Enthalpy Of Vaporization Research Articles

Insights Into Janus Interfaces with Ordered Micro/Nanostructures for Low‐Temperature Differential Evaporation

AbstractLow‐temperature differential evaporation constitutes a promising direction for energy‐saving desalination. Herein, a novel Janus interfacial structure with well‐ordered micro/nanopores is developed. Fabricated Janus interfacial structure can weak the water intermolecular forces and pump water to the hydrophilic–hydrophobic junction. Within well‐ordered nanochannels, the increased curvature of the meniscus increases the ratio of thin water layers, thereby enhancing microscale heat transfer at the heated walls; in addition, the smaller nanopores limit the development of microscale vortices at the liquid–gas interface and prevent back mixing of intermediate water at the interface, which possess the nanoscale effect on intensifying the interfacial evaporation. These effects are validated by theoretical and experimental studies. Optimized Janus (20 nm)95°/25° structure exhibits evaporation fluxes up to 2.4 kg m−2 h−1 at 45 °C (feed side)/25 °C (permeate side, ambient pressure), as the theoretical evaporation enthalpy is only 30% of that for direct evaporation. The unique Janus structure simultaneously inhibits salt accumulation and achieve self‐cleaning, thereby maintaining steady performance during 480 h of continuous desalination and 50 cycles of batch operation. This work highlights a promising structural design strategy for separation materials with specific micro/nanoscopic topologies to achieve high performance thermally driven desalination applications.

Spongy polyelectrolyte hydrogel with Janus porous for solar-driven interfacial evaporation and sustainable seawater desalination

Janus-structured hydrogels exhibit excellent advantages in interfacial solar desalination due to their hydrophilicity and low evaporative enthalpy of evaporation, as well as the better salt resistance and mechanical properties. In this research, a simple one-step self-stratification foaming technique is employed to transform hydrogels into Janus structured for seawater desalination. Polyvinyl alcohol (PVA), poly (diallyldimethylammonium chloride) (PDADMAC), and a photothermal material (carbon black, CB) are mechanically stirred with a foaming agent (sodium dodecyl sulfate, SDS), allowing for full mixing and air incorporation, ultimately forming a sponge-like polymeric electrolyte hydrogel with abundant Janus pore structures (PANS-J). The formation of Janus pores in the hydrogel is attributed to the flocculation and high density of hydrophilic PDADMAC, causing it to sink during gelation while hydrophobic PVA floats to the surface. The Janus structure produced by this method reduces heat loss and enhances evaporation performance, achieving a pure water evaporation rate of 3.35 kg m−2 h−1 under sunlight (1 kW m−2). Moreover, quaternary ammonium ions on PDADMAC effectively separate anions and cations in saltwater, reducing salt ion diffusion into the evaporator, preventing premature pore structure blockage, and thus improving long-term evaporator performance which can improve the salt resistance and mechanical properties. By combining these advantages, Janus evaporators hold significant promise for solar-driven water purification and other applications.

"Coir Raincoat"-Boosted Biomimetic Hydrogel for Efficient Solar Desalination and Wastewater Purification.

Solar-driven interfacial evaporation is an efficient method for purifying contaminated or saline water. Nonetheless, the suboptimal design of the structure and composition still necessitates a compromise between evaporation rate and service life. Therefore, achieving efficient production of clean water remains a key challenge. Here, a biomimetic dictyophora hydrogel based on loofah/carbonized sucrose@ZIF-8/polyvinyl alcohol is demonstrated, which can serve as an independent solar evaporator for clean water recovery. This special structural design achieves effective thermal positioning and minimal heat loss, while reducing the actual enthalpy of water evaporation. The evaporator achieves a pure water evaporation rate of 3.88kg m-2 h-1 and a solar-vapor conversion efficiency of 97.16% under 1 sun irradiation. In comparison, the wastewater evaporation rate of the evaporator with ZIF-8 remains at 3.85kg m-2 h-1 for 30 days, which is 16.3% higher than the light irradiation without ZIF-8. Equally important, the evaporator also showcases the capability to cleanse water from diverse sources of contaminants, including those with small molecules, oil, heavy metal ions, and bacteria, greatly improving the lifespan of the evaporator.

