Solubility characteristics for

Figure 7.8 The pendent groups available on the surface of dendrimer molecules are highly varied. Some groups provide functional or reactive groups for bioconjugation, while other groups create unique solubility characteristics for the dendrimer.

As the natural gas industry developed and expanded, so did the demand for liquids recovered from natural gas. One way of recovering additional liquids is through the use of a heavy absorption oil that has good solubility characteristics for the propane and heavier hydrocarbon components in the gas stream. As in the case of dehydration, the solvent must be regenerated. Figure 20.1311 shows the absorption-stripping section of an absorption-type hydrocarbon liquids recovery facility. The absorbent is circulated to the top of the absorber and flows downward, absorbing liquefiable components from the... 

Solutions. To deliver a spray, the formulated aerosol product should be as homogeneous as possible. That is, the active ingredients, the solvent, and the propellant should form a solution. Because the widely used kalocarbon and hydrocarbon propellants do not always have the desired solubility characteristics for all the components in the product concentrate, special formulating techniques using solvents such as alcohols (qv), acetone (qv), and glycols (qv), are employed. 

These three propellants may be blended to obtain suitable solubility characteristics for MDIs when formulated as solutions. They will produce suitable vapor pressures so that optimum particle-size distribution as well as suitable respiratory fractions may be achieved. 

Slow migration of condensing siloxanols into the latex particles result in loss of primer effectiveness as the latex ages. Methyltrimethoxysilane and Z-6020 have the optimum solubility characteristics for most latex systems. 

Often, the desired solubility characteristics for a particular compound are not found in a single solvent. In these cases, a mixed solvent may be used. You simply select a first solvent in which the solute is soluble and a second solvent, miscible with the first, in which the solute is relatively insoluble. The compound is dissolved in a minimum amount of the boiling solvent in which it is soluble. Following this, the second hot solvent is added to the boiling mixture, dropwise, until the mixture barely becomes cloudy. The cloudiness indicates precipitation. At this point, more of the first solvent should be added. Just enough is added to clear the cloudy mixture. At that point, the solution is saturated, and as it cools, crystals should separate. Common solvent mixtures are listed in Table 11.3. 

The chemical literature is a valuable source of information about solvents that may be used for recrystallizing known compounds. If the compoimd has not been prepared before, it is necessary to resort to trial-and-error techniques to find an appropriate solvent for recrystallization. The process of selection can be aided by consideration of some generalizations about solubility characteristics for classes of solutes. Polar compounds are normally soluble in polar solvents and insoluble in nonpolar solvents, for example, whereas nonpolar compounds are more soluble in nonpolar solvents. Such characteristics are summarized by the adage "like dissolves like." Of course, although a highly polar compound is unlikely to be soluble in a hot, nonpolar solvent, it may be very soluble in a cold, very polar solvent. In this case, a solvent of intermediate polarity may be the choice for a satisfactory recrystallization. 

Uses Emollient, solubilizer, skin and hair conditioner spreading agent for decorative cosmetic products, sunscreens and sunless tanning products improved afterfeel because of inverse solubility characteristic for bath and shower products Pmperties Pract. odorless amber liq., viscosity (25 C) 1600 cps HLB 15 spreading coeff. ( 21 C) 18.8 dynes/cm 100%... 

M. Maus, K. G. Wagner, A. Komherr and G. Zifferer. Molecular dynamics simulations for drug dosage form development Thermal and solubility characteristics for hot-melt... 

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