Diffusivities of bioactive compounds in compressed liquids: molecular dynamics simulation

Detalhes bibliográficos
Autor(a) principal: Iglésias, João António Pereira
Data de Publicação: 2019
Tipo de documento: Dissertação
Idioma: eng
Título da fonte: Repositório Científico de Acesso Aberto de Portugal (Repositórios Cientìficos)
Texto Completo: http://hdl.handle.net/10773/29399
Resumo: Quercetin, a flavonoid that can be extracted from various plant sources, exhibit interesting bioactivity due to relevant antioxidant or anti-carcinogenic properties. One way of extracting this flavonoid is by solid-liquid extraction using, for example, green solvents like ethanol (EtOH) or ethyl acetate (EtOAc), which are well accepted in the food industry. Diffusivity, D12, is an important property in solid-liquid extraction, since this separation is frequently limited by mass transfer kinetics, which requires the knowledge of D12 for the accurate design and optimization of that unitary operation. The diffusivities, D12, of quercetin in ethyl acetate and ethanol were measured by the chromatographic peak broadening (CPB) method in the temperature range 30-60 °C and pressure range 1-150 bar. The diffusivities in ethanol were measured in the same laboratory by another researcher. The D12 values ranged from 3.985×10-6 to 7.826×10-6 cm2 s-1, in the case of ethanol, and 1.018×10-5 to 1.628×10-5 cm2 s-1 for ethyl acetate. The obtained D12 data followed the expected trends with temperature and pressure, namely, positive and negative derivatives, being the influence of temperature much more significant. In parallel, classical molecular dynamics (MD) simulations were performed using the GROMACS software package to estimate the diffusion coefficient in order to assess the possibility of using this computational technique to generate diffusivities for distinct pressure and temperature conditions. Different parameters sets were adopted to carry out simulations in NVT ensemble, such as the cut-off radius for short-range interactions, number of solvent and solute molecules, and simulation duration, with the objective to verify their influence on the quality of D12 estimates. The optimization of the parameters used in the MD simulations led to D12 values in good agreement with the experimental data for ethanol at 1 bar, with relative deviations less than 6.54 %. It was also shown that it is possible to obtain reliable results at higher pressures after introducing a multiplicative factor on the atoms charges of ethanol. In the case of ethyl acetate, the error at 30 °C and 1 bar was −22.51 %. Since the MD self-diffusivities of ethyl acetate also differ significantly from the experimental data, it is suggested in this work to optimize the force field parameters used to model this solvent. The agreement found between experimental and MD quercetin diffusivities in ethanol demonstrates that it is possible to obtain reliable D12 values by classical MD simulations. Further studies are suggested on the influence of different functional groups and structure of other flavonoids on D12, with a structural analysis using the radial distribution and spatial distribution function.
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spelling Diffusivities of bioactive compounds in compressed liquids: molecular dynamics simulationDiffusion coefficientMolecular dynamicsTransport propertiesQuercetinEthanolEthyl acetateQuercetin, a flavonoid that can be extracted from various plant sources, exhibit interesting bioactivity due to relevant antioxidant or anti-carcinogenic properties. One way of extracting this flavonoid is by solid-liquid extraction using, for example, green solvents like ethanol (EtOH) or ethyl acetate (EtOAc), which are well accepted in the food industry. Diffusivity, D12, is an important property in solid-liquid extraction, since this separation is frequently limited by mass transfer kinetics, which requires the knowledge of D12 for the accurate design and optimization of that unitary operation. The diffusivities, D12, of quercetin in ethyl acetate and ethanol were measured by the chromatographic peak broadening (CPB) method in the temperature range 30-60 °C and pressure range 1-150 bar. The diffusivities in ethanol were measured in the same laboratory by another researcher. The D12 values ranged from 3.985×10-6 to 7.826×10-6 cm2 s-1, in the case of ethanol, and 1.018×10-5 to 1.628×10-5 cm2 s-1 for ethyl acetate. The obtained D12 data followed the expected trends with temperature and pressure, namely, positive and negative derivatives, being the influence of temperature much more significant. In parallel, classical