Aiding solubility

Grinding fluids or coolants are fluids employed in grinding to cool the work being ground, to act as a lubricant, and to act as a grinding aid. Soluble oil coolants in which petroleum oils are emulsified in water have been developed to impart some lubricity along with inst-pieventive properties. 

For the preparation of a micellar solution, the water-insoluble drug and lipophilic excipients can be dissolved in a liquid surfactant by mixing at a relatively high temperature (43S 6flntil a clear solution is obtained. If necessary, a cosolvent can be added to aid solubility in the surfactant. Then a water or buffer solution containing hydrophilic excipients is added to the desired volume while mixing. In some cases, the aqueous solution needs to be heated to the same temperature as that > the surfactant to obtain desirable results. 

Programme the Synthesizer for the desired sequence (Lys residues are usually added to the C-terminus and N-terminus, to aid solubility, followed by the activated Cys monomer or bromacetic anhydride for the final coupling). 

Similarly, an example of a detergent is CH3(CH2)2oC6H5S03 Na+ here the S03 Na+ group is the water-soluble group. Notice that sodium ions are present. This also aids solubility as most sodium salts are water-soluble (see also Section 4.11). 

When coated capillaries are employed (case e), conventional buffers without additives to reduce wall effects are used. Urea and/or organic solvents can be added to aid solubility. Reagents for secondary equilibrium can be used as well. It is best to operate at a pH below 8 to maximize the stability of the often labile coating material. Coated capillaries are also used simply to eliminate the EOF in some applications. 

Acyclovir Prepared as stock solution at 1-5 mM in water, stored at -20°C use intravenous (sodium salt) formulation to aid solubility. 

The reaction was not as accommodating as just described and additionally required a cosolvent (10ml of cyclohexane per lOOmmol of MEA) and an acid, which screening identified as methanesulfonic acid (0.2 ml per 100 mmol of MEA). In addition, tetrabutylammonium iodide (20 mg) was required. The combination of these additives enhanced the rate of reaction presumably by aiding solubility in this two phase reaction. 

Another useful class of reactions which has been successfiilly demonstrated as a continuous SCF process are etherfication/cyclisation reactions, again using acid catalysts [52]. Examples include the formation of asymmetric esters and heterocyclic compounds. Scheme 12.2 shows the intramolecular cyclization of 1,4-butanediol over Amberlyst-15 at 120 bar, 170 °C, which produces the heterocyclic compound tetrahydrofuran (THE). 1,4-Butanediol has a melting point of 16 °C, and so, although not strictly required, a small amount of methanol may be added to the reactants to aid solubility during decompression of the SCF. Adding a cosolvent to the system may also improve solubility in SCCO2 [13]. 

Conditions 10 equiv. of anhydride in a minimum of dichioromethane. Note that some anhydrides are not very soiuble, e.g. Phe, Cys(Acm), to which a maximum of 10% v/v OMF may be added to aid solubility. Acylations still proceed adequately if the anhydride remains gelatinous. 

Function in Formula Forms conditioning network on hair Use Concentration 1-5% in shampoos and conditioners, also used in styling aids Solubility Characteristics Water-soluble above pH 5.5, soluble in aqueous surfactant systems at all pHs... 

Supercritical fluids Carbon dioxide forms a supercritical phase under relatively low temperatures and pressures and it therefore has been explored as a solvent for tbe Heck reaction. Following the reaction, the gas can be collected and recycled, allowing the design of true waste-free technology. The dielectric constant of supercritical CO2 is similar to pentane and therefore modified catalytic systems are often required to aid solubility.Unusually, one of the best catalytic precursors in supercritical CO2 is Pd(OCOF3)2, a strong electrophile and oxidant. Heck reactions in supercritical water have also been investigated. ... 

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