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Volume 7
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Chemistry, Volume 7, Issue 1 (February 2025) – 16 articles

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10 pages, 240 KiB  
Review
Nuclear Magnetic Resonance Gas-Phase Studies of Spin-Spin Couplings in Molecules
by Karol Jackowski
Chemistry 2025, 7(1), 16; https://doi.org/10.3390/chemistry7010016 - 26 Jan 2025
Viewed by 301
Abstract
This paper overviews gas phase experiments with respect to one fundamental part of nuclear magnetic resonance (NMR) spectra. Indirect spin-spin coupling is an important parameter of NMR spectra and is observed as the splitting of spectral signals. A molecule containing two different magnetic [...] Read more.
This paper overviews gas phase experiments with respect to one fundamental part of nuclear magnetic resonance (NMR) spectra. Indirect spin-spin coupling is an important parameter of NMR spectra and is observed as the splitting of spectral signals. A molecule containing two different magnetic nuclei (e.g., hydrogen HD, HT, or DT) exhibits this interaction in an external magnetic field measured as the spin-spin coupling parameter, nJ(NN′). Modern quantum chemical methods allow the precise calculation of spin-spin coupling, but it is never easy because nJ(NN′) is modified by temperature and intermolecular interactions. Accurate calculations can be performed only for small isolated molecules. NMR spectroscopy can deliver measurements of spin-spin couplings for isolated molecules if nJ(NN′) parameters are observed in the gas phase as a function of density. The extrapolation of such measurements to the zero-density limit permits nJ0(NN′) determination free from intermolecular interactions. The latter technique can also be applied to liquid vapors in molecules like acetonitrile or water. Spin-spin couplings across one chemical bond (1J0(NN′)) are the largest and most important for theoretical modeling. The present review reports numerous 1J0(NN′) parameters recently measured by multinuclear NMR spectra of gaseous samples. Full article
(This article belongs to the Section Physical Chemistry and Chemical Physics)
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14 pages, 4484 KiB  
Article
Synthesis and Characterization of Quinoxaline-Fused Cyclopenta[cd]azulene
by Tomohiro Oda, Yuina Onishi, Akihito Konishi and Makoto Yasuda
Chemistry 2025, 7(1), 15; https://doi.org/10.3390/chemistry7010015 - 23 Jan 2025
Viewed by 652
Abstract
Azulene-based polycyclic hydrocarbons have garnered much attention as potential materials for organic optoelectronic devices and as molecular models for graphene nanosheets with structural defects. Although various methods for ring fusions to an azulene core have been established for ring fusions to an azulene [...] Read more.
Azulene-based polycyclic hydrocarbons have garnered much attention as potential materials for organic optoelectronic devices and as molecular models for graphene nanosheets with structural defects. Although various methods for ring fusions to an azulene core have been established for ring fusions to an azulene core, efficient synthetic methodologies for ortho- and peri-fusion to an azulene core are still lacking, which hinders the investigation of the effect of the ortho- and peri-fusion on the electronic properties of the embedded azulene core. Herein, we describe the synthesis and characterization of quinoxaline-fused cyclopenta[cd]azulene 4 as a new ortho- and peri-fused azulene derivative. The target molecule 4 was successfully synthesized in four steps from 4-methylazulene. The ring annulation decreased the lowest excitation energy compared with that of azulene and its structural isomer 5 and led to multiple reversible reduction processes. Characterization of the molecular geometry and optoelectronic properties of 4 revealed that the embedded azulene core preserves its original aromaticity, while the fused quinoxaline acts as a nucleophilic and basic site. These features suggest that 4 could serve as a metal ligand, a near-infrared absorber, and a component in organic functional devices. Full article
(This article belongs to the Special Issue Open-Shell Systems—a Memorial Issue Dedicated to Professor Masayoshi Nakano)
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16 pages, 2317 KiB  
Article
Development and Validation of an HPLC-FLD Method for the Determination of Pyridoxine and Melatonin in Chocolate Formulations—Digestion Simulation Study
by Georgios Kamaris, Vasiliki-Panagiota M. Mitsiou, Konstantina Chachlioutaki, Sofia Almpani and Catherine K. Markopoulou
Chemistry 2025, 7(1), 14; https://doi.org/10.3390/chemistry7010014 - 23 Jan 2025
Viewed by 454
Abstract
The undeniable value of sleep is commonly accepted and essential for all aspects of human existence. The aim of the present study was to develop and validate an applicable and sensitive HPLC-FLD method for the quantitative determination of pyridoxine (PYR) and melatonin (MEL) [...] Read more.
