Theoretical insight on the treatment of β-hexachlorocyclohexane waste through alkaline dehydrochlorination

Abstract The occurrence of 4.8–7.2 million tons of hexachlorocyclohexane (HCH) isomers stocked in dumpsites around the world constitutes a huge environmental and economical challenge because of their toxicity and persistence. Alkaline treatment of an HCH mixture in a dehydrochlorination reaction is...

Descripción completa

Guardado en:

Detalles Bibliográficos
Autores principales:	Alicia Bescós, Clara I. Herrerías, Zoel Hormigón, José Antonio Mayoral, Luis Salvatella
Formato:	article
Lenguaje:	EN
Publicado:	Nature Portfolio 2021
Materias:	Medicine R Science Q
Acceso en línea:	https://doaj.org/article/ed9185fa5c9e40cb89d569f1a0cbca64
Etiquetas:	Agregar Etiqueta Sin Etiquetas, Sea el primero en etiquetar este registro!

id	oai:doaj.org-article:ed9185fa5c9e40cb89d569f1a0cbca64
record_format	dspace
spelling	oai:doaj.org-article:ed9185fa5c9e40cb89d569f1a0cbca642021-12-02T13:39:55ZTheoretical insight on the treatment of β-hexachlorocyclohexane waste through alkaline dehydrochlorination10.1038/s41598-021-88060-72045-2322https://doaj.org/article/ed9185fa5c9e40cb89d569f1a0cbca642021-04-01T00:00:00Zhttps://doi.org/10.1038/s41598-021-88060-7https://doaj.org/toc/2045-2322Abstract The occurrence of 4.8–7.2 million tons of hexachlorocyclohexane (HCH) isomers stocked in dumpsites around the world constitutes a huge environmental and economical challenge because of their toxicity and persistence. Alkaline treatment of an HCH mixture in a dehydrochlorination reaction is hampered by the low reactivity of the β-HCH isomer (HCl elimination unavoidably occurring through syn H–C–C–Cl arrangements). More intriguingly, the preferential formation of 1,2,4-trichlorobenzene in the β-HCH dehydrochlorination reaction (despite the larger thermodynamical stability of the 1,3,5-isomer) has remained unexplained up to now, though several kinetic studies had been reported. In this paper, we firstly show a detailed Density Functional study on all paths for the hydroxide anion-induced elimination of β-HCH through a three-stage reaction mechanism (involving two types of reaction intermediates). We have now demonstrated that the first reaction intermediate can follow several alternative paths, the preferred route involving abstraction of the most acidic allylic hydrogen which leads to a second reaction intermediate yielding only 1,2,4-trichlorobenzene as the final reaction product. Our theoretical results allow explaining the available experimental data on the β-HCH dehydrochlorination reaction (rate-determining step, regioselectivity, instability of some reaction intermediates).Alicia BescósClara I. HerreríasZoel HormigónJosé Antonio MayoralLuis SalvatellaNature PortfolioarticleMedicineRScienceQENScientific Reports, Vol 11, Iss 1, Pp 1-8 (2021)
institution	DOAJ
collection	DOAJ
language	EN
topic	Medicine R Science Q
spellingShingle	Medicine R Science Q Alicia Bescós Clara I. Herrerías Zoel Hormigón José Antonio Mayoral Luis Salvatella Theoretical insight on the treatment of β-hexachlorocyclohexane waste through alkaline dehydrochlorination
description	Abstract The occurrence of 4.8–7.2 million tons of hexachlorocyclohexane (HCH) isomers stocked in dumpsites around the world constitutes a huge environmental and economical challenge because of their toxicity and persistence. Alkaline treatment of an HCH mixture in a dehydrochlorination reaction is hampered by the low reactivity of the β-HCH isomer (HCl elimination unavoidably occurring through syn H–C–C–Cl arrangements). More intriguingly, the preferential formation of 1,2,4-trichlorobenzene in the β-HCH dehydrochlorination reaction (despite the larger thermodynamical stability of the 1,3,5-isomer) has remained unexplained up to now, though several kinetic studies had been reported. In this paper, we firstly show a detailed Density Functional study on all paths for the hydroxide anion-induced elimination of β-HCH through a three-stage reaction mechanism (involving two types of reaction intermediates). We have now demonstrated that the first reaction intermediate can follow several alternative paths, the preferred route involving abstraction of the most acidic allylic hydrogen which leads to a second reaction intermediate yielding only 1,2,4-trichlorobenzene as the final reaction product. Our theoretical results allow explaining the available experimental data on the β-HCH dehydrochlorination reaction (rate-determining step, regioselectivity, instability of some reaction intermediates).
format	article
author	Alicia Bescós Clara I. Herrerías Zoel Hormigón José Antonio Mayoral Luis Salvatella
author_facet	Alicia Bescós Clara I. Herrerías Zoel Hormigón José Antonio Mayoral Luis Salvatella
author_sort	Alicia Bescós
title	Theoretical insight on the treatment of β-hexachlorocyclohexane waste through alkaline dehydrochlorination
title_short	Theoretical insight on the treatment of β-hexachlorocyclohexane waste through alkaline dehydrochlorination
title_full	Theoretical insight on the treatment of β-hexachlorocyclohexane waste through alkaline dehydrochlorination
title_fullStr	Theoretical insight on the treatment of β-hexachlorocyclohexane waste through alkaline dehydrochlorination
title_full_unstemmed	Theoretical insight on the treatment of β-hexachlorocyclohexane waste through alkaline dehydrochlorination
title_sort	theoretical insight on the treatment of β-hexachlorocyclohexane waste through alkaline dehydrochlorination
publisher	Nature Portfolio
publishDate	2021
url	https://doaj.org/article/ed9185fa5c9e40cb89d569f1a0cbca64
work_keys_str_mv	AT aliciabescos theoreticalinsightonthetreatmentofbhexachlorocyclohexanewastethroughalkalinedehydrochlorination AT claraiherrerias theoreticalinsightonthetreatmentofbhexachlorocyclohexanewastethroughalkalinedehydrochlorination AT zoelhormigon theoreticalinsightonthetreatmentofbhexachlorocyclohexanewastethroughalkalinedehydrochlorination AT joseantoniomayoral theoreticalinsightonthetreatmentofbhexachlorocyclohexanewastethroughalkalinedehydrochlorination AT luissalvatella theoreticalinsightonthetreatmentofbhexachlorocyclohexanewastethroughalkalinedehydrochlorination
_version_	1718392651454087168

Theoretical insight on the treatment of β-hexachlorocyclohexane waste through alkaline dehydrochlorination

Ejemplares similares