Solubility polarity effect

A second area in which polarization effects show up is the solubility of salts in polar solvents such as water. For example, consider the silver halides, in which we have a polarizing cation and increasingly polarizable anions. Silver fluoride, which is quite ionic, is soluble in water, but the less ionic silver chloride is soluble only with the inducement ofcomplexing ammonia. Silver bromide is only slightly soluble and silver iodide is insoluble even with the addition of ammonia. Increasing covalency from fluoride to iodide is expected and decreased solubility in water is observed. 

On the DB5 capillary column, satisfactory separation of hydroxyl- and methoxyflavones could be obtained using either of the two gradient systems, but the retention times of the analytes for P2 were shorter than those for PL This is due to the variation in the solubilities of flavones in the supercritical mobile phase when the density gradient was employed. The polarity effect of the stationary phase (BPl phase is less polar than the DB5) is illustrated in Table 2. It can be seen that, on BPl, the flavones are less retained and the analysis time is decreased by nearly half, while conserving a satisfactory separation. 

Almost all cross-flow filtration processes are inherently susceptible to flux decline due to membrane fouling (a time-dependent phenomenon) and concentration polarization effects which reflect concentration buildup on the membrane surface. This means lower flux (i.e., product output) which could drive the capital costs higher due to the requirement of a larger surface area to realize the desired production rate. In some situations, the lower flux could also result in lower selectivity which means reduced recoveries and/or incomplete removal of impurities from the filtrate. For example, removal of inhibitory metabolites such as lactic acid bacterial or separation of cells from broth while maximizing recovery of soluble products. 1 1... 

Yamada87 demonstrated that the interaction between polymer and solvent affects the stereoregularity of poly(methyl methacrylate) because large enthalpy differences were observed in good solvents. In the case of poly(methacrylic acid), however, the polar effect of solvent was found to be a more important factor than the solubility of the polymer. 

Solvent effects in heterogeneous catalysis are examined in terms of physical or chemical modifications to control the chemo-, regio- and stereoselectivity of a reaction. The main factors affecting selectivity are reactant solubility, polarity, reactivity or acido-basicity of solvents and competitive chemisorption of products and solvents In the special case of molecular sieves, selectivity control of a reaction by competitive adsorption, diffusion or shape selectivity and confinement catalysis are also examined. 

With the exception of lithium, almost all CNS drugs require metabolism to more water-soluble (polar) metabolites for their elimination. Thus, drugs that modify the activities of drug-metabolizing enzymes may impact on the clearance of CNS drugs, perhaps affecting the intensity or duration of their effects. 

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