Abstract: The kinetics of the Br-atom reactions with C2H4S and ClNO have been studied as a function of temperature at a total pressure of 2 Torr of Helium using a discharge-flow system combined with mass spectrometry: Br + C2H4S  SBr +C2H4 (1) and Br + ClNO  BrCl +NO (2). The rate constant of reaction (1) was determined at T = 340 - 920 K by absolute measurements under pseudo–first order conditions, either by monitoring the kinetics of Br-atom or C2H4S consumption in excess of C2H4S or of Br atoms, respectively, and by using a relative rate method: k1 = (6.6 ± 0.7)10-11 exp(-(2946 ± 60)/T) cm3molecule-1s-1 (where the uncertainties represent the precision at the 2σ level, the estimated total uncertainty on k1 being 15% at all temperatures). The rate coefficient of reaction (2), determined either from the kinetics of the formation of the reaction product, BrCl, or from the decays of Br-atom in an excess of ClNO, showed a non-Arrhenius behavior, being practically independent of temperature below 400 K and increasing significantly at temperatures above 500 K. The measured rate constant is well reproduced by a sum of two exponential functions: k2 = 1.2×10-11 exp(-19/T) + 8.0×10-11 exp(-1734/T) cm3 molecule-1 s-1 (with an estimated overall temperature-independent uncertainty of 15 %) at T = 225 – 960 K.

Abstract: Sensitized radiation-induced polymerization of indene monomer was achieved at a dose rate of 3 kGy/h. The sensitizer (1,1,2,2-tetrachloroethane or TCE) leads to higher polyindene yields and faster polymerization kinetics with respect to bulk radiation-induced polymerization of indene. The radiation chemical yield Gp was found to increase with dose in sensitized polymerization of indene following a power law, while an opposite trend was detected in the absence of the sensitizer. The sensitizer enhances the cationic polymerization mechanism in parallel to the free radical mechanism, as shown with both electronic absorption spectroscopy and FT-IR analysis of the polyindenes. Despite the enhancement of the polymer yield and the faster polymerization kinetics offered by the presence of TCE the molecular weight of the resulting polyindene was found rather low either by end group analysis by X-ray fluorescence and from the glass transition temperature determination with respect to the polyindenes produced with γ radiation without sensitizer or with pure cationic mechanism.

Abstract: The gas phase delivery of lignin into the hot zone of cw-CO2 laser powered homogeneous pyrolysis (LPHP) reactor under “wall-less” conditions led to break down of lignin macromolecules into neutral oligomers and paramagnetic fragments deposited onto the reactor cell walls. Formation of PAHs was observed during defragmentation of lignin accelerated with increased laser power. Remarkably, no phenolic compounds were detected among lignin fragments - intermediate radicals and neutral oligomers. It is concluded that the PAH and soot-like conjugated particulates are formed in the hot zone of the LPHP reactor resembling the high temperature combustion processes. The key role of the resonantly stabilized radicals in the formation of low molecular weight PAHs is outlined. An alternative pathway is proposed for generation of PAH involving formation of cyclopentadienyl radical precursors (CPDa) that are adsorbed onto or trapped within lignin macromolecules.

Abstract: The study approaches the characterization of Ferroxite and Hematite and the test of their magnetic properties on the degradation and adsorption of Atrazine, an herbicide of the triazine class. This herbicide was compared with a sample of Ferroxite in the absence of magnetic field and with Hematite, a non-magnetic material which should not be attracted by the magnet. In the sample, the Atrazine determination was carried out by Fenton analysis. Preliminary results were satisfactory, gathering reduction rate up to 85% for Ferroxite in the presence of magnetic field and 53% for Hematite. The Fenton reaction, however, showed 87% reduction rate for Ferroxite in the presence of magnetic field, and 56% for Hematite. These findings have shown that there is a relation between the magnetic field intensity and the adsorption capacity for these materials.

Abstract: Perfluoropropionic acid (CF₃CF₂C(O)OH) will be investigated with a focus on its complex structural properties. As a formal derivative of propanoic acid, the incorporation of fluorine atoms imparts unique structural features, including three distinct monomeric conformations and a dimeric structure. This study presents experimental findings, supported by computational modeling, to explore these characteristics. The analysis includes an FTIR study of the isolated species in an Ar-cryogenic matrix and the low-temperature determination of its crystalline structure using single-crystal X-ray diffraction.