molecular dynamics (MD) simulations were performed using the GROMACS software package to estimate the diffusion coefficient in order to assess the possibility of using this computational technique to generate diffusivities for distinct pressure and temperature conditions. Different parameters sets were adopted to carry out simulations in NVT ensemble, such as the cut-off radius for short-range interactions, number of solvent and solute molecules, and simulation duration, with the objective to verify their influence on the quality of D12 estimates. The optimization of the parameters used in the MD simulations led to D12 values in good agreement with the experimental data for ethanol at 1 bar, with relative deviations less than 6.54 %. It was also shown that it is possible to obtain reliable results at higher pressures after introducing a multiplicative factor on the atoms charges of ethanol. In the case of ethyl acetate, the error at 30 °C and 1 bar was −22.51 %. Since the MD self-diffusivities of ethyl acetate also differ significantly from the experimental data, it is suggested in this work to optimize the force field parameters used to model this solvent. The agreement found between experimental and MD quercetin diffusivities in ethanol demonstrates that it is possible to obtain reliable D12 values by classical MD simulations. Further studies are suggested on the influence of different functional groups and structure of other flavonoids on D12, with a structural analysis using the radial distribution and spatial distribution function.A quercetina, um flavonoide que pode ser extraído de várias fontes vegetais, apresenta bioatividade interessante, devido às suas boas propriedades antioxidantes ou anti-carcinogénicas. Uma das técnicas de extração deste flavonoide é por extração sólido-líquido, usando, por exemplo, solventes verdes como etanol (EtOH) ou acetato de etilo (EtOAc), utilizados na indústria alimentar. A difusividade, D12, é uma propriedade importante nas extrações sólido-líquido pois, muito frequentemente, estas operações unitárias encontram-se limitadas pela cinética de transferência de massa, sendo assim relevante conhecer o coeficiente de difusão para o projeto e otimização destes processos. As difusividades da quercetina em acetato de etilo e em etanol foram medidas pelo método cromatográfico de abertura de pico (CPB), na gama de temperaturas de 303,15 a 333,15 K e de pressões de 1 a 150 bar. No caso do etanol, os valores de D12 já tinham sido medidos anteriormente, no mesmo laboratório, por outro investigador. Os valores experimentais de D12 da quercetina em etanol encontram-se entre 3,985×10-6 e 7,826×10-6 cm2 s-1, e no caso da quercetina em acetato de etilo entre 1,018×10-5 e 1,628×10-5 cm2·s-1. Os resultados experimentais obtidos seguem as dependências esperadas com a temperatura e pressão, nomeadamente, derivadas positivas e negativas, sendo a variação com a temperatura muito mais expressiva. Paralelamente, foram realizadas simulações de dinâmica molecular (MD) clássica utilizando o software GROMACS para estimar as difusividades e averiguar a possibilidade de utilizar esta técnica computacional para calcular valores de D12 noutras condições de pressão e de temperatura. Com este fim em vista, foram testados diferentes conjuntos de parâmetros em simulações no ensemble NVT, tais como o raio de corte das interações de curto alcance, número de moléculas de solvente e duração da simulação, para analisar a sua influência na exatidão das estimativas. A otimização dos parâmetros usados nas simulações de MD conduziu a valores de D12 em boa concordância com os dados experimentais no caso do etanol a 1 bar, com erro relativo inferior a 6.54 %. Foi ainda demonstrado que a pressões mais elevadas é possível obter valores fiáveis de D12, introduzindo um fator multiplicativo nas cargas dos átomos do etanol. No caso do acetato de etilo, o erro a 30 °C e 1 bar foi −22.51 %. Como os valores do coeficiente de auto-difusão do acetato de etilo, estimados por MD, diferem bastante dos valores experimentais, sugere-se neste trabalho a otimização dos parâmetros do campo de forças utilizado para modelar este solvente. A concordância entre as difusividades da quercetina em etanol medidas e estimadas por MD clássica demonstra que é realmente possível obter valores fiáveis de D12 por esta técnica computacional. Sugerem-se estudos adicionais focados em diferentes grupos funcionais e estruturas de flavonoides, através de análises estruturais usando funções de distribuição radial e de distribuição espacial.2019-122019-12-01T00:00:00Z2021-12-06T00:00:00Zinfo:eu-repo/semantics/publishedVersioninfo:eu-repo/semantics/masterThesisapplication/pdfhttp://hdl.handle.net/10773/29399engIglésias, João António Pereirainfo: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:RCAAP2024-02-22T11:56:52Zoai:ria.ua.pt:10773/29399Portal AgregadorONGhttps://www.rcaap.pt/oai/openaireopendoar:71602024-03-20T03:01:45.088618Repositório 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 Diffusivities of bioactive compounds in compressed liquids: molecular dynamics simulation
