Higher cosolvent

S/v is the solubility in water, and f is the fraction of organic solvent in the cosolvent mixture. If the cosolvent mixture contains more than two organic solvents (i.e., a ternary or higher cosolvent mixture), the total drug solubility can be approximated by a summation of solubilization potentials as... 

The cosolvents are a mixture of ethanol, propyl, butyl and higher alcohols up to octyl alcohol. Corrosion inhibitor is also requited. 

Polymerization Solvent. Sulfolane can be used alone or in combination with a cosolvent as a polymerization solvent for polyureas, polysulfones, polysUoxanes, polyether polyols, polybenzimidazoles, polyphenylene ethers, poly(l,4-benzamide) (poly(imino-l,4-phenylenecarbonyl)), sUylated poly(amides), poly(arylene ether ketones), polythioamides, and poly(vinylnaphthalene/fumaronitrile) initiated by laser (134—144). Advantages of using sulfolane as a polymerization solvent include increased polymerization rate, ease of polymer purification, better solubilizing characteristics, and improved thermal stabUity. The increased polymerization rate has been attributed not only to an increase in the reaction temperature because of the higher boiling point of sulfolane, but also to a decrease in the activation energy of polymerization as a result of the contribution from the sulfonic group of the solvent. 

In the condensation of 2-butanone with citral, if the reaction temperature is kept at 0—10°C, higher yields of the isomethyl pseudoionones, which are the more thermodynamically stable isomers, are obtained. The aldol iatermediates have more time to equilibrate to the more stable isomers at the lower temperature. The type of base used and a cosolvent such as methanol are also very important ia getting a high yield of the isomethyl pseudoionones (168). 

The reaction involves two electrons per thionyl chloride [7719-09-7] molecule (40). Also, one of the products, SO2, is a Hquid under the internal pressure of the cell, facihtating a more complete use of the reactant. Finally, no cosolvent is required for the solution, because thionyl chloride is a Hquid having only a modest vapor pressure at room temperature. The electrolyte salt most commonly used is lithium aluminum chloride [14024-11-4] LiAlCl. Initially, the sulfur product is also soluble in the electrolyte, but as the composition changes to a higher SO2 concentration and sulfur [7704-34-9] huA.ds up, a saturation point is reached and the sulfur precipitates. 

A partial solution to the problem of producing sharp peaks at low elution temperatures is to add a small amount of a higher-boiling co-solvent to the main solvent. As suggested by Grob and Muller (23, 24), butoxyethanol can be used as a suitable cosolvent for aqueous mixtures in such cases. 

Section 3.3.4 pointed out that cosolvents alter aqueous ionization constants as the dielectric constant of the mixture decreases, acids appear to have higher pKa values and bases appear (to a lesser extent than acids) to have lower values. A lower dielectric constant implies that the force between charged species increases, according to Coulomb s law. The equilibrium reaction in Eq. (3.1) is shifted to the left in a decreased dielectric medium, which is the same as saying that pKa increases. Numerous studies indicate that the dielectric constant in the region of the polar head groups of phospholipids is 32, the same as the value of methanol. [381,446-453] Table 5.2 summarizes many of the results. 

The most soluble gasoline compound is methyl tertiary-butyl ether (MTBE) (43,000 mg/L). In addition, MTBE in solution has a cosolvent effect, causing some of the other compounds in gasoline to solubilize at higher concentrations than they normally would in clean water. 

Use of cosolvent. Various cosolvents, such as acetone, ethanol, methanol, hexane, dichloromethane, and water, have been used for the removal of carotenoids using SC-CO2 extraction (Ollanketo and others 2001). All these cosolvents except water (only 2% of recovery) increased the carotenoid recovery. The use of vegetable oils such as hazelnut and canola oil as a cosolvent for the recovery of carotenoids from carrots and tomatoes have been reported (Sun and Temelli, 2006 Shi, 2001 Vasapollo and others 2004). For the extraction without cosolvent addition, the lycopene yield was below 10% for 2- to 5-hr extraction time, whereas in the presence of hazelnut oil, the lycopene yield increased to about 20% and 30% in 5 and 8 hr, respectively. The advantages of using vegetable oils as cosolvents are the higher extraction yield the elimination of organic solvent addition, which needs to be removed later and the enrichment of the oil with carotenoids that can be potentially used in a variety of product applications. 

The cmc decreases with increasing chain length of the apolar groups, and is higher for ionic than for non-ionic or zwitterionic micelles. For ionic micelles it is reduced by addition of electrolytes, especially those having low charge density counterions (Mukerjee and Mysels, 1970). Added solutes or cosolvents which disrupt the three-dimensional structure of water break up micelles, unless the solute is sufficiently apolar to be micellar bound (Ionescu et al., 1984). 

Cosolvent flooding is accomplished by the introduction of a cosolvent solution, with subsequent extraction of contaminated groundwater and NAPL. In one reported field test study that focused on enhanced dissolution, the use of about nine pore volumes of a 70% ethanol, 12% pentanol solution injected into a test cell resulted in about 81% bulk NAPL removal, with a higher removal efficiency for several other individual compounds. In another field test study, where mobilization removal was emphasized, injection of about four pore volumes of a mixture of tert-butanol and w-hcxanol into a test cell resulted in the removal of about 80% of the bulk NAPL, and higher removal efficiency of the more-soluble NAPL compounds. 

On the other hand, the presence of these esters in the electrolyte solutions raised concern over the longterm performance at room temperatures, because EIS studies indicated that the resistance associated with the SEI film increased at a much higher rate for ester-based electrolytes as compared with the compositions that were merely based on carbonates. The authors attributed this rising cell impedance to the reactivity of these esters toward the electrode active material, which resulted in the continued growth of the SEI film in the long term and suggested that alkyl esters, especially those of acetic acid, might not be appropriate cosolvents for low-temperature application electrolytes. ... 

While the consideration of nonflammability and SEI stability favors a high concentration of these organophosphorus compounds in electrolytes, the capacity utilization, rate capabilities, and low-temperature operation require that they be used at minimal concentrations. A compromise would be reached between 15 and 20% TFP or BMP in a binary 1.0 M LiPFe in EC/EMC (1 1) system or at higher than 30% in a ternary 1.0 M LiPFe in PC/EC/EMC (1 1 3) system. Such electrolytes are completely or at least nearly nonflammable. To further alleviate the above tradeoff, Xu et al. suggested that new cosolvents of higher flame retarding ability should be tailor-made. 

Like all the phosphates investigated as cosolvents, TBP and TPP showed higher anodic stability, as confirmed by their cycling in lithium ion cells based on a LiNio.8Coo.2O2 cathode up to 4.2 V, and separate cyclic voltammetry tests also showed that they would not decompose anodically below 5.0 V on an inert working electrode. Little capacity fading was detected during the extended tests of TPP or TBP in full lithium ion cells up to 150 cycles. 

Crystalline salts of many organic acids and bases often have a maximum solubility in a mixture of water and water-miscible solvents. The ionic part of snch a molecule requires a strongly polar solvent, snch as water, to initiate dissociation. A mixture of water-miscible solvents hydrates and dissociates the ionic fraction of pollutants at a higher concentration than wonld either solvent alone. Therefore, from a practical point of view, the deliberate nse of a water-soluble solvent as a cosolvent in the formnlation of toxic organic chemicals can lead to an increased solnbility of hydrophobic organic contaminants in the aqueous phase and, conse-qnently, to a potential increase in their transport from land surface to groundwater. 

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