Chemical constitution and the dissociation constants of monocarboxylic acids. Part XIII. Some alkylbenzoic acids exhibiting steric effects

Dippy, J. F. J.; Hughes, S. R. C.; Laxton, J. W.

doi:10.1039/jr9540001470

Cited by 32 publications

(11 citation statements)

References 0 publications

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“…In this paper, we have extended the above studies to methylsubstituted benzoic acids without ortho substituents, uiz 3,3,4, Early studies of the acidities of these acids in water 3*8 as well as in mixed aqueous solvents6*9 did not reveal any significant ABE: the substituent effects were additive within experimental error, and this was adopted as a typical behaviour. However, the experimental enthalpies of formation of 3-5 do not exhibit strict additive behaviour since they cannot be calculated from group contributions without additional correction terms.…”

Section: Introductionmentioning

confidence: 93%

“…7-9 In terms of isodesmic reactions, the additive character can be appreciated using eqn. (3) for the enthalpies of formation, or eqn. (3a) for the acidities.…”

Section: Introductionmentioning

confidence: 99%

“…Estimated average experimental error in the whole line, obtained as a combination of the uncertainties of all quantities involved in the calculation. Deviations from additivity, calculated according to eqn (3)…”

mentioning

confidence: 99%

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Non-classical buttressing effect: gas-phase ionization of some methyl-substituted benzoic acids

Decouzon¹,

Exner²,

Gal³

et al. 1996

J. Chem. Soc., Perkin Trans. 2

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Section: Introductionmentioning

confidence: 93%

“…7-9 In terms of isodesmic reactions, the additive character can be appreciated using eqn. (3) for the enthalpies of formation, or eqn. (3a) for the acidities.…”

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Non-classical buttressing effect: gas-phase ionization of some methyl-substituted benzoic acids

Decouzon¹,

Exner²,

Gal³

et al. 1996

J. Chem. Soc., Perkin Trans. 2

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“…Another alternative method (21,22,23) From tables (5,6,7), the following conclusions were deduced: 1-The acidity of any acid was increased by increasing temperature.…”

Section: Between λ Versus √M For Benzylidene-phydroxyaniline At Diffementioning

confidence: 99%

Determination of pKa for some Schiff bases derived from benzaldehyde and amino phenols by conductivity measurement

AL-Dabbagh¹

2014

J.Edu.Sci.

