Novel solid-state compounds of heavy rare-earth (III) picolinates. A pyrolytic study using

TG-DSC-IR, HSM-MS and GC-MS

A.L.C.S Nascimento, Gage Ashton, Gareth Parkes, B. Ekawa, R.P. Fernandes, A.C.S. Carvalho, M. Ionashiro, F.J. Caires

Research output: Contribution to journalArticle

Abstract

Heavy 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.
Original languageEnglish
Number of pages9
JournalJournal of Analytical and Applied Pyrolysis
Early online date14 Oct 2019
DOIs
Publication statusE-pub ahead of print - 14 Oct 2019

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Gas chromatography
Rare earths
Mass spectrometry
Thermogravimetric analysis
Microscopic examination
Rare Earth Metals
Pyrolysis
Yttrium
Lanthanoid Series Elements
Carbonates
Rare earth elements
Complexation
Stoichiometry
Powders
Stretching
Fourier transform infrared spectroscopy
Differential scanning calorimetry
Degradation
X rays
Acids

Cite this

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title = "Novel solid-state compounds of heavy rare-earth (III) picolinates. A pyrolytic study using: TG-DSC-IR, HSM-MS and GC-MS",
abstract = "Heavy 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.",
keywords = "Heavy trivalent lanthanide picolinates, evolved gas analysis (EGA), TG-DSC-IR, HSM-MS, GC-MS, TG-DSC-FTIR",
author = "A.L.C.S Nascimento and Gage Ashton and Gareth Parkes and B. Ekawa and R.P. Fernandes and A.C.S. Carvalho and M. Ionashiro and F.J. Caires",
year = "2019",
month = "10",
day = "14",
doi = "10.1016/j.jaap.2019.104709",
language = "English",
journal = "Journal of Analytical and Applied Pyrolysis",
issn = "0165-2370",
publisher = "Elsevier",

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Novel solid-state compounds of heavy rare-earth (III) picolinates. A pyrolytic study using : TG-DSC-IR, HSM-MS and GC-MS. / Nascimento, A.L.C.S; Ashton, Gage; Parkes, Gareth; Ekawa, B.; Fernandes, R.P.; Carvalho, A.C.S.; Ionashiro, M.; Caires, F.J.

In: Journal of Analytical and Applied Pyrolysis, 14.10.2019.

Research output: Contribution to journalArticle

TY - JOUR

T1 - Novel solid-state compounds of heavy rare-earth (III) picolinates. A pyrolytic study using

T2 - TG-DSC-IR, HSM-MS and GC-MS

AU - Nascimento, A.L.C.S

AU - Ashton, Gage

AU - Parkes, Gareth

AU - Ekawa, B.

AU - Fernandes, R.P.

AU - Carvalho, A.C.S.

AU - Ionashiro, M.

AU - Caires, F.J.

PY - 2019/10/14

Y1 - 2019/10/14

N2 - Heavy 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.

AB - Heavy 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.

KW - Heavy trivalent lanthanide picolinates

KW - evolved gas analysis (EGA)

KW - TG-DSC-IR

KW - HSM-MS

KW - GC-MS

KW - TG-DSC-FTIR

U2 - 10.1016/j.jaap.2019.104709

DO - 10.1016/j.jaap.2019.104709

M3 - Article

JO - Journal of Analytical and Applied Pyrolysis

JF - Journal of Analytical and Applied Pyrolysis

SN - 0165-2370

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