Solvent Parameters Research Articles

Retention properties of acetone-water mobile phases on a biphenylsiloxane-bonded silica stationary phase in reversed-phase liquid chromatography.

The solvation parameter model system constants and retention factors were used to interpret retention properties of 39 calibration compounds on a biphenylsiloxane-bonded stationary phase (Kinetex biphenyl) for acetone-water binary mobile phase systems containing 30-70% v/v. Variation in system constants, phase ratios, and retention factors of acetone-water binary mobile phases systems were compared with more commonly used acetonitrile and methanol mobile phase systems. Retention properties of acetone mobile phases on a Kinetex biphenyl column were more similar to that of acetonitrile than methanol mobile phases except with respect to selectivity equivalency. Importantly, selectivity differences arising between acetone and acetonitrile systems (the lower hydrogen-bond basicity of acetone-water mobile phases and differences in hydrogen-bond acidity, cavity formation and dispersion interactions) could be exploited in reversed-phase liquid chromatography method development on a Kinetex biphenyl stationary phase.

Reply to “comment for ‘Measurement and correlation of solubility of 2-chloro-3-(trifluoromethyl)pyridine in pure solvents and ethanol + n-propanol mixtures’”

Zhao and co-author made a valuable comment for wang’ paper. In the comment, ξ should be the volume fraction for Hildebrand solubility parameters, not the mole fraction. The aim of the reply was to revise the mistake. The revised results were listed in the reply.

Mixed Solvents in Multilayer Ceramic Capacitors (MLCC) Electronic Paste and Their Effects on the Properties of Organic Vehicle.

The copper end paste used in multilayer ceramic capacitors sintered in nitrogen atmosphere leads to carbon residues of organic vehicles, which leads to a reduction in electrode conductivity and high scrap rate. With an attempt to leave no residue in the sintering, the compatibility of solvents and thickeners should be improved because it has an important influence on the hierarchical volatilization and carbon residue of organic vehicles. In this work, the volatility of different solvents was compared, and several solvents were mixed in a definite proportion to prepare an organic vehicle with polyacrylate resins. The hierarchical volatility and solubility parameters of mixed solvents were effectively adjusted by changing proportions of different components. The thermogravimetric curves of resins and organic vehicles were measured by thermogravimetric analyzer, and the effect of solubility parameter on the dissolvability of resins in the solvent and the residual of organic vehicles were studied. Results showed that the hierarchical volatilization of solvents can be obtained by mixing different solvents; the intrinsic viscosity of the organic vehicle is higher, and the thermal decomposition residue of polyacrylate resins is lower when the solubility parameters of mixed solvents and polyacrylate resins are closer. The low residual sintering of organic vehicles can be achieved by using a mixed solvent with hierarchical volatility and approximate solubility parameters as resins.

Predicting the Drug Clearance Pathway with Structural Descriptors.

The clearance, by renal elimination or hepatic metabolism, is one of the most important pharmacokinetic parameters of a drug. It allows the half-life, bioavailability, and drug-drug interactions to be predicted, and it can also affect the dose regimen of a drug. Predicting the clearance pathways of new chemical candidates during drug development is vital in order to minimize the risks of possible side effects and drug interactions. Many in vivo methods have been established to predict drug clearance in humans, and these mainly rely on data from in vivo studies in preclinical species-mainly rats, dogs, and monkeys. They are also time consuming and expensive. The aim of this study was to find the relationship between structural parameters of drugs and their clearance pathways. The clearance pathway of each drug was obtained from the literature. Various structural descriptors [Abraham solvation parameters, topological polar surface area, numbers of hydrogen-bond donors and acceptors, number of rotatable bonds, molecular weight, logarithm of the partition coefficient (logP), and logarithm of the distribution coefficient at pH7.4 (logD7.4)] were applied to develop a mechanistic model for predicting clearance pathways. The results of this study indicate that compounds with logD7.4>1 or with zero or one hydrogen-bond donor undergo hepatic metabolism, whereas the clearance pathway for chemicals with logD7.4 < - 2 is renal elimination. Furthermore, models established using logistic regression based on five structural parameters for compounds with - 2 < logD7.4 < 1 could be used in a clearance pathway prediction tool. The overall prediction accuracies of the first and second models were 84.8% and 84.4%, respectively. The developed model can be used to find the clearance pathways of new drug candidates with acceptable accuracy. The main descriptors that are used to evaluate this parameter are the hydrophobicity and the number of hydrogen-bonding functional groups of the compound.

