Salt effect normal

Rubidium chloride even slows the reaction, this is especially well seen within a time span of 1-3 hr after the start of the process (Fig. 2, curve 2). In this case the normal salt effect is likely to prevail over the effect of oximate ion pair separation due to substitution of the potassium cation by the rubidium cation. The addition of cesium carbonate during the first 1.5 hr does not much affect the rate of the formation of 2-phenylpyrrole. The accelerating effect of these additives becomes evident only 2 hr after the beginning of the reaction and gradually increases (5 hr later the yield gain of pyrrole is 7% as compared with a standard run, Fig. 2, curve 4) which seems to result from a slow rate of heterophase exchange process ... 

A long series on the kinetics and mechanism of the unimolecular heterolysis of commercial haloorganic compounds has continued in a study of the effect of bromide salts and lithium perchlorate on the ionization rate of benzhydryl bromide in y-butyrolactone and acetone.122 The verdazyl indicator method was applied. The nature of special and normal salt effects has also been discussed.123... 

The pH-independent reaction of cyclopentadiene oxide 12 in water is clearly different from that of 13.97 This reaction yields 33% of 3-cyclopentenone, 35% of cis-2,4-pentadienal and 35% of a mixture of cis and trans 1,2- and 1,4-diols (Scheme 28). When the reaction is carried out in D20 instead of H20, no deuterium is incorporated into the ketone product. Thus, 1,2-hydrogen migration is required for this reaction just as it is in the rearrangement of arene oxides to phenols. The mechanisms of product formation in this reaction are not fully understood. The observation that the diol mixture is similar to that from the acid-catalyzed hydrolysis of 12 suggests that an allylic carbocation may be involved in the diol-forming reaction. Ketone (96) and dienal (97) products are potentially formed either by stepwise or concerted mechanisms, and there is insufficient evidence to rule out either one. There is a significant normal salt effect on this pH-independent... 

The effect of ionic environment on the rate of diffusion controlled e"aq reactions is revealed when one compares the experimental rate constants with the calculated values. In Table I the highly charged bis-pentacyano cobaltic peroxide (I) is much more reactive than expected for a pentavalent anion (1.11). It has been claimed (19) that polyvalent anions exhibit a lower effective charge in their kinetic behavior than expected from their structural formulae. We have checked the salt effect on the reaction of I + e m and compared it with the NOjf e m reaction. The results presented in Table IV and Figure 1 show that nitrate ions possess a normal salt effect, a result previously obtained by competition kinetics (15, 17). On the other hand, the salt effect of the I + e"aq reaction shows that this bis-pentacyano cobaltic peroxide ion has an... 

If the reaction mixture for an SnI reaction includes added nucleophiles, particularly anions, then not only the rate but also the product of the reaction can be affected. For example, adding 0.05 M sodium azide to a solution of 4,4 -dimethylbenzhydryl chloride in 85% aqueous acetone was seen to increase the observed rate constants for the solvolysis reaction by 50%, and the product was found to consist of 66% of 4,4 -dimethylbenzhydryl azide and 34% of the alcohol. ° This increase in reactivity is explained on the basis of a normal salt effect, meaning that the increased ionic strength of the reaction medium increases the effective "polarity" of the reaction medium. Various theoretical and empirical treatments suggest that the rate constant should increase with the log of the concentration of added salt, with the first power of concentration of added salt, or with the square root of the concentration of added salt, depending on the reactants and solvents. 

In this reaction the effect of changing the ionic strength of the medium was also studied by addition of sodium perchlorate which caused the rate coefficient to decrease. However, this was shown to arise from the resultant change in pH of the solution, for when this was allowed for, the normal positive salt effect was observed. 

In highly aqueous media, salt effects on nonelectrolyte-nonelectrolyte reactions should normally be of the form (Gordon,... 

Assuming the argument is valid, it would then be possible to contact fused NaCl (or, presumably NaOH, Na2S, or smelts with these constituents) with water and to state that the resulting explosion stemmed from a homogeneous nucleation of a solution of salt in water. Their hypothesis therefore explains qualitatively the effect of variations in smelt composition on explosivity. It also clarifies the result that green liquor normally explodes more violently than pure water since, in the former, there are dissolved salts (of the NaCl type) to enhance the salt effect at the interface. 

The special salt effect. The addition of LiC104 or LiBr in the acetolysis of certain tosylates produced an initial steep rate acceleration that then decreased to the normal linear acceleration (caused by the ordinary salt effect).45 This is interpreted as follows the CIO., ... 

The Sulphites.—Sulphurous acid gives rise to normal sulphites of the type M2S03 and acid salts of the type MHS03, where M represents a univalent metal atom. The normal salts are odourless and do not resemble the free acid or sulphur dioxide in their very harmful effect on living organisms. On the other hand, the acid sulphites readily yield sulphur dioxide they have an acid reaction towards phenolphthalein, but are neutral towards methyl orange. 

Since the heat developed by the 1st, 2nd, and 3rd eq. of alkali progressively increases, it would appear as if the acid here behaves as if it were dibasic. E. Cornec examined the effect of the progressive neutralization of hypophosphorie acid by potassium hydroxide on its f.p., and the resulting curve is lowered down to that required for the normal salt, K4P206. There are breaks in the curve indicating the existence of the primary, secondary, tertiary, and quaternary salts. Analogous results were obtained with aq. ammonia and hypophosphorie acid. The behaviour of the acid is very similar to that of pyrophosphoric acid. 

Lithium salts effect, that the intermediate betaines do not react further. These lithiobetaines which are quite stable may be deprotonated. Deprotonation is equal to the lost of one stereogenic centre. Use of a steric hindered proton donator then leads to the trans lithiobetaine. The reaction takes normal course, if lithium is exchanged by potassium. 

A normal, a special, and a negative special salt effect have been detected in the SnI reaction between benzhydryl chloride and LiC104 in y-butyrolactone.71... 

FPA results obtained at different salt conditions may not be directly comparable because the fluorescence properties of 6-MI, including the lifetime (t), are salt dependent. The salt dependence of the FPA of a helix in a complex construct should thereby be normalized relative to the FPA of a short control duplex of the same sequence of the targeted helix to account for salt effects on the local environment of the 6-MI fluorophore. The normalization ratio, rnoml, can be calculated as the ratio between the apparent rotational correlation time, 9, of the constructs and the control duplex only, rnomi = construct/ control- is related to the rate of anisotropy decay, with larger 9 associated with higher anisotropy. If the basic Perrin equation for a sphere (Eq. (14.3)) is used to simplify calculation, then... 

Performance of an RO system, specifically the permeate flow rate, salt rejection and pressure drop, is a function of membrane fouling, scaling, and degradation, as previously discussed (See Chapter 11.3). This chapter covers the detailed effects of membrane fouling, scaling, and degradation have on normalized product flow, normalized salt rejection, and pressure drop. 

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