The undeniable value of sleep is commonly accepted and essential for all aspects of human existence. The aim of the present study was to develop and validate an applicable and sensitive HPLC-FLD method for the quantitative determination of pyridoxine (PYR) and melatonin (MEL) in a chocolate formulation that is suitable for the treatment of insomnia. The proposed chromatographic process was performed on an Aqua column (250 mm × 4.6 mm, 5 mm) at 45 °C, with a mobile phase consisting of two solvents (A, water with 0.2% formic acid; and B, acetonitrile with 0.2% formic acid) in a gradient elution and with a flow rate of 1.2 mL/min. Method validation was carried out according to ICH specifications in terms of linearity (R2 > 0.999), precision, and repeatability (%RSD < 2). The limits of detection (LODs: PYR = 0.09 ng/mL; MEL = 0.92 ng/mL) and quantification (LOQs: PYR = 0.29 ng/mL; LOQMEL = 3.04 ng/mL) for both analytes were also determined. A mixture D-Optimal methodology of experimental design technique was applied for the quantitative recovery of the two APIs from chocolate (% recovery > 97.4%). Finally, to simulate the digestion process of the new preparation, three phases in vitro, a digestion method was applied. According to the study, 73.8% of pyridoxine and 55.9% of melatonin (on the indicated dose) were released from the formulation and ended up in the intestine. Full article
(This article belongs to the Section Medicinal Chemistry)
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11 pages, 2105 KiB  
Article
Nitrogen-Doped MXene Electrodes for High-Voltage Window Supercapacitors in Organic Electrolytes
by Yingyi Liao, Xiaoqing Bin, Jing Xu, Xuedong He and Wenxiu Que
Chemistry 2025, 7(1), 13; https://doi.org/10.3390/chemistry7010013 - 23 Jan 2025
Viewed by 312
Abstract
MXene has excellent electrochemical performance in aqueous electrolytes; however, its narrow voltage window (hydrolysis voltage ≤ 1.2 V) limits the energy density of supercapacitors. Compared to conventional aqueous electrolytes, ionic liquid (IL) electrolytes exhibit a much larger voltage window, but their larger ion [...] Read more.
