Solvent Parameters Research Articles

Photophysical and Solvatochromic Studies of 4-(methylthio)-2-oxo-6-phenyl-2H-pyran-3-carbonitrile Derivatives

Herein we report a photophysical and solvatochromic study of (4-(methylthio)-2-oxo-6-phenyl-2H-pyran-3-carbonitrile derivatives. Photophysical properties of synthesized compounds were investigated in different solvents of varying polarity. It was found that for all studied compounds no distinguishable behaviour was observed for absorption in different solvents whereas some notable changes were observed in emission spectra. Solvent dependent spectral properties of compounds were investigated using Lippert- Mataga plot and empirical solvent parameter ET(30).

Comparative Study of Two Spectral Methods for Estimating the Excited State Dipole Moment of Non-Fluorescent Molecules.

The electronic absorption spectral characteristics of cycloimmonium ylids with a zwitterionic structure have been analyzed in forty-three solvents with different hydrogen bonding abilities. The two ylids lack fluorescence emission but are very dynamic in electronic absorption spectra. Using the maximum of the ICT band, the goal was to establish an accurate relationship between the shift of the ICT visible band and the solvent parameters and to estimate two of the descriptors of the first (the) excited state: the dipole moment and the polarizability. Two procedures were involved: the variational method and the relationships of the Abe model. The results indicate that the excited state dipole moment of the two methylids decreases in the absorption process in comparison with the ground state. The introduction of a correction term in the Abe model that neglects the intermolecular H-bonding interactions leads to a more accurate determination of the two descriptors. The strong solvatochromic response of both ylids has been further applied in distinguishing the solvents as a function of their specific parameters. Principal component analysis was applied to five selected properties, including the maximum of the charge transfer band. The results were further applied to discriminate several binary solvent mixtures.

Application of Abraham's solvation parameter model to extractables and leachables studies in pharmaceutical and medical device industries: A tutorial

The Abraham's solvation parameter model is an important tool to model and predict distribution properties of compounds in numerous partitioning systems in chemistry, environmental chemistry, medicine, and biology. The evaluation of the distribution properties in extractables and leachables (E&L) studies in pharmaceutical and medical device industries is another major application of this model. This tutorial is aimed at illustrating the applications of the model in E&L studies. Specific examples of the application illustrated in this tutorial include: (a) establishment of equivalent or similar solvents; (b) determination of polarity of solvents, biological tissues, and materials; (c) development of drug product simulating solvents; (d) understanding solvent extraction power for a material; (e) selection of solvent and standards in pretreatment of extraction samples; and (f) chromatography retention prediction for E&L.

Modeling Study on Heat Capacity, Viscosity, and Density of Ionic Liquid–Organic Solvent–Organic Solvent Ternary Mixtures via Machine Learning

Physicochemical properties of ionic liquids (ILs) are essential in solvent screening and process design. However, due to their vast diversity, acquiring IL properties through experimentation alone is both time-consuming and costly. For this reason, the creation of prediction models that can accurately forecast the characteristics of IL and its mixtures is crucial to their application. This study proposes a model for predicting the three important parameters of the IL-organic solvent–organic solvent ternary system: density, viscosity, and heat capacity. The model incorporates group contribution (GC) and machine learning (ML) methods. A link between variables such as temperature, pressure, and molecular structure is established by the model. We gathered 2775 viscosity, 6515 density, and 1057 heat capacity data points to compare the prediction accuracy of three machine learning methods, namely, artificial neural networks (ANNs), extreme gradient boosting (XGBoost), and light gradient boosting machine (LightGBM). As can be observed from the findings, the ANN model produced the best results out of the three GC-based ML methods, even though all three produced dependable predictions. For heat capacity, the mean absolute error (MAE) of the ANN model is 1.7320 and the squared correlation coefficient (R2) is 0.9929. Regarding viscosity, the MAE of the ANN model is 0.0225 and the R2 is 0.9973. For density, the MAE of the ANN model is 7.3760 and the R2 is 0.9943. The Shapley additive explanatory (SHAP) approach was applied to the study to comprehend the significance of each feature in the prediction findings. The analysis results indicated that the R-CH3 group of the ILs, followed by the imidazolium (Im) group, had the highest impact on the heat capacity property of the ternary system. On the other hand, the Im group and the R-H group of ILs had the most effects on viscosity. In terms of density, the Im group of the ILs had the greatest effect on the ternary system, followed by the molar fraction of the organic solvent.

