Solubility influence

Further investigations, however, have shown that the above four-component peptide condensation is exceptionally efficient in terms of stereoselectivity70. A number of factors, including side reactions and insufficient solubility, influence this complex multistep reaction and these results cannot be reproduced with other amino acid combinations71. 

Glycosylation For some proteins glycosylation can increase solubility, influence biological half-life and/or biological activity... 

This chapter documents enhancements of the efficiency of SFE extraction of alkaloids from plant matrices using basified modifiers. Hence (1) The pure compound solubility of some free bases in pure supercritical C02 has been measured by investigating the effects of temperature, pressure or density of C02 (2) The solubilities of the alkaloidal salts were compared with those of their free bases in order to evaluate the difference of their solubilities influenced by a changing from free bases to salts (3) Polar solvents such as methanol and water, as initial modifiers, were used for the enhancement of the solubilities (4) The solubilities of the salts by non-basified modifiers such as neat methanol or water were compared with those of methanol or water basified with diethylamine (5) The effect of modifiers employed on the desorption of the compounds from a matrix were measured and compared with each other (5) On the basis of the results of pure compound extractability, SFE was performed on alkaloids from the plant... 

Substrates of hydroxyethyl cellulose (HEC) samples of different molar substitution (MS) of oxirane give similar results in grafting with AN as EC (Table IV). At MS-values of 0.40 and 0.60, the water solubility influences the results, especially the grafting efficiency. HEC-samples of low MS (0.25) give the best results in grafting. 

WOL Wolf, B.A., Improvment of polymer solubility influence of shear and pressure, Pure Appl. 

Net AgX solubility influenced by temperature, halide excess (through the... 

So there it is, perhaps the fundamental dichotomy within toxicology the issue of water-solubility. The behavior of virtually every toxic compound is directed by the fundamental dichotomy of solubility water versus lipid. Compound solubility influences fundamental processes such as absorption from the environment, delivery in the blood, diffusion into the target tissues, excretion from the target tissue, metabolism, sequestration, and whole-body elimination. These functions are not as strongly regulated by molecule size or shape as they are by the relative lipid/water solubility. Contaminant solubility, the road to toxicology, begins here. 

The percolation argument is based on the idea that with an increasing Cr content an insoluble interlinked cliromium oxide network can fonn which is also protective by embedding the otherwise soluble iron oxide species. As the tlireshold composition for a high stability of the oxide film is strongly influenced by solution chemistry and is different for different dissolution reactions [73], a comprehensive model, however, cannot be based solely on geometrical considerations but has in addition to consider the dissolution chemistry in a concrete way. 

In order to develop a proper QSPR model for solubility prediction, the first task is to select appropriate input deseriptors that are highly correlated with solubility. Clearly, many factors influence solubility - to name but a few, the si2e of a molecule, the polarity of the molecule, and the ability of molecules to participate in hydrogen honding. For a large diverse data set, some indicators for describing the differences in the molecules are also important. 

The theory underlying the removal of impurities by crystaUisation may be understood from the following considerations. It is assumed that the impurities are present in comparatively small proportion—usually less than 5 per cent, of the whole. Let the pure substance be denoted by A and the impurities by B, and let the proportion of the latter be assumed to be 5 per cent. In most instances the solubilities of A (SJ and of B (/Sb) are different in a particular solvent the influence of each compound upon the solubility of the other will be neglected. Two cases will arise for an3 particular solvent (i) the impurity is more soluble than the compound which is being purified (/Sg > SA and (ii) the impurity is less soluble than the compound Sg < S ). It is evident that in case (i) several recrystallisations will give a pure sample of A, and B will remain in the mother liquors. Case (ii) can be more clearly illustrated by a specific example. Let us assume that the solubility of A and 5 in a given solvent at the temperature of the laboratory (15°) are 10 g. and 3 g. per 100 ml. of solvent respectively. If 50 g. of the crude material (containing 47 5 g. of A and 2-5 g. of B) are dissolved in 100 ml. of the hot solvent and the solution allowed to cool to 15°, the mother liquor will contain 10 g. of A and 2-5 g. (i.e., the whole) of B 37-5 g. of pure crystals of A will be obtained. 

The normal form A can pass by tautomeric change under the influence of alkali into the acidic hydroxy form B, which in turn can 3deld the sodium salt C. Nitroparaffins are therrfore pseudo-acids, and are soluble in alkaline solution. 

Acetaldehyde, b.p. 21°, undergoes rapid pol5unerisation under the influence of a little sulphuric acid as catalyst to give the trimeride paraldehyde, a liquid b.p. 124°, which is sparingly soluble in water. The reaction is reversible, but attains equilibrium when the conversion is about 95 per cent, complete the unreacted acetaldehyde and the acid catalyst may be removed by washing with water ... 

The lower members of other homologous series of oxygen compounds— the acids, aldehydes, ketones, anhydrides, ethers and esters—have approximately the same limits of solubility as the alcohols and substitution and branching of the carbon chain has a similar influence. For the amines (primary, secondary and tertiary), the limit of solubility is about C whilst for the amides and nitriles it is about C4. 

Determine the equilibrium composition of saturated solution of AgCl. Assume that the solubility of AgCl is influenced by the following reactions. 

Initiators of suspension polymerization are organic peroxides or azo compounds that are soluble in the monomer phase but insoluble in the water phase. The amount of initiator influences both the polymerization rate and the molecular weight of the product (95). 

Volatilization. The susceptibility of a herbicide to loss through volatilization has received much attention, due in part to the realization that herbicides in the vapor phase may be transported large distances from the point of application. Volatilization losses can be as high as 80—90% of the total applied herbicide within several days of application. The processes that control the amount of herbicide volatilized are the evaporation of the herbicide from the solution or soHd phase into the air, and dispersal and dilution of the resulting vapor into the atmosphere (250). These processes are influenced by many factors including herbicide application rate, wind velocity, temperature, soil moisture content, and the compound s sorption to soil organic and mineral surfaces. Properties of the herbicide that influence volatility include vapor pressure, water solubility, and chemical stmcture (251). 

In addition to cost, several factors influence the choice of salt for a particular appHcation. The ammonium salt is the most soluble in water, but for some apphcations the presence of the ammonium ion maybe undesirable. The sodium salt is almost as soluble as the ammonium salt at ambient temperatures and above. The potassium salt is much less soluble. 

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