Extended Hildebrand solubility approach and Yalkowsky-Roseman model for estimating the solubility of sulfadiazine and sulfamethazine in some {ethylene glycol (1) + water (2)} mixtures at several temperatures

Aim: extended Hildebrand Solubility Approach (EHSA) and Yalkowsky Roseman (YR) were applied to evaluate the solubility of sulfadiazine, and sulfamethazine in ethylene glycol + water mixtures. Methodology: reported experimental equilibrium solubilities and some fusion properties of these drugs were used for the calculations.Results: a good predictive character of EHSA (with mean deviations lower than 3.0%) were found by using regular polynomials in order two correlating the inter-action parameter W with the Hildebrand solubility parameter of solvent mixtures without drug ; however, the results obtained from YR model show relatively high deviations greater than 50%.

Improvement of theoretical UV–Vis spectra calculations by empirical solvatochromic parameters: Case study of 5-arylazo-3-cyano-1-ethyl-6-hydroxy-4-methyl-2-pyridones

In order to improve the performance of theoretical UV–Vis spectra predictions, a theoretical and experimental study of solvatochromic properties of ten azo pyridone dyes has been performed. For quantitative estimation of intermolecular solvent–solute interactions, a concept of the linear solvation energy relationships has been applied using Kamlet-Taft and Catalán models. Theoretical UV–Vis spectra for all dyes have been calculated using four TD-DFT methods in nine different solvents with the aim to define the most reliable model. Finally, new polylinear equations for more accurate theoretical prediction of UV–Vis maxima are developed using empirical Kamlet-Taft and Catalán solvent parameters as additive corrections for specific and nonspecific solvent–solute interactions.

Machine Learning-Enabled Prediction and High-Throughput Screening of Polymer Membranes for Pervaporation Separation.

Pervaporation (PV) is considered as a robust membrane-based separation technology for liquid mixtures. However, the development of PV membranes is impeded largely by the lack of adequate models capable of reliably predicting the performance of PV membranes. In this study, we collect an experimental data set with a total of 681 data samples including 16 polymers and 6 organic solvents for a wide variety of water/organic mixtures under various operating conditions. Then, two types of machine learning (ML) models are developed for prediction and high-throughput screening of polymer membranes for PV separation. Based on the intrinsic properties of polymer and solvent (water contact angle of polymer and solubility parameter of solvent) as gross descriptors, the first type accurately predicts PV separation performance (total flux and separation factor). The second type is based on the molecular representation of polymer and solvent, giving accuracy comparable to the first type, and applied to screen ∼1 million hypothetical polymers for PV separation of water/ethanol mixtures. With a threshold of 700 for the PV separation index, 20 polymers are shortlisted, with many surpassing experimental samples. Among these, 10 are further identified to be synthesizable in terms of a synthetic complexity score. The ML models developed in this study would facilitate the optimization of operating conditions and accelerate the development of new polymer membranes for high-performance PV separation.

