Type Of Solvent Research Articles

A Straightforward Method for the Generation of Hyperpolarized Orthohydrogen with a Partially Negative Line.

The hydrogen molecule, which exists in two spin isomers (ortho- and parahydrogen), is a highly studied system due to its fundamental properties and practical applications. Parahydrogen is used for Nuclear Magnetic Resonance signal enhancement, which is hyperpolarization of other molecules, including biorelevant ones. Hyperpolarization can be achieved by using Signal Amplification by Reversible Exchange (SABRE). SABRE can also convert parahydrogen into orthohydrogen, and surprisingly, in some cases, it has been discovered that orthohydrogen's resonance has the Partially Negative Line (PNL) pattern. Here, an approach for obtaining orthohydrogen with a PNL signal is presented for two catalysts: Ir-IMes, and Ir-IMesBn. The type of solvent in which SABRE is conducted is crucial for the observation of PNL. Specifically, a PNL signal can be easily generated in benzene using both catalysts, but it is more intense for Ir-IMesBn. In acetone, PNL is observed only for Ir-IMesBn. In methanol, no PNL is detected. The PNL effect is only detectable during the initial steps of pre-catalyst activation, and disappears as the activation process progresses. We have proposed a working hypothesis that explains our results. The presented data may facilitate the further investigation of PNL and its applications in material science and catalysis.

A Straightforward Method for the Generation of Hyperpolarized Orthohydrogen with a Partially Negative Line

AbstractThe hydrogen molecule, which exists in two spin isomers (ortho‐ and parahydrogen), is a highly studied system due to its fundamental properties and practical applications. Parahydrogen is used for Nuclear Magnetic Resonance signal enhancement, which is hyperpolarization of other molecules, including biorelevant ones. Hyperpolarization can be achieved by using Signal Amplification by Reversible Exchange (SABRE). SABRE can also convert parahydrogen into orthohydrogen, and surprisingly, in some cases, it has been discovered that orthohydrogen's resonance has the Partially Negative Line (PNL) pattern. Here, an approach for obtaining orthohydrogen with a PNL signal is presented for two catalysts: Ir−IMes, and Ir−IMesBn. The type of solvent in which SABRE is conducted is crucial for the observation of PNL. Specifically, a PNL signal can be easily generated in benzene using both catalysts, but it is more intense for Ir−IMesBn. In acetone, PNL is observed only for Ir−IMesBn. In methanol, no PNL is detected. The PNL effect is only detectable during the initial steps of pre‐catalyst activation, and disappears as the activation process progresses. We have proposed a working hypothesis that explains our results. The presented data may facilitate the further investigation of PNL and its applications in material science and catalysis.

Evaluation of the extracts of purple basil (Ocimum basilicum L.) as natural pH‐indicator dyes anticipated to be utilised in intelligent food packaging—an optimisation study

AbstractPurple basil (Ocimum basilicum L.) extract has significant potential as a natural colorimetric pH‐indicator material owing to its abundance in anthocyanins. This contribution is the first to optimise the ultrasound‐assisted extraction of purple basil by response surface methodology in terms of maximum total monomeric anthocyanin (TMA) content and pH‐dependent increase in green intensity (IGI) using a three‐level, three‐factor Box–Behnken design. The latter was considered as a measure of the pH‐indicator ability of the extracts. The independent variables were ethanol concentration, solvent/solid ratio, and extraction time for two types of solvents [aqueous ethanol with 0.1% (v/v) acetic acid (Ac) or hydrochloric acid]. Optimum conditions were determined for single and combined responses. The extracts were further characterised according to total phenolic content (TPC), percentage polymeric colour (PPC), 2,2'‐azino‐bis(3‐ethylbenzothiazoline‐6‐sulfonic acid (ABTS) antioxidant, and 2,2‐diphenyl‐1‐picrylhydrazyl (DPPH) radical scavenging activities. All models explained more than 93% of the variability. The combined response model for the Ac‐acidified system gave more favourable optimal conditions [55.25% (v/v) ethanol, 30 mL/g solvent/solid ratio and 39.24 min] regarding lower ethanol consumption and shorter times. Validation experiments verified the model successfully predicted the responses. The corresponding TMA, IGI, PPC, TPC, ABTS, and DPPH values were determined as 4.83 ± 0.18 mg cyanidin‐3‐glucoside equivalent, 2.29 ± 0.05, 68.07 ± 3.17, 28.79 ± 1.54 mg gallic acid equivalent, 55.85 ± 1.71 mg Trolox equivalent, and 16.80 ± 1.08 mg ascorbic acid equivalent per gram dry weight, respectively.