MXene has excellent electrochemical performance in aqueous electrolytes; however, its narrow voltage window (hydrolysis voltage ≤ 1.2 V) limits the energy density of supercapacitors. Compared to conventional aqueous electrolytes, ionic liquid (IL) electrolytes exhibit a much larger voltage window, but their larger ion size limits the transport and intercalation of IL cations in MXene electrodes. Therefore, the electrochemical performances for three different types of organic electrolytes based on nitrogen-doped MXene electrodes in supercapacitors were investigated, with the voltage windows of the devices effectively widened to 2.4 V. In addition, the nitrogen-doped MXene electrodes also effectively adjusted the interlayer spacing of the MXene nanosheets, with the enlarged interlayer spacing (from 12.60 Å to 14.24 Å) being more favorable for the intercalation and de-intercalation of larger-sized organic ions within the electrodes, thus effectively storing a charge. Among them, the 1 M EMIMTFSI/LiTFSI/ACN electrolyte is optimal due to the introduction of a smaller ion size for Li+, and so the corresponding supercapacitor achieves the electrode capacitance of up to 147 F g−1, with the maximum energy density of 29.4 Wh kg−1. This work provides a new strategy for reasonably optimizing the design of organic electrolytes matching modified MXene electrodes to effectively enhance the energy density of supercapacitors. Full article
(This article belongs to the Section Electrochemistry and Photoredox Processes)
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12 pages, 1727 KiB  
Article
Tethered Antigenic Suppression Shields the Hemagglutinin Head Domain and Refocuses the Antibody Response to the Stalk Domain
by Donguk Kim, Kathryn Loeffler, Yixin Hu, Ammar Arsiwala, Steven Frey, Shruthi Murali, Vivek Hariharan, Alberto Moreno and Ravi S. Kane
Chemistry 2025, 7(1), 12; https://doi.org/10.3390/chemistry7010012 - 21 Jan 2025
Viewed by 499
Abstract
Influenza has been a global health concern for the past century. Current seasonal influenza vaccines primarily elicit an antibody response that targets the immunodominant head domain of the viral glycoprotein hemagglutinin (HA), which consistently mutates due to selective pressure. To circumvent this problem, [...] Read more.
Influenza has been a global health concern for the past century. Current seasonal influenza vaccines primarily elicit an antibody response that targets the immunodominant head domain of the viral glycoprotein hemagglutinin (HA), which consistently mutates due to selective pressure. To circumvent this problem, we introduce a “tethered antigenic suppression” strategy to shield the HA head domain and refocus the immune response towards the conserved but immunosubdominant stalk domain of HA. Specifically, we tethered an antibody fragment (Fab) that recognizes the Sb antigenic site in the HA head domain to the HA protein with a linker. We immunized separate groups of female mice with the Fab-tethered HA or regular HA and characterized the elicited antibody response. We demonstrate that shielding the HA head domain with a tethered Fab suppresses the antibody titers towards all five key antigenic sites in the HA head domain while eliciting a robust anti-stalk antibody response. Our work highlights the potential of tethered antigenic suppression as a strategy to refocus the antibody response towards conserved epitopes on protein antigens. Full article
(This article belongs to the Special Issue A Themed Issue in Honor of Professor George Whitesides on the Occasion of His 85th Birthday Anniversary)
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28 pages, 1219 KiB  
Review
Chemometric Approaches for Sustainable Pharmaceutical Analysis Using Liquid Chromatography
by Dina Aboushady, Liza Samir, Alaa Masoud, Yasmin Elshoura, Abdelgawad Mohamed, Rasha S. Hanafi and Sami El Deeb
Chemistry 2025, 7(1), 11; https://doi.org/10.3390/chemistry7010011 - 20 Jan 2025
Viewed by 710
Abstract
Chemometrics, which applies mathematical and statistical methods to aid in experimental design, data analysis, and process optimization, is gaining more importance. It plays an important role in enhancing the sustainability of analytical methods when integrated with green analytical chemistry. Applying chemometrics to liquid [...] Read more.
Chemometrics, which applies mathematical and statistical methods to aid in experimental design, data analysis, and process optimization, is gaining more importance. It plays an important role in enhancing the sustainability of analytical methods when integrated with green analytical chemistry. Applying chemometrics to liquid chromatographic methods can speed up the analytical method, saving time, energy, and solvent consumption. This would be reflected by a low energy footprint and environmental impact. This review discusses the application of chemometric methods like multivariant data analysis, design of experiments, retention time prediction, and peak deconvolution in green liquid chromatographic analysis of pharmaceuticals. The review highlights the impact of chemometric approaches on the global push for sustainable practices. The integration of chemometrics into sustainable chromatographic analysis will continue to revolutionize the field leading to better performance of analytical methods. Full article
(This article belongs to the Section Medicinal Chemistry)
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19 pages, 1295 KiB  
Article
Dielectrically Monitored Flow Synthesis of Functional Vaccine Adjuvant Mixtures via Microwave-Assisted Catalytic Chain Transfer Processing
by Cordula S. Hege, Ian E. Hamilton, Adam A. Dundas, Kevin Adlington, Edward Walker, Helena Henke, Kaiyang Wang, Georgios Dimitrakis, Adam Buttress, Christopher Dodds, Christopher B. Fox and Derek J. Irvine
Chemistry 2025, 7(1), 10; https://doi.org/10.3390/chemistry7010010 - 17 Jan 2025
Viewed by 451
Abstract
A novel flow process to produce low-molecular-weight (Mwt) methacrylate oligomer mixtures that have potential as vaccine adjuvants and chain transfer agents (CTAs) is reported. The chemistry and process were designed to significantly reduce the number of stages required to manufacture methyl methacrylate oligomer-in-monomer [...] Read more.
