First, HMF is reduced to BHMF in the presence of NaBH4, and then the Diels-Alder reaction of BHMF and N-phenylmaleimide derivatives is investigated to produce Diels-Alder adducts. All novel compounds are synthesized in acceptable yields and effectively characterized by employing important techniques such as one-dimensional (1D) NMR spectroscopy (1H, 13C, DEPT-90, and DEPT- 135), two-dimensional (2D) NMR spectroscopy (1H-1H COSY, 1H-13C HSQC, and 1H-13C HMBC), IR spectroscopy, elemental analysis, mass spectrum (QTOF), and single-crystal X-ray diffraction (SC-XRD). Furthermore, this study underlines the necessity of sustainable synthetic methodologies and gives critical insights into the progress of ecologically friendly methodologies, providing a new avenue as a tunable precursor for the challenging functionalized polymer in the future.

Formic acid as a sacrificial agent for byproduct suppression in glucose dehydration to 5-hydroxymethylfurfural using NaY zeolite catalyst

Biomass-derived 5-hydroxymethylfurfural (HMF) holds potential for applications in green materials, but its conventional synthesis is hindered by undesired side reactions. This study presents a catalytic system that effectively suppresses the formation of byproducts, thus enhancing HMF yield. The system demonstrated synergistic effects between Lewis acid NaY zeolite and formic acid sacrificial agent for the production of HMF from glucose. The results indicate that formic acid reacts with reactive intermediates from glucose decomposition, preventing their interactions with other sugar-derived species in the dehydration path to HMF. Such effect originates from the neutral formic acid species rather than the dissociated acidic proton normally observed in Brønsted acid-catalyzed reactions. The NaY/formic acid catalysts in isopropanol/water achieved a 57% HMF yield, a significant improvement over 31% and 27% yields with NaY or formic acid alone, respectively. Moreover, performance of the spent catalysts was easily restored to the original state via a simple NaCl wash.

Combination of deep eutectic solvent and functionalized metal-organic frameworks as a green process for the production of 5-hydroxymethylfurfural and furfural from sugars

Biomass is an abundant and sustainable resource that can be converted into energy and chemicals. Therefore, the development of efficient methods for the conversion of biomass into platform intermediates is crucial. In this study, the one-pot conversion of sugars into 5-hydroxymethylfurfural (HMF) and furfural was achieved using the metal-organic framework combined with metal ions [MIL-101(Cr)] as a high-activity catalyst, and a deep eutectic solvent (choline chloride and lactic acid) as a green solvent. The optimal temperature, time, amount of catalyst used, and amount of deep eutectic solvent used were all determined. The highest HMF yield of 49.74% and furfural yield of 55.90% were obtained. The recyclability of the catalysts and deep eutectic solvent was also investigated. After three reaction runs, the HMF yield was still nearly 30.00%. Finally, the MIL-101(Cr) catalytic system was selected to study the kinetic mechanism underlying the conversion of glucose into HMF.

Highly effective synthesis of 5-hydroxymethylfurfural from lignocellulosic biomass over a green and one-pot reaction in biphasic system

In this study, different types of lignocellulosic biomas were used as substrates for the conversion to 5-HMF via biphasic reaction system that is composed of a reaction phase (aqueous phase) and an extraction phase (organic phase) under the catalysis of various metal salts. Deep eutectic solvents (DESs), ionic liquid [BMIM]Cl, aqueous choline chloride, aqueous betaine hydrochloride, and ethylamine hydrochloride were used as the reaction phase in the combination of dimethyl sulfoxide (DMSO) as organic solvents. The highest yields of 5-HMF obtained from pineapple stems in reactions with DES were 40.98%, 37.26%, and 23.44% for ChCl:Lac, ChCl:OA, and EaCl:Lac, respectively. Moreover, the combination of dimethyl sulfoxide, betaine hydrochloride aqueous solution, and AlCl3·6H2O with the pineapple stem conversion system resulted in a maximum yield of 61.04% ± 0.55% of 5-HMF. This study also demonstrated that AlCl3·6H2O and betaine hydrochloride could be effectively reused four times, which indicates a green and effective process.