Structure and Thermodynamics of Li+Arn Clusters beyond the Second Solvation Shell

Small Li+Arn clusters are employed in this work as model systems to study microsolvation. Although first and second solvation shells are expected to be the most relevant ones for this type of atomic solvents, it is also interesting to explore larger clusters in order to identify the influence of external atoms on structural and thermodynamic properties. In this work, we perform a global geometry optimization for Li+Arn clusters (with n = 41–100) and parallel tempering Monte Carlo (PTMC) simulations for some selected sizes. The results show that global minimum structures of large clusters always have 6 argon atoms in the first solvation shell while maintaining the number of 14 or 16 argon atoms in the second one. By contrast, third and fourth solvation shells vary significantly the number of argon atoms with the cluster size, and other shells can hardly be assigned due to the reduced influence of Li+ on the external argon atoms for large clusters. In turn, PTMC calculations show that the melting of the most external solvation shells of large microsolvation clusters occurs at T∼50K, which is independent of cluster size. Structural transitions can be observed between quasi-degenerated structures at low temperatures. Moreover, the present results highlight the fluxional character of the external solvation shells of these large Li+Arn clusters, which may be seen as typical “snowball” structures.

A Green Approach to Nucleophilic Aromatic Substitutions of Nicotinic Esters in Cyrene

AbstractThe green solvent CyreneTM has emerged as a valuable substitute for conventional polar aprotic organic solvents such as DMF, DMSO and NMP (renowned for their toxicity and environmental concerns). However, in the presence of bases, Cyrene is prone to polymerization, thus potentially incompatible with reactions where a base is needed to generate reactive nucleophiles. In this study, we developed an efficient synthetic strategy for nucleophilic aromatic substitutions of nicotinic esters in Cyrene. The success of this protocol relies on a very short reaction time (only 15 minutes) which prevents polymerization from occurring. Indeed, Cyrene not only outperformed typical solvents such as DMF and DMSO, but also, being highly soluble in water, allowed an easy purification of the desired products by simple precipitation upon the addition of ice‐water.

Diglyme as a Promoter for the Electrochemical Formation of Quaternary Graphite Intercalation Compounds Containing two Different Types of Solvents

AbstractCo‐intercalation using ether‐based electrolytes renders graphite as a promising anode material in sodium‐ion batteries (SIBs). While most research on electrochemical solvent co‐intercalation in graphite has focused on linear ethers such as mono‐, di‐, tri‐, tetra‐, and penta‐glyme, we herein investigate the possibility of reversible electrochemical co‐intercalation with alternative solvents, especially cyclic ethers tetrahydrofuran (THF) and 1,3‐dioxolane (DOL), which show no signs of co‐intercalation on their own. We demonstrate, however, that this reaction becomes feasible when incorporating diethylene glycol dimethyl ether (2G, diglyme) as an additive. Operando X‐ray diffraction and ex‐situ ss‐NMR techniques are employed comprehensively to understand the co‐intercalation reaction of these cyclic ethers, along with Na+‐glymes, into graphite during cycling. When using these mixed electrolytes i. e., THF/2G and DOL/2G, the voltage profiles changes compared to the pure glyme‐based electrolyte, while showing comparable specific capacities and good long‐term durability. Overall, we propose that even trace amounts of diglyme prompt the co‐intercalation of THF and DOL into graphite layers. This leads to the formation of quaternary graphite intercalation compounds (q‐GICs), expanding beyond the realm of ternary graphite intercalation compounds (t‐GICs).

Formic acid stability in different solvents by DFT calculations.