A novel flow process to produce low-molecular-weight (Mwt) methacrylate oligomer mixtures that have potential as vaccine adjuvants and chain transfer agents (CTAs) is reported. The chemistry and process were designed to significantly reduce the number of stages required to manufacture methyl methacrylate oligomer-in-monomer mixtures with an oligomer Mwt range of dimers to pentamers and >50% conversion. Combining rapid in-flow, in situ catalytic chain transfer polymerization catalyst synthesis and volumetric microwave heating of the reaction medium resulted in catalyst flow synthesis being completed in <4 min, removing the need to pre-synthesize it. The steady-state operation was then successfully maintained with very low levels of external energy, as the process utilized the reaction exotherm. The microwave process outperformed a comparative conventionally heated system by delivering a 20% increase in process throughput with no change in final product quality or conversion. Additionally, combining flow and in situ catalyst processing enabled the use of a more oxidatively unstable catalyst. This allowed for in situ catalyst deactivation post-generation of the oligomers, such that residual catalyst did not need to be removed prior to preparing subsequent vaccine adjuvant or CTA screening formulations. Finally, dielectric property measurements were able to monitor the onset of reaction and steady-state operation. Full article
(This article belongs to the Section Molecular Organics)
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14 pages, 2389 KiB  
Review
Prof. George Whitesides’ Contributions to Self-Assembled Monolayers (SAMs): Advancing Biointerface Science and Beyond
by Tomohiro Hayashi
Chemistry 2025, 7(1), 9; https://doi.org/10.3390/chemistry7010009 - 16 Jan 2025
Viewed by 715
Abstract
Prof. George Whitesides’ pioneering contributions to the field of self-assembled monolayers (SAMs) have profoundly influenced biointerface science and beyond. This review explores the development of SAMs as highly organized molecular structures, focusing on their role in advancing surface science, biointerface research, and biomedical [...] Read more.
Prof. George Whitesides’ pioneering contributions to the field of self-assembled monolayers (SAMs) have profoundly influenced biointerface science and beyond. This review explores the development of SAMs as highly organized molecular structures, focusing on their role in advancing surface science, biointerface research, and biomedical applications. Prof. Whitesides’ systematic investigations into the effects of SAMs’ terminal group chemistries on protein adsorption and cell behavior culminated in formulating “Whitesides’ Rules”, which provide essential guidelines for designing bioinert surfaces. These principles have driven innovations in anti-fouling coatings for medical devices, diagnostics, and other biotechnological applications. We also discuss the critical role of interfacial water in SAM bioinertness, with studies demonstrating its function as a physical barrier preventing protein and cell adhesion. Furthermore, this review highlights how data science and machine learning have expanded the scope of SAM research, enabling predictive models for bioinert surface design. Remarkably, Whitesides’ Rules have proven applicable not only to SAMs but also to polymer-brush films, illustrating their broad relevance. Prof. Whitesides’ work provides a framework for interdisciplinary advancements in material science, bioengineering, and beyond. The enduring legacy of his contributions continues to inspire innovative approaches to addressing challenges in biomedicine and biotechnology. Full article
(This article belongs to the Special Issue A Themed Issue in Honor of Professor George Whitesides on the Occasion of His 85th Birthday Anniversary)
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12 pages, 773 KiB  
Article
Survey of Aconitum Alkaloids to Establish an Aconitum carmichaeli (Fu-Zi) Processing Procedure and Quality Index
by Kun-Teng Wang, Ming-Chung Lee and Wu-Chang Chuang
Chemistry 2025, 7(1), 8; https://doi.org/10.3390/chemistry7010008 - 14 Jan 2025
Viewed by 466
Abstract
Processed Fu-Zi (the lateral roots of Aconitum carmichaeli) is beneficial for the cardiac system, but, because it contains toxins, raw Fu-Zi produces arrhythmia and breathing difficulties. C19 diester diterpenoid alkaloids (DDAs), including aconitine, mesaconitine, and hypaconitine, are toxic Aconitum alkaloids found [...] Read more.
