75. Chemical constitution and the dissociation constants of monocarboxylic acids. Part III

Dippy, J. F. J.; Williams, Frank R.; Lewis, R. H.

doi:10.1039/jr9350000343

Cited by 6 publications

(2 citation statements)

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“…Minimization of SS was carried out by adjusting the p K a values of all the acids in Table except for 3‐ and 4‐fluorobenzoic acids, which were used as anchor compounds, and their p K a values were fixed to the literature values 3.86 and 4.14, respectively. These acids were used as anchor points because they have been previously measured repeatedly, and the values have been rated as trustworthy . Although both of the anchor points are on the bottom of the scale (see Table ), it can be seen, that there is no systematic error comparing the assigned p K a values and values from the literature at the top of the scale.…”

Section: Resultsmentioning

confidence: 99%

“…An average compound is linked to the scale by at least three measurements, so, the average uncertainty because of random effects of the obtained p K a values can be estimated as 0.052/

\sqrt{3}

= 0.030. From the literature, the standard uncertainty of the p K a values of 3‐ and 4‐fluorobenzoic acids can be conservatively estimated as 0.01 p K a units. This value can serve as estimate of standard uncertainty because of systematic effects, affecting all the acids on the scale the same way.…”

Section: Resultsmentioning

confidence: 99%

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Determination of pK_a values of fluorocompounds in water using ¹⁹F NMR

Parman

Toom

Selberg

et al. 2019

J of Physical Organic Chem

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Brønsted acidities of 19 fluorocompounds in the pKa range from 3.5 to 10 have been measured in aqueous solution using an approach involving absolute and relative pKa measurements with 19F NMR. 19F NMR has not been frequently used for determining pKa values, but it has a number of advantages, especially when relative values are considered: accurate concentrations not needed, tolerant to impurities, several compounds can be measured simultaneously, several uncertainty sources cancel out.

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Section: Resultsmentioning

confidence: 99%

“…An average compound is linked to the scale by at least three measurements, so, the average uncertainty because of random effects of the obtained p K a values can be estimated as 0.052/

\sqrt{3}

Section: Resultsmentioning

confidence: 99%

Determination of pK_a values of fluorocompounds in water using ¹⁹F NMR

Parman

Toom

Selberg

et al. 2019

J of Physical Organic Chem

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Mass Spectrometric Investigations of Phenylacetic Acid Derivatives, III: Fragmentations of meta‐ and para‐substituted Phenylacetamides after Electron Impact

Lee

Mayer

Wiegrebe

1988

Archiv der Pharmazie

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The electron impact induced fragmentations of m-and p-substituted phenylacetamides and N,N-dimethyl-phenylacetamides 1-14 were investigated and compared with the o-analogues. All m-and p-substituted amides yield molecular ions with high relative intensities which do not lose their meta-and para-substituents. Loss of HNCO from M+. is dominant in the prim. amides, whilst for the tert. amides the classical benzyl cleavage is the most favourable fragmentation pathway. We have previously reported on the fragmentations of ortho-substituted phenylacetamides,) and phenylacetate~~) after electron impact. Of the ortho-substituted phenylacetamides studied (substituent X = CI, Br, F, NO,, OCH,, CH,, and CN) only the 0-0, o-Br-, and o-NO,-amides lose the ortho substituents directly from their M+. giving rise to large (M-'XPsignals, and do not yield detectable M+'(

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