New technologies have been developed toward the use of green energies. The production of formic acid (FA) from carbon dioxide (CO[Formula: see text]) hydrogenation with H[Formula: see text] is a sustainable process for H[Formula: see text] storage. However, the FA adduct stabilization is thermodynamically dependent on the type of solvent and thermodynamic conditions. The results suggest a wide range of dielectric permittivity values between the dimethyl sulfoxide (DMSO) and water solvents to stabilize the FA in the absence of base. The thermodynamics analysis and the infrared and charge density difference results show that the formation of the FA complex with H[Formula: see text]O is temperature dependent and has a major influence on aqueous solvents compared to the FA adduct with amine, in good agreement with the experiment. In these conditions, the stability thermodynamic of the FA molecule may be favorable at non-organic solvents and dielectric permittivity values closer to water. Therefore, a mixture of aqueous solvents with possible ionic composition could be used to increase the thermodynamic stability of H[Formula: see text] storage in CO[Formula: see text] conversion processes. Using the Quantum ESPRESSO package, density functional theory (DFT) calculations were performed with periodic boundary conditions, and the electronic wave functions were expanded in plane waves. For the exchange-correlation functional, we use the vdW-DF functional with the inclusion of van der Waals (vdW) forces. Electron-ion interactions are treated by the projector augmented wave (PAW) method with pseudopotentials available in the PSlibrary repository. The wave functions and the electronic densities were expanded employing accurate cut-off energies of 6.80[Formula: see text]10[Formula: see text] and 5.44[Formula: see text]10[Formula: see text] eV, respectively. The electronic density was computed from the wave functions calculated at the [Formula: see text]-point in the first Brillouin-zone. Each structural optimization was minimized according to the Broyden-Fletcher-Goldfarb-Shanno (BFGS) algorithm, with force and energy convergence criteria of 25 meV[Formula: see text]Å[Formula: see text] and 1.36 meV, respectively. The electrostatic solvation effects were performed by the [Formula: see text] package with the Self-Consistent Continuum Solvation (SCCS) approach.

Electric Field‐induced Orientation of Carbon Nanomaterials in Dispersions

AbstractCarbon nanomaterials (CNMs) exhibit excellent performance and potential application value in optical, electric, magnetic and thermal owing to their unique low dimensional structures, high specific surface areas and excellent electrical conductivities, however, the random orientation of CNMs in polymer dispersions negatively affects their optimal performances. Herein, the orientation of CNMs induced by an electric field in dispersions was investigated. The arrangement of carbon black, carbon nanotubes and graphite nanoplatelets in solvents under an electric field was characterized using a stereoscopic microscope. The effects of solvent type, nanomaterial concentration and electric field conditions on the orientation of the CNMs were systematically investigated. The results showed that the CNMs generally exhibited good electric field‐induced orientations in solvents with a low relative dielectric constant. The orientation structure resulting from using an appropriate CNMs concentration was relatively uniform and continuous. In particular, a more regular orientation structure was achieved upon applying an electric field (100 V/mm; 1000 Hz) for 30 s. Interestingly, well‐oriented CNMs in a solvent can also orient in polymer dispersions that are soluble in such a solvent. This extension of the orientation of CNMs from solvents to polymer dispersion systems provides a novel idea for preparing high‐performance composites.

Rapid coating of millimeter‐scale hydrogel capsules with interfacial polymerization

AbstractA rapid and mild coating strategy was applied on the millimeter scale calcium alginate capsules (Ca‐SA caps) by in situ interfacial polymerization of ethyl cyanoacrylate (ECA). The generated poly(ethyl cyanoacrylate) (PECA) coating was initiated by trace water in the surface of the Ca‐SA caps. The effects of ECA content, reaction time, and type of aromatic solvent on the morphology and control‐release property of the resulting PECA‐coated Ca‐SA caps (Ca‐SA caps@PECA) were investigated. The results demonstrated a white PECA layer successfully coated on the surface of Ca‐SA caps. Notably, the Ca‐SA caps@PECA remained consistently pleasing spherical shape as prepared in methylbenzene and ethylbenzene. When the ECA was 6 mL, the thickness of PECA layer of the Ca‐SA caps@PECA was 43.52 μm. Compared with the Ca‐SA caps, the weight retention ratio of water in the Ca‐SA caps@PECA increased by 254.61%, indicating the effective delay of water diffusion from core of the Ca‐SA caps@PECA. Moreover, the PECA coating improved the stability of the Ca‐SA caps@PECA, which achieved release‐controlling of dye at different pH. This method provides solution for surface modification of fragile hydrogel capsules to effectively control the releasing of liquid core, which is highly valuable in the field of food, cosmetic, and medical delivery.