Processed Fu-Zi (the lateral roots of Aconitum carmichaeli) is beneficial for the cardiac system, but, because it contains toxins, raw Fu-Zi produces arrhythmia and breathing difficulties. C19 diester diterpenoid alkaloids (DDAs), including aconitine, mesaconitine, and hypaconitine, are toxic Aconitum alkaloids found in Fu-Zi and can be hydrolyzed to nontoxic monoester diterpenoid alkaloids (MDAs), including benzoylaconine, benzoylmesaconine, and benzoylhypaconine. In this study, six processed Fu-Zi decoction pieces and herbal medicines were analyzed. The highest DDA contents were found in Shengfupian, the raw Fu-Zi samples. A processing quality index (Grades A to D) was established to evaluate the processing quality of Fu-Zi. The data demonstrated that few Fu-Zi decoction pieces did not conform to the government regulation. The results of testing the inorganic elements showed that the calcium content increased by approximately 5 to 30 fold compared to raw Fu-Zi due to substances assisting with processing. Raw Fu-Zi processed by boiling, without additional substances, may have a decreased DDA content. This study provides a method of determining the quality status of pieces of Fu-Zi decoction and establishes a processing quality index for pieces of Fu-Zi decoction and herbal medicine. Furthermore, our results suggest that it is not necessary to use additional substance to assist with the processing of Fu-Zi. Through the established processing quality index, Fu-Zi may be used more safely and may demonstrate a greater consistency in quality. Full article
(This article belongs to the Section Biological and Natural Products)
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39 pages, 8429 KiB  
Review
Chemical Space of Fluorinated Nucleosides/Nucleotides in Biomedical Research and Anticancer Drug Discovery
by Yugandhar Kothapalli, Tucker A. Lesperance, Ransom A. Jones, Chung K. Chu and Uma S. Singh
Chemistry 2025, 7(1), 7; https://doi.org/10.3390/chemistry7010007 - 13 Jan 2025
Viewed by 600
Abstract
Fluorinated nucleos(t)ide drugs have proven to be successful chemotherapeutic agents in treating various cancers. The Food and Drug Administration (FDA) has approved several drugs that fit within the fluorinated nucleoside pharmacophore, and many more are either in preclinical development or clinical trials. The [...] Read more.
