Dipole-induced Dipole Research Articles

Molecular interactions and structural studies of toluene and (C5 − C10) 1-alkanol; mutual diffusion and virial coefficients

In this study, to obtain useful information about the structure of binary mixtures, identify the governing interactions and investigate the influence of alcohol chain length on the structure and nature of interactions in the binary mixtures of toluene (TOL) with 1-pentanol up to 1-decanol, values of second and third virial coefficients for the above binary mixtures were calculated regarding the Peng-Robinson-Stryjek-Vera (PRSV) cubic equation of state. Estimation of the thermodynamic factor for the binary systems was performed by the COSMO-RS model, and results indicate that the considered mixtures exhibit a positive deviation from the Raoult's Law. Besides, the diffusion coefficients for the binary mixtures in the whole composition range were determined regarding the experimental viscosities. Findings demonstrate that the weak dispersion forces (induced dipole-induced dipole attraction) between TOL and 1-alkanol are the most frequent type of interactions, and change with the alcohol chain length. The collected information from the mentioned parameter has been shown that increasing the alcohol chain length reinforces the strength of intermolecular interactions.

Tutorial for the Characterization of Fatty Acid Methyl Esters by Gas Chromatography with Highly Polar Capillary Columns.

The fatty acid composition of fats and oils is commonly determined by gas chromatography after preparing fatty acid methyl esters (FAME). Capillary columns coated with polyethylene glycol emerged as the preferred separation tool for the quantification of the polyunsaturated fatty acids contained primarily in marine oils. However, their selectivity is inadequate for measuring the trans fatty acids (TFA) contained in refined vegetable oils, dairy fats, and marine oils. Highly polar 100% poly(biscyanopropyl siloxane) capillary columns provide the necessary selectivity, but small differences in the phase polarity caused by column age, conditioning, or manufacturing variations affect the reproducibility of their separations of these complex samples. In this study, a simple procedure is described to compensate for small variations in column selectivity by adjusting the elution temperature. The balance between the dipole-induced dipole interactions and dispersive interactions was determined by measuring selectivity factors [SF(i)] corresponding to the elution of an unsaturated FAME such as 18:3n-3 relative to two saturated FAME such as 20:0 and 22:0. Knowing the SF(i) provided by the installed capillary column at a given elution temperature, and the SF(i) of the target separation, we propose a simple calculation to determine the necessary elution temperature adjustment to achieve (or restore) the desired separation. After determining the SF(i) which provides the optimal separation of TFA, the novel methodology was applied to the separation of refined vegetable oils, butter fats, and marine oils.

Vibrational predissociation in the bending levels of the à state of C3Ar.

Vibrational predissociation (VP) has been observed in 16 bands of the C3Ar van der Waals complex near the 0 v2 0 - 000 (v2 = 2-, 4-, 2+) and 0 2- 2 - 100 bands of the Ã1Π-X̃1Σ+ g system of C3. New higher resolution wavelength-resolved emission (WRE) spectra covering a wider spectral range have been recorded for many of these C3Ar bands, which show that most of the features observed in fluorescence must be reassigned as emission from the C3 fragment. Two types of VP processes have been recognized. The first type gives rise to vibrationally hot C3 fragments, mostly following |Δv| = 1, |ΔP| = 1 propensity rules, where P is the vibronic angular momentum of C3. The second type gives vibrationally cooled fragments. The VP processes can change abruptly from one type to the other with comparatively small differences in vibrational energy. Although the initial states are associated with both orbital components of the C3, Ã1Πu state, most of the VP fragments belong to the lower orbital component. A dipole-induced dipole model has been used to interpret the observed ΔP- propensities. Ab initio calculations of the binding energies of the ground and excited electronic states of C3Ar have been carried out; the calculated values are consistent with estimates of ≤144 cm-1 and 164 cm-1, respectively, given by the WRE spectra.

Separation of saccharides using fullerene-bonded silica monolithic columns via \u03c0 interactions in liquid chromatography

We report on a potential method to separate sugars by using the specific interaction between fullerenes and saccharides in liquid chromatography (LC). Aromatic rings with high electron density are believed to interact strongly with saccharides due to CH–π and/or OH–π interactions. In this study, the fullerene-bonded columns were used to separate saccharides by LC under aqueous conditions. As a result, 2-aminobenzamide-labeled glucose homopolymer (Glcs) was effectively separated by both C60 and C70 columns in the range of Glc-1 to Glc-20 and high blood glucose level being retained in greater quantity. Furthermore, similar separations were identified by LC–mass spectrometry with non-labeled glucose homopolymers. Theoretical study based on molecular dynamics and DFT calculation demonstrated that a supramolecular complex of saccharide–fullerene was formed through CH–π and/or OH–π interactions, and that the interactions between saccharide and fullerene increase with the increase units of the saccharide. Additionally, the C60 column retained disaccharides containing maltose, trehalose, and sucrose. In this case, it was assumed that the retention rates were determined by the difference of the dipole moment in each saccharide. These results suggest that the dipole-induced dipole interaction was dominant, and that maltose—with the higher dipole moment—was more strongly retained compared to other disaccharides having lower dipole moment.