A green extrusion-based 3D printing of hierarchically porous aluminum

Additive manufacturing (AM) of porous Al via laser-assisted techniques is limited by the intrinsic high reflectivity of the laser and high oxidation propensity of Al. Herein, a green extrusion-based three-dimensional (3D) printing method was proposed for the fabrication of Al structures, whereby, hierarchical porosity is generated via solvent evaporation, starch removal, and parameter optimization. The process comprises slurry preparation, 3D printing and thermal post-treatment. The feasibility of the procedure and the effect of starch addition on the porous Al microstructure were investigated. An ethyl alcohol-based slurry exhibiting appropriate shear thinning behavior with sufficient yield stress was utilized for the extrusion-based 3D printing, and slurry filaments could be extruded smoothly and unyieldingly deposited by adjusting the nozzle diameter, applied air pressure, and printing speed. Furthermore, hierarchically porous Al structures were obtained following sintering, demonstrating that the proposed extrusion-based 3D printing method is suitable for direct AM of Al structures.

Effect of shape and nano-segregation in Δ2-isoxazoline and isoxazole on the mesogenic behavior of 1,3-bis-isophthalimines

ABSTRACT Bis-1,3-isophthalimines flanked by two side 3-aryl-5-perfluoroalkylisoxazoline or 3-aryl-5-perfluoroalkylisoxazol arms were produced and liquid crystal properties were analysed. Monotropic smectic A mesophase was found for bis-1,3-isophthalimines containing the 3-aryl-5-perfluorooctylisoxazoline (8b). Thermal behaviour was analysed and discussed by DSC, POM, DFT calculations, cohesive energy density (CED), Hildebrand solubility parameters and molecular-shape features. Notably, for long side arm perfluorooctyl 8b, the reduced value of CED is partially compensated by molecular shape of the molecules in the condensed state favouring the SmA mesophase formation.

Photochemistry of para substituted benzanilides in solution: Preparative and mechanistic studies.

Preparative and mechanistic studies on the photochemical reaction of a series of p-substituted benzanilides in polar and nonpolar solvents have been carried out. The aim of this work is mainly focused to show whether the reaction solvent and the electronic effects of the substituents affect the product distribution, the chemical yields and the rate of formation of the 5-substituted-2-aminobenzophenone derivatives. Application of the Hammett linear free energy relationship (LFER) on the rate of formation of 2-aminobenzophenone derivatives, on the lower energy band of the UV-visible absorption spectra of the benzanilides and 5-substituted-2-aminobenzophenone derivatives allows a satisfactory quantification of the substituent effects. Furthermore, the solvent effect was also analyzed on the photoreaction by means of the Reichardt's solvent parameter (ET(30). Finally, (TD-) DFT calculations have been carried out to support the trends observed experimentally.

Application of Pressurized Liquid Extractions to Obtain Bioactive Compounds from Tuber aestivum and Terfezia claveryi

A PLE (pressurized liquid extraction) method was adjusted following a full-factorial experimental design to obtain bioactive-enriched fractions from Tuber aestivum and Terfezia claveryi. Temperature, time and solvent (water, ethanol and ethanol–water 1:1) parameters were investigated. The response variables investigated were: obtained yield and the levels of total carbohydrate (compounds, β-glucans, chitin, proteins, phenolic compounds and sterols). Principal component analysis indicated water solvent and high temperatures as more adequate parameters to extract polysaccharide-rich fractions (up to 68% of content), whereas ethanol was more suitable to extract fungal sterols (up to 12.5% of content). The fractions obtained at optimal conditions (16.7 MPa, 180 °C, 30 min) were able to protect Caco2 cells from free radical exposure, acting as antioxidants, and were able to reduce secretion of pro-inflammatory cytokines in vitro: IL-6 (50%), and TNFα (80% only T. claveryi ethanol extract), as well as reduce high inhibitory activity (T. aestivum IC50: 9.44 mG/mL).