Abstract: Engineered substances that demonstrate superior properties compared with conventional materials are called advanced materials. Thermal energy storage systems based on Phase Change Materials (PCMs) offer an eco-friendly solution to reduce fuel and electricity consumption. The PCMs are compounds that can store thermal energy in the form of latent heat during phase transitions. Green synthesis of core/shell composite PCMs is an environmentally friendly method for producing these materials, focusing on reducing energy consumption, minimizing the use of harmful chemicals, and utilizing biodegradable or sustainable materials. Green synthesis methods typically involve natural materials, solvent-free techniques, green solvents, biomimetic approaches, and energy-efficient processes. This review presents the principles of latent heat thermal energy storage systems with PCMs in accordance with physical chemistry guidance. Furthermore, materials that can be used as PCMs, along with the most effective methods for improving their thermal performance, as well as various passive applications in the building sector, are highlighted. Finally, the focus on the combination of environmentally friendly processes and the performance benefits of composite PCMs that offer a sustainable solution for thermal energy storage and management is also discussed.

Abstract:

The Selective Catalytic Oxidation of ammonia (NH₃-SCO) is gaining attention due to the hazardous nature of NH₃ and its inclusion in emission reduction frameworks such as the National Emission Ceilings Directive and the Gothenburg Protocol (1999). Copper-based hydroxyapatite (Cu/HAP) catalysts have emerged as a promising solution, offering high activity and cost-effectiveness.This study evaluates two preparation methods: a one-pot co-precipitation technique and post-synthesis copper deposition, varying contact time and copper concentration. The influence of copper loading and preparation method on catalyst performance in NH₃-SCO was investigated in a continuous flow reactor over a temperature range of 200–500°C, with a fixed gas hourly space velocity (GHSV) of 120,000 h⁻¹ and an NH₃/O₂ ratio of 0.03.X-ray diffraction and DR-UV spectroscopy confirmed the high crystallinity of HAP and provided insights into copper speciation. X-ray photoelectron spectroscopy revealed that Cu/HAP catalysts prepared via one-pot co-precipitation predominantly contained isolated Cu²⁺ species, which were associated with high catalytic activity in selective NH₃-SCO. Conversely, a higher degree of copper structuring was observed in catalysts prepared by post-synthesis deposition, particularly at higher Cu loadings.These findings highlight the potential to tailor Cu structuring on HAP to enhance performance in NH₃-SCO through optimized preparation strategies.

Abstract: Two graphitized thermal soot (GTS6, GTS80) and graphitized soot with a deposited overlayer of organic carboxylic acid (GTS80 impregnated with 1,2,4-benzenetricarboxylic acid (4.88 % (w/w) 1,2,4 BTCA)) have been investigated in a flowing gas experiment under molecular flow conditions in a Knudsen cell reactor. As a comparison commercial soot T900 has a significantly larger coverage of surface functional groups (SFG’s) than both GTS6 and GTS80 probed by NO2, O3, NH2OH, CF3COOH, HCl and N(CH3)3. NO2 (weak oxidizer) and O3 (strong oxidizer) probe oxidizable (or reduced) SFG’s, NH2OH interacts with surface –OH groups whereas CF3COOH, HCl and N(CH3)3 probe basic and acidic SFG’s because of their acidic and basic properties, respectively. The interface of GTS6 and GTS80 still retains a significant coverage of reduced sites probed using O3 to the extent of approximately 10 % of a monolayer (ML) compared to 46 % for T900. Using N(CH3)3 as a probe gas we established that BTCA-doped GTS80 is highly acidic having a -COOH group coverage of 51.7 ± 10.5 % of a ML. The use of NH2OH as a probe gas leads to a substantial increase in uptake upon coating GTS80 with BTCA owing to the weakly basic character of the probe interacting with the acidic monolayer. Less than 10 % of all basic sites are strong on BTCA-doped GTS80. The corresponding initial uptake coefficients or uptake probability of most of probe gases on T900 are significantly larger than both GTS, in line with the trends in coverage after saturating adsorption. For NO2 and O3 the steady-state (ss), that is long-term uptake or loss, is observed indicating a chemical reaction as opposed to mere (reversible) adsorption. The corresponding rate constant is 5·10-3 s-1 for all samples except for GTS6 where it is smaller by a factor of 8 which corresponds to the slowest uptake.