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‫ي‬ ‫عنى‬ ‫ه‬ ‫ل‬ ‫ي‬ ‫دير‬ ‫ت‬ ‫لبح‬ pKa ‫ت‬ ‫ليد‬ ‫ت‬ ‫ةر‬ ‫لل‬ ‫لت‬ ‫ق‬ ‫دد‬ ‫ا‬ ‫ا‬ ‫ش‬ ‫عد‬ ‫بعو‬ ‫ل‬ ‫ع‬ ‫نات‬ ‫اليم‬ ‫ت‬ ‫حض‬ ‫مع‬ ‫يهاي‬ ‫ل‬ ‫لبنز‬ ‫تفاشالت‬ ‫ةق‬ ‫ط‬ ‫شن‬ ‫قت‬ ‫ر‬ ‫ل‬ p,m,o ‫م‬ ‫باقيخ‬ ‫ندل‬ ‫ف‬ ‫ند‬ ‫م‬ ‫ت‬ ‫اق‬ ‫لس‬ ‫ت‬ ‫ةر‬ ‫لل‬ . ‫د‬ ‫ف‬ ‫عت‬ ‫الا‬ ‫ات‬ ‫اق‬ ‫ى‬ ‫ش‬ ‫اق‬ ‫باالشيم‬ ‫ت‬ ‫ب‬ ‫ع‬ ‫لي‬ ‫ا‬ ‫باته‬ ‫ه‬ ‫ن‬ ‫م‬ ‫لياه‬ ‫ك‬ ‫ت‬ ‫وع‬ ‫ل‬ ‫النصهار.‬ ‫قرجات‬ ‫لى‬ ‫باالضافت‬ ‫ء‬ ‫لحم‬ ‫وتحت‬ ‫ت‬ ‫بنفسج‬ ‫ا‬ ‫شم‬ ‫دحع‬ ‫ل‬ " ‫ل‬ ‫ت‬ ‫م‬ ‫اة‬ ‫نرص‬ ‫ه‬ ‫ف‬ ‫اهك‬ ‫تس‬ ‫ع‬ ‫ت‬ ‫ن‬ ‫روج‬ ‫له‬ ‫و‬ ‫ال‬ ‫ة‬ ‫ت‬ ‫ق‬ ‫ر‬ ‫ل‬ ‫د‬ ‫ه‬ ‫ه‬ ‫ف‬ pKa ‫ل‬ benzylidene -o-hydroxy aniline. ‫ه‬ ‫ف‬ ‫دل‬ ‫ن‬ ‫لف‬ ‫ت‬ ‫مجمدش‬ ‫دق‬ ‫لدج‬ ‫ة‬ ‫دحع‬ ‫ل‬ ‫ا‬ ‫عم‬ ‫عع‬ ‫مد‬ p,m ‫لد‬ ‫ليأث‬ ‫ا‬ ‫ا‬ ‫ش‬ ‫لرد‬ ‫الوله‬ ‫ن‬ ‫الم‬ ‫جهت‬ ‫من‬ ‫ل‬ ‫ك‬ ‫ى‬ ‫ش‬ ‫ضح‬ pKa ‫ت.‬ ‫لمسيحص‬ ‫خ‬ ‫ه‬ ‫لي‬ ‫ا‬ ‫ا‬ ‫ش‬ ‫عد‬ ‫أين‬ ‫ت‬ ‫اشالت‬ ‫ليف‬ ‫ت‬ ‫ال‬ ‫ينم‬ ‫مدق‬ ‫لي‬ ‫ت‬ ‫لميا‬ ‫اغ‬ ‫حس‬ ‫ك‬ ‫ت‬ ' ‫تظه‬ ‫ك‬ ‫لس‬ ‫ت‬ ‫لمدجب‬ ‫و‬ ‫ار‬ ‫الا‬ ΔG˚ ‫و‬ ΔH˚ ‫ك‬ ‫م‬ ‫تمي‬ ‫ا‬ ‫نم‬ ‫د‬ ΔS˚ ‫يها‬ ‫مناع‬ ‫ك‬ ‫ت‬ ‫ه‬ ‫لي‬ ‫و‬ ‫البت‬ ‫لس‬ ‫و‬ ‫ار‬ ‫الا‬ ‫ل‬ ‫باليفص‬ . Abstract:The aim of this work is concerned with the determination of pka for some Schiff bases by conductivity method.These imines are prepared by reactions of benzaldehyde with o,m,p-amino phenols by standard method.The structures of these imines are confirmed by using some physical methods, namely, U.V,I.R and melting points.Experimentally it is observed,that intramolecular hydrogen bonding may contribute in decreasing pka value of benzylidene-ohydroxyaniline. The presence of phenolic groups at m and p-positions of Determination of pKa for some Schiff bases derived from benzaldehyde and … 2 primary amine side of the Schiff bases, have a noticeable influence on the collected pka values.The thermodynamic of ionization reactions of these Schiff bases are determined. These showed a positive sign values of ΔG˚ and ΔH˚ thermodynamic parameters. Also ΔS˚ value has a negative sign. These positive and negative signs values are discussed in detail.

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“…Methyl-substituted benzoic acids were one of the first sets of compounds on which steric effects were investigated. [1][2][3][4] They represent a suitable model for studying steric effects since the methyl group has a defined size and polarizability but is itself practically nonpolar. On the basis of their dissociation constants in water, the terms of steric hindrance to conjugation 1 and of the buttressing effect 5 were defined.…”

Section: Introductionmentioning

confidence: 99%

Solvation and steric hindrance in methyl-substituted benzoic acids

Kulhánek¹,

Exner²

1998

J. Chem. Soc., Perkin Trans. 2

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Chemical constitution and the dissociation constants of monocarboxylic acids. Part XIII. Some alkylbenzoic acids exhibiting steric effects

Abstract: Two earlier papers (J., 1941, 550; 1944, 411), which appeared under specific titles, are regarded as Parts XI and XI1 of this series.

Cited by 32 publications

References 0 publications

Non-classical buttressing effect: gas-phase ionization of some methyl-substituted benzoic acids

Non-classical buttressing effect: gas-phase ionization of some methyl-substituted benzoic acids

Determination of pKa for some Schiff bases derived from benzaldehyde and amino phenols by conductivity measurement

Solvation and steric hindrance in methyl-substituted benzoic acids

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