Effect of hydrolysis

The effect of hydrolysis and molecular weight is ihustrated in Figure 1. The variations in properties with molecular weight ate for a constant degree of hydrolysis (mol %) (8) and the effect of hydrolysis is at a constant molecular weight. Representative properties are shown in Table 1. 

The most common method of purification of inorganic species is by recrystallisation, usually from water. However, especially with salts of weak acids or of cations other than the alkaline and alkaline earth metals, care must be taken to minimise the effect of hydrolysis. This can be achieved, for example, by recrystallising acetates in the presence of dilute acetic acid. Nevertheless, there are many inorganic chemicals that are too insoluble or are hydrolysed by water so that no general purification method can be given. It is convenient that many inorganic substances have large temperature coefficients for their solubility in water, but in other cases recrystallisation is still possible by partial solvent evaporation. 

The extent of hydrolysis of (MY)(n 4)+ depends upon the characteristics of the metal ion, and is largely controlled by the solubility product of the metallic hydroxide and, of course, the stability constant of the complex. Thus iron(III) is precipitated as hydroxide (Ksal = 1 x 10 36) in basic solution, but nickel(II), for which the relevant solubility product is 6.5 x 10 l8, remains complexed. Clearly the use of excess EDTA will tend to reduce the effect of hydrolysis in basic solutions. It follows that for each metal ion there exists an optimum pH which will give rise to a maximum value for the apparent stability constant. 

The effect of hydrolysis, as a function of pH, on the concentration of hydrated Pu cationic species. The initial (log [Pu] at pH = 0) concentrations are those at pH 8 which correspond to the k values of the hydroxide precipitate of each species. 

Albin, D. M., Wubben, J. E., and Gabert, V. M., Effect of hydrolysis time on the determination of amino acids in samples of soybean products with ion-exchange chromatography or precolumn derivatization with phenyl isothiocyanate,. Agr. Food Chem., 48, 1684, 2000. 

Poly(starch-g-(l-amidoethylene)) copolymer is not a polyelectrolyte and will be a smaller molecule in water than an equal molecular weight, partially hydrolyzed poly(l-amidoethylene). Polyelectrolyte effect should, however, cause the graft copolymer to expand in solution in the same way it causes poly(l -amidoethylene) to expand, so a series of hydrolyzed graft copolymers were prepared from poly(starch-g-(l-amidoethylene))(41-43) and these derivatives were tested to determine the effect of hydrolysis on copolymer properties in solution. 

Jim, S., Jones, V., Copley, M. S., Ambrose, S. H. and Evershed, R. P. (2003a) Effects of hydrolysis on the delta C 13 values of individual amino acids derived from polypeptides and proteins. Rapid Communications in Mass Spectrometry 17, 2283 2289. 

To maximize the modification of amines and minimize the effects of hydrolysis, maintain a high concentration of protein or other target molecule. By adjusting the molar ratio of crosslinker to target molecule(s), the level of modification and conjugation may be controlled to create an optimal product. 

For interpretation of the dependence of f2 on the nature of the alkali cation, we must consider the effect of hydrolysis expressed by the following equilibrium ... 

Schwartz, R. W. Lakeman, C. D. E. Payne, D. A. 1990. The effects of hydrolysis conditions, and acid and base additions, on the gel-to-ceramic conversion in sol-gel derived PbTi03. In Better Ceramics Through Chemistry IV, edited by Zelinski,... 

Schwartz, R. W. Payne, D. A. Holland, A. J. 1989. The effects of hydrolysis and catalysis conditions on the surface area and decomposition behavior of polymeric sol-gel derived PbTi03 powders. In Ceramic Powder Processing Science, edited by Hausner, H. Messing, G. W. Hirano, S. Deutsche Keramische Gesellschaft. pp. 165-172. 

Many of the results reported are of a dubious nature. For example, Perkins (219, 222) assumed that complexes of the type ML2 were formed and quoted log /32 values between 9.8 and 14.2. Not only was the possible formation of a simple complex of the type ML excluded (not to mention any other complexes), but the effects of hydrolysis (which, to be fair, were poorly understood at the time) were completely ignored. The high stability of amino acid complexes was put in doubt in successive publications (220, 229, 232, 233). It has even been suggested, on the basis of Raman spectra, that the amino group does not coordinate to the beryllium atom (232). Unfortunately the opposite conclusion was reached on the basis of IR measurements, namely that only the amino group was coordinated (234). 

Effect of Hydrolysis on Moisture-Regain (at 70°F., 65% rel. humidity) of Cotton Lintersl>... 

Effects of hydrolysis and adsorption on the oxygenation of transition-metal ions. Arrows indicate lower limit. (From Wehrli and Stumm, 1989)... 

Ishida, H. and Koenig, J.L. (1980). Effect of hydrolysis and drying on the siloxane bonds of a silane coupling agent deposited on E-glass fibers. J. Polym. Sci. Polym. Phys. Edition 18, 233-237. 

Chiellini E, Corti A, Del Sarto G, D Antone S (2006) Oxo-biodegradable polymers - effect of hydrolysis degree o biodegradation behaviour of poly(vinyl alcohol). Polym Degrad Stab 91 3397-3406... 

My other question concerns the general theme of the effect of ligands in the coordination shell of a metal ion on the rate of water displacement. I refer particularly to the effect of hydroxide as a ligand,—i.e., to the effect of hydrolysis of metal ions on the substitution of water. 

AM Rowan, PJ Moughan, MN Wilson. Effect of hydrolysis time on the determination of the amino acid composition of diet, ileal digesta, and feces samples and on the determination of dietary amino acid digestibility coefficients. J Agric Food Chem 40 981-985, 1992. 

Figure 5. Effect of hydrolysis of plastic-attached gangliosides with V. cholerae sialidase on their binding capacity for tetanus (%) and cholera toxins as determined by ganglioside-ELlSA method...

In the discussion of the loading and curing step, we have focused on the conformation of the silicon side of the aminosilane molecules. Siloxane bond formation and effect of hydrolysis of the alkoxy groups have been characterized clearly. The special reactivity of aminosilanes, compared to other organosilanes, however, is due to the presence of the amino group inside the molecule. The inter- and intramolecular interactions of this group cause special stability and reactivity according to the conditions used. Therefore we will now focus on this side of the bifunctional molecule. 

Silver, G. L. Effect of Hydrolysis on the Disproportionation of Tetravalent and Pentavalent Plutonium Ions, U.S. AEC Report MLM-1743, Mound Laboratory, Miamisburg, OH, 1970. 

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