Preferential solvation study of (Z)-N-benzyl-2-{5-(4-hydroxybenzylidene)-2,4-dioxothiazolidin-3-yl)acetamide (3) in {NMP + Water } co-solvent mixture and GastroPlus software based in vitro simulation

(Z)-N-benzyl-2-{5-(4-hydroxybenzylidene)-2,4-dioxothiazolidin-3-yl)acetamide (3) (SE11) is a newly synthesized benzylidine thiazolidinedione to inhibit aldose reductase (AR) to control Diabetes Mellitus (DM) and related complications. This reported compound exhibits poor water solubility and based on Hansen solubility parameter (HSP) considerations NMP (N-methyl-2-pyrrolidone) is expected to be a suitable co-solvent. SE11 was soluble in various ratios of (NMP + water) mixture at 298.15 K. Moreover, preferential-solvation (PS) of SE11 by the mixed components was investigated (thermodynamic functional parameters and Kirkwood-Buff integrals) followed by in-vitro dissolution, and simulation (GastroPlus) of dissolution data for the best fit of Weibull model. Hansen solubility parameters (HSP) analysis suggested NMP as the most relevant solvent for SE11 solubility at 298 K and predicted physicochemical properties. In PS, the molar-volume (214.0 cm3·mol−1), Hildebrand solubility parameter (31.11 MPa1/2), and molecular-radius (0.44 nm) of SE11 were calculated. The inverse Kirkwood-Buff integral computational analysis showed that the PS of SE11 through NMP was found in all explored ratios. The highest value (δx1,3 = 0.67 × 10–2) of PS was obtained at x1 = 0.60–0.65 in NMP. Finally, the GastroPlus software simulated in vitro dissolution profile and the impact of shape factor on release behaviour followed by computational assessment. Hence, the explored binary mixture can be used as a suitable approach to treat systemic DM.

The remarkable role of hydrogen bond, halogen, and solvent effect on self-healing supramolecular gel

Self-healing supramolecular gels of low-molecular-weight (LMW) molecules are smart soft materials; however, the development of self-healing LMW gelator is still a challenging task because of the lack of in-depth studies about self-healing mechanisms of LMW gels and the solvent effect on gel properties. Therefore, herein a different perspective was used to study a family of D-gluconic acetal-based gelators with variable structural fragments in 14 different solvents, and a more detailed understanding of self-assembly and self-healing mechanism of supramolecular gels was attained. Based on the critical gelation concentration, phase transition temperature, and rheological data, A8 bearing an amide group in side chain and two chlorine atoms linked to benzene ring was found to be an outstanding gelator, which could form gels with good self-healing ability in a variety of solvents. Interestingly, A8 gel formed in n-BuOH demonstrates high transparency, good mechanical strength, self-supporting behavior, and great self-healing ability from mechanical damage. Based on the Fourier transform infrared spectroscopy, nuclear magnetic resonance spectroscopy, X-ray photoelectron spectroscopy, X-ray diffraction, and theoretical calculation analysis, the self-assembly and self-healing mechanisms of A8 gel were proposed, indicating that a combination of hydrogen bonding and halogen effect was responsible for the efficient self-healing behavior of supramolecular gel. Furthermore, the analysis of solvent parameters indicated that the dispersion force of solvent favored gelators to self-assemble, hydrogen bonding donor ability of solvent mainly affected the formation of one-dimensional assembly, and hydrogen bonding receptor ability and polarity of solvent mainly influenced the supramolecular interactions among assemblies, significantly intervening the self-healing ability of gels. Overall, this study provides a new perspective to the understanding of gelator structure–property correlation in solvents and sheds light for future development of self-healing supramolecular gels.

Investigation on co-solvency, solvent effect, Hansen solubility parameter and preferential solvation of fenbufen dissolution and models correlation

