Hydrolytic behavior

Protic Materials. The hydrolytic behavior of tetrachlorosilane was described by Mendeleyev (164), and is summarized herein. Orthosihcic acid formed by the action of water on tetrachlorosilane ... 

Diaziridines, discovered in 1958, six years after the oxaziridines, were almost immediately realized to be structural analogs of oxaziridines. Like these they showed oxidizing properties unexpected for other classes of organic nitrogen compound. Properties in common with oxaziridines include the rearrangement to open chain isomers on heating above 100 °C (for several diaziridines), and their hydrolytic behavior in acidic media, which leads to carbonyl compounds with conservation of the hetero-hetero bond. 

Previous studies of the hydrothermal hydrolysis of tetravalent Th, U and Np (1-4) have shown a remarkable similarity in the behavior of these elements. In each case compounds of stoichiometry M(0H)2S0i, represent the major product. In order to extend our knowledge of the hydrolytic behavior of the actinides and to elucidate similarities and differences among this group of elements, we have investigated the behavior of tetravalent plutonium under similar conditions. The relationships between the major product of the hydrothermal hydrolysis of Pu(IV), Pu2(OH)2(SO.,)3 (H20) t, (I)> and other tetravalent actinide, lanthanide and Group IVB hydroxysulfates are the subject of this re-... 

We have investigated the hydrothermal hydrolytic behavior of Pu(IV) sulfate solutions in the temperature range 140-200°C. 

The hydrolytic behavior of sulfosuccinates as such and in formulations is depicted in the following pictures (Figs. 4-7). Two substances-DLAS and DLSS—were chosen to illustrate these properties. The tests were performed at room temperature and 40°C at various pH values (pH = 5, 6, 8) and—in the case of DLSS—without adjusting pH in a long-term run (24 weeks). Changes were evaluated by determination of pH and active matter. 

To gain an insight into the likely hydrolytic behavior of sulfated simple sugars and polysaccharides, Brimacombe, Foster, Hancock, Overend, and Stacey carried out a rigorous set of experiments with the cyclic sulfates of cyclohexane cis-and trims-1,2-diol as model compounds. The results were interpreted on the reasonable assumption that, in all cases, the cyclic sulfates initially afford a diol monosulfate. Examples of both S-0 and C-0 bond cleavage were encountered. A qualitative reaction mechanism was proposed for use as a working hypothesis for the hydrolysis of sugar sulfates. 

R. P. Iyer, J. H. Boal, L. R. Phillips, D. R. Thakker, W. Egan, Synthesis, Hydrolytic Behavior, and Anti-HIV Activity of Selected Acyloxyalkyl Esters of Trisodium Phosphonoformate (Foscarnet Sodium) , J. Pharm. Sci. 1994, 83, 1269- 1273. 

For a given pesticide which undergoes hydrolysis, any or all of these hydrolytic pathways may be relevant at various pH s. Organophosphorothioates, for example, have measurable neutral and alkaline hydrolysis rate constants (7). Esters of 2,4-dichlorophenoxyacetic acid (2,4-D), on the other hand, hydrolyze by acid and alkaline catalyzed reactions, but have extremely small neutral hydrolysis rate constants ( ). Thus, any study of the hydrolysis of sorbed pesticides must be prefaced by an understanding of the hydrolytic behavior of individual pesticides in aqueous solution. 

O. M. Friedman and E. Boger, Colorimetric estimation of nitrogen mustards in aqueous media. Hydrolytic behavior of bis(2-chloroethyl)amine, nor-HN2. Analytical Chemistry, 1961,33,906-910. 

An obvious difficulty arises with this rather elaborate rationale when phosphoramidate and aryl phosphoramidate monoanions are compared for example, the dissimilarity of the dioxan effect yet the identity of product distribution observed in methanol-water competition experiments. Preliminary studies in the author s laboratory have revealed striking differences in the hydrolytic behavior between a series of phosphoramidafes derived from primary aliphatic amines and the above aryl systems. No linear structure-reactivity relationship between the logarithmic rate of hydrolysis of the monoanion species and the pKa of the amine is observed19. Moreover, the rate of hydrolysis of phosphoramidate monoanions derived from aliphatic amines is at least 104 times slower than those formed from aryl amines. In contrast, only a thirtyfold decrease in rate is observed for the corresponding ApKa in the O-phos-phate monoester series. The suspicion that mechanism (1), even with the above proposed modification, is not an accurate description of phosphoramidate monoanion hydrolysis derives some further support from the observation that the monoanion is subject to nucleophilic attack by substituted pyridines al-... 

The hydrolytic behavior of both NaX and NaY as measured at 10 2ilf. NaCl by isotopic dilution methods has also been measured as a function of the zeolite content. The results, along with standard deviations from the mean, are summarized in Table II the figure in parenthesis indicates the... 

Two types of keratan sulfate, corneal and skeletal, have been differentiated by the hydrolytic behavior of the linkage region. The former has an N-... 

Tn the past 20 years several physical inorganic chemistry laboratories have re-examined extensively the nature of the simple inorganic solutes in water. Substantial contributions to man s knowledge of the hydrolytic behavior of metal cations and metallate anions in water solvent have resulted. Various new techniques have been applied with varying degrees of efficacy. The details of the behavior, within specified conditions, of a number of solute ions are now matters of fact. In many more cases and over wider variations of conditions, all of the important variables which affect hydrolysis phenomena have not yet been identified. 

Temperature and Time. It is my opinion that these two variables are of the utmost importance in any consideration of the hydrolytic behavior of metal cations and metallate anions. Furthermore, as yet it is impossible to separate the two variables in all cases. The reasons for these two statements will become apparent by considering several specific cases. 

The ether elimination is also observed as the first step in thermal decomposition of these alkoxides. The same reaction appears also to be responsible for the observed difference in the hydrolytic behavior of molybdenum and tungsten alkoxides the hydrolysis of the W alkoxides leads as for the majority of other metal alkoxides to the formation of hydroxospecies, forming sols and gels on polycondensation, while in the case of Mo alkoxides the added water, being a stronger acid than alcohols, acts as a catalyst for the ether elimination reaction and causes the formation of individual isopolyanions (independently of the nature of the alkyl radical or quantity of water added) [1774] ... 

In order to evaluate the hydrolytic behavior of polymeric drugs having theophylline, the degree of hydrolysis of AThe, MAThe, poly(AThe) and poly-... 

From the above it can be seen that the hydrolytic behavior of N2F2 is quite different from those of the other binary nitrogen fluorides discussed earlier. Difluorodiazine is strongly endothermic (12) and thermodynamically unstable (11) this makes it necessary to consider not only direct chemical attack by water but also the thermal decomposition to the elements. The reactivity of d -N2F2 toward glass (2) presents an additional question of possible competing reactions with the container walls. 

Influence of Physical Structure. The hydrolytic behavior of cellulose is much influenced by its physical structure and lateral order [121-132]. Wood cellulose was hydrolyzed twice as fast as cotton [125]. Hydrolysis rate was significantly increased by physical or chemical pretreatment, with the effect depending on the source of cellulose. Hill and coworkers [127,128] reported that mercerization increased the hydrolysis rate of cotton (by 40%) and of ramie (7%), whereas the opposite effect was observed for linen and a-cellulose samples showing an approximately 30% reduction. Based on kinetic analysis, they concluded that the end-attach model proposed by Sharpies [121] can only be applied to the cellulose II structure and not to the cellulose I crystallite. Thus, the conformation of cellulose is also a significant factor affecting its reactivity and possibly the hydrolytic mechanism as well. 

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