Nucleoside Analogs: A Review of Its Source and Separation Processes

Nucleoside analogs play a crucial role in the production of high-value antitumor and antimicrobial drugs. Currently, nucleoside analogs are mainly obtained through nucleic acid degradation, chemical synthesis, and biotransformation. However, these methods face several challenges, such as low concentration of the main product, the presence of complex matrices, and the generation of numerous by-products that significantly limit the development of new drugs and their pharmacological studies. Therefore, this work aims to summarize the universal separation methods of nucleoside analogs, including crystallization, high-performance liquid chromatography (HPLC), column chromatography, solvent extraction, and adsorption. The review also explores the application of molecular imprinting techniques (MITs) in enhancing the identification of the separation process. It compares existing studies reported on adsorbents of molecularly imprinted polymers (MIPs) for the separation of nucleoside analogs. The development of new methods for selective separation and purification of nucleosides is vital to improving the efficiency and quality of nucleoside production. It enables us to obtain nucleoside products that are essential for the development of antitumor and antiviral drugs. Additionally, these methods possess immense potential in the prevention and control of serious diseases, offering significant economic, social, and scientific benefits to the fields of environment, biomedical research, and clinical therapeutics.

Band Structure Engineering of Polyimide Photocatalyst for Efficient and Selective Oxidation of Biomass-Derived 5-Hydroxymethylfurfural

Solar-driven high-value utilization of biomass and its derivatives has attracted tremendous attention in replacing fossil sources to generate chemicals. Developing high-performance photocatalysts to selectively catalyze bio-platform molecules remains a challenge. Herein, biomass-based 5-hydroxymethylfurfural (HMF) was efficiently and selectively photooxidized to 2, 5-diformylfuran (DFF) using a metal-free polyimide (PI). PI with moderate photooxidation capacity delivered high DFF selectivity of 91 % and high apparent quantum efficiency of 1.13 %, nearly 7 times higher than that of graphitic carbon nitride. Experimental measurements and theoretical calculations revealed that the band structure and photooxidation capability of PI can be continuously modulated by varying the molar ratio of amine and anhydride. Mechanism analysis depicted that holes and superoxide radicals play crucial roles in the efficient photooxidation of HMF to DFF. This work provides guidance on designing efficient polymeric photocatalysts for oxidating biomass and its derivatives to value-added chemicals.

A Review of Biodegradable Plastics: Chemistry, Applications, Properties, and Future Research Needs

Environmental concerns over waste plastics' effect on the environment are leading to the creation of biodegradable plastics. Biodegradable plastics may serve as a promising approach to manage the issue of environmental accumulation of plastic waste in the ocean and soil. Biodegradable plastics are the type of polymers that can be degraded by microorganisms into small molecules (e.g., H2O, CO2, and CH4). However, there are misconceptions surrounding biodegradable plastics. For example, the term "biodegradable" on product labeling can be misconstrued by the public to imply that the product will degrade under any environmental conditions. Such misleading information leads to consumer encouragement of excessive consumption of certain goods and increased littering of products labeled as "biodegradable". This review not only provides a comprehensive overview of the state-of-the-art biodegradable plastics but also clarifies the definitions and various terms associated with biodegradable plastics, including oxo-degradable plastics, enzyme-mediated plastics, and biodegradation agents. Analytical techniques and standard test methods to evaluate the biodegradability of polymeric materials in alignment with international standards are summarized. The review summarizes the properties and industrial applications of previously developed biodegradable plastics and then discusses how biomass-derived monomers can create new types of biodegradable polymers by utilizing their unique chemical properties from oxygen-containing functional groups. The terminology and methodologies covered in the paper provide a perspective on directions for the design of new biodegradable polymers that possess not only advanced performance for practical applications but also environmental benefits.

Enzymatic reactions towards aldehydes: An overview

Many aldehydes are volatile compounds with distinct and characteristic olfactory properties. The aldehydic functional group is reactive and, as such, an invaluable chemical multi-tool to make all sorts of products. Owing to the reactivity, the selective synthesis of aldehydic is a challenging task. Nature has evolved a number of enzymatic reactions to produce aldehydes, and this review provides an overview of aldehyde-forming reactions in biological systems and beyond. Whereas some of these biotransformations are still in their infancy in terms of synthetic applicability, others are developed to an extent that allows their implementation as industrial biocatalysts.

Design of supported organocatalysts from a biomass-derived difuran compound and catalytic assessment for lactose hydrolysis

The engineered structures and active sites of enzyme catalysts give rise to high catalytic activity and selectivity toward desired reactions. We have employed a biomass-derived difuran compound to append N-substituted maleimides with amino acid (glutamic acid) substitution by Diels-Alder reaction to mimic the chemical functional groups that comprise the active site channels in enzyme catalysts. The difunctionality of the biomass-derived difuran allows production of Diels-Alder adducts by appending two amino acid moieties to form a difunctional organocatalyst. The catalytic activity of the organocatalyst can be improved by immobilizing the organocatalyst on solid supporting materials. Accordingly, the structures of these immobilized organocatalysts can be engineered to mimic enzymatic active sites and to control the interaction between reactants, products, and transition states of catalytic reactions. Lactose hydrolysis was carried out to provide an example of industrial application of this approach to design and fabricate new supported organocatalysts as artificial enzymes.