Evaluation of Diffusivity and Wettability of Crude Oil-Contaminated Sand from Offshore Petroleum Facility Prior to Remediation Process

Cleansing of crude oil-contaminated sand is anticipated to rely heavily on the ability of cleaning solution to access the contamination sites and the bonding strength between crude oil and sand. In this research, the actual produced sand sample from an oilfield and reference sand sample taken from a beach were subjected to porosity, permeability, and wettability tests. Results revealed that the particle size of the sands dominated the porosity and permeability outcomes. While the porosity of the reference sand at 46.64% was barely higher than the produced sand, the permeability (in Darcy) of the former exceeded the latter by 10 folds. In wettability and interfacial study, the highest adhesion strengths at the oil-sand interface were calculated according to Young-Dupre equation. The computed values were 58.42 mN/m for the reference sand and 65.88 mN/m for the produced sand, assuming 3-species geometric-mean model from Owen/Wendt theory. The types of intermolecular bonding at the interface were dispersive (London dispersion force from Van der Waals bonding), dipole-induced dipole attraction and mechanical adhesions, justifiable through elementary analysis. All the findings including corroboration from thermogravimetric analysis suggest that relatively higher energy was required to remediate the produced sand from oil reservoir as compared to the reference sand retrieved from shoreline.

The contribution of fatty acids composition of soybean oil on natural and electro-optics polarization

A study of light polarization as a new alternative test of cooking oil quality today provides an advantage in biophysics and other fields. In this research, we determined the relation between polarization and fatty acids composition of soybean oil. The light source was a green pointer laser with λ = 532 nm, and the electro-optics polarization was produced through high DC voltage 0-9 kV across the sample. The results show that natural polarization and electro-optics polarization give different physical meanings in relation to oil fatty acid composition. The natural polarization informed that the increasing polarization was caused by increasing poly-unsaturated acids and saturated acids in asymmetric triglyceride molecules. It was accompanied by the decreasing polarization due to the increasing monounsaturated in symmetric triglyceride molecules. While the electro-optics polarization described that all fatty acids contribute to the increasing polarization due to increased induced dipole from all acids.

Transfer Energetics of Some Nucleobases in Aqueous Protic Ethylene Glycol Mixtures

In this article spectrophotometry is applied to measure the saturated solubility of some nucleobases in aquo-organic solvent mixtures of protic ethylene glycol at five equi-distant temperatures from 288.15 to 308.15 K under experimental pressure, p = 0.1 MPa. Standard Gibbs energies $$[\Delta G_{\text{t}}^{^\circ } (i)]$$ and entropies $$[T\Delta S_{\text{t}}^{^\circ } (i)]$$ of transfer from water to aqueous mixture of protic ethylene glycol have been evaluated at 298.15 K. The chemical contributions of these energetics $$[\Delta G_{\text{t,chem}}^{^\circ } (i)]$$ and $$[T\Delta S_{\text{t,chem}}^{^\circ } (i)]$$ of the involved nucleic acid bases have been computed by subtracting the cavity effect, dipole–dipole and dipole-induced dipole type interaction effects. The chemical composition of transfer energetics of nucleo bases is guided by different effects like dispersion interaction, basicity-acidity, hydrogen bonding, hydrophobic and hydrophilic interaction effects of aqueous ethylene glycol as compared to that of the reference solvent, water. The cavity effect has been estimated by using the Scaled Particle Theory. Computation of dipole–dipole and dipole-induced interactions has been performed using Keesom orientation expressions. The trend of variation of Gibbs energies due to chemical interactions are guided by decreased hydrophobic hydration (HbH), increased acidity and dispersion effects of aqueous ethylene glycol solvent mixtures as compared to the reference solvent, water.

