Solvent and substituent effects on the kinetics of thermolysis of cis-fused 1,2,4-trioxanes
- Autores
- Cafferata, Lázaro F. R.; Jefford, Charles W.
- Año de publicación
- 2001
- Idioma
- inglés
- Tipo de recurso
- artículo
- Estado
- versión publicada
- Descripción
- The kinetics of the thermal decomposition reaction of cis-6-phenyl-5,6-(2- phenylpropyliden)-3,3-pentamethylene-1,2,4-trioxacyclohexane (Ia) were investigated in benzene and methanol solutions in the temperature and concentration ranges of 353.3-413.2 K and (1.1 - 13.1)×10-3 M, respectively. First-order rate constant values were obtained for up to at least ca. 20% conversions of that cyclic peroxide. The activation parameter values for the initial unimolecular homolysis of that molecule, results supported by the effect of the addition of di-tert-butyl-p-cresol as a free radical scavenger, indicate a stepwise reaction mechanism which is in keeping with the reaction products analysis. The corresponding activation parameters for the reaction of Ia in methanol (ΔH# = 20.2 ± 0.6 kcal mol-1; ΔS# = 0.1 ± 1.6 cal mol-1K-1; ΔG# = 20.2 ± 0.6 kcal mol-1 and in benzene (ΔH# = 15.4 ± 0.2 kcal mol-1; ΔS# = -13.2 ± 0.5 cal mol-1K-1; ΔG# = 20.5 ± 0.2 kcal mol-1 solutions are compared with values obtained for cis-6-phenyl-5,6-(2-phenylpropyliden)-3,3- tetramethylene-1,2,4-trioxacyclohexane (Ib) thermolysis in the same solvents. The thermolysis kinetics of Ia are less sensitive to solvent changes compared to the behaviour already reported for the analogous reactions of Ib. Because both molecules in solution are flexible structures due to their configurations, the relatively small solvent effect found on the former trioxane reaction is attributed to the extent of the chain of methylene groups attached on C-3 of the corresponding molecular rings. Furthermore, the pertinent substituent effect on the peroxidic bond strength of those molecules in solution was evaluated.
Facultad de Ciencias Exactas - Materia
-
Ciencias Exactas
Química
cis-Substituted 1,2,4-trioxanes
cresol
kinetics
cyclohexane derivative
methanol
solvent and substituent effects
stepwise reaction mechanism
peroxide
scavenger
solvent
unclassified drug
chemical bond - Nivel de accesibilidad
- acceso abierto
- Condiciones de uso
- http://creativecommons.org/licenses/by/3.0/
- Repositorio
- Institución
- Universidad Nacional de La Plata
- OAI Identificador
- oai:sedici.unlp.edu.ar:10915/35056
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Solvent and substituent effects on the kinetics of thermolysis of cis-fused 1,2,4-trioxanesCafferata, Lázaro F. R.Jefford, Charles W.Ciencias ExactasQuímicacis-Substituted 1,2,4-trioxanescresolkineticscyclohexane derivativemethanolsolvent and substituent effectsstepwise reaction mechanismperoxidescavengersolventunclassified drugchemical bondThe kinetics of the thermal decomposition reaction of <i>cis</i>-6-phenyl-5,6-(2- phenylpropyliden)-3,3-pentamethylene-1,2,4-trioxacyclohexane <b>(Ia)</b> were investigated in benzene and methanol solutions in the temperature and concentration ranges of 353.3-413.2 K and (1.1 - 13.1)×10<SUP>-3</SUP> M, respectively. First-order rate constant values were obtained for up to at least ca. 20% conversions of that cyclic peroxide. The activation parameter values for the initial unimolecular homolysis of that molecule, results supported by the effect of the addition of di-<i>tert</i>-butyl-<i>p</i>-cresol as a free radical scavenger, indicate a stepwise reaction mechanism which is in keeping with the reaction products analysis. The corresponding activation parameters for the reaction of <b>Ia</b> in methanol (ΔH<SUP>#</SUP> = 20.2 ± 0.6 kcal mol<SUP>-1</SUP>; ΔS<SUP>#</SUP> = 0.1 ± 1.6 cal mol<SUP>-1</SUP>K<SUP>-1</SUP>; ΔG<SUP>#</SUP> = 20.2 ± 0.6 kcal mol<SUP>-1</SUP> and in benzene (ΔH<SUP>#</SUP> = 15.4 ± 0.2 kcal mol<SUP>-1</SUP>; ΔS<SUP>#</SUP> = -13.2 ± 0.5 cal mol<SUP>-1</SUP>K<SUP>-1</SUP>; ΔG# = 20.5 ± 0.2 kcal mol<SUP>-1</SUP> solutions are compared with values obtained for cis-6-phenyl-5,6-(2-phenylpropyliden)-3,3- tetramethylene-1,2,4-trioxacyclohexane (<b>Ib</b>) thermolysis in the same