The Relation Between Rates of General Basic Catalysis in Different Reactions

Pfluger, Helmuth L.

doi:10.1021/ja01273a511

Cited by 7 publications

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“…One of the present authors has made this point previously ,and it still seems to him legitimate [20]. Table 1 gives the Pfluger analysis for the eight compounds investigated [12,13] . Since it was not possible to take rate measurements with exactly the same acid strengths for all the phenylacetylenes, some of the values were interpolated from the profiles in Fig.…”

Section: Resultsmentioning

confidence: 64%

“…Rather we restrict our attention to the experimentally observed regions of overlap, which gave direct evidence, on the one hand, as to the operation of any correlation of reactivity with selectivity, or on the other, as to the applicability of the Ht acidity function. Table 1 gives the Pfluger analysis for the eight compounds investigated [12,13] . As such this may be said to be over 50 years out of date!…”

Section: Resultsmentioning

confidence: 99%

“…This would enable examination of the degree ofIinearity and parallelism of Pfluger plots [12,13] over as wide an acidity range as possible, and thus permit as accurate an assessment as possible of whether any RSP effect arose to limit the validity of the proposed Htscale. This would enable examination of the degree ofIinearity and parallelism of Pfluger plots [12,13] over as wide an acidity range as possible, and thus permit as accurate an assessment as possible of whether any RSP effect arose to limit the validity of the proposed Htscale.…”

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confidence: 99%

“…Our aim was to extend the range ofoverlap, between one set of measurements and the next, to a maximum, within the range of applicability of the experimental procedure. This would enable examination of the degree ofIinearity and parallelism of Pfluger plots [12,13] over as wide an acidity range as possible, and thus permit as accurate an assessment as possible of whether any RSP effect arose to limit the validity of the proposed Htscale. to 10 ml with acid of the appropriate strength.…”

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confidence: 99%

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Constant Selectivity in Proton Exchange Reactions Between Aqueous Sulphuric Acid and Acetylenes

Chokotho

Johnson

1985

Israel Journal of Chemistry

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Linear Pfluger plots of unit slope are obtained from logarithmic rate constants for acid–catalysed hydration of phenylacetylene and its substituted derivatives p‐OCH3, p‐CH3, m‐CH3, p‐Br, m‐Cl, m‐NO2, p‐NO2 in aqueous sulphuric acid solution. This direct experimental observation of absence of any dependence on selectivity gives evidence for the applicability of the kinetic acidity function in these systems.

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Section: Resultsmentioning

confidence: 64%

Section: Resultsmentioning

confidence: 99%

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confidence: 99%

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confidence: 99%

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Constant Selectivity in Proton Exchange Reactions Between Aqueous Sulphuric Acid and Acetylenes

Chokotho

Johnson

1985

Israel Journal of Chemistry

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“…Energy curves for removal of a proton Finally, a brief account will be given of some apparent anomalies in catalysis by amines. In the decomposition of nitramide in aqueous solution the catalytic effect of seven nuclear-substituted anilines conforms accurately to a Br0nsted relation ( 10), but isolated data for tertiary amines show considerable deviations from this relation (18). A recent study of the same reaction (7) shows that primary and tertiary bases each obey a relation like equation 1, with the same value of ß, but that the value of G¡, for tertiary bases is about four times as great as that for primary bases.…”

Section: +O-mentioning

confidence: 61%

Molecular Structure and Deviations from the Bro***nsted Relation.

Bell¹

1951

J. Phys. Chem.

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Kinetics and mechanism of the cyclic‐hemiacetal ring opening in 2‐keto‐L‐gulonic acid. A polarographic study

Los

Gaspar

1960

Recl. Trav. Chim. Pays‐Bas

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The Occurrence of two consecutive cathodic waves, both with absolute rate control, in the case of the polarographic reduction of 2-keto-~-gulonic acid in a buffer solution of malonic acid (pH between 4.8 and 6.3) is de-scribed. The theory of this case is based on the assumption that 2dketo-gulonic acid or its anion predominantly exists in the cyclic-hemiacetal form, which is non-reducible, but which produces the free keto-acid or its anion by a very rapid reaction in the zone around the dropping mercury electrode. The latter substances are reducible, with different half wave potentials. Expressions in the relevant rate constants are derived for both the total current and the current of the first wave. This does not permit the calculation of all the rate constants involved. However, it could be shown that the wave heights are related to pH in the way predicted by the theory. Definite conclusions with respect to the relative magnitude of the rate constants could be drawn. The single wave in the lower pH range of 0.2 to 3.5 was also studied as a function of pH. The reaction mechanism is discussed on the basis of the relationships found and in connection with the expected influence of the ionization of the carboxyl group upon the reactivity of the catalytic species present. The process of ring closure or opening was shown to be second-order, rather than third.In 1947, Brdicka* reported on the polarography of pyruvic acid and phenylglyoxylic acid. In the pH range of 5 to 8 (Mclluaine buffer) the solmutions of these compounds were shown to give two consecutive waves. The first of these waves, at the more positive potential, was attributed to the reduction of the acid, the second to the reduction of its anion. Although the total wave height was that expected for complete diffusion control, corresponding to the analytical concentration of the acid, the height of the first wave was much too large to be accounted for in terms of diffusion of the acid. The first wave thereupon was posbulated to be of a kinetic nature, i.e. caused

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The Relation Between Rates of General Basic Catalysis in Different Reactions

Cited by 7 publications

References 0 publications

Constant Selectivity in Proton Exchange Reactions Between Aqueous Sulphuric Acid and Acetylenes

Constant Selectivity in Proton Exchange Reactions Between Aqueous Sulphuric Acid and Acetylenes

Molecular Structure and Deviations from the Bro***nsted Relation.

Kinetics and mechanism of the cyclic‐hemiacetal ring opening in 2‐keto‐L‐gulonic acid. A polarographic study

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