Novel solid-state compounds of heavy rare-earth (III) picolinates. A pyrolytic study using: TG-DSC-IR, HSM-MS and GC-MS

dc.contributor.authorNascimento, A. L.C.S. [UNESP]
dc.contributor.authorAshton, G. P.
dc.contributor.authorParkes, G. M.B.
dc.contributor.authorEkawa, B. [UNESP]
dc.contributor.authorFernandes, R. P. [UNESP]
dc.contributor.authorCarvalho, A. C.S. [UNESP]
dc.contributor.authorIonashiro, M. [UNESP]
dc.contributor.authorCaires, F. J. [UNESP]
dc.contributor.institutionUniversity of Huddersfield
dc.contributor.institutionUniversidade Estadual Paulista (Unesp)
dc.description.abstractHeavy trivalent lanthanides and yttrium picolinates were synthesized by complexation of basic rare-earth metal carbonates with an aqueous solution of picolinic acid. The novel compounds were obtained with the general formula Ln(L)3∙nH2O, where L is picolinate and n = 1.5 H2O (Dy, Ho, Yb, Lu and Y), 2 H2O (Tb and Tm) and 2.5 H2O (Er). The stoichiometry of the complexes was calculated through mass losses found using thermogravimetry (TG), complexometry and elemental analysis (EA). The thermal behavior in oxidative and pyrolytic atmospheres of the compounds was analyzed by simultaneous thermogravimetry - differential scanning calorimetry (TG-DSC). The gaseous products of the pyrolysis were determined throughout by monitoring the evolved species using TG-DSC couple to Fourier transform infrared spectroscopy (TG-DSC-IR), hot-stage microscopy mass spectrometry (HSM-MS), and gas chromatography-mass spectrometry (GC-MS). The obtained results validated mass loss assignments made using the TG curves. However, gaseous product analysis indicates the degradation processes are more complex than the thermoanalytical techniques suggest alone. This study used a GC-MS technique to identify the condensed gaseous products obtained during the second step of thermal degradation of the picolinate complexes. The analysis of the symmetric and asymmetric stretching frequencies of the carboxylate group in the IR spectra showed a monodentate bonding mode. The compounds were obtained in the amorphous state, as indicated by the powder x-ray diffractometry (PXRD) data.en
dc.description.affiliationThermal Methods Research Unit School of Applied Sciences University of Huddersfield, Queensgate
dc.description.affiliationInstituto de Química Universidade Estadual Paulista, CP 355
dc.description.affiliationFaculdade de Ciências UNESP—Univ. Estadual Paulista Campus Bauru Departamento de Química
dc.description.affiliationUnespInstituto de Química Universidade Estadual Paulista, CP 355
dc.description.affiliationUnespFaculdade de Ciências UNESP—Univ. Estadual Paulista Campus Bauru Departamento de Química
dc.description.sponsorshipFundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)
dc.description.sponsorshipConselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)
dc.description.sponsorshipUniversity of Huddersfield
dc.description.sponsorshipIdFAPESP: 2017/14936-9
dc.description.sponsorshipIdFAPESP: 2018/12463-9
dc.description.sponsorshipIdFAPESP: 2018/24378-6
dc.description.sponsorshipIdCNPq: 421469/2016-1
dc.identifier.citationJournal of Analytical and Applied Pyrolysis, v. 144.
dc.relation.ispartofJournal of Analytical and Applied Pyrolysis
dc.subjectevolved gas analysis (EGA)
dc.subjectHeavy trivalent lanthanide picolinates
dc.titleNovel solid-state compounds of heavy rare-earth (III) picolinates. A pyrolytic study using: TG-DSC-IR, HSM-MS and GC-MSen