Fluorinated nucleos(t)ide drugs have proven to be successful chemotherapeutic agents in treating various cancers. The Food and Drug Administration (FDA) has approved several drugs that fit within the fluorinated nucleoside pharmacophore, and many more are either in preclinical development or clinical trials. The addition of fluorine atoms to nucleos(t)ides improves the metabolic stability of the glycosidic bond and, in certain instances, facilitates additional interactions of nucleons(t)ides with receptors. The insertion of fluorine either on sugar or the base of nucleos(t)ides proved to enhance the lipophilicity, pharmacokinetic, and pharmacodynamic properties. Overall, the fluorine atom feeds diverse advantages to the biological profile of nucleos(t)ide analogs by improving their drug-like properties and therapeutic potential. This review article covers the often-used fluorinating reagents in nucleoside chemistry, the clinical significance of [18F]-labeled nucleosides, the synthesis and anticancer activity of FDA-approved fluoro-nucleos(t)ide drugs, as well as clinical candidates, which are at various stages of clinical development as anticancer agents. Full article
(This article belongs to the Section Medicinal Chemistry)
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11 pages, 1997 KiB  
Article
Expanding the Chemical Diversity of Stemona parviflora: Isolation and Characterization of New Parvistemoline-Type Alkaloids
by Shuaizhen Zhou, Ruolin Geng, Changqiang Ke, Fan Ge, Ying Chen, Chunping Tang and Yang Ye
Chemistry 2025, 7(1), 6; https://doi.org/10.3390/chemistry7010006 - 13 Jan 2025
Viewed by 325
Abstract
A comprehensive phytochemical investigation of the whole plant of Stemona parviflora led to the isolation of 13 alkaloidal constituents, including five new alkaloids, parvistemonines B–F (1–5). The structures of these compounds were elucidated through extensive analyses of 1D and [...] Read more.
A comprehensive phytochemical investigation of the whole plant of Stemona parviflora led to the isolation of 13 alkaloidal constituents, including five new alkaloids, parvistemonines B–F (1–5). The structures of these compounds were elucidated through extensive analyses of 1D and 2D NMR spectra, DFT NMR calculation, and comparisons with data in the literature. Notably, compounds 1–4 represent new examples of the rare parvistemoline-type alkaloids, with compound 4 showcasing a unique rearranged skeleton. Additionally, parvistemonine F (5) was identified as a distinct alkaloid skeleton characterized by a n-butyl side chain. These findings significantly expand our understanding of the chemical diversity of parvistemoline-type alkaloids and provide clues for elucidating the biosynthetic pathways of these structurally unique parvistemoline alkaloids. Full article
(This article belongs to the Section Biological and Natural Products)
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11 pages, 3570 KiB  
Article
Starting Electroosmosis in a Fibrous Porous Medium with Arbitrary Electric Double-Layer Thickness
by Wei Z. Chen and Huan J. Keh
Chemistry 2025, 7(1), 5; https://doi.org/10.3390/chemistry7010005 - 8 Jan 2025
Viewed by 505
Abstract
The transient electroosmotic response in a charged porous medium consisting of a uniform array of parallel circular cylindrical fibers with arbitrary electric double layers filled with an electrolyte solution, for the stepwise application of a transverse electric field, is analyzed. The fluid momentum [...] Read more.
The transient electroosmotic response in a charged porous medium consisting of a uniform array of parallel circular cylindrical fibers with arbitrary electric double layers filled with an electrolyte solution, for the stepwise application of a transverse electric field, is analyzed. The fluid momentum conservation equation is solved for each cell by using a unit cell model, where a single cylinder is surrounded by a coaxial shell of the electrolyte solution. A closed-form expression for the transient electroosmotic velocity of the bulk fluid in the Laplace transform is obtained as a function of the ratio of the cylinder radius to the Debye screening length and the porosity of the fiber matrix. The effect of the fiber matrix porosity on the continuous growth of the electroosmotic velocity over time is substantial and complicated. For a fiber matrix with larger porosity, the bulk fluid velocity takes longer to reach a certain percentage of its final value. Although the final value of the bulk fluid velocity generally increases with increasing porosity, early velocities may decrease with increasing porosity. For a given fiber matrix porosity, the transient electroosmotic velocity is a monotonically increasing function of the ratio of the cylinder radius to the Debye length. Full article
(This article belongs to the Section Physical Chemistry and Chemical Physics)
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12 pages, 1468 KiB  
Article
Comprehensive Chemical Analysis of Codonopsis lanceolata Roots Using Ultra-High-Performance Liquid Chromatography–Quadrupole-Exactive–Orbitrap Mass Spectrometry
by Chang Luo, Zenan Duan, Takashi Kikuchi, Kouharu Otsuki, Mi Zhang, Ryuichi Kambayashi, Katsuhiko Ito, Atsushi Sugiyama and Wei Li
Chemistry 2025, 7(1), 4; https://doi.org/10.3390/chemistry7010004 - 6 Jan 2025
Viewed by 487
Abstract
The roots of Codonopsis lanceolata (Siebold & Zucc.) Benth. & Hook.f. ex Trautv. have been traditionally used for medicinal purposes across East Asia. However, their chemical constituents in Japanese-grown varieties remain uninvestigated. This study employed ultra-high-performance liquid chromatography–quadrupole–orbitrap mass spectrometry to perform a [...] Read more.
