Lithium containing MgAl mixed oxides obtained from sol-gel hydrotalcite for transesterification

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dc.creatorRenata de Aquino Brito Lima Correa
dc.creatorCinthia de Castro Oliveira
dc.creatorJosé Mansur Assaf
dc.date.accessioned2025-01-24T13:39:29Z
dc.date.accessioned2025-09-09T00:19:29Z
dc.date.available2025-01-24T13:39:29Z
dc.date.issued2018
dc.description.sponsorshipCNPq - Conselho Nacional de Desenvolvimento Científico e Tecnológico
dc.format.mimetypepdf
dc.identifier.doihttps://doi.org/10.1590/0104-6632.20180351s20160146
dc.identifier.issn1678-4383
dc.identifier.urihttps://hdl.handle.net/1843/79464
dc.languageeng
dc.publisherUniversidade Federal de Minas Gerais
dc.relation.ispartofBrazilian Journal of Chemical Engineering
dc.rightsAcesso Aberto
dc.subjectEsterificação (Química)
dc.subjectLítio
dc.subjectCatálise heterogênea
dc.subjectBiodiesel
dc.subjectCatalisadores
dc.subjectÓxidos metálicos
dc.subjectLigas de alumínio
dc.subjectLigas de magnésio
dc.subject.otherHydrotalcite
dc.subject.otherSol-gel method
dc.subject.otherTransesterification
dc.subject.otherLithium
dc.subject.otherMixed oxide
dc.subject.otherHeterogeneous catalysis
dc.titleLithium containing MgAl mixed oxides obtained from sol-gel hydrotalcite for transesterification
dc.typeArtigo de periódico
local.citation.epage198
local.citation.issue1
local.citation.spage189
local.citation.volume35
local.description.resumoThe innumerous advantages of heterogeneous catalysts employed in biodiesel production have stimulated the search for a solid catalyst capable of replacing the industrially used homogeneous catalysts. This paper investigates the effect of the sol-gel method in the catalytic activity and stability of Li-MgAl mixed oxides prepared by the “in situ” lithium addition to a MgAl hydrotalcite. The analyses based on N2 physisorption, thermogravimetric analysis, X-ray diffractometry, scanning electron microscopy and temperature-programmed desorption of CO2 were carried out to elucidate the properties of the catalysts. Considerable differences in the physico-chemical properties of the catalysts were observed with the Li addition. Li reduced the surface area and increased the crystallite size of the oxides. Furthermore, Li-MgAl mixed oxides prepared by the calcination of the sol-gel MgAl hydrotalcites presented substantial morphological differences when compared to the same oxides obtained by heat treatment of hydrotalcites synthesized via the conventional co-precipitation route. Furthermore, Li increased the number and strength of the base sites which resulted in the increase of the oxide reactivities towards the transesterification reaction between methyl acetate and ethanol. The activity was dependent on the Li loading on the catalysts. The catalyst containing only 5 wt.% Li turned out to be highly active (( 85% conversion at 50°C, ethanol/methyl acetate molar ratio = 6/1, 4 wt.% of catalyst and 30 min of reaction). Stability tests showed that the Li-MgAl catalysts lose activity after 3 reuse cycles.
local.identifier.orcidhttps://orcid.org/0000-0001-6517-7307
local.identifier.orcidhttps://orcid.org/0000-0001-5486-6879
local.identifier.orcidhttps://orcid.org/0000-0002-8112-7788
local.publisher.countryBrasil
local.publisher.departmentICX - DEPARTAMENTO DE QUÍMICA
local.publisher.initialsUFMG
local.url.externahttps://www.scielo.br/j/bjce/a/tMxxMJtbMTnpkXPC8nKrfZj/?lang=en

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