Soluble additives

Water—Glycol Solutions. These materials are transparent solutions of water and glycol having good low temperature properties. They frequently contain water-soluble additives to improve performance in corrosion resistance, anti-wear, etc. A water-soluble polymer is commonly utilized to boost viscosity. As solutions their advantage over emulsions is their inherent stabdity. 

In the development of a SE-HPLC method the variables that may be manipulated and optimized are the column (matrix type, particle and pore size, and physical dimension), buffer system (type and ionic strength), pH, and solubility additives (e.g., organic solvents, detergents). Once a column and mobile phase system have been selected the system parameters of protein load (amount of material and volume) and flow rate should also be optimized. A beneficial approach to the development of a SE-HPLC method is to optimize the multiple variables by the use of statistical experimental design. Also, information about the physical and chemical properties such as pH or ionic strength, solubility, and especially conditions that promote aggregation can be applied to the development of a SE-HPLC assay. Typical problems encountered during the development of a SE-HPLC assay are protein insolubility and column stationary phase... 

Mechanistically chromium additions have been shown to significantly enrich (lOX) in the magnetite oxide layer and, it has been suggested that this lowers its solubility. Additions of small amounts of oxygen to the water, increases the metal s potential and promotes the formation of haematite... 

If the concentration of a solute is lower than its solubility, additional solute can dissolve, but once the concentration of solute reaches the solubility of that substance, no further net changes occur. Individual solute molecules still enter the solution, but the solubility process is balanced by precipitation, as Figure 12-6 illustrates. A saturated solution in contact with excess solute is in a state of dynamic equilibrium. For eveiy molecule or ion that enters the solution, another returns to the solid state. We represent d Tiamic equilibria by writing the equations using double arrows, showing that both processes occur simultaneously ... 

Notes on the preparation of secondary alkylarylamines. The preparation of -propyl-, ijopropyl- and -butyl-anilines can be conveniently carried out by heating the alkyl bromide with an excess (2-5-4mols) of aniline for 6-12 hours. The tendency for the alkyl halide to yield the corresponding tertiary amine is thus repressed and the product consists almost entirely of the secondary amine and the excess of primary amine combined with the hydrogen bromide liberated in the reaction. The separation of the primary and secondary amines is easily accomplished by the addition of an excess of per cent, zinc chloride solution aniline and its homologues form sparingly soluble additive compounds of the type B ZnCl whereas the alkylanilines do not react with sine chloride in the presence of water. The excess of primary amine can be readily recovered by decomposing the zincichloride with sodium hydroxide solution followed by steam distillation or solvent extraction. The yield of secondary amine is about 70 per cent, of the theoretical. 

Solvent restrictions (matrix solubility additive interaction NMR requirements)... 

In polymer/additive deformulation (of extracts, solutions and in-polymer), spectroscopic methods (nowadays mainly UV, IR and to a lesser extent NMR followed at a large distance by Raman) play an important role, and even more so in process analysis, where the time-consuming chromatographic techniques are less favoured. Some methods, as NMR and Raman spectrometry, were once relatively insensitive, but seem poised to become better performing. Quantitative polymer/additive analysis may benefit from more extensive use of 600-800 MHz 1-NMR equipped with a high-temperature accessory (soluble additives only). 

Sunartio D, Ashokkumar M, Grieser F (2007) Study of the coalescence of acoustic bubbles as a function of frequency, power, and water-soluble additives. J Am Chem Soc 129 6031-6036... 

Microballoons have the advantage of giving a well controlled addition of sensitiser and also improved stability on storage. They are however less effective than direct gas occlusions when measured at constant explosive density and therefore tend to have most use in conjunction with the soluble additives described below. 

It has been pointed out that the water present in a slurry explosive must be vaporised during detonation and thus absorbs energy. Although the water vapour increases the total volume of gas produced the nett effect is still a reduction in strength. Many attempts have therefore been made to find a soluble additive which will replace part of the water to give both increased power and sensitivity. One such substance which has found success is ethylene glycol mononitrate. This when pure is explosive, but for... 

The common ion effect (Chapter 3) is a further important factor affecting solubilities. Addition of A or B to the above system (equation (5.28)) will shift the equilibrium to the left and reduce the solubility of AB. In practice, this situation would arise when an excess of a precipitating reagent has been added to an analyte solution. Such an excess leads to the possibility of complexation reactions occurring which will tend to increase the solubility of AB. For example, when aluminium or zinc is precipitated by hydroxyl ions, the following reactions with excess reagent can occur... 

