Diluents choice

The heterogeneous copolymerization of styrene and acrylonitrile in various diluents as reported by Riess and Desvalois (22). Although the copolymer composition in these studies was not strongly influenced by the diluent choice, the preferential adsorption of acrylonitrile monomer onto the polymer particles shifted the azeotropic copolymerization point from the 38 mole % acrylonitrile observed in solution to 55 mole % acrylonitrile. 

The development of a suitable solvent system is important for successful operation. Solvent systems generally consist of at least the following components extractant, diluent, inorganic salts or acids, and water. The relative optimization of these components yields the best conditions with which to achieve separation. A key factor to success is the choice of the appropriate extractant. Many extractants may be used for REE separation. These may be divided into three groups on the basis of the mechanisms involved. These extractants are tisted in Table 7. 

The procedure of choice utilizes a mixture of the orthoformate, the corresponding alcohol and p-toluenesulfonic acid, with or without a diluent. Dimethoxypropane also gives good yields of 3-methoxy-A ethers with a high degree of selectivity in the presence of 17- and 20-ketones. " ... 

This concept meshes with another important environmental issue solvents for organic reactions. The use of chlorinated hydrocarbon solvents, traditionally the solvent of choice for a wide variety of organic reactions, has been severely curtailed. In fact, so many of the solvents favoured by organic chemists have been blacklisted that the whole question of solvents requires rethinking. The best solvent is no solvent and if a solvent (diluent) is needed then water is preferred. Water is non-toxic, non-inflammable, abundantly available, and inexpensive. Moreover, owing to its highly polar character, one can expect novel reactivities and selectivities for organometallic catalysis in water. 

An essential step in industrial solvent extraction is the regeneration of the extractant. This can be done in many ways, e.g., by distillation, evaporation, or stripping (back-extraction). While distillation and evaporation do not discriminate between solutes (the diluent is simply removed by heating), stripping, by careful choice of strip solution and conditions, can be made highly selective. Alternatively, aU the solutes can be stripped and then subjected to a selective extraction by changing the extractant examples of both types of process will be found in Chapter 13. The possibilities are many, and it may be worthwhile to explore new paths. 

The choice of organic diluent only affects the distribution constant, not the acid dissociation constant. 

If performing manually, use a pipette of your choice. If performed by a robot, the robotic system is programmed to revisit the drops and/or the resen/oirs at given times in order to add the diluent (Chayen, 2006). 

The third point is especially important when the process runs at high temperature, but the choice of the diluent also affects the settling characteristics of the mixed phases. As it can be seen in Table VII, many different diluents may be considered. It should be realized that the commercial diluents are "cuts" obtained during the production of chemicals from petroleum "feedstocks" and as such are complex mixtures. 

To be reconstituted in 5 mL diluent of choice from an IV bag. The following preservative-free diluents are recommended for reconstitution 5% dextrose injection (D5W), USP 0.9% sodium chloride injection, USP 5%... 

Choice of an Internal Standard. One of the difficulties in the spec-trometric trace analysis of coal ash samples, in addition to choosing a suitable comparison standard matrix, is choosing an internal standard. The first choice in both analytical methods was indium, which was used as a constant internal standard added to the graphite powder diluent-buffer. The results obtained had poor reproducibility, as previously... 

Overall rates of polymerization are generally rather insensitive to the presence of diluent. Das, Chatterjee and Palit (50) compared rates at 50 mole percent concentration in a variety of liquids. In the range of their experiments, polymerization rate was nearly independent of the choice of diluent. Bamford, Jenkins and White (22) point out that transfer agents reduce the mean degree of occlusion. Since the termination rate is increased under these conditions, the overall polymerization rate is reduced. The extent of polymer swelling will vary from one liquid to another (32, 130), and this obscures the interpretation to be made from limited data. 

The choice is wide for the formulation of the chemical system developed to separate the target species (e.g., number and nature of the extracting agent(s), including the use of binary synergistic systems or phase modifiers, concentration of species, nature of the organic diluent). 

Choice of a Phase Modifier for Calixarene Crown-6 Diluted in Aliphatic Hydrocarbon Diluents... 

Still, in most liquid—liquid distribution systems one of the liquid phases is more aqueous while the other is mainly non-aqueous. Therefore, a major consideration of the choice of the solvent for solvent extraction is its immiscibility with water and the expected losses of the solvent to the aqueous phase. In many solvent extraction applications the solvent is used as a diluent for an active extractant, which may be either a solid or a liquid when neat. In these cases, where a separate active extractant is used, the chemical processes taking place in the selective extraction of the desired solute or solutes and their recovery in the stripping stage are of prime importance, but a discussion of which is outside the... 

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