Ionic liquids as hydrotropes: the key towards solubility increase

Detalhes bibliográficos
Autor(a) principal: Martins, Afonso Cerqueira
Data de Publicação: 2021
Tipo de documento: Dissertação
Idioma: eng
Título da fonte: Repositório Científico de Acesso Aberto de Portugal (Repositórios Cientìficos)
Texto Completo: http://hdl.handle.net/10773/31141
Resumo: Water solubility of hydrophobic compounds is a crucial factor in the formulation of drugs, cleaning products and personal hygiene. Therefore, technology that allows us to increase their solubility and dissolution rate has attracted considerable interest not only at an academic level but also at an industrial one. In this sense, hydrotropes have been under the spotlight. These compounds are characterized as molecules possessing the capacity of promoting a drastic, several-fold increase in aqueous solubility of highly hydrophobic compounds. Recently, ionic liquids have been appointed as a promising class of catanionic hydrotropes, since both the cation and anion can contribute to the solubility increase. Although there is a vast amount of reviewing work centred on hydrotropy, its underlying mechanism is not yet fully understood. This work proposes to study the impact of salt addition on the hydrotropy phenomenon as to better understand its mechanism, both experimentally and through simulation. Herein the addition of chloride salts to aqueous solutions of an ionic liquid was found to hinder solubility by promoting aggregation of the latter, with a notably nuanced behaviour according to the salt cation valence. Hydrophobic interactions were found to be central to the aggregative effect of the hydrotrope around the solute, which seem to drive hydrotropy. The interactions between the hydrotrope and the solute presented a degree of site-specificity, lost with salt addition. Hydrotrope aggregation showed to be detrimental to the hydrotropic effect, disproving one of the dominant theories justifying the mechanism of hydrotropy.
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spelling Ionic liquids as hydrotropes: the key towards solubility increaseHydrotropyIonic liquidsHydrophobic compoundsSolubilitySaltsWater solubility of hydrophobic compounds is a crucial factor in the formulation of drugs, cleaning products and personal hygiene. Therefore, technology that allows us to increase their solubility and dissolution rate has attracted considerable interest not only at an academic level but also at an industrial one. In this sense, hydrotropes have been under the spotlight. These compounds are characterized as molecules possessing the capacity of promoting a drastic, several-fold increase in aqueous solubility of highly hydrophobic compounds. Recently, ionic liquids have been appointed as a promising class of catanionic hydrotropes, since both the cation and anion can contribute to the solubility increase. Although there is a vast amount of reviewing work centred on hydrotropy, its underlying mechanism is not yet fully understood. This work proposes to study the impact of salt addition on the hydrotropy phenomenon as to better understand its mechanism, both experimentally and through simulation. Herein the addition of chloride salts to aqueous solutions of an ionic liquid was found to hinder solubility by promoting aggregation of the latter, with a notably nuanced behaviour according to the salt cation valence. Hydrophobic interactions were found to be central to the aggregative effect of the hydrotrope around the solute, which seem to drive hydrotropy. The interactions between the hydrotrope and the solute presented a degree of site-specificity, lost with salt addition. Hydrotrope aggregation showed to be detrimental to the hydrotropic effect, disproving one of the dominant theories justifying the mechanism of hydrotropy.A solubilidade em água de compostos hidrofóbicos é um fator crucial na formulação de fármacos, produtos de limpeza e de higiene pessoal. Assim, a tecnologia que permite aumentar a solubilidade e a taxa de dissolução dos mesmos tem atraído um considerável interesse não só a nível académico como industrial. Neste sentido, os hidrótropos têm sido alvo de muita atenção. Estes compostos são caracterizados como moléculas com capacidade de promover um drástico aumento da solubilidade aquosa de compostos fortemente hidrofóbicos, aumento este em várias ordens de magnitude. Recentemente, os líquidos iónicos foram apontados como uma classe promissora de hidrótropos cataniónicos, uma vez que quer o catião como o anião pode contribuir para o aumento da solubilidade. Embora haja um vasto número de trabalho de revisão com foco na hidrotropia, o