Solvent properties of liquid

Schuerch C (1952) The solvent properties of liquids and their relation to the solubility, swelling, isolation and fractionation of lignin J Am Chem Soc 74 5061-5067 Scott JAN, Procter AR, Fergus BJ, Goring DAI (1969) The application of ultraviolet microscopy to the distribution of lignin in wood Description and validity of the technique Wood Sci Technol 3 73 - 92... 

The solubility of amides in liquid ammonia differs appreciably and increases from lithium to rubidium. Because of the high reactivity of amides and the excellent solvent properties of liquid ammonia, amide-ammonia solutions are highly reactive and react with most substances.f ... 

Furton KG, Morales R (1991) Effect of anion chain length on the solvent properties of liquid tetrabutylammonium alkylsuHonate salts studied by gas-liquid chromatography. Anal Chim Acta 246 171-179... 

AP Abbott, CA Eardley. Solvent properties of liquid and supercritical 1,1,1,2-tetrafluoroethane. J Phys Chem B 102 8574, 1998. 

Shetty, P.H., Youngberg, P.J., Kersten, B.R. Poole, C.F. (1987). Solvent properties of liquid organic salts used as mobile phases in microcolumn reversed-phase liquid chromatography, /. Chromatogr.A Vol.411 61-79. 

A useful property of liquids is their ability to dissolve gases, other liquids and solids. The solutions produced may be end-products, e.g. carbonated drinks, paints, disinfectants or the process itself may serve a useful function, e.g. pickling of metals, removal of pollutant gas from air by absorption (Chapter 17), leaching of a constituent from bulk solid. Clearly a solution s properties can differ significantly from the individual constituents. Solvents are covalent compounds in which molecules are much closer together than in a gas and the intermolecular forces are therefore relatively strong. When the molecules of a covalent solute are physically and chemically similar to those of a liquid solvent the intermolecular forces of each are the same and the solute and solvent will usually mix readily with each other. The quantity of solute in solvent is often expressed as a concentration, e.g. in grams/litre. 

Electrical properties of liquids and solids are sometimes crucially influenced by H bonding. The ionic mobility and conductance of H30 and OH in aqueous solutions are substantially greater than those of other univalent ions due to a proton-switch mechanism in the H-bonded associated solvent, water. For example, at 25°C the conductance of H3O+ and OH are 350 and 192ohm cm mol , whereas for other (viscosity-controlled) ions the values fall... 

Amphiprotic solvents consist of liquids, such as water, alcohols and weak organic acids, which are slightly ionised and combine both protogenic and protophilic properties in being able to donate and to accept protons. 

Considerable progress has been made in the last decade in the development of more analytical methods for studying the structural and thermodynamic properties of liquids. One particularly successful theoretical approach is. based on an Ornstein-Zernike type integral equation for determining the solvent structure of polar liquids as well as the solvation of solutes.Although the theory provides a powerful tool for elucidating the structure of liquids in... 

The HcReynolds abroach, which was based on earlier theoretical considerations proposed by Rohrschneider, is formulated on the assumption that intermolecular forces are additive and their Individual contributions to retention can be evaluated from differences between the retention index values for a series of test solutes measured on the liquid phase to be characterized and squalane at a fixed temperature of 120 C. The test solutes. Table 2.12, were selected to express dominant Intermolecular interactions. HcReynolds suggested that ten solutes were needed for this purpose. This included the original five test solutes proposed by Rohrschneider or higher molecular weight homologs of those test solutes to improve the accuracy of the retention index measurements. The number of test solutes required to adequately characterize the solvent properties of a stationary phase has remained controversial but in conventional practice the first five solutes in Table 2.12, identified by symbols x through s have been the most widely used [6). It was further assumed that for each type of intermolecular interaction, the interaction energy is proportional to a value a, b, c, d, or e, etc., characteristic of each test solute and proportional to its susceptibility for a particular interaction, and to a value x, X, Z, U, s, etc., characteristic of the capacity of the liquid phase... 

The interactions between solutes and solvents are noncovalent in nature (barring the occurrence of chemical reactions), and therefore fall into the same category as those that govern molecular recognition processes, the formation and properties of liquids and solids, physical adsorption, etc. Hydrogen bonding, in its many manifestations, is a particularly prominent and important example. 

Table 5.12 Ratio of solubilities of H2 and D2 in various solvents (Rabinovich, I. B. Influence of isotopy on the physicochemical properties of liquids. Consultants Bureau, New York, 1970)...

There are properties of liquids used as solvents, such as the liquid range, viscosity, surface tension, and vapor pressure that, although important from the practical and technical points of view, are not listed in Table 2.1. These can be found in Refs. [1,2]. Tables 12.2, 13.1, and 13.2 list solvents used in extraction with some further information. 

An ionic liquid can be used as a pure solvent or as a co-solvent. An enzyme-ionic liquid system can be operated in a single phase or in multiple phases. Although most research has focused on enzymatic catalysis in ionic liquids, application to whole cell systems has also been reported (272). Besides searches for an alternative non-volatile and polar media with reduced water and orgamc solvents for biocatalysis, significant attention has been paid to the dispersion of enzymes and microorganisms in ionic liquids so that repeated use of the expensive biocatalysts can be realized. Another incentive for biocatalysis in ionic liquid media is to take advantage of the tunability of the solvent properties of the ionic liquids to achieve improved catalytic performance. Because biocatalysts are applied predominantly at lower temperatures (occasionally exceeding 100°C), thermal stability limitations of ionic liquids are typically not a concern. Instead, the solvent properties are most critical to the performance of biocatalysts. 

L.R. Snyder, Classification of the solvent properties of common liquids, J. 

Poole, C.R, Chromatographic and spectroscopic methods for the determination of solvent properties of room temperature ionic liquids, /. Chromatogr. A, 1037, 49-82, 2004. 

Carda-Broch, S., Berthod, A., and Armstrong, D. W., Solvent properties of the l-butyl-3-methylimidazolium hexafluorophosphate ionic liquid. Anal. Bioanal. Chem., 375,191-199, 2003. 

Lu, J., Liotta, G.L., Eckert, G.A., Spectroscopically probing microscopic solvent properties of room-temperature ionic liquids with the addition of carbon dioxide, /. Phys. Chem. A, 107, 3995-4000, 2003. 

Ionic liquids are a class of solvents and they are the subject of keen research interest in chemistry (Freemantle, 1998). Hydrophobic ionic liquids with low melting points (from -30°C to ambient temperature) have been synthesized and investigated, based on 1,3-dialkyl imidazolium cations and hydrophobic anions. Other imidazolium molten salts with hydrophilic anions and thus water-soluble are also of interest. NMR and elemental analysis have characterized the molten salts. Their density, melting point, viscosity, conductivity, refractive index, electrochemical window, thermal stability, and miscibility with water and organic solvents were determined. The influence of the alkyl substituents in 1,2, 3, and 4(5)-positions on the imidazolium cation on these properties has been scrutinized. Viscosities as low as 35 cP (for l-ethyl-3-methylimi-dazolium bis((trifluoromethyl)sulfonyl)amide (bis(triflyl)amide) and trifluoroacetate) and conductivities as high as 9.6 mS/cm were obtained. Photophysical probe studies were carried out to establish more precisely the solvent properties of l-ethyl-3-methyl-imidazolium bis((trifluoromethyl)sulfonyl)amide. The hydrophobic molten salts are promising solvents for electrochemical, photovoltaic, and synthetic applications (Bon-hote et al., 1996). 

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