Solvents function

In terms of general solvency, solvents may be described as active solvents, latent solvents, or diluents. This differentiation is particularly popular in coatings applications, but the designations are useful for almost any solvent appHcation. Active solvents are strong solvents for the particular solute in the apphcation, and are most commonly ketones or esters. Latent solvents function as active solvents in the presence of a strong active solvent. Alcohols exhibit this effect in nitrocellulose and acryUc resin solutions. Diluents, most often hydrocarbons, are nonsolvents for the solute in the apphcation. 

In the early work on the thermolysis of metal complexes for the synthesis of metal nanoparticles, the precursor carbonyl complex of transition metals, e.g., Co2(CO)8, in organic solvent functions as a metal source of nanoparticles and thermally decomposes in the presence of various polymers to afford polymer-protected metal nanoparticles under relatively mild conditions [1-3]. Particle sizes depend on the kind of polymers, ranging from 5 to >100 nm. The particle size distribution sometimes became wide. Other cobalt, iron [4], nickel [5], rhodium, iridium, rutheniuim, osmium, palladium, and platinum nanoparticles stabilized by polymers have been prepared by similar thermolysis procedures. Besides carbonyl complexes, palladium acetate, palladium acetylacetonate, and platinum acetylac-etonate were also used as a precursor complex in organic solvents like methyl-wo-butylketone [6-9]. These results proposed facile preparative method of metal nanoparticles. However, it may be considered that the size-regulated preparation of metal nanoparticles by thermolysis procedure should be conducted under the limited condition. 

In addition to the reactions in which the solvent is also a reactant (such as solvolysis), there are many others in which the solvent functions only to make reactants accessible to each other. Even in those... 

For hydrogenation (or oxidation) reactions, the aqueous solvent functions as a convenient source of hydrogen (or... 

The chemical properties of solvents have obviously a strong bearing on their applicability for various purposes. The solvents function by selectively dissolving desired solutes, by remaining inactive in the chemical reactions undergone by the solutes, and by solvating (selectively), reactants, transition-state intermediates, and products (Marcus, 1998a). 

As a result, some approaches to computing dispersion energy have involved using either experimental or theoretical data for gas-phase clusters to estimate the strength of dispersion interactions between different possible solute and solvent functional groups. However,... 

A. C. Ross, G. Bell, and P. J. Halling, Organic solvent functional group effect on enzyme inactivation by the interfacial mechanism, J. Mol. Cat. B Enzymatic 2000, 8, 183-192. 

At the upper limit of the ci range, v decreases to a minimum as the molecules are progressively immobilized, effectively making good and poor solvents functionally indistinguishable. In this regime, viscosity merges into elasticity, P becomes independent of c, and the dispersion simulates the behavior of a molten polymer. 

One major obstacle to effective use of UV monitoring of HPLC effluent in the range of 200-220 nm was solvent incompatibility. Two types of incompatibilities were noted 1) impurities in the solvent 2) solvent functional group absorbance, i.e. UV cutoff. The former incompatibility was easily overcome by using high quality solvents from the same lot. Solvent functional group absorbance proved to be the more difficult of the two incompatibilities. 

Aprotic protophillic solvents all nitrogen bases without protons, e.g., pyridine, and other conjugated amines, and fully alkylated amines or amides. The solvents function as Bronsted bases as well as Lewis bases and may have high permittivity. 

Cellulose ethers also have gained their positions on the market due to their multifunctional effects. They are soluble in both water and organic solvents, functioning as thickeners, flow control agents, suspending aids, protective colloids, water binders, liquid crystals, film formers, or thermoplastics. Because of their properties, they are used in such diverse industries as food. 

A fourth class may be considered, though it contains non-ionic entities. This is the liquid state of various ionic solvates. In these systems molecules usually thought of as solvent molecules are tightly bound to high field cations and have no solvent function. Such molten solvates have very low vapor pressures at ambient, and only bod at temperatures near 200°C, for instance, LiZnBt4 3H2O, has Tb= 190°C while Tg= -120°C [22]. 

Simultaneous stabilization of both cations and anions may also be effected by combination of an EPD solvent (with poorly developed EPA properties) and a suitable EPA. For example, nitromethane (NM) as a solvent functions as a weak EPD and hence compounds such as CoClg remain insoluble in this solvent. Addition of a strong EPA, such as SbClg, to this suspension leads to dissolution of C0CI2 with simultaneous heterolysis of the Co—Cl bonds, owing to " stabilization of both cationic and anionic species ... 

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