Solar-driven salt-free deposition evaporation for simultaneous desalination and electricity generation based on tip-effect and siphon-effect

Solar-driven desalination is a promising way to alleviate the freshwater shortage, while is facing challenges posed by low evaporation rates and severe salt accumulation. Herein, a high-performance two-dimensional (2D) solar absorber with Co3O4 nanoneedle arrays (Co3O4-NN) grown on the surface of reduced graphene oxide-coated pyrolyzed silk cloth (Co3O4-NN/rGO/PSC) was prepared, and a salt-free evaporator system was assembled based on the composite material and siphonage-the flowing water delivery. It is revealed that the evaporation enthalpy of water can be reduced over the 2D solar absorber grown with Co3O4-NN, enabling an evaporation rate of up to 2.35 kg m−2 h−1 in DI water under one solar irradiation. The desalination process can be carried out continuously even with salt concentration up to 20 wt%, due to the timely removal of concentrated brine from the interface with the assistance of directed flowing water. Moreover, the 2D structure and the flowing water also provide an opportunity to convert waste solar heat into electricity in the evaporator based on the seebeck effect, ensuring simultaneous freshwater production and power generation. It is believed that this work provides insights into designing hybrid systems with high evaporation rate, salt resistance, and electricity generation.

Helmholtz energy models for dipole interactions: Review and comprehensive assessment

Dipolar interactions play an important role for thermodynamic properties of many fluids and accordingly for their modeling. In molecular-based equation of state models, the effect of dipolar interactions is usually described by Helmholtz energy models. There are several Helmholtz energy models for dipolar interactions available in the literature today. In this work, eight dipole contribution models describing the dipole–dipole interactions of fluids were critically assessed by comparing their results with molecular simulation reference data of Stockmayer fluids. Therefore, the dipole contribution models were combined with an accurate Lennard-Jones (LJ) Helmholtz energy model. The following thermodynamic properties were considered in the comparison: vapor pressure, saturated densities, enthalpy of vaporization, surface tension (by using density gradient theory), critical point, second virial coefficient, and thermodynamic properties at homogeneous state points, such as the Helmholtz energy, pressure, chemical potential, internal energy, isochoric heat capacity, isobaric heat capacity, thermal expansion coefficient, isothermal compressibility, thermal pressure coefficient, speed of sound, Joule–Thomson coefficient, and Grüneisen parameter. For the evaluation of the dipole contribution models, molecular simulations for the Stockmayer fluid with the dipole moments of μ2/4πϵ0ɛσ3=0.5,1,2,3,4,5 were carried out. The results indicate, that all considered dipole models exhibit some significant weaknesses. Nevertheless, some dipole contribution models are found to provide a robust description for many properties and state ranges. Overall, the deviations of the dipole contribution models from the Stockmayer simulation data are, in most cases, an order of magnitude higher than the deviations of the LJ EOS from LJ simulation data.

Vaporization Enthalpies and Vapor Pressures of 5α-Androstane and 5α-Cholestane by Correlation Gas Chromatography

Vaporization Enthalpies and Vapor Pressures of 5α-Androstane and 5α-Cholestane by Correlation Gas Chromatography

Thermochemical and physical characteristics of isomeric tetracycloundecanes obtained from endo- and exo-dicyclopentadienes

By combining the cyclopropanation and hydrogenation processes of endo- and exo-isomers of dicyclopentadiene, two pairs of tetracycloundecane stereoisomers were obtained, differing in the position of a three-membered cycle. For the first time, under the same conditions for the exo,endo- and exo,exo-tetracyclo[5.3.1.02,6.08,10]undecanes and endo,anti- and exo,anti-tetracyclo[6.2.1.02,7.03,5]undecanes obtained the enthalpy of combustion and formation, saturated vapor pressure and enthalpy and entropy of vaporization were determined, and critical temperatures, pressures, volumes, Pitzer's acentric factors and critical compressibility factors were calculated. The isomers obtained have a higher energy density than JP-10.

Efficient CO2 capture by non-aqueous imide/ethylene glycol solvent

Man-made CO2 emissions give rise to an important influence on climate and human survival, which has attracted widespread attention. Traditional absorbents such as aqueous amines used for CO2 capture often suffer from high regeneration energy and corrosiveness. In this regard, non-aqueous amine solutions have high energy-saving potential because organics have lower vaporization enthalpy and heat capacity than water. Herein, we explored the potential absorbent composed of ethylene glycol and imide-based bases to capture CO2. The CO2 uptake in imide-based ethylene glycol absorbent was studied, experimental results showed that succinimide/glycol-20 wt% have the highest CO2 solubility, and still maintains a high absorption capacity after 8 regeneration cycles. And the absorption mechanism has been confirmed the possible intermolecular hydrogen bonding and van der Waals forces between carbon dioxide and succinimide molecules through molecular simulation. The regeneration energy consumption is only 2.243 GJ/t CO2 through process simulation calculation, which is lower than the conventional absorbent, further indicating that the fabricated absorbent have exhibits the large potential to absorb CO2 from flue gas.