Optimizing the Extraction Process of Value-Added Products from Olive Cake Using Neuro-Fuzzy Models

The use of olive cake, an abundant residue in the olive oil industry, has been studied by developing a biorefinery scheme. The aim was to develop a novel, efficient, and environmentally friendly strategy for the valorization of olive cake, contributing to sustainable agriculture. A special extraction procedure based on a combination of hydrothermal treatments with liquid/liquid extractions was designed to produce value-added products, along with solids that can be used for energy or adsorbent production. The optimal extraction conditions were determined by exploring the influence of the operating variables (temperature, extraction time, solvent type, solvent/extract ratio, extraction stages, and pH) on the extraction yield. The decision about the optimal conditions was made by adjusting the experimental results to a neuro-fuzzy model. Glucose and inositol showed similar response surfaces, allowing simultaneous concentration in a single process. Under optimal extraction conditions, the concentration of inositol increased by up to 70%, while glucose and fructose increased by 70 and 30 times, respectively, compared to the initial feed. The proposed methodology successfully extracted significant amounts of bioactive polyols (mainly inositol) (1126 mg/L), saccharides (15,960 mg/L glucose, 385 mg/L xylose, 5550 mg/L fructose, 165 mg/L lactose, and 248 mg/L sucrose), and polyphenols (4792 mg/L) under mild conditions, i.e., 30 °C and 30 min. Thus, olive cake extracts have a great unexploited potential for application in several industrial sectors, including, but not limited to, food and pharmaceuticals.

Solvent effects on the optical properties of photosynthetic pigments evaluated by evolutionary optimization

With the development of computational technologies, it became possible to do numerical simulations of the optical properties of molecules and organic crystals taking into account the modern sophisticated theoretical approaches. Our work is devoted to the study of carotenoids in different solvents. Carotenoids, being photosynthetic pigments, are located inside pigment-protein complexes and are covalently bound to the proteins. They have a wide variety and despite their relative simple structure, their optical properties remain poorly understood. Thus, their role in photosynthetic machinery is still an open question. In this study, we investigate the properties of carotenoid electronic excitations by fitting their absorption spectra considering pigments in polar and nonpolar solvents. As it is known, carotenoids have four main nuclear vibration modes. Each mode is characterized by three parameters: frequency, Huang-Rhys factor and damping factor. In particular, the Huang-Rhys factor cannot be measured experimentally. To do the modeling, we developed special software to fit experimental data using differential evolution (DE) algorithm, which allows obtaining an unambiguous solution for applied quantum models. With the help of DE, it was possible to estimate the influence of the solvent on the excited states of a pigment. Examining astaxanthin and lycopene spectra in three solvents (chloroform, hexane, ethanol), we have shown that some quantum parameters are very sensitive to the type of solvent and can be considered as markers of polarity.

Phytochemical and antioxidant profile of citrus peel extracts in relation to different extraction parameters