Evaluation of the Goss-modified solvation parameter model for the characterization of biphasic systems and descriptor assignments

The solvation parameter model uses six descriptors identified as excess molar refraction, E, dipolarity/polarizability, S, overall hydrogen-bond acidity, A, overall hydrogen-bond basicity, B, McGowan's characteristic volume, V, and the gas-liquid partition constant on hexadecane at 25 °C, L to model the distribution of neutral compounds in biphasic systems. Abraham's version of this model uses all six descriptors with two separate linear free energy relationship models for the transfer of compounds from a gas phase to a condensed phase and between condensed phases. Goss proposed a modification to this model that uses a single calibration model regardless of the physical state for each phase and five of the descriptors employed in Abraham's model (E descriptor is eliminated). The capability of Abraham's model and the Goss-modified model to characterize the contribution of intermolecular interaction to retention for gas and reversed-phase liquid chromatographic systems and distribution in liquid-liquid partition systems is evaluated using the WSU compound descriptor database. These more accurate values for the Abraham descriptors have not been utilized previously for the evaluation of the Goss-modified model and should be more capable of discerning subtle differences in model performance. It is shown that model quality defined by statistical parameters favors Abraham's model over the Goss-modified model with differences in model quality greater for systems in which Abraham's model indicates a significant contribution from electron lone pair interactions and for systems in which one phase is a solvent containing perfluoroalkyl substituents. There is a small systematic difference for the terms describing the combined contributions of cavity formation and dispersion interactions and for interactions of a dipole-type. The contribution of hydrogen-bonding interactions is virtually identical for the two models. The model intercepts are generally different and potentially assigned to a larger contribution from lack-of-fit for the Goss-modified model. Although the Abraham model descriptors have been routinely employed for applications using the Goss-modified model the possibility that Goss-model specific descriptors should be employed was evaluated. Using the Solver method and Goss-model specific calibration models for chromatographic and liquid-liquid partition systems a new set of Goss-specific descriptors was calculated for 28 varied compounds. These descriptors show good statistical agreement with the Abraham descriptor values with an average deviation of 0.009, -0.003, -0.004, and -0.023, respectively, for the S, A, B, and L descriptors, corresponding to a relative absolute deviation in percent of 2.2 %, 3.9 %, 4.3 %, and 1.2 %, respectively.

Abraham General Solvation Parameter Model: Predictive Expressions for Solute Transfer into Isobutyl Acetate

Mole fraction of solubilities are reported for the: o-acetoacetanisidide, anthracene, benzoin, 4-tert-butylbenzoic acid, 3-chlorobenzoic acid, 3-chlorobenzoic acid, 2-chloro-5-nitrobenzoic acid, 4-chloro-3-nitrobenzoic acid, 3,4-dichlorobenzoic acid, 2,3-dimethoxybenzoic acid, 3,4-dimethoxybenzoic acid, 3,5-dimethoxybenzoic acid, 3,5-dinitrobenzoic acid, diphenyl sulfone, 2-ethylanthraquinone, 2-methoxybenzoic acid, 4-methoxybenzoic acid, 2-methylbenzoic acid, 3-methylbenzoic acid, 2-methyl-3-nitrobenzoic acid, 3-methyl-4-nitrobenzoic acid, 4-methyl-3-nitrobenzoic acid, 2-naphthoxyacetic acid, 3-nitrobenzoic acid, 4-nitrobenzoic acid, salicylamide, thioxanthene-9-one, 3,4,5-trimethoxybenzoic acid, and xanthene dissolved in isobutyl acetate at 298.15 K. The results of our experimental measurements, combined with the published literature data, were used to obtain Abraham model equations for isobutyl acetate. The mathematical correlations presented in the current study describe the observed molar solubility ratios of the solutes dissolved in isobutyl acetate to within an overall standard deviation of 0.12 log units or less.