Enhancing Solar Steam Generation of Hydrogels via Silver Nanoparticle-Doped Cellulose Nanofibers.

Solar steam generation (SSG) is regarded as an efficient approach for harnessing solar energy to purify polluted or saline water. Herein, we demonstrate a hydrogel composed of cellulose nanofibers (CNFs), polyethylenimine (PEI), and reduced graphene oxide (rGO) that functions as an independent solar steam generator, which shows enhanced solar water evaporation efficiency by incorporating silver nanoparticles (AgNPs). It presented that the presence of AgNPs increases the photothermal conversion efficiency and thermal conductivity of the evaporator and reduces the enthalpy of evaporation. As a result, an outstanding water evaporation rate of 3.62 kg m-2 h-1 and a photothermal conversion efficiency of 96.25% are successfully obtained under one sun illumination. Also, the resulting hydrogel exhibits exceptional mechanical properties, as well as outstanding desalination and salt-resistant abilities during prolonged seawater desalination. In oil/water mixtures, the evaporation of the hydrogel decreases to 2.94 kg m-2 h-1, owing to the oil layer barrier. This work paves a reference approach to produce easily addressed cellulose nanofiber (CNF)-based hydrogel evaporators with significantly enhanced evaporation rates.

Hollow carbon fiber wrapped by regular rGO wave-like folds for efficient solar driven interfacial water steam generation

Efficient seawater desalination is an effective way to solve the shortages of fresh water and energy but with limitations of the low fresh water production rate and high cost. Here, a hollow carbon fiber (HCF) wrapped by regular reduced graphene oxide (rGO) wave-like folds (rGO@HCF) is prepared on account of the differences in thermal shrinkage performance between graphene oxide (GO) and willow catkins fiber. Under one sun irradiation (1 kW m−2), the dry and wet surface temperature of the resulting evaporator reached up to 119.1 °C and 61.7 °C, respectively, and the water steam production rate reached 3.42 kg m−2 h−1. Also, for the outdoor experiment, the rGO@HCF exhibits good evaporator performance which reach up 27.8 kg m−2 day−1. Additionally, rGO@HCF also shows good seawater desalination performance and excellent durability for longtime work. DSC results indicate that the evaporation enthalpy of bulk water and adsorbed water decreased from 2503.92 to 1020.54 J g−1. The excellent evaporating performance is mainly attributed to the regular wave-like microstructure surface of the HCF, which can enhance the light absorption, reduced the vaporization enthalpy of the adsorption water. The findings not only introduce a novel approach for agricultural utilization, but also establish a crucial theoretical foundation for the design of regular wave-like microstructures.

Sustainable upcycling of waste polyethylene terephthalate into hierarchically porous carbon nanosheet for interfacial solar steam and hydroelectricity generation

Solar-driven interfacial evaporation coupled with hydroelectricity technology is regarded as a hopeful tactic to co-generate freshwater and electricity. However, constructing low-cost evaporators/generators remain a grand challenge. Herein, we report a salt-assisted carbonization method to convert waste polyethylene terephthalate to be hierarchically porous carbon nanosheet (HPCN) and build a flexible HPCN-based evaporator for freshwater and hydroelectricity co-generation. HPCN exhibits a wrinkled structure with the thickness of ca. 3.4 nm. The HPCN-based evaporator displays good hydrophilicity, high sunlight absorption (98%), high solar-to-thermal conversion, reduced water evaporation enthalpy, and low thermal conductivity. It exhibits high evaporation rate (2.65 kg m−2 h−1) and conversion efficiency (98.0%) through 1 kW m−2 irradiation, exceeding many advanced solar evaporators. Importantly, the HPCN evaporator-based hydroelectricity generator realizes high voltage (255 mV) and current (310 nA) with good stability. The combination of large specific surface area with wealthy oxygen-containing groups of HPCN plays important roles in hydroelectricity generation. In outdoor experiment, the freshwater production amount from per meter square achieves 6.32 kg. This work provides a green approach to upcycle waste plastics to be functional carbon materials and offers a new platform to construct advanced evaporators for solar evaporation and hydroelectricity generation.