Abstract: Solid oxide fuel cells (SOFCs) have become promising devices for converting chemical energy into electrical energy. Altering the microstructure of cathode materials to enhance the activity and stability of the oxygen reduction reaction is particularly important. Herein, Pr0.5Ba0.5Co1-XNiXO3+δ with a tetragonal perovskite structure was synthesized through the sol–gel method. The polarization resistance of the symmetrical half-cell with Pr0.5Ba0.5Co0.9Ni0.1O3+δ as the cathode was 0.041 Ω·cm2 at 800 °C and 0.118 Ω·cm2 lower than that of the symmetrical cell with Pr0.5Ba0.5CoO3+δ as the cathode, indicating that the Pr0.5Ba0.5Co1-XNiXO3+δ cathode material has high catalytic activity during the electrochemical reaction. The results of electron paramagnetic resonance revealed that the concentration of oxygen vacancies increased as the Ni doping amount increased to 0.15. As a result of the increase in the Ni doping amount, the thermal expansion coefficient of the Pr0.5Ba0.5CoO3+δ cathode material effectively reduced, resulting in improved matching between the cathode and electrolyte material. The power density of the single cell increased by 69 mW/cm2. Therefore, Pr0.5Ba0.5Co1-XNiXO3+δ is a promising candidate cathode material for high-performance SOFCs.

Abstract: Hydrogels find widespread use in bioapplications for their ability to retain large amounts of water while maintaining structural integrity. In this article we investigate hybrid hydrogels made of nanocellulose and either amino-polyethylenglycol or sodium alginates and we demonstrate two novel results: 1) the biocompatibility of the amino containing hybrid gel synthesized using a simplified receipt that does not require any intermediate synthetic step to functionalize either components and 2) the fact that the fluctuation of the 2nd order correlation function of a Dynamic Light Scattering experiment provides relevant information about the characteristic internal dynamic of the materials across the entire sol-gel transition as well as quantitative information about the ion-specific gel formation. This novel approach offers significantly better temporal (10’s μs) and spatial (10’s μm) resolution than many other state-of-the-art techniques commonly used for such analyses (such as rheometry, SAXS, and NMR) and it might find widespread application in the characterization of the nano to microscale dynamics in soft materials.

Abstract: A recent increase in targeted attacks using chemical warfare agents by dictators and authoritarian regimes against politicians, journalists, and other civilians is a major concern. To aid the civil investigators in identifying poisonous substances in such cases, we developed an algorithm and a lightweight and simple-to-use software, ToxicMassSceptic, with a database of 394 mass spectra entries, which include many poisonous and explosive agents. The identification relies on a window-based reduction of the experimental spectra and four statistical metrics that are combined into a single metametric. The software also features automatic spectral background removal. Furthermore, we provide the workflow for increasing the size of this database by performing theoretical calculations of mass spectra with a molecular dynamics-based approach. The accuracy of both the theoretical prediction workflow and ToxicMassSceptic is validated on the experimental spectra. Our results demonstrate that the proposed software package can aid in the preliminary identification of traces of poisonous and explosive substances.

Abstract: This paper like contributions to leading developments of nonlinear optical materials research aims for interdisciplinary readership and recognizing experimental and theoretical crystallographic, linear and nonlinear optical properties of non-centrosymmetric crystals of substituted aliphatic secondary amines as prospective templates for technological application. It deals with crystal structure of (2-piperazin-1-yl-ethyl)-nitrimine dihydrate (1) reported first, herein, that can be solved into both the P-1 and P1 space groups and 3,3,5-trimethyl-5-((nitroamino)methyl)cyclohexanaminium hydroxide (2) that could be solved into Pc and Pca21 ones. Crystals of (1) and (2) exhibit optical transparency within 190–1100 nm. Comparative analysis with data on novel crystal structure of (2-piperazin-1-yl-ethyl)-carbamic acid dihydrate (3) is also carried out. There is utilizes high resolution single crystal X-ray diffraction, high accuracy quantum chemical methods for in-depth understanding of relation among molecular and crystal structures, crystallographic packing, symmetry, linear optical and nonlinear optical properties. There are also used electronic and Fourier transform infrared vibration spectroscopy. Organic material research might provide evolutionary development in the face of innovative change of photonics technologies. The research effort, so far, has shown that they are mainly rigid crystals. However, future photonics technologies mandate organic flexible devices; thus, opening research avenue for implementation of organic photonics and electronics devices.

