Protolysis reaction

As expected, the high reactivity of the polar Si=P bond favors protolysis reactions with HX (X = OH, OMe, Cl), in which the phosphorus is protonated and the silicon center bonds to X (Eq. 5).IOa... 

The equilibrium constants given above for the hydrolysis and protolysis reactions of cis- and trans-DDP can be employed to construct distribution diagrams of various species as a function of the pH. In human blood plasma ([Cl-] = 0.1 M) the dichloro species predominates at about pH 7.4 for both cis- and frans-DDP (Figure 4). By contrast, in intracellular conditions ([Cl ]ambient = 0.004 M) the hydrolysis products dominate, but the distribution behavior of the two isomers is quite... 

One of the main drawbacks to the development of the chemistry of many of the boron hydrides has been the absence of synthetic procedures for producing these materials in reasonable yields and quantities by relatively safe and simple techniques. Classical approaches are heavily dependent upon pyrolytic procedures. Although they have been developed to a "fine art," they require a high degree of skill in order to be employed safely in ordinary laboratory environments. Other important classical methods are dependent upon controlled protolysis reactions, frequently giving mixtures of materials which are difficult to separate. 

The acidity constants for the surface protolysis reactions provide a measure of the extent to which the reaction will proceed. For the iron oxides the values of the pJC,s usually fall between 5 and 10, but there is considerable variation in the values for dif... 

The similar reaction of triisobutylaluminum with potassium should give K2[iBu3Al-Ak Bu3], which was characterized by a protolysis reaction and NMR spectroscopy.156 A reinvestigation showed that actually the aluminum(III) compound K[Ah Bu4] had formed, which has identical chemical shifts in the NMR spectra compared to those reported for the hypothetical dialanate(6).157 The formation of elemental hydrogen upon... 

Model Adjustable Parameters Protolysis Reaction Surface Complexation Reaction Surface Mass Balance... 

The conditions for this equation to be reasonably accurate are that the solid be of uniform composition and large grain size. In addition, it is assumed that no protolysis reactions nor ion pairing occur and that no complexes nor multinuclear species are formed). 

It is not always possible to specify a protolysis reaction unambiguously in terms of the actual acid or base species. As it is possible to ignore the extent of hydration of the proton in dilute aqueous solutions, the hydration of an acid or base species can be included in a composite acidity constant for example, it is difficult analytically to distinguish between C02(aq) and H2CO3. The equilibria are... 

The cations and anions of these salts do not undergo protolysis reactions to any appreciable extent in solutions that are near neutrality. Furthermore, complex formation (or ion-pair binding) between cation and anion may be assumed to be negligible as long as free metal-ion and free anion concentration is small (approximately <10 M) (Dashed lines in Figure 7.1 indicate where the foregoing assumptions are no longer valid.)... 

Usually these reactions have been studied in water or in other protic solvents such as the alcohols. Thus, the acid-base properties of the solvent are important in determining the relative strength of acids and bases which are solutes in water. This leads to the definition of two other types of proton transfer reaction, namely, the protolysis reaction,... 

This means that a complete analysis of this system involves determination of ten rate constants two for direct proton transfer, two for the protolysis reaction, two for the hydrolysis reaction, and four for proton transfer reactions such as (7.3.14) and (7.3.15). The relationship among these reactions is shown in fig. 7.4 for a general reaction involving the acid HA and the base B in water. 

NMR has been used extensively to study the kineties of proton transfer reaetions in water and other solvents. In the ease of the protolysis reaction... 

The equation can be seen to be correct at the limit of very fast pulsing rates when the right-hand side becomes zero, while with very slow pulse repetition rates (g -> 0) the equation becomes that of Piette and Anderson (1959), given before as equations (45) and (58). The equation has been applied to the protolysis reactions of the trimethylammonium ion in... 

The rapid protonation-deprotonation process can be monitored by using either a deuterated alkane or a deuterated superacid. When the reaction is carried out in the presence of carbon monoxide, it is also possible to compare the isotope exchange process with the protolysis reaction which produces a smaller alkane and a smaller carbenium ion which is trapped by CO, forming stable oxocarbenium ions that are easily converted into esters for analysis (e.g.. Scheme 2). 