The solubility behavior as a significant molecular property in pharmaceuticals development is challenging in modern pharmaceutical industry. The high quality solubility is advantageous to crystal forms optimization, dosage forms design and product purification. In this work, the saturated solubility of fenbufen in 2-butanone, acetone, ethyl acetate, 1-propanol, 2-propanol, 1-butanol, methanol, ethanol, acetonitrile, water, cyclohexane, toluene and two mixtures (ethanol + water and acetone + water) at region of 278.15 K-318.15 K was measured by employing isothermal saturation method. The preferential solvation investigation, solvent effect analysis, Hansen solubility parameters discussion, models correlation and thermodynamics properties were explored. The molarity solubility of fenbufen present as a positive relation with temperature and enhance as the rise of temperature with a different rate of increase in different solvents. In view of mono-solvent systems, the tendency of molarity solubility was as 2-butanone > acetone > ethyl acetate > 1-butanol > 1-propanol > ethanol > methanol > 2-propanol > acetonitrile > toluene > water > cyclohexane. Solvent effect was analyzed by KAT-LSER model which indicated that the solute–solvent interactions came into prominence in solubility of fenbufen. In addition, the Hansen solubility parameter (HSP) was employed to discuss the dissolution ability of solvents to fenbufen. In view of mixtures systems, the co-solvency phenomenon appeared in acetone + water systems. The solubility of fenbufen in mixtures could be explained in depth by HSP. Moreover, the preferential solvation of fenbufen was investigated by IKBI method. The positive preferential solvation parameters (δx1,3) occurred at 0.24 < x1 < 1 for ethanol (1) + water (2) mixtures and 0.20 < x1 < 0.70 for acetone (1) + water (2) which indicated that ethanol/acetone solvated fenbufen preferentially. In other regions, the δx1,3 values were negative which indicated that water solvated fenbufen preferentially. What’s more, fenbufen solubility data was correlated by four famous models (Apelblat, Wilson, Jouyban-Acree and Apelblat-Jouyban-Acree models). The maximum relative average deviation (RAD) and root-mean-square deviation (RMSD) values were 1.99% and 3.35 × 10-4 for mono-solvents systems, 1.91% and 1.30 × 10-4 for mixtures systems, respectively. Finally, all positive values of these thermodynamics properties illustrated that the dissolution of fenbufen was an entropy increment and endothermic process.

Thermodynamic properties of N-octyl pyridinium hexafluorophosphate ionic liquid: Characterization and application in separation of the azeotrope

The experimental data of the weight fraction activity coefficient (Ω12∞), the Flory–Huggins interaction parameter (χ12∞), the activity coefficient at infinite dilution (γ12∞) and the Hildebrand solubility parameters (δ2) involving N-octyl pyridinium hexafluorophosphate ([OPY][PF6]) ionic liquid (IL) have been evaluated by Inverse gas chromatography (IGC). The values indicated the interaction of solvents-IL depended on the structure of the solvents and the experimental temperatures. Based on IGC data, the isothermal vapor–liquid equilibrium (VLE) data of solvent-IL at 343.15 K were derived and related to the NRTL model. The acquired binary interaction parameters have a great significance in order to model. The equilibrium phase diagram of the [OPY][PF6]-acetone/chloroform–methanol ternary system was obtained by Aspen Plus simulation. The result showed that the IL can be used as a potential solvent for separating azeotropic mixtures of chloroform (1)/methanol (2) and acetone (1)/methanol (2).

Measurement and correlation of the solubility of kojic acid in pure and binary solvents