Solubility measurement, calculation, solvent effect and preferential solvation of fenoxaprop-p-ethyl in four cosolvent mixtures at (278.15–323.15) K

Equilibrium solubility of fenoxaprop-p-ethyl in aqueous mixtures of ethanol/ isopropanol/acetonitrile/N,N-dimethylformamide (DMF) plus water was experimentally measured by isothermal saturation method at (278.15–323.15) K under 101.2 kPa. The order of solubility (mole fraction) of fenoxaprop-p-ethyl in pure solvents from high to low is 4.233 × 10−2 (DMF 323.15 K) > 2.044 × 10−2 (acetonitrile 323.15 K) > 7.727 × 10−3 (isopropanol 323.15 K) > 5.338 × 10−3 (ethanol 323.15 K) > 2.565 × 10−5 (water 323.15 K). Experimental results showed that temperature and type of solvent were decisive factors for the dissolution of fenoxaprop-p-ethyl. The content of fenoxaprop-p-ethyl in solution was analyzed by high-performance liquid chromatography (HPLC). Moreover, the solubility data of fenoxaprop-p-ethyl was correlated by Jouyban-Acree (J-A) model, van’t Hoff-Jouyban-Acree (V-J-A) model and Apelblat-Jouyban-Acree (A-J-A) model. The maximum of root-mean-square deviation (RMSD), relative average deviation (RAD) and standard deviation (SD) predicted via three thermodynamic models were 1.78 × 10−4 (DMF + water), 2.87 × 10−2 (acetonitrile + water) and 1.79 × 10−4 (DMF + water), respectively. In addition, the solvent effect between solute and solvent molecules was deduced by KAT-LSER model and the result showed that dipolarity/polarizability interactions between the solute and solvent molecules were dominant in the dissolution of fenoxaprop-p-ethyl. Finally, the preferential solvation parameter (δx1,3) of fenoxaprop-p-ethyl was obtained by the method of inverse Kirkwood–Buff integrals and the preferential dissolution behavior of each concentration range is explained by Lewis acid base theory. However, for acetonitrile + water, the change of δx1,3 may be due to the polarization effects and it is not suitable for Lewis acid base theory.

EVALUATION OF THE GRAPHENE DISPERSIONS FOR KEVLAR FABRICS FUNCTIONALIZATION OBTAINED BY THE LIQUID-EXFOLIATION OF GRAPHITE

The process where pristine graphite is subjected to a solvent treatment seems simple and scalable and has attracted the attention of researchers over many years. However, for successful exfoliation, overcoming the van der Waals attractions between the adjacent layers of graphite is necessary. Over time, several methods have been created to overcome the attraction between layers. Graphene’s liquid phase exfoliation (LPE) occurs due to the strong interactions between the solvent molecules and the basal planes of graphite, overcoming the energetic resistance to exfoliation and subsequent dispersion. Ultra sonication used for exfoliation can produce single or few layered graphene flakes. During sonication the sound waves propagate through liquid medium in alternating high- and low-pressure cycles, strong mechanical and thermal energy released by acoustic cavitation results in splitting up large particles into fine ones and dispersing them. Simultaneous insertion of solvent and/or intercalation molecules in between the graphite layers takes place supporting graphite separation into graphene layers. ; The dispersion capacity of graphene flakes depends on how appropriate the solvent properties are to the corresponding properties of graphene, such as surface tension, Hildebrand, and Hansen solubility parameters. Only certain solvents can disperse graphene well and form a dispersion appropriate for specific future applications. In addition, after exfoliation by ultra sonication graphene flakes aggregation due to the van der Waals attractions must be overcome to prepare in long-term stable dispersions of nanometres-size graphene sheets. ; The research has focused on the preparation of stable dispersion ready for transfer without intermediate processes to the Kevlar fabrics. An experimental comparison of the potentials of the 4 solvents for the application resulted in three corresponding to the intended use, two of them examined in detail, supplementing the composition of the LPE liquid medium with triethanolamine to obtain sufficient performance graphene coverage on Kevlar textile fibres.

Thermodynamic parameters of L-carnosine dissolution and solvation in binary aqueous-organic mixtures at T = 298.15 K.