Abstract: This work is a continuation of our recent work on the prediction of hydrogen-bonding (HB) interaction enthalpies [1]. In the present work, a simple method is proposed for the prediction of the HB interaction free energies. Quantum chemical (QC) calculations are combined with the Linear Solvation Energy Relationship (LSER) approach for the determination of novel QC-LSER molecular descriptors and the development of the method. Each hydrogen-bonded molecule is characterized by an acidity or proton donor capacity, , and/or a basicity or proton acceptor capacity. These descriptors suffice for the prediction of HB interaction free energy when the interacting molecules possess one acidic and or one basic site. In this case of two interacting molecules, 1 and 2, their overall HB interaction free energy is , where c is a universal constant equal to (ln10)RT = 5.71 kJ/mol at 25 oC. This holds true over the full composition range, that is, regardless of which molecule is solute and which solvent. In the case of complex multi-sited molecules possessing more than one distant acidic sites and/or more than one types of distant basic sites, two sets of and descriptors are needed, one for the molecule as solute in any solvent and the one for the same molecule as solvent of any solute. Descriptors and are reported for a number of common hydrogen bonded molecules but they may be obtained for any other hydrogen-bonded molecule of interest from its molecular surface charge distribution already available or easily obtained via relatively cheap DFT / basis-set QC calculations. The new predictive scheme is validated against corresponding estimations of the widely used Abraham’s LSER model. The developments in the present work and the previous one are useful for solvation studies in chemical and biochemical systems and, particularly, for equation-of-state developments in molecular thermodynamics. The strengths and limitations of the new predictive method are critically discussed.

Abstract: Chalcogen-bonded [Se–N]2 is a strong cyclic supramolecular synthon in supramolecular chemistry. Selenadiazole is commonly used in the synthesis of [Se–N]₂. One nitrogen atom in a selenadiazole molecule participates in the formation of [Se–N]₂, while the other nitrogen atom can participate in the formation of other types of noncovalent bonds. Investigating the effect of neighboring noncovalent bonds on [Se–N]₂ is beneficial for its further synthesis and application. In this study, we combined theoretical calculations and crystallography to explore the effect of I···N halogen bonds on [Se–N]₂ in both the gas phase and the crystalline phase. Gas-phase calculations show that the formation of halogen bonds increases the strength of [Se–N]₂, and the strength of halogen bond is directly proportional to the strength of [Se–N]₂. In the crystalline phase, [Se–N]₂ is influenced by more noncovalent bonds in addition to halogen bonds, making the results more complex. However, if the effect of other noncovalent bonds is relatively small, the strength of halogen bond remains directly proportional to the strength of [Se–N]₂. It is believed that the conclusions drawn from halogen bonds are also applicable to other types of noncovalent bonds.

Abstract:

In an earlier report, we had conjectured that oligo-phenylenevinylene (OPV) molecules bearing terminal OH groups may form molecular complexes in organogels prepared in benzyl alcohol. This assumption was based on circumstantial evidence only. In this paper we report on new ex-perimental evidence by means of neutron diffraction that unambiguously demonstrate this con-jecture. After ascertaining that thermodynamics properties of OPV gels are not altered by the use of a solvent isotope (hydrogenous vs deuterated benzyl alcohol), we do show that the neutron diffraction pattern in hydrogenous benzyl alcohol differs from that in deuterated benzyl alcohol. These patterns also exhibit additional peaks with respect to that obtained by X-ray. Comparison is further achieved with an OPV molecule without hydrogen bond terminal groups. In the latter case, no molecular complex is formed. These molecular structures may have a direct bearing upon the differences observed in the gel morphologies.

Abstract:

The development of Evosmosis Cycles introduces a novel method for harnessing ambient thermal energy, offering a transformative solution for sustainable energy production. These cycles operate through vapor pressure gradients within a closed system, integrating the principles of osmosis and Raoult’s law to create a self-sustaining energy loop. The experimental system consists of two chambers separated by a selectively permeable membrane, each containing solutions of differing solute concentrations. Enhanced evaporation in the low-solute chamber and increased condensation in the high-solute chamber sustain continuous energy flow. Additionally, the incorporation of highly soluble gases, such as carbon dioxide, amplifies vapor pressure gradients and energy output. This system uses readily available materials, including cellophane membranes and polymer solutions, and operates at ambient temperature without external energy input. Preliminary findings demonstrate its potential for renewable energy generation with minimal environmental impact. This paper explores the theoretical and experimental foundations of the Evosmosis Cycle, emphasizing its significance for scalability and practical applications in sustainable energy systems.