The solubility of kojic acid in seven pure solvents (isopropanol, n-butanol, 2-butanol, n-pentanol, acetonitrile, methyl acetate, THF) and two binary solvents (2-methoxyethanol + water, 2-ethoxyethanol + water) were determined from 278.15 K to 323.15 K under 101.3 kPa by the gravimetric method. Besides, the modified Apelblat equation, λh model, van't Hoff model, NRTL model, Wilson model and UNIQUAC model were selected to correlate the experimental data in pure solvents, and the modified Apelblat equation, λh model, van't Hoff model, NRTL model, CNIBS/R-K model and the modified Apelblat-Jouyban-Acree model were applied for binary solvents. The results indicated that in this work the modified Apelblat model had the highest accuracy among those semi-empirical models, while UNIQUAC model was the most representative local component model with the best fitting effect among all models. The solubility of kojic acid in all the tested pure and binary solvent systems monotonously increased with increasing of the temperature. Under the isothermal condition, the solubility value of kojic acid increased first and then decreased with the increase of the mass fraction of 2-methoxyethanol and 2-ethoxyethanol, and reached the maximum value when the mass fraction of 2-methoxyethanol and 2-ethoxyethanol were 0.9 and 0.7, respectively. The solubility parameters of solvents were determined by the improved mixing rule. According to the solubility parameters obtained, the co-solvency in the binary solvent mixtures can be explained. To further explain the observed phenomena, the molecular electrostatic potential surface (MEPS), Hirshfeld surface analysis (HS) and KAT-LSER model were applied. Furthermore, the standard thermodynamic properties of the mixtures, including Gibbs energy, entropy and enthalpy were calculated and discussed, which indicated that the dissolution of the kojic acid in all solvents was spontaneous and entropy-driven. The conductor-like screening model for real solvents (COSMO-RS) was also applied to calculate solvation free energy of kojic acid in the studied solvents. The results showed a reasonable explanation to the dissolution behavior of kojic acid.

Preferential Solvation Study of the Synthesized Aldose Reductase Inhibitor (SE415) in the {PEG 400 (1) + Water (2)} Cosolvent Mixture and GastroPlus-Based Prediction.

(Z)-N-Benzyl-2-{2,4-dioxo-5-(4-prop-2-yl-1-yloxyl)benzylidene)thiazolin-3-yl)}acetamide (SE415) is a novel aldose reductase inhibitor used in the management of diabetes mellitus (DM) and associated complications. Herein, the drug was solubilized (mole fraction solubility) in a “PEG 400 (polyethylene glycol 400) + water” mixture of various ratios at 298.15 K. We reported the preferential solvation of SE415 by PEG 400 using Kirkwood–Buff integrals, the thermodynamic functional parameter, in vitro dissolution, and GastroPlus-based predictions for in vivo performance. The result of Hansen solubility parameter analysis suggested PEG 400 as a suitable solvent for SE415 solubilization at 298.0 K, followed by prediction of several physicochemical properties. In the preferential solvation study, the molar volume, Hildebrand solubility parameters, and the molecular radius of SE415 were estimated as 258.4 cm3·mol–1, 27.62 MPa1/2, and 0.468 nm, respectively, using Fedors’ method. The inverse Kirkwood-Buff integrals indicated that the preferential solvation of SE415 by PEG 400 occurred in all studied ratios of the (PEG 400 + water) mixtures. The maximum value (δx1,3 = 1.21 × 10–2) of the preferential solvation of SE415 by PEG 400 was achieved at x1 = 0.15. Then, using GastroPlus software, the maximum dissolution, improved in vivo oral absorption, and high regional compartmental absorption (total 99.0%) of SE415 in humans were predicted. Finally, the solubility data were correlated/predicted using various cosolvency models with satisfactory results. Thus, the binary cosolvent system can be a promising approach for enhanced oral absorption in controlling DM and associated complications in humans.