Physico-chemical Studies of Isomeric Butanols in Aniline with m-Xylene

The values of sound velocity, density and viscosity have been measured at 303 K in the ternary systems of aniline + m-xylene + n, sec, tert and iso-butanols. From these data, acoustical parameters such as molar volume, adiabatic compressibility, free length, free volume and internal pressure have been estimated using the standard relations. The results are interpreted in terms of molecular interaction between the components of the mixtures. The presence of weak dipole-induced dipole interactions of larger magnitude is confirmed in the ternary systems. Of all the isomeric butanols, 1-ol, and especially 2-ol are found to be good structure makers that make the ternary complexes. In addition the possible interactions between the components are further confirmed by their excess values.

Elucidation of molecular interactions in the mixtures of 2-methoxyaniline with isomeric xylenes through transport and thermodynamic properties at T = 303.15, 308.15, and 313.15 K

ABSTRACT Experimental values of the density (ρ), speed of sound (u), and viscosity (η) have been measured for binary mixtures of 2-methoxyaniline with toluene, and isomeric xylenes (o-xylene, m-xylene, and p-xylene) at temperatures of 303.15, 308.15, and 313.15 K over the entire mole fraction range. By using this data, the excess parameters (excess molar volumes, excess isentropic compressibility, and viscosity deviation) for the binary systems at the above-mentioned temperatures were calculated and fitted to Redlich–Kister equation to determine the fitting parameters and the root-mean-square deviations. The excess parameters have been analysed in terms of n–π interactions and dipole-induced dipole interaction between unlike molecules.

An Ultrasonic Study on Acoustical and Excess Properties of Ternary Liquid Mixtures of 2-Bromoanisole + 1-Butanol + n-Hexane at Different Temperatures 303K, 308K and 313K and a Frequency 2MHz

The behaviour of liquid mixture of 2-Bromoanisole, 1-Butanol and n-Hexane as a function of temperature and composition has been investigated by measuring ultrasonic velocity in conjunction with density and viscosity at 303K, 308K and 318K for frequency 2 MHz using ultrasonic interferometer. With the help of the measured values ultrasonic velocity (u), viscosity (η) and density (ρ), the acoustical parameters like acoustic impedance, adiabatic compressibility, free length, free volume and internal pressure have been calculated. In order to know the molecular interaction between the components in the ternary liquid mixture, nature and strength of molecular interaction in the components of the ternary mixture, the actual values of acoustical parameters were computed in to their excess properties. Excess ultrasonic velocity (UE), excess acoustic impedance (ZE), excess intermolecular free length (LEf) excess adiabatic compressibility (βE), excess free volume (VfE) and excess internal pressure have been calculated for the ternary liquid mixtures containing 2-bromoanisole, 1-butanol in n-hexane at various temperatures 303K, 308K and 313K at fixed frequency 2MHz, for different concentrations ranges from 0.001M to 0.01M and fitted to the Redlich-Kister polynomial equation. The computed excess values of excess ultrasonic velocity, excess acoustic impedance, excess intermolecular free length, excess adiabatic compressibility, excess free volume and excess internal pressure were plotted against the concentration of ternary liquid of the mixture at different temperatures 303K, 308K and 313K at a fixed frequency of 2MHz. A good agreement has been found between the experimental and calculated values of the ultrasonic velocity. The strength and the nature of the interactions between like and unlike molecules have been discussed in terms of dipole-dipole, dipole-induced dipole, and induced dipole-induced dipole interaction through hydrogen bonding. The present study aims to evolve the impact of ultrasonic sound over the molecular interaction of ternary liquid mixture consisting of 2-bromoanisole, 1-butanol in n-hexane mixture at different temperature 303K, 308K and 313K.

Nanostructured Silver Coating as a Stationary Phase for Capillary Gas Chromatography.

A capillary column coated with nanostructured silver coating was fabricated for gas chromatography. The nanostructured silver coating, about 80–120 nm in thickness, was prepared as the stationary phase via silver mirror reaction, and was characterized by SEM and EDS. The column was evaluated using different types of model analytes, including n-alkanes, n-alcohols, benzenes, and Grob mixture. A baseline separation of ten n-alkanes on the silver column (15 m × 0.20 mm i.d.) was achieved within 3.5 min through the main hydrophobic mechanism. A mixture of six n-alcohols, or another mixture containing three butanol isomers and two octanol isomers, was separated well on the column. The column separated some benzenes containing benzene, toluene, ethylbenzene, p-xylene, o-xylene, styrene, benzaldehyde, and benzyl alcohol. A Grob mixture containing seven analytes was also separated successfully. Based on a multiple retention mechanism such as hydrophobic, dipole-dipole, and dipole-induced dipole interactions, the silver column achieved a good separation of twelve different types of compounds within 2.5 min. The column presented satisfactory separation repeatability with relative standard deviation of retention time between 0.073% and 0.591%. The results indicate that the silver column is promising for gas chromatographic separation.