Abstract: Complexation of alkaline earth metal cations with fluorescent tertiary-amide lower-rim calix[4]arene derivative bearing two phenanthridine moieties was studied experimentally (UV spectrophotometry, fluorimetry, isothermal microcalorimetry, NMR spectroscopy) and computationally (classical molecular dynamics and DFT calculations) at 25 °C. The complexation reactions were studied in acetonitrile, methanol, and ethanol, whereby the solvent effect on cation-binding processes was particularly addressed. The complex stability constants and standard reaction thermodynamic quantities (Gibbs energies, enthalpies, and entropies) were determined. The receptor exhibited particularly high affinity towards alkaline earth metal cations in acetonitrile, with peak affinity for Ca2+. The stability of all complexes was significantly lower in ethanol and methanol, where the most stable complex was formed with Sr2+. The decrease in cation-binding abilities was a consequence of the differences in solvation of the reactants and products of the complexation reactions (involving inclusion of the solvent molecule in the calixarene cone), cation charge density, as well as the cation-ligand binding site compatibility. The reactions were enthalpically controlled in acetonitrile, whereas in methanol and ethanol the binding processes were endothermic, and thus entropy driven. The results of 1H NMR measurements, MD simulations, and DFT calculations provided an insight into the structure of the complexes and the corresponding adducts with solvent molecules, as well as on the structural aspects behind the differences in complexation thermodynamics. Due to the significant increase of its fluorescence upon cation binding, the studied calixarene derivative was proven to be a promising luminescent sensor for alkaline earth metal cations.

Abstract:

The cleaning process of metallic surfaces has been studied by means of digital video monitoring. Two theoretical models based on experimental observations are proposed for two possible cleaning mechanisms and two practical cases that can be adapted to these models are analyzed. As a kinetic parameter, the duration of the cleaning of a metallic surface is defined from the time evolution of the color intensities and their variance. These times allow us to characterize and to optimize the cleaning process procedure. Apparent activation energies are estimated from the characteristic times at different temperatures.

Abstract:

Crystals of mandelic acid are of significant importance. They are commercial pharmaceutics formulations modulating active ingredient solubility and its pharmacological effect. Commercial pharmaceuticals are at about 50 % crystals. Salt formulation is among the most used strategy for improving properties of medications. Salt crystallization screening is routinely implemented into pharmaceutical industry. Via disproportionation there is produced free therapeutics forms. The process is thermodynamically and kinetically driven. It is tackled by crystallographic and quantum chemical methods for salt screening as integral parts of development workflow in pharmaceutical industry. Correlations among crystallographic, Fourier-transform infrared, and electronic spectroscopic data on salts, and theoretical thermochemical approaches are of primary importance for determining relations among molecular structure « crystal structure « properties of crystals. This paper presents novel structural and molecular spectroscopic data on crystals of mandelic acid such as DL-mandelic acid (1), 4-phenyl-pyridinium mandelate mandelic acid (2) ¾ first, reported, herein, ¾ and catena-((μ₃-DL-mandelato)-silver(I)) (3). It also utilizes chemometrics. The major conclusion follows from relation between crystallographic potential energy data on bond critical point using Abramov’s formula and theoretical bond dissociation energy showing |r|=0.9999. The approach seems best characterizes experimental crystallographic energetics of chemical bonds of molecules fitted off theoretical data.

Abstract: The Oxidative Coupling of Methane (OCM) is a promising process for converting methane directly into more valuable ethane and ethylene. In this work, high-time-resolution online mass spectrometry was employed to track the OCM reaction over a commercial La2O3 catalyst, focusing on the effects of methane to oxygen ratio, Gas Hourly Space Velocity (GHSV), and the presence of H2O and CO in the feed gas on methane conversion and C2 yield. The results demonstrated that an optimized GHSV (44640 to 93000 mL·g−1·h−1) and methane to oxygen ratio (CH4/O2= 3) would achieve the highest methane conversion and C2 yield at 740 °C. Furthermore, the introduction of 1% H2O into the reaction mixture resulted in a twofold increase in C2 yield at 650 °C, while the addition of 1% CO led to a threefold increase in C2 yield at 550 °C. A model in which only the front-end catalyst is active was also developed to show excellent agreement with the experimental data. The relationship between catalytic performance and the effective catalyst position in the catalyst bed provides important insights into optimizing reactor design and operating conditions to maximize C2 yield and selectivity in the OCM reaction.