Isothermal calorimetry was used to measure the enthalpies of L-carnosine digestion in aqueous solutions of acetonitrile (AN) 1,4-dioxane (DO), acetone (AC), dimethyl sulfoxide (DMSO), ethanol EtOH), 1-propanol (1-PrOH), and 2-propanol (2-PrOH). The values of ΔsolH° obtained were combined with the standard enthalpies of L-carnosine sublimation to obtain the corresponding enthalpies of solvation ΔsolvH°. In addition, the enthalpic coefficients of pairwise interactions (hxy) of L-carnosine with organic solvent molecules and the enthalpy of transfer (ΔtrH°) from water in their mixture with the latter were calculated. It is established that the solvation of L-carnosine is weakened in a series of (H2O + EtOH) > (H2O + 1-PrOH) > (H2O + 2-PrOH). This may be due to an increase in the hydrophobicity of alcohols of the same order as well as the presence of CH3-groups within the alcohol molecule. The weakening of the solvation energy of L-carnosine by co-solvent molecules in a series of mixed solvents: (H2O + AN) < (H2O + AC) < (H2O + DO) < (H2O + DMSO) is associated both with an increase in the hydration energy of co-solvents in the same order and with their physicochemical properties. The enthalpic coefficients of water-organic solvent pairwise interactions were discovered to be linearly related to the corresponding coefficients of L-carnosine-organic solvent interactions. An increase in the polarity and acidity of an organic solvent increases the energy of pairwise interactions between L-carnosine and the organic solvent. Increasing the cohesion energy density, molar volume, and basicity of the organic solvent reduces the energy of the pairwise interactions between L-carnosine and the organic solvent.

A Collection of Dispersion Induction DI, Electrostatic ES, and Hydrogen Bonding α1 and β1 Parameters for 380 Solvents and What They Say on Solvent Effects on Rates, Equilibria, and Spectra.

The solvent parameters DI, ES, α1, and β1 are intended for the description of solute-solvent intermolecular forces, i.e., dispersion-induction, electrostatic, hydrogen-bond donation, and hydrogen-bond acceptance, respectively. An up-to-date collection of these parameters is presented for 380 solvents including green solvents, ionic liquids, and deep eutectic solvents. Their determination for additional solvents requires three commercial indicators, betaine dye B(30), 4-F-phenol, and 4-F-anisole (as well as the refractive index). The chemical significance of these parameters is outlined. Their use in the linear solvation energy relationship P = P° + di DI + e ES + a α1 + b β1 for 62 physicochemical properties P (reaction rates, equilibrium constants, and IR, UV, and NMR spectra) yields determination coefficients generally greater than 0.90 and regression coefficients whose sign and relative magnitude provide consistent information on the intermolecular forces acting on these properties.

Enhanced Antioxidant Extraction from Lonicerae japonicae Flos Based on a Novel Optimization Strategy with Tailored Deep Eutectic Solvents

Lonicerae japonicae Flos (LJF) is a natural plant containing abundant antioxidant ingredients. In order to extract more antioxidants from LJF, in this study, a novel strategy was proposed for optimizing the extraction factor level by response surface methodology with a tailored deep eutectic solvent (DES) as the extraction solvent and antioxidant ability as the evaluation index. After optimizing the composition of DES and the extraction condition, the extracts obtained by our proposed method yielded better antioxidant ability (229.1–249.1 μmol TE/g DW) and higher antioxidant contents (34.2–36.5 mg GAE/g DW for total phenolics and 119.6–123.0 mg RE/g DW for total flavonoids) from LJF in 5 min without organic solvent consumption that were significantly superior to the Chinese Pharmacopoeia extraction method. The K-T solvation parameter and a scanning electron microscope were adopted to explore the extraction mechanism, and the results showed that the polarity and damage effect on plant cells of DES were crucial for the extraction of antioxidants. In addition, after combining the HPLC fingerprint and partial least squares model, chlorogenic acid, rutin, and 3,5-O-Dicaffeoylquinic acid were screened as the antioxidant Q-markers of LJF. This work demonstrates that an optimization strategy based on antioxidant ability and tailored DES has the potential to extract more antioxidants from natural plants.

Exploring green solvents for the sustainable fabrication of bio-based polylactic acid membranes using nonsolvent-induced phase separation

Green and sustainable membrane technology has recently gained attention from the membrane community to minimize the negative environmental impacts associated with conventional membrane production in industries, which rely on petrochemical engineering plastics and toxic organic solvents. While the fabrication of biobased and biodegradable polymeric membranes using common organic solvents has been reported, eco-friendly membrane-fabrication techniques using greener solvents are required to improve sustainability and reduce the negative environmental impact of the membrane industry. For the first time, this study comprehensively investigates the potential use of green solvents for preparing polylactic acid (PLA) membranes via the phase separation technique. PLA solubility and phase separation experiments, employing various green solvents were conducted to examine the potential applicability of these solvents for membrane fabrication. Porous PLA membranes exhibit different surface and pore structures depending on the thermodynamic and kinetic parameters of the green solvents. Based on the phase separation study, both fine PLA ultrafiltration membranes with controllable molecular weight cut-off and mechanically robust PLA microfiltration membranes with bi-continuous pore structure were successfully prepared using methyl lactate. The prepared green membranes showed a competitive filtration performance implying that the fully bio-based PLA membranes could substitute the conventional engineering plastic-based membranes in versatile membrane filtration and separation processes, especially single-use or consumable membrane products in environmental and healthcare industries.

