Solvent capacity definition

To synthesize coordination compounds of definite type, the following properties of a solvent should be taken into account, additionally to its capacity to dissolve ligands and metal sources physical properties (mainly dielectric constant, dipole moment, boiling and melting points) and chemical ones (solvation activity, including acid-base characteristics, specific interaction) [208,222-229],... 

Both these considerations would be taken into accoimt if the activation process were assumed to occur at a constant pressure, p, such that the partial molar volume of the solvent is independent of the temperature, though this possibility does not appear to have been considered. A full discussion is beyond the scope of this chapter, but the resulting heat capacities of activation are unlikely to differ greatly from those determined at a constant pressme of, say, 1 atm. (see p. 137). Unfortunately, this approach requires the definition of rather clumsy standard states for solutes, e.g., hypothetically ideal, 1 molal, under a pressure such that a given mass of the pure solvent occupies a particular volume. 

Column dimensions—length (L) and column inner diameter (dc or i.d.)— control column performance (N, speed, sensitivity, sample capacity) and its operating characteristics (flow rate, back pressure). Designations of various column types based on column inner diameters and their associated characteristics are shown in Table 3.1. Note that void volume, sample capacity, and operating flow rate are proportional to (dc)2, while detection limit, or sensitivity, is inversely proportional to (dc)2. Note also that prep columns (>10mm i.d.), microbore (micro columns (<0.5 mm i.d.) will require specialized HPLC instruments (see Chapter 4). There is a definitive trend toward the increased use of shorter and smaller inner diameter analytical columns due to their higher sensitivity performance and lower solvent usage.9"11 This trend will be explored later. 

Solvent strength and selectivity are the properties commonly used to classify liquid stationary phases as selection tools for method development in gas chromatography [29,102-104]. Solvent strength and polarity are often used interchangeably and can cause confusion. Polarity is sometimes considered to be the capacity of a stationary phase for dipole-type interactions alone, while more generally solvent strength is defined as the capacity of a stationary phase for all possible intermolecular interactions. The latter definition is quite sensible but unworkable because there is no substance that is uniquely polar that might be used to probe the polarity of other substances. Indirect measurements of polarity, such as those scales related one way or another to the... 

The definition for catalytic purposes of a zeolite reads as follows a crystalline material with micropores and cation-exchange capacity that is insoluble in water and common organic solvents and has sufficient thermal stability that allows removal of all pore-filling agents present in the as-synthesized materials. This definition is narrower than that of the IZA Constitution, which includes mesoporous solids, metal organic frameworks (MOFs), cationic and anionic clays [3]. 

Various scales of solvent strength (polarity) and selectivity have been used to classify stationary phases. Classification based on polarity had to be abandoned because of the lack of a working definition. There is no substance that is uniquely polar and suitable to probe the polarity of other substances. Selectivity is defined as the relative capacity of a stationary phase for specific intermolecular interactions, such as dispersion, induction, orientation, and hydrogen-bond formation. Early attempts at a systematic definition of selectivity scales were based on the system of phase constants introduced by Rohrschneider and... 

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