ABSTRACT The citrus processing industry generates around 50% fruit waste, encompassing peels, pulp, seeds, and other residues. Citrus peel, among these by-products, contains significant amounts of bioactive compounds, representing a sustainable and renewable source of phenolics. In this context, the present study was conducted to probe phytochemical profile and antioxidant potency of orange peel extracts. Moreover, the quantification of hesperidin and nobiletin was carried out using HPLC. The extracts were obtained using water and 50% aqueous-methanol and aqueous-ethanol, separately alongside varying time intervals, i.e. 30, 45 and 60 min. The obtained extracts were then investigated for their phytochemical and antioxidant profile. Afterwards, three best treatments, one from each extracts (aqueous-ethanol, methanol, and water), were chosen based on their phytochemical profiling. The phytochemical analyses and in vitro antioxidant assays showed the highest total phenolics (2010 mg GAE/100 g), flavonoids (90 mg/100 g), and flavonols (2.2 mg/100 g) in methanolic extracts obtained at 60 min. Likewise, the highest DPPH (60.55%), antioxidant activity (51.7 %), FRAP (13.6 mg TE/g), and ABTS (7.4 µmol TE/g) were also attributed to methanolic extract of orange peel obtained at 60 min except for antioxidant activity which was obtained at 30 min. Likewise, HPLC analysis depicted maximum content of hesperidin and nobiletin (133.70 and 8.50 mg/g) in methanol extract as compared to ethanol (98.80 and 5.50 mg/g) and water (61.90 and 1.25 mg/g), correspondingly. It was concluded that aqueous-methanol could be used as solvent of choice for isolation of orange peel flavonoids with extraction duration of 60 min. Flavonoid and antioxidant levels in orange peel extracts are significantly influenced by extraction time and solvent type.

Polyurethane as a versatile polymer for coating and anti-corrosion applications: A review

The development of polyurethane materials and process optimization are currently the subjects of extensive study. Polyurethane is characterized by high physicochemical and operational properties. Polyurethanes have high wear resistance, and oil and gasoline resistance. They have excellent thermophysical and elastic properties. This allows the use of polyurethanes in many industries where materials with high-performance properties are required. Polyurethanes are widely used in many industrial applications, protective coating manufacturing, and anti-corrosion agent applications. A significant number of studies have been conducted to improve the physical, mechanical, and operational properties of polyurethane polymers, in particular the anti-corrosion properties of modified polyurethane coatings. The properties of polyurethane polymers for various applications can be improved by changing monomers and their ratios and the process of preparations. Preparation of polyurethane polymers based on polyols and isocyanate monomers using a polyaddition process in the presence of a catalyst as well as solvents including toluene, xylene, and acetone. There are different factors affecting the physical and mechanical properties of polyurethane polymers were investigated by different techniques. The factors were types of isocyanates, polyols, OCN/OH ratios, solvents, catalysts, and temperatures. Generally, the polyols are responsible for the flexibility of the polyurethane polymers and isocyanates are responsible for the rigidity of the polyurethane polymer and crosslinking between the backbone of the polymer. Because of the flexibility of its chemistry, they may modify the coating's characteristics based on the intended use. The effects of different polyols and polyisocyanates' chemistry are assessed. The hydrophobicity, thermal stability, and mechanical and anti-corrosion properties of polyurethane polymers were investigated. As a result, the properties of polyurethane polymers such as hydrophobicity, thermal stability, and mechanical and anti-corrosion properties were all enhanced when all the above factors. An outline of the most modern, financially successful methods for creating protective polyurethane coatings and using them as anti-corrosion agents is given in this review article.

Effect of stoichiometry upon the characteristics of quercetin-arginine cocrystals formulated through solution crystallization

Objective The aim of this study is to demonstrate the effect of stoichiometry upon characteristics of quercetin-arginine (QCT-Arg) cocrystals. Significance Quercetin (QCT) is a most abundant flavonoid in vegetables and fruits and has been widely used as an antioxidant. However, its oral bioavailability remains low due to poor aqueous solubility. We illustrate that QCT-Arg cocrystals formulated through an optimized stoichiometry can be a useful approach for its solubilization. Method Cocrystals were prepared using solvent evaporation method. Characterizations were performed through microscopic, spectroscopic, and thermal techniques. The stoichiometry was confirmed from the binary phase diagram which was prepared using thermograms derived from differential scanning calorimetric experiments. Result Cocrystal formation was accompanied by the conversion of isotropic phase into anisotropic one. Thread-like cocrystals were formed, regardless of QCT-Arg stoichiometry and solvent’s polarity. Spectral analyses suggested that cocrystal structure was held together by hydrogen bonding between QCT and Arg. We ruled out the existence of eutectic mixture based on the observation of two eutectic points in the binary phase diagram. Conclusion Morphology of cocrystals remained unaffected by the solvent type, stoichiometry and the presence of surfactant. We noticed that the cocrystals could improve the aqueous solubility of QCT.