solvents. The thermolysis kinetics of <b>Ia</b> are less sensitive to solvent changes compared to the behaviour already reported for the analogous reactions of <b>Ib</b>. Because both molecules in solution are flexible structures due to their configurations, the relatively small solvent effect found on the former trioxane reaction is attributed to the extent of the chain of methylene groups attached on C-3 of the corresponding molecular rings. Furthermore, the pertinent substituent effect on the peroxidic bond strength of those molecules in solution was evaluated.Facultad de Ciencias Exactas2001info:eu-repo/semantics/articleinfo:eu-repo/semantics/publishedVersionArticulohttp://purl.org/coar/resource_type/c_6501info:ar-repo/semantics/articuloapplication/pdf699-709http://sedici.unlp.edu.ar/handle/10915/35056enginfo:eu-repo/semantics/altIdentifier/url/http://www.mdpi.com/1420-3049/6/8/699info:eu-repo/semantics/altIdentifier/issn/1420-3049info:eu-repo/semantics/openAccesshttp://creativecommons.org/licenses/by/3.0/Creative Commons Attribution 3.0 Unported (CC BY 3.0)reponame:SEDICI (UNLP)instname:Universidad Nacional de La Platainstacron:UNLP2025-10-15T10:49:41Zoai:sedici.unlp.edu.ar:10915/35056Institucionalhttp://sedici.unlp.edu.ar/Universidad públicaNo correspondehttp://sedici.unlp.edu.ar/oai/snrdalira@sedici.unlp.edu.arArgentinaNo correspondeNo correspondeNo correspondeopendoar:13292025-10-15 10:49:42.243SEDICI (UNLP) - Universidad Nacional de La Platafalse |
dc.title.none.fl_str_mv |
Solvent and substituent effects on the kinetics of thermolysis of cis-fused 1,2,4-trioxanes |
title |
Solvent and substituent effects on the kinetics of thermolysis of cis-fused 1,2,4-trioxanes |
spellingShingle |
Solvent and substituent effects on the kinetics of thermolysis of cis-fused 1,2,4-trioxanes Cafferata, Lázaro F. R. Ciencias Exactas Química cis-Substituted 1,2,4-trioxanes cresol kinetics cyclohexane derivative methanol solvent and substituent effects stepwise reaction mechanism peroxide scavenger solvent unclassified drug chemical bond |
title_short |
Solvent and substituent effects on the kinetics of thermolysis of cis-fused 1,2,4-trioxanes |
title_full |
Solvent and substituent effects on the kinetics of thermolysis of cis-fused 1,2,4-trioxanes |
title_fullStr |
Solvent and substituent effects on the kinetics of thermolysis of cis-fused 1,2,4-trioxanes |
title_full_unstemmed |
Solvent and substituent effects on the kinetics of thermolysis of cis-fused 1,2,4-trioxanes |
title_sort |
Solvent and substituent effects on the kinetics of thermolysis of cis-fused 1,2,4-trioxanes |
dc.creator.none.fl_str_mv |
Cafferata, Lázaro F. R. Jefford, Charles W. |
author |
Cafferata, Lázaro F. R. |
author_facet |
Cafferata, Lázaro F. R. Jefford, Charles W. |
author_role |
author |
author2 |
Jefford, Charles W. |
author2_role |
author |
dc.subject.none.fl_str_mv |
Ciencias Exactas Química cis-Substituted 1,2,4-trioxanes cresol kinetics cyclohexane derivative methanol solvent and substituent effects stepwise reaction mechanism peroxide scavenger solvent unclassified drug chemical bond |
topic |
Ciencias Exactas Química cis-Substituted 1,2,4-trioxanes cresol kinetics cyclohexane derivative methanol solvent and substituent effects stepwise reaction mechanism peroxide scavenger solvent unclassified drug chemical bond |
dc.description.none.fl_txt_mv |
The kinetics of the thermal decomposition reaction of <i>cis</i>-6-phenyl-5,6-(2- phenylpropyliden)-3,3-pentamethylene-1,2,4-trioxacyclohexane <b>(Ia)</b> were investigated in benzene and methanol solutions in the temperature and concentration ranges of 353.3-413.2 K and (1.1 - 13.1)×10<SUP>-3</SUP> M, respectively. First-order rate constant values were obtained for up to at least ca. 20% conversions of that cyclic peroxide. The activation parameter values for the initial unimolecular homolysis of that molecule, results supported by the effect of the addition of di-<i>tert</i>-butyl-<i>p</i>-cresol as a free radical scavenger, indicate a stepwise reaction mechanism which is in keeping with the reaction products analysis. The corresponding activation