Non-covalent interactions in organic-inorganic hybrid compounds derived from amino amides

Abstract Here, we report the synthesis of six organic-inorganic hybrid compounds from amino amides and tetrachlorozincate anions to study the processes underlying the modulation of hydrogen bonds and π∙∙∙π interactions in these salts. Thus, 2-((2-ammoniopropanamido)-methyl)-1H-benzimidazole-3-ium tetrachlorozincate 7, 2-(1-(2-ammoniopropanamido)-ethyl)-1H-benzimidazole-3-ium tetrachlorozincate 8, 2-((2-ammonio-3-methylbutanamido)methyl)-1H-benzimidazole-3-ium tetrachlorozincate 9, 2-(1-(2-ammonio-3-methylbutanamido)-2-methylpropyl)-1H-benzimidazole-3-ium tetrachlorozincate 10, 2-((2-ammonio-4-methylpentanamido)methyl)-1H-benzimidazole-3-ium tetrachlorozincate 11, and 2-(1-(2-ammonio-4-methylpentanamido)-3-methylbutyl)-1H-benzimidazoel-3-ium tetrachlorozincate 12 were obtained from the corresponding hydrochlorides (1–6). Crystallographic experiments using compounds 7–12 revealed that the presence of bulky substituents situated on C10 and C13 reduces the efficacy of stacking phenomena. Moreover, the ZnCl42− ∙∙∙H–N hydrogen bonds induce the polarization of the imidazole ring and the π∙∙∙π interactions occur through the “dipole-induced dipole” mechanism. In the case of N–H∙∙∙solvent interactions, the stacking phenomena occur preferentially through the “induced dipole-induced dipole” mechanism.

A “Dipole–Induced Dipole” Quantum Model and the Effect of an Inert Environment on the Intensity of Infrared Absorption

A theory of the imaginary part of isotropic polarizability induced by dipole–dipole interactions between isotropically polarizable particles has been developed on the basis of diagram technique. A classification of single infrared resonances corresponding to the cases of allowed absorption and absorption induced by intermolecular interactions has been proposed. A summation of the diagram contributions describing the change in the intensity of the allowed absorption due to the effect of the reaction field of the environment has been carried out for the dipole–induced dipole (DID) scheme. The strict results obtained in such a way contradict the Onsager–Bettcher model, which is semiempirical. The numerical estimates show that the role of the reaction field in the observed changes in the intensity of the vibrational bands of the simplest model systems (HCl and HBr in inert solvents) is small and decreases with increasing solvent particle size, which indicates the inadequacy of the DID and Onsager–Bettcher models to the experimental data.

Mode of hydrophilic and hydrophobic interactions of DL-Tyrosine, DL-Leucine, DL-Isoleucine and DL-Threonine in aqueous binary mixture of dipolar aprotic acetonitrile

The saturated solubilities of DL- Tyrosine, DL-Leucine, DL-Isoleucine and DL-Threonine in binary aqueous dipolar aprotic acetonitrile solvent were estimated by ‘formol titrimetry’ at nine equidistant temperatures under 0.1 MPa pressure. The chemical effects of the standard transfer energetics of these amino acids obtained after elimination of cavity forming, dipole-dipole and dipole-induced dipole interaction effect from the total, are useful to know about chemical stability of it in such system and solvent-solvent interaction therein. Hydrophobic and hydrophilic interactions of standard transfer Gibbs free energies and entropies, as obtained after subtraction of dispersion from chemical interaction are guided by the attached side chains.

Structural Manifestations of the Polarizability Effect in 1-Halogensilatranes According to the Dipole-Induced Dipole Mechanism

A new mechanism of the dipole-induced dipole polarizability effect by the example of Open image in new window 1-halogensilatranes is proposed. The mechanism involves a through-space interaction between the dipole moment μ of the core and the dipole Δμ which is induced on the halogen and, in turn, induces an extra dipole ΔΔμ on the transannular bond Si ← N to make it stronger. This effect explains for the first time the previously discovered contradiction for 1-halogensilatranes where an inverse dependence in the linear correlations between the Si ← N bond length, δ15N, δ1H(CH2N) chemical shifts, and the inductive constant σ are observed. For example, the length of the Si ← N coordination bond is shorter in 1-chlorosilatranе than in 1-fluorosilatrane due to the fact that the polarizability effect is stronger than the inductive effect in the case of the Cl atom.

