dc.contributor.author |
Ximenis Campins, Marta
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dc.contributor.author |
Bustelo, Emilio
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dc.contributor.author |
Algarra, Andrés G.
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dc.contributor.author |
Vega Reynés, Manuel
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dc.contributor.author |
Rotger Pons, María del Carmen
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dc.contributor.author |
Basallote, Manuel G.
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dc.contributor.author |
Costa Torres, Antonio
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dc.date.accessioned |
2018-12-11T11:50:51Z |
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dc.date.available |
2018-12-11T11:50:51Z |
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dc.identifier.uri |
http://hdl.handle.net/11201/148656 |
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dc.description.abstract |
[eng] The hydrolytic degradation of squaramides and squaramic acids, the product of partial hydrolysis of squaramides, has been evaluated by UV spectroscopy at 37 °C in the pH range 3−10. Under these conditions, the compounds are kinetically stable over long time periods (>100 days). At pH >10, the hydrolysis of the squaramate anions shows first-order dependence on both squaramate and OH−. At the same temperature and [OH−], the hydrolysis of squaramides usually displays biphasic spectral changes (A → B → C kinetic model) with formation of squaramates as detectable reaction intermediates. The measured rates for the first step (k1 ≈ 10−4 M−1 s−1) are 2−3 orders of magnitude faster than those for the second step (k2 ≈ 10−6 M−1 s−1). Experiments at different temperatures provide activation parameters with values of ΔH⧧ ≈ 9−18 kcal mol−1 and ΔS⧧ ≈ −5 to −30 cal K−1 mol−1. DFT calculations show that the mechanism for the alkaline hydrolysis of squaramic acids is quite similar to that of amides. |
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dc.format |
application/pdf |
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dc.relation.isformatof |
Versió postprint del document publicat a: https://doi.org/10.1021/acs.joc.6b02963 |
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dc.relation.ispartof |
Journal of Organic Chemistry, 2017, vol. 82, p. 2160-2170 |
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dc.rights |
(c) American Chemical Society , 2017 |
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dc.subject.classification |
54 - Química |
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dc.subject.other |
54 - Chemistry. Crystallography. Mineralogy |
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dc.title |
Kinetic analysis and mechanism of the hydrolytic degradation of squaramides and squaramic Acids |
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dc.type |
info:eu-repo/semantics/article |
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dc.type |
info:eu-repo/semantics/acceptedVersion |
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dc.date.updated |
2018-12-11T11:50:52Z |
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dc.rights.accessRights |
info:eu-repo/semantics/openAccess |
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dc.identifier.doi |
https://doi.org/10.1021/acs.joc.6b02963 |
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