First report for fluorometric determination of kasugamycin based on amino acid-functionalized bimetallic nanoclusters

A rapid and straightforward turn-off fluorescence sensor has been developed for the detection of kasugamycin (KASN) using tryptophan-capped silver/gold bimetallic nanoclusters (Trp@Ag-Au NCs). The sensor's parameters, including reaction time and solvent type, were optimized to enhance its performance. The fluorescence emission of Trp@Ag-Au NCs is quenched upon the addition of KASN due to the aggregation of the Trp@Ag-Au NCs induced by the electrostatic and non-covalent interactions between the negatively charged Trp@Ag-Au NCs and the positively charged KASN. The sensor exhibited excellent sensitivity for KASN detection, demonstrating a linear concentration range from 0.5 to 500 µM and a low limit of detection (LOD) of 0.14 µM, determined at a signal-to-noise ratio of 3. These values indicate the sensor's ability to accurately detect KASN even at low concentrations. To evaluate its practical utility, spike recovery analysis was performed in synthetic samples, confirming its effectiveness in real-world sample matrices. The optimized sensor parameters, wide linear range, low LOD, and successful application in various samples highlight the sensor's potential for practical use in various applications, including food safety and biomedical research. Its simplicity, rapidity, and sensitivity make it a promising tool for the detection of KASN.

3D-printed extraction devices fabricated from silica particles suspended in acrylate resin

In recent years, there has been an increasing worldwide interest in the use of alternative sample preparation methods. Digital light processing (DLP) is a 3D printing technique based on using UV light to form photo-curable resin layer upon layer, which results in a printed shape. This study explores the application of this technique for the development of novel drug extraction devices in analytical chemistry. A composite material consisting of a photocurable resin and C18-modified silica particles was employed as a sorbent device, demonstrating its effectiveness in pharmaceutical analysis. Apart from estimating optimal printing parameters, microscopic examination of the material surface, and sorbent powder to resin ratio, the extraction procedure was also optimised. Optimisation included the type and amount of sample matrix additives, desorption solvent, sorption and desorption times, and proper number of sorbent devices needed in extraction protocol. To demonstrate this method's applicability for sample analysis, the solid-phase extraction followed by gas chromatography coupled with mass spectrometry (SPE-GC–MS) method was validated for its ability to quantify benzodiazepine-type drugs. This evaluation confirmed good linearity in the concentration range of 50–1000 ng/mL, with R2 values being 0.9932 and 0.9952 for medazepam and diazepam, respectively. Validation parameters proved that the presented method is precise (with values ranging in-between 2.98 %-7.40 %), and accurate (88.81 % to 110.80 %). A negative control was also performed to investigate possible sorption properties of the resin itself, proving that the addition of C18-modified silica particles significantly increases the extraction efficiency and repeatability.The cost-effectiveness of this approach makes it particularly advantageous for single-use scenarios, eliminating the need for time-consuming sorbent-cleaning procedures, common in traditional solid-phase extraction techniques. Future optimisation opportunities include refining sorbent size, shape, and geometry to achieve lower limits of quantification. As a result of these findings, 3D-printed extraction devices can serve as a viable alternative to commercially available SPE or solid-phase microextraction (SPME) protocols for studying new sample preparation approaches.

Devolatilization characteristics of a bio-residue (potato stems) with high contents of alkali metals and non-structural components – Influences of the washing pretreatment severity

A bio-residue (potato stems), rich in alkali metals and non-structural components, is subjected to hot (353 K) or acidic (0.1 mol/L hydrochloric acid) water washing. The acidic pretreatment is more effective for the demineralization, with alkalis reduced by 99 (powders) or 90 (particles) %, corresponding to organic matter dissolution around 35 or 17 wt%, respectively. The latter figures remain approximately the same for hot water washing (38 and 19 wt%) but alkalis are reduced only by 78 or 64 %. The leachate properties are significantly dependent on the solvent type and the residue granulometry, as indicated by thermogravimetric and SEM-EDX analysis. Washed bio-residues decompose at temperatures and with rates progressively increasing as the pretreatment becomes more severe (fine granulometry and acidic water washing). Multi-step global kinetics, previously developed for the untreated material and properly revisited to incorporate washing effects, reveals trends with important compositional changes. Despite starch dissolution, volatile product yields for the absolute peak rate zone increase by about 40–65 %, testifying augmented cellulose contents. The pectin compounds are almost eliminated, to the advantage of the shoulder rate zone, representing hemicellulose decomposition, with an increase in the volatile product yields around 22–78 %.

