Solvation in Pure and Mixed Solvents: Some Recent Developments

Seoud, Omar A. El

doi:10.1002/chin.200742279

Cited by 9 publications

(24 citation statements)

References 25 publications

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“…As shown, the dependence of all parameters on E-DS are best described by polynomials, of the fifth power for E T (33), a, and p*, and the fourth power for b. As discussed in detail elsewhere (El Seoud 2007, 2009, the non-linear dependence of E T (33), and presumably of the other solvatochromic parameters, on E-DS (EtAc) is a consequence of the preferential solvation of WB by some component of the mixture. Because the E T (33) curve bungles upward, the preferential solvation is by ethanol, the solvent of higher polarity and relative permittivity, e r .…”

Section: Solvatochromism In the Model Systemsmentioning

confidence: 95%

“…Briefly, we consider that a mixture of water (W) and a miscible organic solvent (S) is made of these precursors plus the ''complex solvent'' or hydrogen-bonded species (S-W). This model has been successfully applied to mixtures of water plus protic or aprotic solvents, and ionic liquids (El Seoud 2007, 2009Sato et al 2010), but not for the present case (alcohol/ aprotic solvent). We were interested, therefore, in testing the applicability of the model to solvatochromism of WB in EtOH-EtAc.…”

Section: Use Of Model Systems For Cellulose Acetatementioning

confidence: 96%

“…These results show clearly the importance of hydrogen bonding to WB-solvent interaction. EtAcEtOH is efficient because it solvates the probe by both hydrogen bonding and solvophobic interactions (El Seoud 2007, 2009). …”

Section: Solvatochromism In the Model Systemsmentioning

confidence: 98%

“…The probes that we have selected have been employed for a myriad of pure solvents and solvent mixtures (El Seoud 2007, 2009, and solid surfaces (Khristenko et al 2006;Macquarrie et al 1999), including cellulose (Matsuguchi et al 1997). We have employed WB because its pKa in water is conveniently low, 4.78, so that any surfaceinduced pKa increase, if it occurs, does not pose a problem (the solvatochromic, intra-molecular chargetransfer band disappears if the indicator is protonated at its phenolate oxygen).…”

Section: Use Of Model Systems For Cellulose Acetatementioning

confidence: 99%

“…We can draw on our knowledge of solvatochromism in order to analyze the effects of DS on the above-mentioned properties. A general discussion of this approach to study the properties of any medium can be found elsewhere (El Seoud 2007, 2009Reichardt 2003Reichardt , 2004Reichardt , 2008. Solvatochromic dyes (hereafter designated as ''probes'') are substances whose UV-vis spectra, absorption or emission, are particularly sensitive to the medium where they are present; solvent, solvent mixtures, solid surfaces, etc.…”

Section: Introductionmentioning

confidence: 99%

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Probing the dependence of the properties of cellulose acetates and their films on the degree of biopolymer substitution: use of solvatochromic indicators and thermal analysis

et al. 2010

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Section: Solvatochromism In the Model Systemsmentioning

confidence: 95%

Section: Use Of Model Systems For Cellulose Acetatementioning

confidence: 96%

Section: Solvatochromism In the Model Systemsmentioning

confidence: 98%

Section: Use Of Model Systems For Cellulose Acetatementioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 3 more Smart Citations

Probing the dependence of the properties of cellulose acetates and their films on the degree of biopolymer substitution: use of solvatochromic indicators and thermal analysis

et al. 2010

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Dissolution of Asphaltene in Binary Mixtures of Organic Solvents and Model Maltenes: Unambiguous Evidence for Asphaltene Preferential Solvation and Relevance to Assessing the Efficiency of Additives for Asphaltene Stabilization