Standardization and selection of organic solvent and extraction parameters for charantin in bitter gourd (Momordica charantin L.) fruits

Bitter gourd (Momordica charantia L. Cucurbitaceae) is an important vegetable and medicinal crop that is grown in several tropical countries such as India, China, Malaysia, Bangladesh, part of Africa, Central North America, South North Asia, Singapore, Japan, and Vietnam. It is also used as raw fruit juice for cooking fruits and vegetable dishes. The fruits, leaves, and seeds of this plant contain charantins, which are insulin-like compounds. Therefore, it is essential to develop nutrient-rich extracts that are more effective for diabetes. Ethanol and methanol are edible solvents that enable the preparation of charantin-rich extracts. Experiments were conducted on charantin extraction using ethanol and methanol in a Soxhlet apparatus. The study concluded that methanol is a better solvent for the production of charantin-rich extracts. Methanolic extracts had fewer impurities, less chlorophyll interference in the analysis, and better peak strength. The results of the study showed that there was 380–990 ug/g dry fruit powder dry weight content of charantin-level expression in fruit dried powder in methanolic extract, compared with ethanolic extract, which was 200–700 ug/g dry weight. The data show the significance of the use of methanol for bitter gourd charantin extraction.

Solvent-resistant isoporous membranes with tailored pore characteristics and on-demand sieving by site-selective hyper-crosslinking

Isoporous block copolymer membranes with high porosity and narrow pore size distribution have been viewed as ideal membrane platforms for precise separation of similarly sized particles or solutes. However, tailored made fabrication of solvent-resistant isoporous membranes with switchable pores and rigid pores for customizable sieving have been rarely reported. Herein, we show that site-selective hyper-crosslinking is effective and robust to prepare such membranes from polystyrene-block-poly(4-vinylpyridine) (PS-b-P4VP). The selective crosslinking in PS domains endows the membrane with excellent solvent resistance and structural stability. Since not participated in the crosslinking reaction, the P4VP brushes located in pore walls endow the crosslinked membranes with adaptive pore size, switchable permeance and tunable rejections that vary with Hansen solubility parameter of solvents. Moreover, by a facile while complete etching the P4VP from pores, the switchable performance is removed and resultant membranes show rigid pore characteristics and constant rejections. Crosslinked membranes with either switchable pores or rigid-likes pores exhibit superior long-term stability (30 days) in harsh solvents. This work presents a top-down method to construct highly stable isoporous membranes with both switchable and rigid pore characteristics from the same block copolymer, which will shed the light on precisely tailoring the pore size and pore rigidity for crosslinked isoporous membranes that will not only enable the tailored sieving but also the modelling of solvent flowing behaviours in nanopores.

Laser synthesis of nanoparticles in organic solvents - products, reactions, and perspectives.

Laser synthesis and processing of colloids (LSPC) is an established method for producing functional and durable nanomaterials and catalysts in virtually any liquid of choice. While the redox reactions during laser synthesis in water are fairly well understood, the corresponding reactions in organic liquids remain elusive, particularly because of the much greater complexity of carbon chemistry. To this end, this article first reviews the knowledge base of chemical reactions during LSPC and then deduces identifiable reaction pathways and mechanisms. This review also includes findings that are specific to the LSPC method variants laser ablation (LAL), fragmentation (LFL), melting (LML), and reduction (LRL) in organic liquids. A particular focus will be set on permanent gases, liquid hydrocarbons, and solid, carbonaceous species generated, including the formation of doped, compounded, and encapsulated nanoparticles. It will be shown how the choice of solvent, synthesis method, and laser parameters influence the nanostructure formation as well as the amount and chain length of the generated polyyne by-products. Finally, theoretical approaches to address the mechanisms of organic liquid decomposition and carbon shell formation are highlighted and discussed regarding current challenges and future perspectives of LSPC using organic liquids instead of water.

Synergistic Solvation as the Enhancement of Local Mixing.

