Cation, hydrolysis

Henry M, Jolivet JP, Livage J (1991) Aqueous Chemistry of Metal Cations Hydrolysis, Condensation and Complexation. 77 153-206 Hider RC (1984) Siderophores Mediated Absorption of Iron. 57 25-88 Hill HAO, Rdder A, Williams RJP (1970) The Chemical Nature and Reactivity of Cytochrome P-450. 8 123-151... 

Zeolites can be over-washed during workup, resulting in decationization, also known as cation hydrolysis [64]. Decationization involves replacement of alkali... 

Kumar M. D. (1987). Cation hydrolysis and the regulation of trace metal composition in seawater. Geochim. Cosmochim. Acta, 51 2137-2145. 

Hydrolysis is a very common process in solution chemistry, and it is observed for cations as well as for anions. For each case an example is presented here, As3+ for cation hydrolysis and AsO3-for the anionic analog. In both cases the hydrolysis reaction leading to hydronium and hydroxyl ions, respectively, occurs on the subpicosecond range, which makes an experimental investigation of them almost unfeasible. 

They exhibit strong acidity, which is usually of the Bronsted type, partly because of the influence of the strong internal electrostatic fields (ca. 106 Vcm 1) exerted on the interlamellar water (which generates protons by dissociation) or, because of the additional influence of certain hydrated interlamellar cations, notably Al3+. Cation hydrolysis, just as with strongly polarizing cations in zeolites, yields free protons, thus ... 

The synthesis of thiols 19 is well managed if thiourea 28 is used instead of NaSH or Na2S as the nucleophile. Thiourea is itself highly delocalised but it is still a good nucleophile for saturated carbon through the sulfur atom 29. The product is a thiouronium salt 30 and is not nucleophilic at all, being a cation. Hydrolysis with aqueous base liberates urea 31 and the thiol 19. 

The molecular sieve behaviour of zeolites can be controlled by a hydrolytic process at elevated temperatures. Water vapour in contact with zeolite crystals at elevated temperatures results in a variation of the zeolitic adsorption characteristics. The amount of water vapour, the pretreatment temperature and the pretreatment time, can control the effect pore size of zeolites. It appears, that a steam treatment causes a cation migration and a cation hydrolysis of the exchangeable cations. However, the effect of steam on the adsorption behaviour of zeolites is influenced by the nature of the initial exchangeable cations. 

The dichloride (347) is converted to (348) on heating, apparently again through an intermediate cyclobutenyl cation. Hydrolysis of either compound with water leads to the ketone (349), which is reconverted to the cyclobutene by treatment with phosphorus pentachloride 274). 

Unlike alkali-metal or alkaline-earth-metal cations, hydrolysis of trivalent lanthanides proceeds significantly at this pH. 

Hydrolysis in General. The word hydrolysis is used not only in the above way but also in referring to more general chemical reactions in which a molecule or ion is converted into two or more molecules or ions by reaction with water. The examples discussed above are cases of anion hydrolysis and cation hydrolysis, such as... 

Hydrolysis of Salts. Anion hydrolysis cation hydrolysis hydrolysis in general. Buffered solutions. Coordination number of elements formulas of the oxygen acids. Strengths of the oxygen acids. Simple rules. General concepts of acids and bases. Proton donors and acceptors. Acid strength and tendency to undergo condensation. 

A. K. Cheetham, M. M. Eddy and J. M. Thomas, The direct observation of cation hydrolysis in lanthanium-zeolite Y by neutron diffraction, y. Chem. Soc. Chem. Commun., 1984, 1337. 

If calculations of the solubilities of heavy-metal salts are to be accurate, careful attention must be paid to the nature of the hydrolytic species present. As the following example illustrates, however, in an absolute sense the effect of cation hydrolysis is often of minor importance. 

Henry, M., J. P. Jolivet, Livage, J. Aqueous Chemistry ofMetal Cations Hydrolysis, Condensation and Complexation. Vol. 77, pp. 153-206. 

Figure 10.28 Correlations between (a) cation hydrolysis constants and TL intrinsic adsorption constants for cations adsorbed by HFO (goethite and amorphous...

Henry, M., Jolivet, J.-P, and Livage, J., Aqueous chemistry of metal cations hydrolysis, condensation and complexation. Struct. Bonding, 77, 154, 1992. 

The equihbrium constant for the metal cation hydrolysis is given by... 

K. Conversely, if for the anion is smaller than for the cation, the solution will be acidic because cation hydrolysis will be more extensive than anion hydrolysis. 

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