The roots of Codonopsis lanceolata (Siebold & Zucc.) Benth. & Hook.f. ex Trautv. have been traditionally used for medicinal purposes across East Asia. However, their chemical constituents in Japanese-grown varieties remain uninvestigated. This study employed ultra-high-performance liquid chromatography–quadrupole–orbitrap mass spectrometry to perform a comprehensive chemical analysis of the roots of C. lanceolata cultivated in Nagano Prefecture, Japan, leveraging fragment pattern analysis of both isolated and commercially available compounds as references compounds. As a result, 27 compounds, including triterpenoid saponins (19–22), polyacetylenes (6, 15, 18), flavonoids (16, 17), phenylpropanoids (3–5, 7, 9), a lignan (10), glycolipids (8, 11–14), phospholipids (23–27), and amino acids (1, 2), were identified. Notably, a triterpenoid saponin (19) was identified as a previously unreported compound, and ten compounds (3, 6, 8, 10, 13, 17, and 23–27) were identified from C. lanceolata roots for the first time. The ex vivo study revealed that lancemaside A (22) exhibited a time-dependent vasodilatory effect on rat aortic ring specimens. These findings not only advanced the understanding of the chemical constituents and biological activity of C. lanceolata roots but also provided valuable insights for their future applications and quality control. Full article
(This article belongs to the Section Biological and Natural Products)
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15 pages, 9586 KiB  
Article
Zeolite Synthesized from Solid Waste for Eco-System Remediation: Selective Adsorption in Wastewater
by Mariana S. Araujo, Danilo Costa-Silva, Juliana C. Izidoro, Denise A. Fungaro and Sonia Mello Castanho
Chemistry 2025, 7(1), 3; https://doi.org/10.3390/chemistry7010003 - 31 Dec 2024
Viewed by 586
Abstract
The present investigation explores the potential of two synthesized zeolites, derived from coal fly ash (CFA; thermoelectric waste) and sugarcane bagasse ash (SCBA; agro-industrial waste), for the selective adsorption of cesium in wastewater. The synthesized zeolites (ZCFA and ZSCBA) were characterized and compared [...] Read more.