Solubility of Gallic Acid in Single and Mixed Solvents

Gallic acid, known for its biological activity contributing to human health, including antioxidant, anti-inflammatory, anticancer, and antimutagenic properties, was the focus of this study. The solubility of gallic acid was experimentally measured in pure and mixed solvents of water, ethanol, and acetic acid and predicted using the COSMO-SAC model and the Hansen solubility parameter. The Hansen solubility parameter method predicted a higher solubility of gallic acid in pure water than in pure ethanol, and in a mixed solvent, it predicted the maximum solubility at 80% water content, showing different results from the experimental data trends. However, using the molar volume obtained from COSMO calculations resulted in a tendency that matched the experimental results. The results revealed higher solubility in ethanol compared to water, with the solubility in mixed solvent falling within the range between them. Using the same method, the Hansen solubility parameter obtained was applied to acetic acid/water and acetic acid/ethanol mixtures, and similar trends were observed compared to experimental data. In particular, gallic acid in the acetic acid/water mixture solvent exhibited maximum solubility, and this phenomenon was well-predicted. As the temperature increased, solubility in both pure and mixed solvents also increased. While the COSMO-SAC model effectively captured this trend, the predicted solubility values were slightly lower than the experimental data. The solubility trends depending on solvent types were confirmed by comparing the σ-profiles of each compound. The σ-profile of gallic acid closely resembled that of ethanol, and this result led to higher solubility than water and acetic acid. The maximum solubility in ethanol/water and acetic acid/water mixed solvents could be anticipated when two solvents with significant differences in their σ-profiles are mixed in an appropriate ratio.

Evaluation of Shear Bond Strength of Composite Resin Bonded to Dentin with Three Different Adhesive Systems

Aim of the study to measure the shear bond strength of composite resin bonded to dentin with three different adhesive system.The buccal surfaces of 30 non-carious, intact, extracted upper premolar (Freshly extracted for orthodontic treatment), were grinded with 600 grit silicon carbide paper to expose dentin surface. the samples were divided into three groups: G1, 10 teeth were bonded with an acetone-base total-etch Prime&Bond NT G2, 10 teeth were bonded with an ethanol-base total-etch Excite. G3,10 teeth were bonded with an ethanol-and water-base total-etch Schotchbond 1. Shear bond strength is determined by using Instron testing machine.Results showed that excite adhesive system has statistically high significant increase in shear bond strength than Schotchbond 1.As conclusion; the lack of water in the adhesive may play a more important role than the type of solvent itself.

Facile dissolution of cellulose by superbase-derived ionic liquid using organic solvents as co-solvents at mild temperatures

Dissolving cellulose at low temperatures is a key step in its efficient utilization as a renewable resource to produce high-value-added platform chemicals and high-performance materials. Here, the potential of four aprotic organic solvents was investigated for use as co-solvents with a sustainable DBU-derived ionic liquid (SIL) for the low-temperature dissolution and regeneration of cellulose. Combined experiments, density functional theory calculations, and molecular dynamic simulations were performed. The type and amount of co-solvent were found to have a significant impact on the solubility of cellulose, the dissolution process, and the structure of regenerated cellulose. The addition of organic solvents can significantly reduce the cellulose dissolution temperature and increase the solubility. Among the solvents assessed, 40 wt% DMSO exhibited the most effective synergistic interaction with SIL, where the solubility of cellulose was 14.6 wt% at 75 °C. Subsequently, the effects of the different types and amounts of co-solvents on the microscopic morphology and chemical structure of regenerated cellulose were thoroughly explored. The results showed that different types of organic solvents had different effects on the microstructure of regenerated cellulose. The results may guide the manufacturing specifications of high-performance regenerated fiber materials.