parameters for the reaction of <b>Ia</b> in methanol (ΔH<SUP>#</SUP> = 20.2 ± 0.6 kcal mol<SUP>-1</SUP>; ΔS<SUP>#</SUP> = 0.1 ± 1.6 cal mol<SUP>-1</SUP>K<SUP>-1</SUP>; ΔG<SUP>#</SUP> = 20.2 ± 0.6 kcal mol<SUP>-1</SUP> and in benzene (ΔH<SUP>#</SUP> = 15.4 ± 0.2 kcal mol<SUP>-1</SUP>; ΔS<SUP>#</SUP> = -13.2 ± 0.5 cal mol<SUP>-1</SUP>K<SUP>-1</SUP>; ΔG# = 20.5 ± 0.2 kcal mol<SUP>-1</SUP> solutions are compared with values obtained for cis-6-phenyl-5,6-(2-phenylpropyliden)-3,3- tetramethylene-1,2,4-trioxacyclohexane (<b>Ib</b>) thermolysis in the same solvents. The thermolysis kinetics of <b>Ia</b> are less sensitive to solvent changes compared to the behaviour already reported for the analogous reactions of <b>Ib</b>. Because both molecules in solution are flexible structures due to their configurations, the relatively small solvent effect found on the former trioxane reaction is attributed to the extent of the chain of methylene groups attached on C-3 of the corresponding molecular rings. Furthermore, the pertinent substituent effect on the peroxidic bond strength of those molecules in solution was evaluated. Facultad de Ciencias Exactas |
description |
The kinetics of the thermal decomposition reaction of <i>cis</i>-6-phenyl-5,6-(2- phenylpropyliden)-3,3-pentamethylene-1,2,4-trioxacyclohexane <b>(Ia)</b> were investigated in benzene and methanol solutions in the temperature and concentration ranges of 353.3-413.2 K and (1.1 - 13.1)×10<SUP>-3</SUP> M, respectively. First-order rate constant values were obtained for up to at least ca. 20% conversions of that cyclic peroxide. The activation parameter values for the initial unimolecular homolysis of that molecule, results supported by the effect of the addition of di-<i>tert</i>-butyl-<i>p</i>-cresol as a free radical scavenger, indicate a stepwise reaction mechanism which is in keeping with the reaction products analysis. The corresponding activation parameters for the reaction of <b>Ia</b> in methanol (ΔH<SUP>#</SUP> = 20.2 ± 0.6 kcal mol<SUP>-1</SUP>; ΔS<SUP>#</SUP> = 0.1 ± 1.6 cal mol<SUP>-1</SUP>K<SUP>-1</SUP>; ΔG<SUP>#</SUP> = 20.2 ± 0.6 kcal mol<SUP>-1</SUP> and in benzene (ΔH<SUP>#</SUP> = 15.4 ± 0.2 kcal mol<SUP>-1</SUP>; ΔS<SUP>#</SUP> = -13.2 ± 0.5 cal mol<SUP>-1</SUP>K<SUP>-1</SUP>; ΔG# = 20.5 ± 0.2 kcal mol<SUP>-1</SUP> solutions are compared with values obtained for cis-6-phenyl-5,6-(2-phenylpropyliden)-3,3- tetramethylene-1,2,4-trioxacyclohexane (<b>Ib</b>) thermolysis in the same solvents. The thermolysis kinetics of <b>Ia</b> are less sensitive to solvent changes compared to the behaviour already reported for the analogous reactions of <b>Ib</b>. Because both molecules in solution are flexible structures due to their configurations, the relatively small solvent effect found on the former trioxane reaction is attributed to the extent of the chain of methylene groups attached on C-3 of the corresponding molecular rings. Furthermore, the pertinent substituent effect on the peroxidic bond strength of those molecules in solution was evaluated. |
publishDate |
2001 |
dc.date.none.fl_str_mv |
2001 |
dc.type.none.fl_str_mv |
info:eu-repo/semantics/article info:eu-repo/semantics/publishedVersion Articulo http://purl.org/coar/resource_type/c_6501 info:ar-repo/semantics/articulo |
format |
article |
status_str |
publishedVersion |
dc.identifier.none.fl_str_mv |
http://sedici.unlp.edu.ar/handle/10915/35056 |
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http://sedici.unlp.edu.ar/handle/10915/35056 |
dc.language.none.fl_str_mv |
eng |
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eng |
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info:eu-repo/semantics/openAccess http://creativecommons.org/licenses/by/3.0/ Creative Commons Attribution 3.0 Unported (CC BY 3.0) |
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openAccess |
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http://creativecommons.org/licenses/by/3.0/ Creative Commons Attribution 3.0 Unported (CC BY 3.0) |
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application/pdf 699-709 |
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