For FAB/LSIMS, the analyte should be soluble to at least 0.1 mgml in some solvent or even better directly in the matrix concentrations of 0.1-3 [jg piP in the matrix are ideal. In case of extremely low solubility, additives such as other solvents, acids or surfactants can help. [74]... 

The use of a charged chiral selector is probably the best solution to improve the classical PET when CE is hyphenated with MS. Better solubility, additional electrostatic interactions, and improvement of the stereoselective separation power afforded by the self-mobility of the chiral additives into the BGE are among the numerous advantages of these charged selectors. When electromigration of the chiral species and the analytes are opposite (PFT-countercurrent approach), the mobility difference between free and complexed analytes is increased, leading to a higher resolution than with a neutral chiral selector. In optimized countercurrent... 

A common feature of the solubihty curves, as outlined in Fig. 16, is the exponential increase with the pressure due to the increasing density of CO2. From the solubility measurements [125], it can be concluded that the modification of phosphines by fluorous substituents is not necessarily required to reach sufficient solubilities of the corresponding metal complexes in SCCO2. In particular, alkyl substitution on phosphorus promotes complex solubility. Additional aryl groups, e.g., in lb and 4b, cause a reduced solubility of the corresponding complexes. Moreover, trans-Co2(CO)6 (PC6H5)3 2 (7b) is completely insoluble in SCCO2. 

Polymers of thiophene carboxylic acids (9) undergo different chromatic transitions upon the addition of a variety of cations (McCullough et al. 1997). Although the acid form of the polymer was not water soluble, addition of various ammonium or metal... 

The effects of various formulation factors on the in vitro release characteristics of spherical polymethylmethacrylate implants were studied. Physical and mathematical models were proposed to describe the in vitro release profiles. The in vitro release data could be described by a biexponential equation of the following type fraction of tobramycin remaining in the implant at time t=Aerai+BQ, where a, and P represent the rate constants for the initial rapid and subsequent slow phases of release. The influence of drug loading, volume of dissolution medium, implant size and type of cement and the incorporation of water-soluble additives on the release profiles and a and P rate constants is described. 

Our studies indicated that the inclusion of water-soluble additives could alter both the rate and extent of tobramycin release from Palacos PMMA. The three additives PEG 3400, PEG 400 and lactose significantly affected the slower diffusion phase of the matrix (Fig. 2 and Table 2). 

Fig. 2—The effect of incorporation of 10% water-soluble additives on tobramycin sulphate release profiles. The solid lines represent the lines of best fit. The symbols represent the observed values.

Scanning electron microscopic examination before and after dissolution and in vivo implantation show no significant changes in surface topography for the implants prepared as they are clinically used, that is, without additives. However, distinct changes in surface characteristics and the appearance of pores are evident with the inclusion of water-soluble additives such as polyethylene glycol 400. 

Because Hg2Cl2 is so slightly soluble, additional Cl obtained from Hg2Cl2 is negligible compared with 0.10 M Cl. ... 

Hydrocellulose is formed when pure cellulose is subjected to the action of cold mineral acids solutions. Hydrolysis then proceeds by stages to yield glucose as the final product. It is possible to stop the hydrolysis at any desired moment, for example by diluting the reaction mixture with water. Hydrocellulose then remains in the form of non dissolved fibres or as powder (Girard [47]). The hydrolysis is usually performed by means of hydrochloric acid or with hydrogen chloride in an anhydrous medium. In the latter case, a water-soluble addition compound (C6H10O5)2.3HCl may occur as a transient product, as reported by Hess and M. Ullman [48]. 

Within this group, the linear polymers have been most intensively studied and researched. The main area of interest lies in water-soluble polymers. However, there have also been many studies into organic solutions, although there exist problems with odor and toxicity in the case of analytical studies. Among the water-soluble additives, tests were made especially on polyethyleneoxide (PEO), polyacrylamide and the coacrylates (PAAm, PAAm/AAcNa), polyacrylic add (PAA), guar gum (GG), carboxymethylcellulose (CMC) and sodium salts, as well as hydroxyethylcellulose (HEC). From these tests, PEO proved to be the most effective flow improver, followed closely by PAAm, which is somewhat more stable than PEO in turbulent flow. 

In the present method until oxidation is complete some [Co(en)3]++ ion is present to bring about electron transfer racemization. The necessary condition of separation of a solid phase is achieved by performing the reaction in 25 to 30% ethanolic solution in which (+)-[Co(en)3]Cl(d-tart) alone is sparingly soluble. Addition of a little activated carbon facilitates oxidation and, as well, ensures rapid equilibrium between the various products. 

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