Oxidation of the N,N–dimethylaniline by peroxynonanic acid in organic solvents

The rate of oxidation reaction of the N,N–dimethylaniline with peroxynonanic acid in various organic solvents was studied. It has been found the effective rate constants ( k ) and the activation energy ( E akt ) of the studied process. Between the parameters of the transition state Δ Н ≠ and Δ Ѕ ≠ is some linear relationship, indicating the presence of the compensation effect in our series of experiments. The rate of oxidation and activation energy inflation of solvation peroxyacid and N,N–dimethylaniline. The reaction medium affects the rate of oxidation. Correlation equations between the rate constants of the reactions in the study and the physic-chemical parameters of the solvents were proposed. The correlation equation for effective rate constants and the basic physic-chemical parameters of solvents at 313 K has the form: lgk = 5 . 0118 – ( 8 . 8 421 ± 0.00 08 )f(n) + (0. 8624 ± 0.0001)f( ε ) – (0.003 9 ± 0.0000)B – (0.03 68 ± 0.0000)E T + (0.00 36 ± 0.0000) δ 2 – (0.00 32 ± 0.0000)V M . N =7; R =1.0; S =0.000; F =10.8537. The polarizability, basicity (B), E T , V M and δ 2 of solvent have effect on the oxidation process. Correlation equations for effective rate constants for other temperatures are similar. The correlation equation for effective energies of activation ( E akt ) and the basic physicochemical parameters of solvents has the form: l g Е а kt = 0 . 8844 + (0.0008 ± 0.0003) B + (0.0142 ± 0.0031) E T . N =7; R =0.9592; S =0.0409; F =86.3553. The basicity ( B ) and E T parameters of solvent have an effect on the energy of the activation process. The proposed correlation equations relate the parameters of the transition state of the oxidation process and the physic-chemical parameters of solvents. Keywords: N,N–dimethylaniline, oxidation reaction, peroxynonanic acid, rate constant, activation energy, correlation equation.

EFFECT OF THE H2O-EtOH AND H2O-DMSO SOLVENTS ON THE γ-CYCLODEXTRIN SOLVATION

Cyclodextrins are cyclic molecules that consist of D-glucopyranose units connected by α-1,4 glycoside bonds. Cyclodextrins are already used in the composition of drugs to increase the solubility of active substances and are ever more in demand in technologies for the development of new hybrid materials for various industrial processes. A structural feature of cyclodextrins is the presence of a hydrophobic cavity capable of including hydrophobic molecules with the formation of molecular complexes both in solution and in the solid phase. Thermodynamic parameters of cyclodextrin solvation are necessary for the scientific selection of the solvent and prediction of the reactivity of cyclodextrins for carrying out processes with the greatest efficiency. In this regard, in this work, distribution coefficients of γ-cyclodextrin were determined by the method of distribution of the substance between two immiscible phases with a water-dimethyl sulfoxide (water-ethanol) solvent of variable composition and n-hexane and the changes in the Gibbs energy of re-solvation were calculated. The distribution coefficient of γ-CD in mixed solvents is higher than in water. The change in the Gibbs energy during the transfer of γ-CD from water to its mixture with dimethyl sulfoxide and ethanol indicates a weakening of the macrocycle solvation. A comparative analysis of the effect of H2O-EtOH and H2O-DMSO solvents on changes in the solvated state of β-cyclodextrin, hydroxypropyl-β-cyclodextrin, and γ-cyclodextrin was carried out. It was assumed that the changes in the solvated state of cyclodextrins have a major effect on the stability of molecular complexes of cyclodextrins with flavonoids rutin and quercetin in aqueous-ethanol media.

Rational synthesis of polymer coated inorganic nanoparticles-MWCNT hybrids via solvophobic effects

The efficient synthesis of inorganic nanoparticle-carbon nanotube hybrids requires the development of models and synthetic guidelines that can be used to maximise the interactions between both nanomaterials. Herein we report the application of the Hansen surface energy based solubility parameter theory as a model for the selection of solvents that can maximise the interactions between iron oxide nanoparticles and MWCNTs. To achieve this, we synthesized iron oxide nanoparticle-MWCNT hybrid materials in three different solvents and characterized their composition with TGA. The solvent was found to have a significant impact in the final amount of iron oxide composition of the hybrids. The Hansen surface energy based solubility parameters of MWCNTs were characterized via inverse gas chromatography and were used to evaluate the interactions between the MWCNTs and the solvent media. Under this model we expected that large differences between the Hansen surface energy based solubility parameters of solvents and MWCNTs would be correlated with larger incorporation of iron oxide nanoparticles in the hybrids. The amount of iron oxide nanoparticles found in the hybrids were indeed consistent with the predictions of the Hansen surface energy based solubility parameter theory making it a powerful tool for the design of nanoparticle-carbon nanotube hybrids.