The present investigation explores the potential of two synthesized zeolites, derived from coal fly ash (CFA; thermoelectric waste) and sugarcane bagasse ash (SCBA; agro-industrial waste), for the selective adsorption of cesium in wastewater. The synthesized zeolites (ZCFA and ZSCBA) were characterized and compared with a commercial zeolite to evaluate their physicochemical properties and effectiveness in removing cesium ions (Cs+) from simulated radioactive wastewater. The results obtained from X-ray diffraction, scanning electron microscopy, and elemental analysis confirmed the successful synthesis of high-purity zeolite from both solid wastes. The impurities present in the ashes impacted the Si/Al ratio and consequently influenced the exchange capacity. After adsorption experiments, neutron activation analysis (NAA) revealed that ZSCBA adsorbed 33.4% of Cs2O by weight, outperforming both ZCFA (26.0%) and commercial zeolite (27.9%). The superior performance of ZSCBA is attributed to its distinct Si/Al ratio and lower levels of impurities, highlighting the impact of these factors on adsorption selectivity. The findings in this study demonstrate the feasibility of valorizing agro-industrial waste for synthesizing zeolites, offering a sustainable approach for managing these residues while producing valuable materials for environmental remediation. Full article
(This article belongs to the Section Chemistry of Materials)
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17 pages, 4918 KiB  
Article
Mechanistic Insights into Sugar Racemization and Oxidative Degradation via Fenton and Alkaline Peroxide Systems
by Zoltán Köntös and Áron Németh
Chemistry 2025, 7(1), 2; https://doi.org/10.3390/chemistry7010002 - 26 Dec 2024
Viewed by 507
Abstract
This study explores the oxidation and racemization of selected C5 and C6 sugars using hydrogen peroxide (H2O2) in alkaline and Fenton reaction conditions. The sugars studied include D-Glucose, D-Fructose, D-Mannose, D-Xylose, D-Lactose, D-Arabinose, D-Cellobiose, Sucrose, and D-Galactose. Oxidation reactions [...] Read more.
This study explores the oxidation and racemization of selected C5 and C6 sugars using hydrogen peroxide (H2O2) in alkaline and Fenton reaction conditions. The sugars studied include D-Glucose, D-Fructose, D-Mannose, D-Xylose, D-Lactose, D-Arabinose, D-Cellobiose, Sucrose, and D-Galactose. Oxidation reactions were conducted using both Fenton’s reagent and NaOH/H2O2 to examine product formation, yield distribution, and stereochemical transformations. Under alkaline conditions, sugars primarily oxidized to yield sodium formate and hydrogen, with the minimal formation of intermediate sugar acids. Excess alkaline conditions further promoted the rapid degradation of sugars to sodium formate and hydrogen as primary products, indicating the strong influence of reaction conditions on oxidation pathways. A significant observation was that both alkaline and Fenton oxidation led to racemization, converting optically pure sugars into a racemic mixture of D- and L-enantiomers, thus producing products with zero optical rotation. The generation of L-enantiomers, metabolically inactive in biological systems, has implications for energy yield and biochemical efficiency. Full article
(This article belongs to the Section Theoretical and Computational Chemistry)
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20 pages, 5266 KiB  
Article
Synthesis of Spherical and Layered Ag-SiO2-TiO2/TiO2-Ag Structures
by Aleksander A. Buzaev, Valerya A. Tkachuk, Alexandra M. Zakharkiva and Lyudmila P. Borilo
Chemistry 2025, 7(1), 1; https://doi.org/10.3390/chemistry7010001 - 25 Dec 2024
Viewed by 416
Abstract
Due to the unique properties of titanium dioxide (TiO2), titanium oxide catalysts hold significant potential for photo-oxidative processes involving organic substances in liquid media. The current research has focused on developing new preparation methods that enable the manipulation of the properties, [...] Read more.
Due to the unique properties of titanium dioxide (TiO2), titanium oxide catalysts hold significant potential for photo-oxidative processes involving organic substances in liquid media. The current research has focused on developing new preparation methods that enable the manipulation of the properties, structure, and geometric shape of catalysts to enhance their efficiency in targeted reactions. This study developed a method for preparing Ag-SiO2-TiO2/TiO2-Ag layered structures with a spherical shape, featuring particle diameters ranging from 232 to 653 μm and mesopores of 2–20 nm. This was achieved by combining sol–gel and template synthesis methods. A comprehensive analysis of the obtained materials was conducted using methods such as X-ray phase analysis, micro-X-ray spectral analysis, X-ray microanalysis, and scanning electron spectroscopy. The photocatalytic properties were assessed by measuring the degree of decomposition of methyl orange in a model oxidation reaction under light radiation. The obtained spherical Ag-SiO2-TiO2/TiO2-Ag layered structures demonstrated high efficiency in the photooxidation of methyl orange in the model reaction. Full article
(This article belongs to the Section Catalysis)
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