Molecular Interaction Studies in Ternary Liquid Mixtures Containing 2-Nitroanisole and 1- Pentanol in n- Hexane at Different Temperatures using Ultrasonic Techniques

The experimental values of ultrasonic velocity, density and viscosity have been measured for the ternary liquid mixtures containing 2-Nitroanisole and 1-Pentanol in n-Hexane at 303,308 and 313K. To calculate various acoustical parameters like adiabatic compressibility, free volume, internal pressure, acoustical impedance, adsorption co-efficient and molecular interaction parameters have been computed using the experimental data. The linearity of variation in ultrasonic velocity and other parameters are due to the molecular interaction between donor acceptor molecules in liquid-liquid mixture. The various molecular interactions like dipole-dipole, dipole-induced dipole, induced-induced dipole have been discussed for the liquid mixture containing 2-Nitroanisone, 1-Pentanol in n-Hexane at different temperatures and concentration.

A PC-SAFT model for hydrocarbons III: Phantom dipole representation of dipole induced dipole interactions in unsaturated hydrocarbons

Inclusion of polar contributions into the statistical associating fluid theory class of equations of state has been demonstrated to allow for the accurate prediction of solution non-idealities of mixtures composed of paraffins and polar molecules. However, as we demonstrate in this paper, these theories necessarily overpredict the non-idealities in mixtures composed of polar molecules with unsaturated hydrocarbons. The reason for this is that the dipole moment of the polar molecule polarizes the unsaturated bond resulting in a significant dipole-induced dipole attraction. We develop a simple, general and predictive methodology to incorporate this missing physics into the dipolar contribution to the theory. The new approach is shown to accurately predict the phase behavior of unsaturated hydrocarbons with polar molecules.

Comparison of interatomic potential models on the molecular dynamics simulation of fast-ion conductors: A case study of a Li garnet oxide Li7La3Zr2O12

In this work, we performed molecular dynamic simulations of a representative fast-ion conductor (Li7La3Zr2O12) using three different interatomic potential models: non-polarizable core (Core), polarizable core–shell (CS), and induced dipole (ID). To compare these three models, we calculated the phase transition behavior, self-diffusivity, ionic conductivity, dielectric constant, and elastic moduli of Li7La3Zr2O12 and checked results against experimental and other simulation work. We found that overall all three potential models predict results that agree reasonably well with experiments and first-principles calculations. However, we think that the ID model that combines both force-matching, atomic polarization, and first-principles charge has the technical advantage over the other two, while exhibiting slightly higher computational cost. We also discussed ways to further improve these interatomic potential models.

Ethyl Carbazole-Grafted Polysiloxane as Stationary Phase for Gas Chromatography

In this work, we synthesized ethyl carbazole-grafted polysiloxanes, namely, ECP-9 and ECP-18, which possessed ethyl carbazole contents of 9% and 18%, respectively. The results of thermogravimetric analysis showed that ECP-9 and ECP-18 polymers lost 2% of weight at 365 °C and 380 °C. The minimum allowable operating temperature for the ECP-9 and ECP-18 was 40 °C. In addition, the ECP-9 and ECP-18 columns were thermally stable at 340 °C and 360 °C. The column average efficiencies of ECP-9 were 2306–3090 plates m−1 for a 10 m column and 2594–3438 plates m−1 for a 30 m column. The column efficiencies of ECP-18 were 2497–3428 plates m−1 for a 10 m column and 2829–3700 plates m−1 for a 30 m column. ECP-9 and ECP-18 as stationary phases exhibited moderate polarity based on the McReynolds constants. Given its specific dipole–dipole, dipole-induced dipole, π–π stacking interactions, and hydrogen bond force with solutes, the ECP stationary phases achieved excellent separation for aromatic isomers, substituted benzenes, polycyclic aromatic mixtures, polycyclic aromatic hydrocarbons, and fatty acid esters with satisfactory peak shapes.

Квантовая модель диполь-индуцированный диполь и влияние инертного окружения на интенсивность ИК поглощения

Based on the diagrammatic techniques, a theory of the imaginary part of the isotropic polarizability induced by the dipole-dipole interactions between isotropically polarizable particles is elaborated. A classification of single infrared resonances corresponding to cases of the allowed and interaction-induced absorption bands is proposed. The Dipole-Induced-Dipole (DID) diagrammatic terms causing the allowed intensity variations via the reaction-field effect are analytically summed up. The thus-derived rigorous results are in conflict with the semi-empirical Onsager-Bottcher model. For the simplest reference systems (cryogenic solutions of HCl and HBr), our numerical estimations demonstrate the reaction-field contributions to observed intensity variations of vibrational bands to be weak and to become even weaker with a growth of the solvent particle dimensions that suggests the inadequacy of the DID and Onsager-Bottcher models to experimental data.