mecanismo de ação por detrás deste fenómeno ainda não está claramente entendido. Este trabalho pretende averiguar o impacto da adição de um sal no fenómeno de hidrotropia com o intuito de melhor compreender o seu mecanismo, experimentalmente e através de simulação. A adição de cloretos a soluções aquosas de um líquido iónico demonstrou prejudicar a solubilidade ao promover a agregação do hidrótropo, com um comportamento com várias nuances, mas limitadamente sob uma ordenação de acordo com a valência do catião do sal adicionado. Interações hidrofóbicas mostraram-se centrais no efeito de agregação do hidrótropo em volta do soluto, que parece conduzir a hidrotropia. As interações entre o hidrótropo e o soluto apresentam um grau de especificidade de local, perdido com a adição de sal. A agregação do hidrótropo mostrou-se prejudicial para o efeito hidrotrópico, refutando uma das principais teorias justificativas do mecanismo da hidrotropia.2022-01-20T00:00:00Z2021-01-12T00:00:00Z2021-01-12info:eu-repo/semantics/publishedVersioninfo:eu-repo/semantics/masterThesisapplication/pdfhttp://hdl.handle.net/10773/31141engMartins, Afonso Cerqueirainfo:eu-repo/semantics/embargoedAccessreponame:Repositório Científico de Acesso Aberto de Portugal (Repositórios Cientìficos)instname:Agência para a Sociedade do Conhecimento (UMIC) - FCT - Sociedade da Informaçãoinstacron:RCAAP2024-05-06T04:31:26Zoai:ria.ua.pt:10773/31141Portal AgregadorONGhttps://www.rcaap.pt/oai/openairemluisa.alvim@gmail.comopendoar:71602024-05-06T04:31:26Repositório Científico de Acesso Aberto de Portugal (Repositórios Cientìficos) - Agência para a Sociedade do Conhecimento (UMIC) - FCT - Sociedade da Informaçãofalse
dc.title.none.fl_str_mv Ionic liquids as hydrotropes: the key towards solubility increase
title Ionic liquids as hydrotropes: the key towards solubility increase
spellingShingle Ionic liquids as hydrotropes: the key towards solubility increase
Martins, Afonso Cerqueira
Hydrotropy
Ionic liquids
Hydrophobic compounds
Solubility
Salts
title_short Ionic liquids as hydrotropes: the key towards solubility increase
title_full Ionic liquids as hydrotropes: the key towards solubility increase
title_fullStr Ionic liquids as hydrotropes: the key towards solubility increase
title_full_unstemmed Ionic liquids as hydrotropes: the key towards solubility increase
title_sort Ionic liquids as hydrotropes: the key towards solubility increase
author Martins, Afonso Cerqueira
author_facet Martins, Afonso Cerqueira
author_role author
dc.contributor.author.fl_str_mv Martins, Afonso Cerqueira
dc.subject.por.fl_str_mv Hydrotropy
Ionic liquids
Hydrophobic compounds
Solubility
Salts
topic Hydrotropy
Ionic liquids
Hydrophobic compounds
Solubility
Salts
description Water solubility of hydrophobic compounds is a crucial factor in the formulation of drugs, cleaning products and personal hygiene. Therefore, technology that allows us to increase their solubility and dissolution rate has attracted considerable interest not only at an academic level but also at an industrial one. In this sense, hydrotropes have been under the spotlight. These compounds are characterized as molecules possessing the capacity of promoting a drastic, several-fold increase in aqueous solubility of highly hydrophobic compounds. Recently, ionic liquids have been appointed as a promising class of catanionic hydrotropes, since both the cation and anion can contribute to the solubility increase. Although there is a vast amount of reviewing work centred on hydrotropy, its underlying mechanism is not yet fully understood. This work proposes to study the impact of salt addition on the hydrotropy phenomenon as to better understand its mechanism, both experimentally and through simulation. Herein the addition of chloride salts to aqueous solutions of an ionic liquid was found to hinder solubility by promoting aggregation of the latter, with a notably nuanced behaviour according to the salt cation valence. Hydrophobic interactions were found to be central to the aggregative effect of the hydrotrope around the solute, which seem to drive hydrotropy. The interactions between the hydrotrope and the solute presented a degree of site-specificity, lost with salt addition. Hydrotrope aggregation showed to be detrimental to the hydrotropic effect, disproving one of the dominant theories justifying the mechanism of hydrotropy.
publishDate 2021
dc.date.none.fl_str_mv 2021-01-12T00:00:00Z
2021-01-12
2022-01-20T00:00:00Z
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instname_str Agência para a Sociedade do Conhecimento (UMIC) - FCT - Sociedade da Informação
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