Controlled hydrogenation of a biomass-derived platform chemical formed by aldol-condensation of 5-hydroxymethyl furfural (HMF) and acetone over Ru, Pd, and Cu catalysts

We studied the hydrogenation at temperatures from 313 - 393 K of a biomass-derived platform molecule, 5-hydroxymethyl furfural (HMF)-Acetone-HMF (HAH) over Pd, Ru, and Cu based catalysts. HAH was selectively hydrogenated to produce partially-hydrogenated monomers (PHAH) over Cu and Ru catalysts and to fully-hydrogenated HAH monomers (FHAH) over the Ru catalyst. Pd based catalysts yielded a mixture of partially and fully hydrogenated monomers. Lumped reaction kinetics models were employed to quantify the kinetic behavior for hydrogenation over Ru, Cu, and Pd catalysts. The 5-step pathway exhibited over Pd and Ru catalysts consists of both series and parallel reaction steps, where HAH is both converted to fully hydrogenated products sequentially via series reactions of partially hydrogenated intermediates, as well as converted directly in parallel reactions to form the fully hydrogenated products. In contrast, the 3-step pathway over the Cu catalyst consists only of the consecutive reaction steps, where the final product was formed via series reactions of intermediate products. Additionally, reaction over the Cu catalyst did not hydrogenate the furan rings of the HAH molecule and yielded a different final product than those hydrogenation over Pd and Ru catalysts. Batch conditions are determined for each hydrogenated product that give the highest yields in both batch and plug flow reactors.

Design of closed-loop recycling production of a Diels-Alder polymer from a biomass-derived difuran as a functional additive for polyurethanes

Acetalization of biomass-derived 5-hydroxymethyl furfural (HMF) with pentaerythritol produced a difuran (HPH) monomer in the presence of an acid catalyst. A recyclable polymer was then synthesized by Diels-Alder reaction of bismaleimide and the HMF-derived difuran (HPH). A polyurethane, produced from the Diels-Alder polymer has a higher glass transition temperature than a polyurethane, produced from ethylene glycol. The polyurethane, containing Diels-Alder polymer also has a self-healing ability. The Diels-Alder polymer could be hydrolyzed under acidic acetate buffer at 60°C to produce the monomers for recycling. Each produced monomer was separated by solvent extraction, and the extracted monomers were recovered in different solvent fractions, such as aqueous, ethyl acetate, and acetone fractions. Techno economic analysis was used to assess the minimum selling price ($14.1 per kg) for the primary production of Diels-Alder polymer at a feed capacity of 400 tons per year. The economic viability of the primary recovery process for the most expensive recovered monomer, bismaleimide, was assessed by calculating the minimum selling price of the bismaleimide ($15.2 per kg). A circular closed-loop recycling production process for the Diels-Alder polymer was developed and this approach can produce the Diels-Alder polymer at $8.2 per kg when the feed capacity was 40 ktons per year.

Synthesis of performance-advantaged polyurethanes and polyesters from biomass-derived monomers by aldol-condensation of 5-hydroxymethyl furfural and hydrogenation

Functional polyurethanes and polyesters with tunable properties were synthesized from biomass-derived 5-hydroxymethyl furfural (HMF)-Acetone-HMF (HAH) monomers. HAH can be selectively hydrogenated over Cu and Ru catalysts to produce partially-hydrogenated (PHAH) and fully-hydrogenated (FHAH). The HAH units in these polymers improve the thermal stability and stiffness of the polymers compared to polyurethanes produced with ethylene glycol. Polyurethanes produced from PHAH provide diene binding sites for electron deficient C=C double bonds, such as in maleimide compounds, that can participate in Diels-Alder reactions. Such sites can function to create crosslinking by Diels-Alder coupling with bismaleimides and can be used to impart functionality to PHAH (giving rise to anti-microbial activity or controlled drug delivery). The symmetric triol structure of FHAH leads to energy-dissipating rubbers with branched structures. Accordingly, the properties of these biomass-derived polymers can be tuned by controlling the blending ratio of HAH-derived monomers or the degree of Diels-Alder reaction. The polyester produced from HAH can be used in packaging applications.