Mixing two solvents can sometimes make a much better solvent than expected from their weighted mean. This phenomenon, called synergistic solvation, has commonly been explained via the Hildebrand and Hansen solubility parameters, yet their inability in other solubilization phenomena, most notably hydrotropy, necessitates an alternative route to elucidating solubilization. While, recently, the universal theory of solubilization was founded on the statistical thermodynamic fluctuation theory (as a generalization of the Kirkwood-Buff theory), its demand for experimental data processing has been a hindrance for its wider application. This can be overcome by the solubility isotherm theory, which is founded on the fluctuation theory yet reduces experimental data processing significantly to the level of isotherm analysis in sorption. The isotherm analysis identifies the driving force of synergistic solvation as the enhancement of solvent mixing around the solute, opposite in behavior to hydrotropy (characterized by the enhancement of demixing or self-association around the solute). Thus, the fluctuation theory, including its solubility isotherms, provides a universal language for solubilization across the historic subcategorization of solubilizers, for which different (and often contradictory) mechanistic models have been proposed.

Comprehensive kinetic investigation of antiradical activity of urolithins and their potential inhibitory effect on Xanthine Dehydrogenase

This work aimed to explore the antiradical activity of various ellagitannin metabolites, including Urolithin A (UroA), Urolithin B (UroB), Urolithin C (UroC), and Urolithin D (UroD), in a non-polar (benzene) and polar (water) medium. The antiradical effect of the investigated compounds against reactive oxygen species HO• was evaluated in water (physiological conditions) and benzene, while against CH3OO• and CCl3OO• it was assessed solely in benzene, using the Quantum Mechanics-based Test for Overall Free-radical Scavenging Activity (QM-ORSA) methodology. In non-polar media, compounds UroA, UroC, and UroD exhibit antiradical capabilities against the HO• through Proton-coupled electron transfer (PCET) and Radical Adduct Formation (RAF) processes. Conversely, UroB predominantly exhibits inhibitory activity on HO• through the RAF pathway. On the other hand, the reaction with CH3OO• and CCl3OO• only occurs through the Hydrogen Atom Transfer (HAT). Under physiological conditions, all investigated compounds show antiradical capacity against the HO•, primarily via the SPLET and RCF mechanisms. The reactivity of radical species in both solvents decreases in the following order: HO• > CCl3OO• > CH3OO•. The thermodynamic and kinetic parameters in both solvents indicate that the investigated compounds’ reactivity follows a decreasing order of UroD > UroA > UroC > UroB. Furthermore, newly formed radical species of urolithin exhibit lower reactivity towards the fatty acid model in comparison to investigated reactive radical species, potentially preventing lipid peroxidation initiation. The investigated compounds can regenerate glutathione (GSH) by providing a hydrogen atom to the glutathione radical (GS•), which forms during interaction with highly reactive radical species. In water, tested compounds also regenerate GSH by donating H atoms to GS•, as well as by transferring electrons from dominant acid-base species to GS•, followed by protonation of the resulting GS¯. Urolithins showed similar inhibitory effects as the conventional inhibitors Y-700, FYX-051, and Febuxostat on Xanthine Dehydrogenase (XDH). Reactivity towards XDH enzyme decreases in the following order UroC > UroB > UroD > UroA.

Guidelines for descriptor assignments for the solvation parameter model by separation techniques