Biofuel Concentration in Low-Speed Pre-Ignition in Gasoline Engines

Low-Speed Pre-Ignition (LSPI) is a destructive combustion event associated primarily with new, ultra-efficient, downsized gasoline engines, which provide efficiency benefits in general operation. Biofuels, specifically bio-gasoline, are an alternative fuel that attempts to reduce the harmful emissions output by modern Internal Combustion Engines (ICEs). This study attempts to understand the effect of biofuel use on LSPI, through the use of a numerical simulation tool developed in Ricardo Wave. Development of the tool includes the integration of RFlame, an extension capable of modeling autoignition within a 1D domain. Use of the tool highlights the impact of five ethanol blends, E10, E20, E30, E50 and E85, with clear impacts on both the severity and frequency of LSPI events correlated with chemical properties, such as the enthalpy of vaporization (HoV) and octane number. E30 is highlighted as the critical blend for LSPI severity, with both increased severity and intensity seen with a 30% concentration, and a greater sensitivity to effects such as the start of ignition (SOI). Higher-concentration biofuels, such as E50 and E85 bio-gasoline, show much more favorable behaviors, such as a vast reduction in end-gas knock events, but are limited in their use due to their deployment being both cost-prohibitive and potentially damaging in current hardware. Future work on this topic will surround the further development of the simulation tool to integrate 3D solving elements, understand the role of fluid interactions in LSPI, and study optimal fuel characteristics for future use in ICEs.

Multi-strategy coupling of custom hydrogel evaporators for sustained, high-efficiency clean water production and anti-pollution

The emergence of hydrogel evaporators has greatly improved the evaporation rate and has attracted widespread attention. However, single-strategy design yields limited evaporation rates and anti-fouling properties, restricting their utility. Here, we report a superhydrophilic interconnected porous hydrogel (SIPH) evaporator that incorporates multiple strategirs. This design enhances water transport, light absorption, and heat localization, reducing heat loss from the evaporating surfaces. By modulating polymer network-water interactions with −NH2 groups, we achieved a high proportion of activated water, lowering the evaporation enthalpy to about one-third that of pure water. Based on this diversified design, SIPH achieves a high evaporation rate of 4.80 kg m−2 h−1 under one sun. Moreover, SIPH demonstrates excellent stability in various water qualities and long-lasting anti-pollution properties, offering significant practical application potential.

A temperature-responsive, repairable and renewable self-floating hydrogel steam generator

The design and synthesis of materials dedicated to solar evaporation have attracted substantial attention. Hydrogels, known for their elevated evaporation rates, are perceived as potential candidates in the subsequent evolution of solar evaporation technology. This research introduces an efficient, harmless, and sustainable design of a porous hydrogel interface evaporator, possessing self-repair and regenerative capabilities. For a hydrogel matrix composed of carrageenan and konjac gum, an element of activated carbon serving as a light absorber is integrated. Notably, the evaporator’s capability for regeneration and repair is facilitated by the unique thermally reversible three-dimensional architecture of carrageenan. The konjac gum provides the interpenetrating network with carrageenan, which significantly enhances the hydrogel’s mechanical durability. Additionally, its hydroxyl-rich components precisely modulate the state and content of the water molecules, contributing to reduce the enthalpy of water evaporation. Lastly, the inclusion of activated carbon effectively mitigates the retention of low-boiling-point contaminants and endows the hydrogel with a light absorption of 97 %. These outstanding benefits result in an evaporation rate as high as 2.6 kg m−2 h−1 for the formulated hydrogel. Given the ready availability of raw materials, this biomass evaporator introduces new prospects for eco-friendly solar evaporators.

Large-area, low-cost, highly durable solar evaporators for sustainable solarizing seawater

Conventional solarizing seawater technology faces significant challenges including a large footprint, time-consuming processes, and inefficient energy utilization. Solar-driven interfacial water evaporation (SIWE) technology, offers a promising approach for sustainable solarizing seawater, facilitating the production of solid salt with reduced time and land requirements. Nevertheless, the urgent challenge lies in the development of low-cost, large-area solar evaporators that are highly salt-resistant and adaptable, enabling efficient and sustainable solar desalination for solid salt production. As such, a large-area, affordable, and highly durable melamine foam/reduced graphene oxide/sodium alginate (MGS) solar evaporator is proposed for continuous solarizing seawater using a simple method of “immersion-crosslinking-reduction”. Among them, hydrophilic melamine foam serves as the supportive framework, immersed with graphene as light absorption material, and hydrophilic sodium alginate polymeric network for fixing graphene sheets and regulating water evaporation enthalpy. As such, MGS solar evaporator can be prepared in a large-area of 0.5 m × 0.5 m at the cost prices as low as $2.91 m−2. The optimized MGS solar evaporator achieves a high water evaporation rate of 2.30 kg m−2h−1 with the photothermal conversion efficiency of 89.2 % under one sun irradiation. In outdoor environments, MGS allows for timely convective/diffusive salt discharge through its macropores, thus allowing for prolonged seawater solarization without obvious solid salt accumulation. Notably, the original seawater can be highly concentrated until all the water evaporates and solid salt precipitates. This developed MGS solar evaporator offers a novel perspective on efficient seawater solarization, conserving both time and land.