title Diffusivities of bioactive compounds in compressed liquids: molecular dynamics simulation
spellingShingle Diffusivities of bioactive compounds in compressed liquids: molecular dynamics simulation
Iglésias, João António Pereira
Diffusion coefficient
Molecular dynamics
Transport properties
Quercetin
Ethanol
Ethyl acetate
title_short Diffusivities of bioactive compounds in compressed liquids: molecular dynamics simulation
title_full Diffusivities of bioactive compounds in compressed liquids: molecular dynamics simulation
title_fullStr Diffusivities of bioactive compounds in compressed liquids: molecular dynamics simulation
title_full_unstemmed Diffusivities of bioactive compounds in compressed liquids: molecular dynamics simulation
title_sort Diffusivities of bioactive compounds in compressed liquids: molecular dynamics simulation
author Iglésias, João António Pereira
author_facet Iglésias, João António Pereira
author_role author
dc.contributor.author.fl_str_mv Iglésias, João António Pereira
dc.subject.por.fl_str_mv Diffusion coefficient
Molecular dynamics
Transport properties
Quercetin
Ethanol
Ethyl acetate
topic Diffusion coefficient
Molecular dynamics
Transport properties
Quercetin
Ethanol
Ethyl acetate
description Quercetin, a flavonoid that can be extracted from various plant sources, exhibit interesting bioactivity due to relevant antioxidant or anti-carcinogenic properties. One way of extracting this flavonoid is by solid-liquid extraction using, for example, green solvents like ethanol (EtOH) or ethyl acetate (EtOAc), which are well accepted in the food industry. Diffusivity, D12, is an important property in solid-liquid extraction, since this separation is frequently limited by mass transfer kinetics, which requires the knowledge of D12 for the accurate design and optimization of that unitary operation. The diffusivities, D12, of quercetin in ethyl acetate and ethanol were measured by the chromatographic peak broadening (CPB) method in the temperature range 30-60 °C and pressure range 1-150 bar. The diffusivities in ethanol were measured in the same laboratory by another researcher. The D12 values ranged from 3.985×10-6 to 7.826×10-6 cm2 s-1, in the case of ethanol, and 1.018×10-5 to 1.628×10-5 cm2 s-1 for ethyl acetate. The obtained D12 data followed the expected trends with temperature and pressure, namely, positive and negative derivatives, being the influence of temperature much more significant. In parallel, classical molecular dynamics (MD) simulations were performed using the GROMACS software package to estimate the diffusion coefficient in order to assess the possibility of using this computational technique to generate diffusivities for distinct pressure and temperature conditions. Different parameters sets were adopted to carry out simulations in NVT ensemble, such as the cut-off radius for short-range interactions, number of solvent and solute molecules, and simulation duration, with the objective to verify their influence on the quality of D12 estimates. The optimization of the parameters used in the MD simulations led to D12 values in good agreement with the experimental data for ethanol at 1 bar, with relative deviations less than 6.54 %. It was also shown that it is possible to obtain reliable results at higher pressures after introducing a multiplicative factor on the atoms charges of ethanol. In the case of ethyl acetate, the error at 30 °C and 1 bar was −22.51 %. Since the MD self-diffusivities of ethyl acetate also differ significantly from the experimental data, it is suggested in this work to optimize the force field parameters used to model this solvent. The agreement found between experimental and MD quercetin diffusivities in ethanol demonstrates that it is possible to obtain reliable D12 values by classical MD simulations. Further studies are suggested on the influence of different functional groups and structure of other flavonoids on D12, with a structural analysis using the radial distribution and spatial distribution function.
publishDate 2019
dc.date.none.fl_str_mv 2019-12
2019-12-01T00:00:00Z
2021-12-06T00:00:00Z
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