The solvation parameter model uses six compound descriptors to model equilibrium properties in biphasic systems formally defined as excess molar refraction, E, dipolarity/polarizability, S, overall hydrogen-bond acidity, A, overall hydrogen-bond basicity, B, McGowan's characteristic volume, V, and the gas-liquid partition constant on hexadecane at 25 °C, L. The V descriptor can be assigned from structure and the E descriptor for compounds liquid at 20 °C can be calculated from its refractive index and characteristic volume. The E descriptor for compounds solid at 20 °C and the S, A, B, and L descriptors are assigned from experimental properties traditionally obtained by chromatographic, liquid-liquid partition, and solubility measurements. Here I report an efficient experimental design using the Solver method for the accurate assignment of descriptors for neutral compounds that simultaneously minimizes laboratory resources. This multi-technique approach requires 3 retention factor measurements in a 60 °C temperature range per compound on four columns by gas chromatography, 3 retention factor measurements in a 30 % (v/v) acetonitrile composition range per compound on two columns by reversed-phase liquid chromatography, and eight partition constant measurements by liquid-liquid partition in totally organic and aqueous biphasic systems for a total of 26 experimental measurements. The accuracy of the descriptor assignments was validated by comparison with the values in the Wayne State University (WSU) descriptor database taken as the best estimate of the true descriptor values. The E, S, A, B and L descriptors were assigned simultaneously by the Solver method using the above approach without significant bias and with an average absolute deviation (AAD) of 0.054, 0.018, 0.015, 0.013, and 0.040, respectively, compared with the WSU database values, corresponding to a relative absolute average deviation in percent (RAAD) of 7.2, 1.9, 3.6, 5.1, and 0.84 %, respectively, for 32 varied compounds. This streamlined approach represents a significant improvement on earlier single-technique approaches used as the starting point for the development of the multi-technique approach. For compounds of variable hydrogen-bond basicity modifications to the multi-technique approach were implemented while maintaining the same number of experimental measurements. Acceptable descriptor assignments for B/B° were obtained for compounds liquid at 20 °C for which the E descriptor was available by calculation. For solid compounds at 20 °C the E and B/B° descriptors are restricted to qualitative application where approximate values may be acceptable.

MODELING AND SIMULATION OF POST-COMBUSTION CO 2 CAPTURE PROCESS FOR 6.4 MWE BAGASSE FUELED POWER PLANT

The emission of carbon dioxide, a greenhouse gas, contributes to the phenomenon of climate change; the largest source of carbon dioxide emissions are fossil fuel power plants. Post-combustion carbon capture (PCC) technology, which is based on solvents, is currently the most advanced technology for reducing carbon dioxide emissions from power plants. The Post-combustion Process, which uses conventional solvents, has a number of disadvantages, including high energy consumption for regeneration, solvent losses, corrosion of equipment, thermal instability, and environmental impact. Ionic liquids (ILs) and IL-based solvents have produced a novel method of CO 2 capture that is highly efficient, economical, and environmentally friendly. A rate-based steady-state model of the PCC process using the ionic liquid 1-hexyl-3-methylimidazolium glycine ([Hmim] [Gly]) was investigated using Aspen Plus ®. In Aspen Plus ® Electrolyte NRTL method and RK equation of state are used to compute liquid and vapor properties. From the process analysis carried out, it was found that the height and diameter of the absorber packing, the liquid-to-gas ratio and the solvent and flue gas temperatures have a positive effect on the CO 2 capture efficiency. The result showed a maximum CO 2 capture efficiency of 92% at a packed height of 12m and diameter of 0.9m. The best capture efficiency of 98.82% was achieved at an L/G ratio of 4.0.the process simulation study examined five key parameters for ([Hmim] [Gly]) solvent which may reduce the energy and cost required for CO 2 capture. The results show that aqueous ([Hmim] [Gly]) is a promising absorbent for CO 2 capture. Offering a pathway towards more sustainable and efficient carbon capture technologies. This study contributes to the advancement of carbon capture technologies and underscores their significance in mitigating climate change impacts.

Thermodynamic properties of TPAC-EG deep eutectic solvents: A study based on the IGC method with molecular simulations

The study of thermodynamic properties and intermolecular interactions in deep eutectic solvents (DES) is an important innovative step in the development of DES. This research focuses on the synthesis of DES using a 1:2 M ratio of tetrapropylammonium chloride and ethylene glycol. Inverse gas chromatography (IGC) techniques are used to investigate DES of thermodynamics in the temperature range of 303.15–333.15 K. Additionally, molecular dynamics (MD) simulations and density functional theory (DFT) are used to explore intermolecular interactions in DES at both molecular and atomic levels. The research findings yield crucial insights, including the successful determination of infinite dilution activity coefficients, Flory-Huggin’s interaction parameters, solubility parameters, and Abraham solvation parameters of DES through IGC techniques. A careful study of the temperature-dependent trends in these parameters is provided. Analyses of structural properties, including radial distribution functions, hydrogen bond counts, and thermal fluctuation indices, reveal that, at experiments temperatures, the amount and nature of intermolecular hydrogen bonds in binary mixtures are the main factors influencing the thermodynamic properties of DES. Finally, based on DFT calculations, a quantitative assessment of the molecular interaction mechanisms of DES at the atomic level confirms the predominant role of hydrogen bonding in DES formation, with multicenter hydrogen bonds characterized by stronger hydrogen bond strengths emerging as the primary type.