Solubilization solvent selection

As stated previously the main criteria in solvent selection for extraction purposes is the polarity. To prevent miscibihty of the mediator with the product phase at separation temperature the mediator s polarity has to be preferably in the range of the cyclic carbonate. Table 9 shows that with decreasing chain length of the N substituent of a pyrrohdone cycle, the solubil-... 

Ethers are excellent solubilizing solvents for a wide range of polymers and high molecular weight compounds. Ethers are also relatively strong solvents in both RP and NP separations. These properties coupled with their hydrogen bond accepting property often lead to unique selectivities and shorter retention times as compared with comparable alcohol replacements. 

Spherical micelles were prepared by solubilization/enc sulation from rod-coil block copolymers of poly(phenylquinoline)-fc-poly(styrene) (PPQ-PS) using binary solvents selective for the rod-type block copolymers. The resnlting assembhes could be used to encapsulate large molecules, such as Cgo and C70 fnllerenes (Chen and Jenekhe 1999). 

Hildebrand Solubility Parameter at Supercritical Conditions An empirical approach quite often used in solvent selection using the prineipal of like dissolves like is Hildebrand solubility parameter. Solutes that have similar solubility parameters to that of solvent readily solubilize within the solvent. For supercritical conditions, one can incorporate state and chemical effect to the following relation ... 

These solvents differ in volatility and selectivity for the removal of H2S, mercaptans, and CO2 from gases of different composition. Other alkaline solvents used for the absorption of acidic components in gases include potassium carbonate, K CO, solutions combined with a variety of activators and solubilizers to improve gas—Hquid contacting. 

The interest and success of the enzyme-catalyzed reactions in this kind of media is due to several advantages such as (i) solubilization of hydrophobic substrates (ii) ease of recovery of some products (iii) catalysis of reactions that are unfavorable in water (e.g. reversal of hydrolysis reactions in favor of synthesis) (iv) ease of recovery of insoluble biocatalysts (v) increased biocatalyst thermostability (vi) suppression of water-induced side reactions. Furthermore, as already said, enzyme selectivity can be markedly influenced, and even reversed, by the solvent. 

Recent development of the use of reversed micelles (aqueous surfactant aggregates in organic solvents) to solubilize significant quantities of nonpolar materials within their polar cores can be exploited in the development of new concepts for the continuous selective concentration and recovery of heavy metal ions from dilute aqueous streams. The ability of reversed micelle solutions to extract proteins and amino acids selectively from aqueous media has been recently demonstrated the results indicate that strong electrostatic interactions are the primary basis for selectivity. The high charge-to-surface ratio of the valuable heavy metal ions suggests that they too should be extractable from dilute aqueous solutions. 

As well as density the solvent strength and selectivity of the fluid will affect both the solubilizing power of the fluid for specific solutes and retention in SFC. Solvatochromic indicators have been used to rank fluids commonly used in SFC in terms of... 

Solubilizing all or part of a sample matrix by contacting with liquids is one of the most widely used sample preparation techniques for gases, vapors, liquids or solids. Additional selectivity is possible by distributing the sample between pairs of immiscible liquids in which the analyte and its matrix have different solubilities. Equipment requirements are generally very simple for solvent extraction techniques. Table 8.2 [4,10], and solutions are easy to manipulate, convenient to inject into chromatographic instruments, and even small volumes of liquids can be measured accurately. Solids can be recovered from volatile solvents by evaporation. Since relatively large solvent volumes are used in most extraction procedures, solvent impurities, contaminants, etc., are always a common cause for concern [65,66]. 

Because of their beneficial solubilizing characteristics and role in promoting desired reactions, solvents such as 2-methoxyethanol have become widely employed in CSD processes. It should be noted, however, that such compounds frequently demonstrate adverse effects. For example, 2-methoxyethanol is a known teratogen. The reader is encouraged to always review the Material Safety Data Sheet (MSDS) for the selected solvent and starting reagents. These sheets are typically provided by the commercial vendor at the time of purchase. 

For highly asymmetric block copolymers with a large insoluble block, the copolymer chains can t be directly solubilized in the selective solvent. However, micelles can be obtained from these copolymers by the temporary use of a nonselective solvent which is further eliminated (see Sect. 2.2 for further details on this issue). In principle, all the copolymer chains are aggregated... 

GEMEP is a patented technology for the on-site treatment of varions solid matrices impacted with mercnry. GEMEP is an ex situ process based on the selective oxidation and solubilization of mercnry into an aqueous solution, followed by the physical separation of the mercury-laden solvent from the sohd matrix, and the subsequent treatment of the solvent to recover the mercnry and recycle the solvent. 

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