New QSPR molecular descriptors based on low-cost quantum chemistry computations using DFT/COSMO approach

This work presents a simple computational methodology to determine new theoretical molecular descriptor scales convenient for use in QSPR correlations and the analysis of solvation-related properties. On the basis of low-cost quantum chemical computations using DFT/COSMO approach, in particular that implemented in the ADF/COSMO-RS module of the Amsterdam Modeling Studio program package, optimized geometry and local screening charge density of a considered molecule are obtained and related to the proposed descriptors through an a priori simple reasoning. Values of four molecular descriptors, namely volume VCOSMO∗, hydrogen bond/Lewis acidity αCOSMO and basicity βCOSMO, and charge asymmetry of the nonpolar region of the molecule δCOSMO have been calculated and are presented for sets of 128 non-ionic organic molecules and 47 ions composing ionic liquids. Relation of the proposed scales to some others that are widely known or presented recently in the literature has been examined. Although the present methodology is completely independent of any experimental data, the theoretical descriptor scales proposed here have been found to correlate linearly quite well with the respective empirical scales (mostly R2 > 0.8, and for some R2 > 0.9). For non-ionic organics, just the direct proportionality provided adequate fits of the well-established prominent scales such as those of Abraham, Klamt, Kamlet-Taft, Catalan, Gutmann, and Laurence and showed only a few statistically justifiable outliers. For ions composing ILs, the linear fits of seven acidity or basicity scales presented previously with those proposed in this work were of similar quality. Examining the observed outliers, several descriptor values reported in the literature were identified as being in error. Good performance of the new descriptor scales has been demonstrated by employing them for LSER fitting of various solvation-related thermodynamic and kinetic properties such as standard vaporization enthalpy, standard hydration enthalpy, air–water partition coefficient, air-IL partition coefficient, and solvent effects on the activation Gibbs energy or rate constant of SN1 and SNAr reactions. The quality of these correlations appears to be comparable to that of the correlations currently available for these properties, regardless of the role, solute or solvent, the involved molecules played.

Thermosensitive Hydrogel PNIPAAm‐Alg‐PEDOT for Sustainable and Efficient Water Purification Powered by Solar Energy

AbstractUnrestricted access to clean drinking water is essential for the well‐being of the global population, yet this necessary resource is not universally guaranteed, particularly amidst the escalating climate crisis that accentuates disparities across regions. Harnessing solar energy in conjunction with advanced synthetic solar absorbent hydrogels (SAHs) is increasingly recognized as a promising solution and a significant challenge in addressing the purification of brackish water sustainably. This work outlines the development of a SAH using the thermosensitive polymer poly(N‐isopropylacrylamide) (PNIPAAm) in combination with alginate (Alg), enriched with poly(3,4‐ethylenedioxythiophene) (PEDOT) nanoparticles (NPs). Through solar evaporation tests using different conducting polymer (CP) concentrations, a discernible relationship between the ratio of free water to intermediate water (FW/IW) within the hydrogel structure and its performance is observed. The hydrogel's remarkable evaporation rate for synthetic seawater (2.82 kg m−2 h−1) aligns with the lowest FW/IW, which is directly related to a reduction in water vaporization enthalpy. Characterization of intermediate water enables easy adjustment of the optimal conductive polymer content within the hydrogel. This technology, based on thermosensitive materials, not only introduces innovative methodologies for designing and customizing functional composite materials but also aligns with global objectives by addressing challenges in sustainable drinking water supply without additional energy inputs.