et al. 2018

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Asphaltenes (Asps) are operationally defined as the toluene-soluble but n-pentane- or n-heptane-insoluble fractions, e.g., of crude oils. Therefore, there is intense interest in determining the concentration of n-heptane required to precipitate Asps from their solutions in particular media (solvents, solvent mixtures, and maltenes). Here, we report on the dependence of Asp dissolution in binary mixtures of n-heptane (solvent 1, S1)/organic solvent (solvent 2, S2) over the entire mole fraction range of S2, χ S2 , and in few selected maltene models (n-heptane + S2 + benzothiazole + n-octyl-1-napthoate). The S2 employed were benzonitrile, cyclohexanone, ethyl benzoate, 1-methylnaphthalene, tetrahydropyran, and toluene. For all S2 and model maltenes, the dependence of wt % dissolved Asp (determined by mass and UV/vis absorbance) on χ S2 was nonlinear. We attribute this nonlinear, i.e., nonideal dissolution behavior to “preferential solvation” of the Asp by a component(s) of the medium (binary solvent mixtures and maltenes). Although the occurrence of “solvent sorting” during Asp dissolution was alluded to, this is the first direct and unambiguous evidence for its occurrence. We used solvatochromism to corroborate our rationale about the origin of the Asp nonideal dissolution behavior. The term solvatochromism refers to the effect of the solvent on the color of solvatochromic probes, substances whose spectra are sensitive to the properties of the liquid medium, e.g., its empirical polarity, E T (probe). Recently, we used (E)-2,6-di-tert-butyl-4-[2-(1-hexylquinolin-1-ium-4-yl)vinyl]phenolate, HxQMBu2) to study Asp dissolution in pure solvents and model maltenes. We showed that E T (HxQMBu2) correlates linearly with Hildebrand solubility parameters of pure solvents as well as with lg (wt % dissolved Asps). In the present work, we studied the solvatochromic response of HxQMBu2 in the above-mentioned n-heptane/S2 binary mixtures. Except for toluene/n-heptane mixtures, plots of E T (HxQMBu2) versus χS2 were nonlinear due to probe preferential solvation. We successfully fitted a solvation model to the solvatochromic and Asp dissolution data and extracted the enrichment of the solvation layers in the more polar component(s) of the binary mixture and model maltenes. Our results bear on the assessment of additives employed to stabilize Asps: in the absence of adverse effects of the additive on other properties (e.g., viscosity and water/oil emulsion stability), efficient additives should accumulate in the solvation layer of Asp particles where they displace the nonsolvents, e.g., the saturates.

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Solvent-Mediated Vibrational Energy Relaxation from Vaska’s Complex Adducts in Binary Solvent Mixtures

2013

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A vibrational pump-probe and FTIR study was performed on two different adducts of Vaska's complex in two different sets of binary solvent mixtures. The carbonyl vibrational mode in the oxygen adduct exhibits solvatochromic shifts of ~10 cm(-1) in either benzyl alcohol or chloroform relative to benzene-d6, whereas this vibration is nearly unchanged for the iodine adduct for the same three solvents. The width and center frequency of the carbonyl stretch for each adduct are compared to its vibrational lifetime in binary mixtures of benzene-d6 with either benzyl alcohol or chloroform. In neat solvents, the trends in line width, frequency, and vibrational lifetime are consistent for the two adducts, but complex relationships emerge when the trends in each property are compared as a function of mixed solvent composition. ν(CO) is more sensitive to the solvation environment around the trans ligand, whereas the line width and lifetime depend on the environment around the CO group itself. The carbonyl frequency and width vary nonlinearly across the two binary solvent series, indicating preferential solvation. In contrast, the vibrational lifetime changes linearly with solvent composition and is correlated with the mole fraction of chloroform but anticorrelated with the mole fraction of benzyl alcohol. The results are explained by differences in the densities of solvent modes that affect intermolecular relaxation of the carbonyl mode.

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Solvation in Pure and Mixed Solvents: Some Recent Developments

Abstract: ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract, please click on HTML or PDF.

Cited by 9 publications

References 25 publications

Probing the dependence of the properties of cellulose acetates and their films on the degree of biopolymer substitution: use of solvatochromic indicators and thermal analysis

Probing the dependence of the properties of cellulose acetates and their films on the degree of biopolymer substitution: use of solvatochromic indicators and thermal analysis

Dissolution of Asphaltene in Binary Mixtures of Organic Solvents and Model Maltenes: Unambiguous Evidence for Asphaltene Preferential Solvation and Relevance to Assessing the Efficiency of Additives for Asphaltene Stabilization

Solvent-Mediated Vibrational Energy Relaxation from Vaska’s Complex Adducts in Binary Solvent Mixtures

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