Solubility stoichiometry effect

The postulation of the +4 oxidation state of cobalt is necessary to account for the retarding influence of Pb(II). The existence of a dimeric species of Co(II) acetate is required by the rate law and is confirmed by spectrophotometric and solubility measurements. The existence of ionic species of the reactants is inferred by the rate increase on addition of sodium acetate, an observation which cannot be attributed to a salt effect because sodium perchlorate produces a rate decrease. On this scheme an explanation of the effect of water on the stoichiometry is that the step... 

We have now found that replacing water in the melt by methanol leads to large increases in pyridine solubility of product from the treatment, even without tetralin addition. In this paper we characterize the effects of temperature, time, hydrogen pressure, reaction stoichiometry, and addition of various inorganic and organic additives. Because oxygen removal Present Address Chevron Research Co., Box 1627, Richmond, CA 94804. 

A Ca2+-specific fluorescent chemosensor 25 in aqueous buffer signals Ca2+ via a decrease in fluorescence intensity, whereas excess of Mg2+ ions has no effect on the emission [85]. This probe has limited solubility in aqueous solution after binding to Ca2+. A Zn2+ sensitive probe 26 showing different fluorescence responses depending on the complexation stoichiometry is described in [86],... 

In a series of papers (Cohen and Lach, 1963 Lach and Cohen, 1963 Lach and Chin, 1964a,b Pauli and Lach, 1965 Lach and Pauli, 1966), Lach and co-workers used a similar technique to evaluate the effect of the cycloamyloses on the solubilities of a variety of pharmaceuticals. Plots of the solubility of the pharmaceutical against the concentration of added cycloamylose were usually linear with slopes ranging from 0 to 2.25. In theory, these slopes can be related to the dissociation constants for the cycloamylose-substrate complexes if the stoichiometries of the complexes can be determined (Thoma and Stewart, 1965). This technique, however, is inferior to the spectrophotometric method to be discussed presently. 

Ktp, known as the solubility product, is widely used as a measure of the solubility of sparingly soluble salts. It should be noted that the dimensions of this constant will change according to the stoichiometry of the reaction. Temperature effects on solubility products arc readily assessed as most solubility reactions are dearly seen as endothermic aiuj disorder increasing. Raising the temperature will thus Increase A, p together whh the solubility of the solid. 

Solid complexes of defined stoichiometry have been prepared for all the lithium halides with HMPA. For LiBr, both [LiBr(HMPA)2] and [LiBr(HMPA)4] have been obtained as solids of defined m.p., but the 1 1 complex, the kinetically active species for epoxide rearrangement, has not been isolated. The rate of epoxide loss and solubility of LiBr increased proportionately with added solubilizer (HMPA), to a maximum rate at a 1 1 ratio of addend LiBr. Additional HMPA beyond this ratio caused the rate to decrease even though all the LiBr remained in solution. At an addend LiBr ratio of 2 1, the reaction effectively ceased. These observations allow the conclusions that [LiBr(HMPA)2] is more stable than the reactive 1 1 complex in benzene, and that only the latter is kinetically competent. 

A correlation between the conversion of coal to benzene soluble, and the stoichiometry of the iron sulfides was observed by Montano and Granoff (7). Higher conversion is accomplished by a more iron-deficient pyrrhotite (7). Stephens et al ( ) studied the effect of additives to an IL 6 conversion to liquid products. 

The data given in Table VI for removal of arsenic, cadmium, and lead using polysulfide were almost twice that obtained with sulfide at the lower treatment levels. This higher response to polysulfide may be due to the lower solubility of the polysulfide salts, coordination compounds having lower solubilities, or the polysulfides may simply furnish higher effective sulfide concentration. The stoichiometry of the precipitated material was not determined in these tests. 

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