QSPR/QSAR study of antiviral drugs modeled as multigraphs by using TI’s and MLR method to treat COVID-19 disease

The ongoing COVID-19 pandemic continues to pose significant challenges worldwide, despite widespread vaccination. Researchers are actively exploring antiviral treatments to assess their efficacy against emerging virus variants. The aim of the study is to employ M-polynomial, neighborhood M-polynomial approach and QSPR/QSAR analysis to evaluate specific antiviral drugs including Lopinavir, Ritonavir, Arbidol, Thalidomide, Chloroquine, Hydroxychloroquine, Theaflavin and Remdesivir. Utilizing degree-based and neighborhood degree sum-based topological indices on molecular multigraphs reveals insights into the physicochemical properties of these drugs, such as polar surface area, polarizability, surface tension, boiling point, enthalpy of vaporization, flash point, molar refraction and molar volume are crucial in predicting their efficacy against viruses. These properties influence the solubility, permeability, and bio availability of the drugs, which in turn affect their ability to interact with viral targets and inhibit viral replication. In QSPR analysis, molecular multigraphs yield notable correlation coefficients exceeding those from simple graphs: molar refraction (MR) (0.9860), polarizability (P) (0.9861), surface tension (ST) (0.6086), molar volume (MV) (0.9353) using degree-based indices, and flash point (FP) (0.9781), surface tension (ST) (0.7841) using neighborhood degree sum-based indices. QSAR models, constructed through multiple linear regressions (MLR) with a backward elimination approach at a significance level of 0.05, exhibit promising predictive capabilities highlighting the significance of the biological activity IC50\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$IC_{50}$$\\end{document} (Half maximal inhibitory concentration). Notably, the alignment of predicted and observed values for Remdesivir’s with obs pIC50=6.01\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$${pIC_{50} = 6.01}$$\\end{document},pred pIC50=6.01\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$${pIC_{50} = 6.01}$$\\end{document} (pIC50\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$pIC_{50}$$\\end{document} represents the negative logarithm of IC50\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$IC_{50}$$\\end{document}) underscores the accuracy of multigraph-based QSAR analysis. The primary objective is to showcase the valuable contribution of multigraphs to QSPR and QSAR analyses, offering crucial insights into molecular structures and antiviral properties. The integration of physicochemical applications enhances our understanding of factors influencing antiviral drug efficacy, essential for combating emerging viral strains effectively.

Thermochemical Research on Furfurylamine and 5-Methylfurfurylamine: Experimental and Computational Insights.

The need to transition from fossil fuels to renewables arises from factors such as depletion, price fluctuations, and environmental considerations. Lignocellulosic biomass, being abundant, and quickly renewable, and not interfering with food supplies, offers a standout alternative for chemical production. This paper explores the energetic characteristics of two derivatives of furfural-a versatile chemical obtained from biomass with great potential for commercial sustainable chemical and fuel production. The standard (p° = 0.1 MPa) molar enthalpies of formation of the liquids furfurylamine and 5-methylfurfurylamine were derived from the standard molar energies of combustion, determined in oxygen and at T = 298.15 K, by static bomb combustion calorimetry. Their standard molar enthalpies of vaporization were also determined at the same temperature using high-temperature Calvet microcalorimetry. By combining these data, the gas-phase enthalpies of formation at T = 298.15 K were calculated as -(43.5 ± 1.4) kJ·mol-1 for furfurylamine, and -(81.2 ± 1.7) kJ·mol-1 for 5-methylfurfurylamine. Furthermore, a theoretical analysis using G3 level calculations was performed, comparing the calculated enthalpies of formation with the experimental values to validate both results. This method has been successfully applied to similar molecules. The discussion looks into substituent effects in terms of stability and compares them with similar compounds.

Thermophysical Properties of FUNaK (NaF-KF-UF4) Eutectics.

General interest in the deployment of molten salt reactors (MSRs) is growing, while the available data on uranium-containing fuel salt candidates remains scarce. Thermophysical data are one of the key parameters for reactor design and understanding reactor operability. Hence, filling in the gap of the missing data is crucial to allow for the advancement of MSRs. This study provides novel data for two eutectic compositions within the NaF-KF-UF4 ternary system which serve as potential fuel candidates for MSRs. Experimental measurements include their melting point, density, fusion enthalpy, and vapor pressure. Additionally, their boiling point was extrapolated from the vapor pressure data, which were, at the same time, used to determine the enthalpy of vaporization. The obtained thermodynamic values were compared with available data from the literature but also with results from thermochemical equilibrium calculations using the JRCMSD database, finding a good correlation, which thus contributed to database validation. Preliminary thoughts on fluoride salt reactor operability based on the obtained results are discussed in this study.