In the case of dibasic acids H2B, the following two protolysis reactions have to be considered ... 

Dibasic Acids with One Very Strong and One Strong Protolysis Reaction pKai 0, pKa2 > 0 High Concentration... 

The determination of the five variables chjB, t HB-. Ch30+> nd coh requires five independent equations. These are the equations of the law of mass actions of aU protolysis reactions and the equations for charge and amount balances ... 

Diacidic Base with a Strong and a Weak Protolysis Reaction... 

Simplified equation for a diacidic base with a stroi and a weak protolysis reaction, and in high concentration ... 

In this case, the second protolysis reaction can be disregarded. The base behaves like a monoacidic base (see Eq. (105) in Sect. 4.1.3.3). For low concentrations of a diacidic base, a cubic equation has to be solved (see Eq. (63)). 

B.2 Diacidic Base with Two Weak Protolysis Reactions... 

As mentioned in the previous chapters, for the pH of a salt solution it is important whether the anion or the cation or both ions are imdergoing protolysis reactions. If both ions exist in aqueous solutions as hydrated ions which do not undergo protolysis... 

The advantage of the Bronsted theory is that the formation of acids and bases occurs via protolysis reactions including the corresponding acids and bases. The dissociation degree a describes the position of the equilibrium (4.164) and therefore the acid strength. ... 

We will later see when discussing the dry deposition (Chapter 4.4.1) that a similar conception is applied to explain the partial conductance the first term on the right side in Eq. (4.302) denotes the resistance of diffusion and the second the interfacial transfer. The steps that follow after interfacial transfer are the (fast) salvation and/or protolysis reactions until reaching the equilibrium, the diffusion within the droplet (until reaching steady-state concentrations or, in other words, a well-mixed droplet) and finally the aqueous phase chemical reactions. Let us first consider a pseudo-first-order reaction ... 

Fig. 2 shows calculated Tim and Xm values for the 1 and 2 flash experiments assuming the PRE results from one exchangeable H2O. xm is in the range 10-20 ps this is the expected range for protolysis reactions of water coordinated to (+3) or (+4) ions. Measured Tim values in S2 range from <10 ps when T<17°C to near 50 ps at 30°C, with an extremely rapid temperature dependence in this region, which is believed to result from very small electron exchange couplings within the OEC (3). Measured Tim values have been used to calculate electron spin relaxation times xsi of the Mn ion that acts as the H relaxation trap (Fig. 3). Calculations assume an inner sphere dipolar interaction to a single H2O. Four situations were considered (1) that the trap consists of a Mn(lll) monomer (S=2, pe=4.9 BM), (2) a manganese(IV) monomer (S=3/2, pe=3.9 BM), and...

In the Bronsted-Lowry theory all substances are considered, to some extent, ainphoteric. Theoretically, the strength of individual acids can be expressed through the equilibrium constant of process (I), K, called the "acidity constant" its reciprocal is termed the "basicity constant," /Tt,. Since neither acidity nor basicity of a system (system 1) manifest themselves without a proton acceptor or a proton donor (system 2), the individual constants and cannot be measured directly. One can, however, measure the equilibrium constant of the protolysis reaction (II) ... 

The existence of bimolecular proton exchange was demonstrated in aqueous solutions of some amino-acids (36, 42) and nucleotides (381, 3) through ultrasonic absorption measurements. These exchanges occur between differently ionized forms of the same amino-acid or nucleotide. With nucleotides the bimolecular exchange occurs between the secondary phosphoric acid function of the phosphate moiety and a protonatable group of the base ring, and is coupled with a fast stacking process, as well as with protolysis reactions at each of the two protonatable sites (38b,U3). 

This follows from the auto-protolysis reaction equilibrium of hydrofluoric acid [(Eq2.6)], which is displaced to the right by boron trifluoride by the reaction (Eq 2.7). 

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